JUKI MF-7700D Series Engineer's Manual

Download

Semi-dry head, Flat-bed Top and Bottom Coverstitch Machine

MF-7700D Series

ENGINEER’S MANUAL

40084333

No.E386-00

PREFACE

This Engineer’s Manual is written for the technical personnel who are responsible for the service and maintenance of the machine. The Instruction Manual for these machines intended for the maintenance personnel and operators at an apparel factory contains operating instructions in detail. And this manual describes "Standard Adjustment", "Adjustment Procedures", "Results of Improper Adjustment", and other important information which are not covered by the Instruction Manual. It is advisable to use the relevant Instruction Manual and Parts List together with this Engineer’s Manual as well as the MF-7700, SC-500, and SC-510 Series Manuals when carrying out the maintenance of these machines. In addition, for the motor for the sewing machine with thread trimmer, refer to the separate Instruction Manual or Engineer’s Manual for the motor. And for the control panel, refer to the Instruction Manual for the control panel. This manual gives the "Standard Adjustment" on the former page under which the most basic adjustment value is described, and on the latter page "Results of Improper Adjustment" under which stitching errors and troubles arising from mechanical failures are described together with the "Adjustment Procedures".

1. SPECIFICATIONS................................................................................................... 1

2. CONFIGURATION OF THE MACHINE COMPONENTS........................................ 2

3. MODEL NUMBERING SYSTEM ............................................................................ 3

(1) MF-7700D Series . ................................................................................................................... 3

(2) MF-7700D Series Thread trimmer.......................................................................................... 4

4. MOTOR PULLEY AND BELT ................................................................................. 5

5. ST ANDARD ADJUSTMENT ................................................................................... 6

(1) Threading the machine head . ............................................................................................... 6

(2) Adjusting the rocking thread take-up ................................................................................... 8

(3) Adjusting the position of the needle thread guide rod ..................................................... 10

(4) Adjusting the position of the thread receiver .................................................................... 12

(5) Adjusting the position of the spreader thread guide and spreader thread take-up....... 14

(6) Adjusting the spreader......................................................................................................... 16

(7) Adjusting the timing relation between the looper and needle bar................................... 20

(8) Returning amount of the looper .......................................................................................... 22

(9) Height of the needle ............................................................................................................. 24

(10)Locus and longitudinal motion of the looper..................................................................... 26

(11)Adjusting the needle guard ................................................................................................. 28

(12)Installing cover of the looper and needle guard after adjusting ...................................... 32

(13)Adjusting the feed dog ......................................................................................................... 34

(14)Adjusting the feed relation .................................................................................................. 40

(15)Adjusting the presser foot ................................................................................................... 42

(16)Adjusting the micro-lifter ..................................................................................................... 44

(17)Adjusting the looper thread cam......................................................................................... 46

(18)With regard to lubrication .................................................................................................... 48

(19)Setting for functions of SC-500 ........................................................................................... 52

(20)Adjusting and setting SC-510 .............................................................................................. 54

(21) MF-7700D/MF-7800D How to use the timing gauge .......................................................... 58

6. E10/MD10.............................................................................................................. 59

(1) Specifications (E10).............................................................................................................. 59

(2) Specifications (MD10) .......................................................................................................... 59

(3) Adjusting the needle guard ................................................................................................. 60

(4) Adjustment of knife .............................................................................................................. 62

(5) Presser adjustments ............................................................................................................ 66

(6) Method of lubrication ........................................................................................................... 68

(7) Adjustment of the amount of feeding ................................................................................. 70

(8) Adjustments for heavy material sewing ............................................................................. 72

(9) Mounting position of the eccentric cam............................................................................. 74

7. MF-7724DU10D60 (4 needles)............................................................................. 77

(1) Specifications . ..................................................................................................................... 77

(2) Needle .................................................................................................................................... 77

(3) Standard adjustments .......................................................................................................... 78

1) Needle mounting.............................................................................................................................78

2) Threading the machine head .........................................................................................................80

3) Adjusting the rocking thread take-up ...........................................................................................82

4) Adjusting the position of the needle thread guide rod ............................................................... 84

5) Adjusting the rocking thread take-up thread receiver ................................................................86

6) Adjusting the looper.......................................................................................................................88

7) Adjusting the height of the needle................................................................................................ 88

8) Adjusting the rear needle guard....................................................................................................90

9) Adjusting the looper thread cam...................................................................................................90

10)Installing position of the spreader ................................................................................................92

8. UT31...................................................................................................................... 94

(1) Installation of SC-500 ........................................................................................................... 94

(2) Change of the setting ........................................................................................................... 96

(3) Adjusting the synchronizer ................................................................................................. 98

(4) Installation of SC-510 ......................................................................................................... 100

(5) Adjusting the looper thread trimmer mechanism............................................................ 106

9. UT33.................................................................................................................... 120

(1) Installation of SC-500 ......................................................................................................... 120

(2) Installation of SC-510 ......................................................................................................... 122

(3) Piping of the thread trimmer device ................................................................................. 124

(4) Adjusting the looper thread trimmer mechanism............................................................ 126

(5) Adjusting the top covering thread trimmer mechanism ................................................. 130

(6) Adjusting the air-blow wiper.............................................................................................. 132

10.TC13 (Tape cutter) ............................................................................................. 134

(1) Specifications ..................................................................................................................... 134

(2) Adjustment of knife ............................................................................................................ 136

(3) TC13C .................................................................................................................................. 140

11. OTHER CAUTIONS ............................................................................................ 146

(1) MF-7700D dry section......................................................................................................... 146

(2) Application of appropriate grease .................................................................................... 146

(3) Adhesives application spots ............................................................................................. 148

12.TROUBLES AND CORRECTIVE MEASURES .................................................. 149

13.DRAWING OF TABLE......................................................................................... 163

(1) Semi-Submerged Type ....................................................................................................... 163

(2) For MF-7700D/E10 (Semi-Submerged Type) .................................................................... 164

1. SPECIFICATIONS

No. Item Specifications

1Model name Semi-dry head, flat-bed top and bottom coverstitch machine 2 Model MF-7700D series 3Stitch type ISO standard 406, 407, 602, 605 and 607

4 Example of application

5Max. sewing speed 4,000 sti/min (at the time of intermittent operation) 6Needle gauge

7 Differential feed ratio Micro-differential feed adjustment mechanism is provided.

8 Stitch length 1.2 mm to 3.6 mm (can be adjusted up to 4.4 mm) 9 Needle

10 Needle bar stroke 31mm 11 Dimensions Height: 451 mm, Width: 515 mm, Length: 265 mm 12 Weight 46kg, 49kg (with UT33), 52kg (with UT31)

13 Lift of presser foot

14 Feed adjustment method Differential feed....... lever adjustment method (micro-adjustment

15 Looper mechanism Spherical rod drive method 16 Lubricating system Forced lubrication method by gear pump 17 Lubricating oil JUKI MACHINE OIL 18 (Equivalent to ISO VG18) 18 Oil reservoir capacity Oil gauge lower line : 600 cm3 to upper line : 900 cm 19 Installation Semi-submerged type 20 Micro-lifter Provided as standard

21 Provided as standard 22 Cartridge oil filter Provided as standard

Needle tip, needle thread silicone tank

Hemming, covering, and elastic tape attachment for knits and general knitted fabrics

3-needle...........5.6 mm and 6.4 mm 4-needle .................... 6.0 mm

2-needle...........4.0 mm

1 : 0.7 to 1 : 2 (stitch length : less than 2.5 mm)

(Micro-adjustment)

UY128GAS #9S to #12S (standard #10S) (Nm65 to Nm80, standard Nm70)

5 mm (with top covering) 8 mm (without top covering)

Main feed ................ dial type stitch pitch adjustment method

mechanism is provided.)

– 1 –

2. CONFIGURATION OF THE MACHINE COMPONENTS

Presser spring regulator Oil gauge Rocking thread take-up Needle bar thread take-up cover Feed regulating knob Front cover Oil circulation identification window Eye guard cover Slide cover Oil hole cap Throat plate Needle bar thread take-up Micro-lifter Needle tip silicon oil lubricating unit thread receiver Needle thread silicon Differential lock nut Rocking thread take-up oil lubricating unit Micro-adjustment knob thread guide Thread guide No. 1 Finger guard Silicon container thread guide Upper pulley Thread trimming knife Belt cover Thread tension nut Rocking thread take-up receiver

– 2 –

3. MODEL NUMBERING SYSTEM

(1) MF-7700D Series

Semi-dry head, flat-bed top and bottom coverstitch machine Applicable model : MF-7700D Series

123456789101112 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

MF77 D / / –

3 to 6 Model code

7722 2-needle top & bottom covering stitch 7723 3-needle top & bottom covering stitch 7724 4-needle top & bottom covering stitch

11 Tongue shape of throat plate

B Standard D D-type

15 to 23 Device and attachment

Blank Not provided TC13 Solenoid type tape cutter

MD10 Mechanical metering device

8 to 10

U10 C10 For collarette For regular binder

E10 Elastic tape attachment With right hook knife

12 to 13 Needle gauge

40 4.0mm 56 5.6mm 60 6.0mm 64 6.4mm

* Selection of 56 and 64 is prohibited for 2-needle type. * For the triple needle type, the selection of 40 only is possible for the U10. * Applicable only to 60 for 4-needle type

24 TC control voltage division

A 220 to 440V B 100 to 240V

C SC-510

Application Description

For universal Lapseam, Covering,

Application code

Hemming

*When device or attachment is one, delete slash

(/) of 14th digit.

26 Specification Code for Destination

A Standard G For China (domestic China) H For Turkey

* Selected only for TC unit attachment type

27 Accessory Specification Code

Standard (Foreign language manuals in Japanese, English,

Chinese, German, French, Italy, Turkey, and Spanish)

Chinese (available only in China) (2-language manual in

English and Chinese)

– 3 –

(2) MF-7700D Series Thread trimmer

Semi-dry head, flat-bed top and bottom coverstitch machine Applicable model : MF-7700D Series Thread trimmer

1 2345678910111213141516171819202122

MF77 D –

3 to 6 Model code

7723 3-needle top & bottom covering stitch

11 Tongue shape of throat plate

B Standard D D-type

14 to 18 Device and attachment

UT31 Solenoid type vertical thread trimmer unit UT33 Pneumatic type vertical thread trimmer unit

UT33A Pneumatic type vertical thread trimmer unit (ASTAS)

21 Accessory Specification Code

Standard (Foreign language manuals in Japanese, English,

Chinese, German, French, Italy, Turkey, and Spanish)

8 to 10

U10

Application code

Application Description

For universal Lapseam, Covering,

Hemming

12 to 13 Needle gauge

56 5.6mm 64 6.4mm

19 Specification Code for Destination

A Standard G For China (domestic China) H For Turkey

22 Control box and motor classification

B SC-500/M50

C SC-510/M51

Chinese (available only in China) (2-language manual in

English and Chinese)

– 4 –

4. MOTOR PULLEY AND BELT

MF-7700D Series

Sewing speed of the machine

(sti/min) Pulley size (mm) Belt size (inch) Pulley size (mm) Belt size (inch)

3,500 ø80 M-34 ø65 M-33 4,000 ø90 M-35 ø75 M-34

1 . The table shows the numbers when a 3-phase 2-pole 400 W clutch motor (1/2 HP) is used. 2 . The commercially-available motor pulley near to the counted value is designated since the outside diameter of

the commercially-available motor pulley counts by 5 mm.

3 . When you use a new sewing machine, use the machine at a speed of 4,000 sti/min or less for the first 200 hours

(approximately one month). A good result can be obtained in terms of the durability.

(Caution) 1. Use a motor pulley which is adaptable to this sewing machine.

2. This sewing machine will exceed its max. revolutions and max. sewing speed, finally leading to the occurrence of malfunction, unless the adaptable motor pulley is used.

50Hz 60Hz

– 5 –

5. ST ANDARD ADJUSTMENT

(1) Threading the machine head

Standard Adjustment

1. Threading for standard seam

Broken lines A when stretcher thread is used

When using more stretchable thread

When using less stretchable thread

When covering thread is excessively loosened = When covering thread is excessively loosened even after passing

When covering thread is excessively tense =

(Caution) In case of threading for standard seams, rocking thread take-up thread guide is not used.

2. Threading for soft seams (1) Do not pass needle thread through needle bar thread take-up . (2) When soft seams are required, change the threading of needle thread and slide the position of looper thread

cam eyelet.

(3) Do not pass needle thread through needle bar thread take-up . Pass the thread from rocking thread

take-up to rocking thread take-up thread guide .

(4) Other points are same as those of "1. Threading for standard seam".

In case of soft seams

Engraved marker line

(Caution) In case of the soft seams, rocking thread take-up

thread guide is used.

– 6 –

Left

Right

Adjustment Procedure

Results of Improper Adjustment

1. When motion of thread is very rough, and stable seams can not be obtained, there are cases where the condition can be improved by the following threading. (1) Wind thread around 1st thread guide .

(2) Wind thread around the thread tension thread guide .

o When threading is not properly

performed, not only sewing trouble occurs, but also needle breakage is caused. So, be careful.

2. When using more stretchable thread (wooly thread or the like), the threading as given below does not make thread stretch and neat seams can be obtained. (1) Do not pass thread through spreader auxiliary thread tension

Do not pass thread.

(2) Do not pass thread through the looper thread tension disk.

Refer to section E.

(Caution) Even when using wooly thread or the like, seams are

more stabilized by passing thread through looper thread auxiliary thread tension .

Engraved marker line

– 7 –

(2) Adjusting the rocking thread take-up

Standard Adjustment

1. Length of the rocking thread take-up (1) It is the standard that the length of rocking thread take-up from the center of the shaft of rocking thread

take-up support arm to the thread hole face of rocking thread take-up is 95 mm.

95mm

2. Position of the rocking thread take-up (1) Install so that rocking thread take-up is flush with rocking thread take-up when the needle bar is in its

lowest position.

Flush

3. Timing of the rocking thread take-up (1) It is the standard timing that rocking thread take-up is in

its lowest position as well when the needle bar is in its lowest position. Timing of rocking thread take-up is performed by adjusting the position of rocking thread take-up ball arm

4. Relation between the timing of rocking thread take-up and the needle thread loop

(1) When using the excessively stretchable thread or the hard-

to-stretch thread, the size of needle thread loop can be changed by changing the timing of rocking thread take-up

(2) Relation between the timing of the rocking thread take-up

and the size of needle thread loop is as shown in the table on the next page. (The relation becomes reverse when using the needle bar thread take-up = standard seams and when it is not used = soft seams. So, be careful.)

↑

Anti-operatorís side

4mm

Operatorís side

↓

– 8 –

Adjustment Procedure

Results of Improper Adjustment

1. Length of the rocking thread take-up (1) Loosen screws and move rocking thread take-up to the right

or left to adjust the length.

2. Position of the rocking thread take-up (1) Loosen screw and move rocking thread take-up up or down

to adjust the position.

(Caution) When adjusting the position of rocking thread take-up

, adjust the rocking thread take-up to the same plane of the edge of rocking thread take-up shaft and fix it so that spreader thread take-up and spreader thread guide do not come in contact with each other.

3. To adjust the timing of the rocking thread take-up , remove the top cover, loosen setscrew in the rocking thread take-up ball arm and move the position of rocking thread take-up ball arm to and fro.

(1) Standard adjustment figure is the position where the rear end (anti

operator’s side) of rocking thread take-up ball arm aligns with engraved marker line on rocking thread take-up shaft . (As the standard at this time, note that the clearance provided between the rear end of rocking thread take-up ball arm and thrust collar is 4 mm.)

(Caution) 1. When loosening screw in rocking thread take-up

ball arm , there is a case where rocking thread takeup rotates by its weight. After the adjustment, be sure to check the rocking position (flush at the lowest position) of rocking thread take-up .

2. When moving rocking thread take-up ball arm to the operator’s side, adjust rocking thread take-up ball arm within the range where it does not come in contact with rocking thread take-up bushing (operator’s side).

o When length of rocking thread

take-up is lengthened, needle thread is tightened.

(Caution) When lengthening

rocking thread take-up

, check whether it comes in contact with the thread take-up cover.

o When length of rocking thread

take-up is shortened, needle thread is loosened.

o When installing position of

rocking thread take-up is raised, needle thread is loosened when the needle bar thread takeup is used, and needle thread is tightened when the needle bar thread take-up is not used.

4. Relation between timing of rocking thread take-up and needle thread loop

Delay timing Advance timing

(Move to operator’s side.) (Move to anti-operator’s side.) When needle bar thread take-up is used Loop becomes small. Loop becomes large. When needle bar thread take-up is not used Loop becomes large. Loop becomes small.

Adjusting procedure is the same as step 3. Loosen setscrew in rocking thread take-up ball arm and

adjust the position of rocking thread take-up ball arm .

(Caution) Adjust the timing of rocking thread take-up each time in accordance with thread used

or conditions.

– 9 –

(3) Adjusting the position of the needle thread guide rod

Standard Adjustment

1. Position of the needle thread guide rod (1) It is the standard that the height of needle thread guide rods is the position where the dimensions from

the top surface of needle thread guide base to the bottom end of the hole are as follows. Left needle A : 7 mm Middle needle B : 15 mm Right needle C : 23 mm

Extreme right position

A : 7mm B : 15mm C : 23mm

2. Adjusting the position of needle thread guide base and silicon container thread guide (1) It is the standard that the height of silicon container thread guide (refer to 2. CONFIGURATION OF THE

MACHINE COMPONENTS) is the position where the height from the center of setscrew to the bottom end of thread hole is 9 mm.

(2) Move the lateral position of needle thread guide base fully to the right of slot (43 mm).

43mm

9mm

Extreme right position

– 10 –

Adjustment Procedure

Results of Improper Adjustment

1. Loosen setscrews , adjust the height of respective needle thread guide rods , and fix the rods with setscrews .

(Caution) 1. Move the lateral position of needle thread guide base

fully to the right of slot.

2. When adjusting the height of needle thread guide rods , install the rods so that the thread holes are parallel

to the thread holes of silicon container thread guide

so that excessive resistance is not applied to

threads.

2. Adjusting the position of needle thread guide base and silicon container thread guide

(1) Loosen setscrews and and move silicon container thread guide

up or down to adjust the height.

(2) Loosen setscrew and adjust the lateral position of needle thread

guide base .

o When needle thread guide rod

is raised, needle thread is

loosened.

o When needle thread guide rod

is lowered, needle thread is

tightened.

oWhen silicon container thread

guide is raised, needle thread is loosened.

o When silicon container thread

guide is lowered, needle thread is tightened.

o When needle thread guide base

is moved to the left, needle

thread is loosened.

– 11 –

(4) Adjusting the position of the thread receiver

Standard Adjustment

1. Position of the needle bar thread take-up thread receiver (in case of standard seams) (1) It is the standard that the height of needle bar thread take-up thread receiver is in the position where the

bottom end of thread hole to the center of needle bar thread take-up aligns with the top surface of needle bar thread take-up thread receiver when the needle bar is in its lowest position.

Thread hole

Center of hole

This range

To align

2. Position of the rocking thread take-up thread receiver (in case of soft seams) (In case thread is not passed through needle bar thread take-up )

(1) It is the standard that the height of rocking thread take-up receiver is in the position where the top

surface of rocking thread take-up receiver is in the range of the center to the top end of thread hole of rocking thread take-up when rocking thread take-up is in its lowest position.

This range

– 12 –

Adjustment Procedure

Results of Improper Adjustment

1. Loosen setscrew and move needle bar thread take-up thread receiver up or down to adjust the height.

2. When desired to make needle bar thread take-up thread receiver work especially on the right needle where loop is hard to be made, adjust the height of right needle thread receiver with setscrew .

o When the needle bar thread

take-up thread receiver is raised, loop becomes large.

o When the needle bar thread

take-up thread receiver is excessively raised.

1. Loosen setscrew and move rocking thread take-up receiver up or down to adjust the height.

2. When desired to make rocking thread take-up receiver work especially on the right needle where loop is hard to be made, adjust the height of the right needle thread receiver with screw .

– 13 –

(5) Adjusting the position of the spreader thread guide and spreader thread take-up

Standard Adjustment

1. Relation of the position between spreader thread take-up and spreader thread guide is the standard when the top end of thread hole of spreader thread guide aligns with the bottom end of slot of spreader thread take-up when spreader thread take-up is in its highest position. Adjust the relation of the position so that thread is moderately stretched when spreader thread take-up is in its highest position in accordance with thread used or conditions.

Highest position

To align

2. Standard position of the spreader auxiliary thread tension Standard adjustment figure of the spreader auxiliary thread tension is the standard when the top end of thread tension rod is flush with knob .

– 14 –

Adjustment Procedure

Results of Improper Adjustment

1. Loosen setscrews in spreader thread guide and adjust the position of spreader thread guide . (Spreader thread take-up is fixed to rocking thread take-up and can not be adjusted in the height direction.)

2. After the adjustment, turn the sewing machine by hand and check whether spreader thread take-up comes in contact with spreader thread guide , or section A of clearance is too small.

3. Adjusting procedure of the clearance

(1) Loosen setscrews in spreader thread guide and adjust in the

lateral direction, or loosen setscrews in the rocking thread takeup and move spreader thread take-up to the right or left to adjust the clearance.

(Caution) When loosening setscrews in the rocking thread take-

up and adjusting the position of spreader thread takeup , adjust so that 95, length of rocking thread takeup (95mm) does not change.

o When the relation of position

between spreader thread takeup and the spreader thread guide is not proper, sewing troubles such as stitch skipping and the like will be caused.

o If thread is less stretched and

slackness of thread occurs at the thread take-up section when spreader thread take-up is in its highest position, the spreader fails to pick up thread and stitch skipping occurs.

o If stretch or feeding of thread is

excessive when spreader thread take-up is in its highest position, not only thread on the seam side is drawn and needle thread can not be tightened, but also needle bend or needle breakage will be caused.

o If stretch or feeding of thread is

excessive when spreader thread take-up is in its lowest position, thread slacks when the spreader moves from left to right and stitch skipping occurs.

– 15 –

(6) Adjusting the spreader

Standard Adjustment

1. Height of the spreader It is the standard that the height from the top surface of throat plate to the bottom surface of spreader is 8.3 to 8.7 mm.

8.3 to 8.7mm

2. Longitudinal position of the spreader It is the standard that when spreader returns from the extreme left position to the right and top end A of thread hooking section reaches to the front of left needle, the clearance between the spreader and the left needle is 0.1 to 0.3 mm.

Extreme left position

0.1 to 0.3mm

4.5 to 5.5mm

16.0 to 18.0mm

3. Protruding amount It is the standard that the dimension from the center of left needle to top end A of thread hooking section, when spreader is in the extreme left position, is 4.5 to 5.5 mm.

4. Spreader stroke It is the standard that the spreader stroke is 16 to 18 mm at the stroke of thread hooking section.

5. Timing of the spreader Standard position is the position where the spreader is in the extreme left position when the needle bar comes down from the upper dead point by 1.1 ± 0.1 mm.

– 16 –

Adjustment Procedure

Results of Improper Adjustment

1. Adjusting the height of the spreader

2. Adjusting the longitudinal position of the spreader Loosen setscrew and adjust the height and longitudinal position

of the spreader .

3. Protruding amount of the spreader Loosen setscrew in the spreader folder and adjust the protruding

amount. Adjust aiming the adjustment figure of 5 mm.

4. Adjusting the spreader stroke The standard position is located where the notch section of spreader

drive lever aligns with the shaft center of connecting pin . When desired to increase the stroke, loosen lock nut and move in the right direction. When desired to decrease the stroke, loosen lock nut and move in the left direction. Adjust aiming the adjustment figure of 17 mm.

5. Adjusting the timing between the needle bar and the spreader. When changing the timing, loosen two setscrews in spreader

eccentric cam to adjust. Standard position is the position where notch in the main shaft aligns with notch in spreader eccentric cam. When changing, turn the upper pulley and change with spreader eccentric cam fixed.

o Height of the spreader is improper,

stitch skipping of spreader occurs.

o Adjust the height in accordance

with the needle gauge.

o Even when the protruding amount

is excessive or insufficient, stitch skipping of spreader will be caused.

o When the protruding amount is

insufficient, it will be the cause for left needle not to scoop covering thread at overlapped section.

o When the stroke is increased,

disorder of covering thread stitching will be caused.

o When the stroke is decreased,

stitch skipping of spreader will be caused.

o When the timing is excessively

advanced, needle does not take covering thread when it comes down and stitch skipping will be caused.

o When the timing is excessively

retarded, resistance increases when covering thread slips out from the spreader and a load is applied to the right needle. As a result, needle breakage or stitch skipping will be caused.

(Caution) When changing,

temporarily tighten No. 2 screw in the rotation direction of setscrews

and turn the upper

pulley to change.

– 17 –

(6) Adjusting the spreader

Standard Adjustment

6. Adjustment figures of the spreader thread guide (1) It is the standard that the clearance provided between spreader and spreader thread guide is 0.4 to

1.0 mm.

(2) It is the standard that the clearance provided between spreader thread guide and needle clamp thread

guide is 0.8 to 1.2 mm.

(3) Lateral position of the spreader thread guide

Top end of thread hooking section D of the spreader aligns with center E of slot C in spreader thread guide when spreader is in the extreme right position.

0.8 to 1.2mm

0.4 to 1.0mm

– 18 –

Adjustment Procedure

Results of Improper Adjustment

6. Spreader thread guide

(1) Adjust the height of spreader

to 8.3 to 8.7 mm. Loosen setscrews

in the spreader thread guide and adjust the clearance provided

between the top surface of spreader and spreader thread guide

to 0.4 to 1.0 mm.

8.3 to 8.7mm

(2) Needle clamp thread guide

Loosen setscrew in the needle clamp thread guide and adjust

the clearance provided between the needle clamp thread guide and spreader thread guide to 0.8 to 1.2 mm.

(3) For the lateral direction, align the hole of needle clamp thread guide

to the prolonged line of the slot of spreader thread guide .

(Caution) When adjusting spreader thread guide in the lateral

direction, check whether there is any contact at section

(left side of spreader thread guide and needle

clamp )

o When height or position of the

spreader thread guide is improper, stitch skipping of spreader thread will be caused.

oWhen height or position of the

needle clamp thread guide is improper, stitch skipping of spreader thread will be caused.

– 19 –

(7) Adjusting the timing relation between the looper and needle bar

Standard Adjustment

1. Timing relation between the looper and the needle bar (synchronization) It is the standard that dimension A from the top end of needle eyelet to the blade point of looper passes the rear of the needle and comes to the position of the right end of left needle is the same as dimension B from the top end of needle eyelet to the blade point of looper when needle bar comes down from the upper dead point, the blade point of looper passes the front of needle bar and comes to the position of the right end of left needle. (A=B)

Going of looper

Returning of looper

– 20 –

Adjustment Procedure

Results of Improper Adjustment

1. To adjust the timing relation between the needle and the looper, remove the top cover, loosen four setscrews in the sprocket and turn upper pulley in the state that the sprocket is held.

2. Adjusting procedure

(1) When adjusting the timing to "0" (zero)

1) In case dimension A when the looper advances is smaller than dimension B when the looper retreats, the looper timing is retarded (needle timing is advanced). In this case, loosen setscrews in the sprocket and finely turn upper pulley in the reverse direction.

2) In case dimension A when the looper advances is larger than dimension B when the looper retreats, the looper timing is advanced (needle timing is retarded). In this case, loosen setscrews in the sprocket and finely turn upper pulley in the normal direction.

(Caution) Be careful not to excessively turn upper pulley .

oWhen the difference in timing

(going and returning) of looper is excessively large, stitch skipping or entangling of needle thread will be caused.

3. After the adjustment, fix four setscrews in the sprocket.

– 21 –

(8) Returning amount of the looper

Standard Adjustment

1. It is the standard that returning amount of looper from top end of looper to the center of needle bar is

6.5 mm regardless of the needle gauge when looper is in the extreme right position.

6.5mm

2. Returning amount of looper for each gauge (dimension A)

2-needle 3-needle

Needle gauge Returning amount

4 4.5 — — ——5.6 3.7 ——6.4 3.3

(Dimension

is the dimension fromthe center of right needle to the top end of looper .)

Needle gauge Returning amount

0 to 0.05mm

Unit : mm

– 22 –

Adjustment Procedure

Results of Improper Adjustment

1. Loosen setscrew in the looper holder and move looper indicator arm to the right and left for adjust.

2. After the adjustment, tighten setscrew in the looper holder.

Without fine adjustments

With fine adjustments

(Caution) When adjusting looper indicator arm , adjust the lateral

position while being careful that the looper indicator arm

does not move to and fro.

3. Longitudinal position

(1) Without fine adjustments

Adjust so that the clearance provided between blade point of

looper and middle needle is 0 to 0.05 mm when the top end of looper comes to the center of middle needle from the extreme right position.

(2) With fine adjustments

Turn adjusting screw to adjust the longitudinal position. Turn clockwise to move the looper supporting arm to the rear

side and counterclockwise to move it to the front side.

o When the returning amount is

large, loop of needle thread becomes large and it is apt to fall. As a result, stitch skipping or thread breakage will be caused, and stitch skipping on the back is apt to occur. In addition, thread tangling will be caused.

o When the returning amount is

small, loop of needle thread is small and stitch skipping or thread breakage will be caused. In addition, thread tangling will be caused.

After the adjustment, fix the looper holder with setscrew in the

looper holder.

* Blade point of the looper comes in contact with the right needle

when rear needle guard fails to work. So, be careful.

– 23 –

(9) Height of the needle

Standard Adjustment

1. It is the standard that the top end of needle eyelet of left needle aligns with the bottom end of looper when the top end of looper passes the rear of the needle from the extreme right position and protrudes from the left end of left needle by approximately 1 mm (1.1 mm), dimension B.

To align

Reference : Dimension C, height of left needle from top surface A of throat plate

Unit : mm

2-needle 3-needle

Needle gauge Height of left needle C Needle gauge Height of left needle C

4.0 9.3 — — ——5.6 8.5 ——6.4 8.0

2. Scooping height of looper , dimension from the top end of needle eyelet to the top end of looper is 1.2 to 1.4 mm.

1.2 to 1.4mm

– 24 –

Adjustment Procedure

Results of Improper Adjustment

1. Remove rubber cap in the face plate, loosen setscrew in the needle bar bracket and adjust the height of the needle bar.

2. After adjusting the height, equally adjust the clearance A between needle and needle hole in the throat plate and fix the needle bar with setscrew in the needle bar bracket.

o When the height of the needle

is excessively different, stitch skipping, needle breakage, thread breakage, etc. will be caused.

Equal

– 25 –

(10)Locus and longitudinal motion of the looper

Standard Adjustment

1. Standard longitudinal motion of the looper (1) It is the standard that the top end of left needle touches

the position of 1/4 to 1/3 from the bottom face of the back of the looper when the looper returns from the extreme left position.

(2) The position where the engraved marker line on looper

drive arm aligns with the center of the shaft of pin is the standard.

1/4 to 1/3

—

2. Locus of the looper

0.1 to 0.2mm

2.5 to 2.7mm

It is the standard locus of the looper that the clearance between the top end of looper and middle needle is within 0.05mm (when the rear needle guard fails to work) and the looper passes the left needle with a clearance of 0.1 to 0.2 mm.

Lower pulley side

The standard position of the cam is the position where the notch of looper longitudinal motion eccentric cam aligns with notches of looper driving shaft.

– 26 –

Adjustment Procedure

Results of Improper Adjustment

1. Changing the longitudinal motion of the looper

(1) Remove 11 setscrews in bed top cover and remove the cover. (2) When increasing the longitudinal motion of the looper, loosen nut

and lower the arm downward . from the engraved marker line.

(3) When decreasing the longitudinal motion of the looper, loosen nut

raise the arm upward from the engraved marker line.

Perform the adjustment in accordance with the needle used.

(Caution) After adjusting the longitudinal motion of the looper,

move the looper holder and re-adjust the longitudinal position of the needle and the looper. (Refer to "(8) Returning amount of the looper.)

2. Changing the locus of the looper

(1) Loosen two setscrews in the cam and change the locus of the

looper by turning the upper pulley with the cam fixed.

When it is turned in the direction of rotation, the timing is retarded,

and when turning in the reverse direction of rotation, the timing is advanced.

(Caution) 1. It is possible to change the locus of the looper.

However, do not excessively change it from the standard position.

2. When changing the locus of the looper, be sure to check whether the top end of left needle touches the position of 1/4 to 1/3 from the bottom face of the back of the looper.

—

o When the longitudinal motion of

the looper is small, the rate that needle touches the back of the looper is increased and blunt needle tip will be caused.

o When the longitudinal motion of

the looper is large, the clearance provided between the needle and the back of the looper is increased and stitch skipping at the time of returning of the looper will be caused.

o When the timing is retarded, stitch

skipping is apt to occur at the time of going of the looper, and especially the clearance provided between the looper and the left needle is widened. Needle strongly touches the back of the looper and blunt needle tip will be caused.

o When the timing is advanced,

stitch skipping is apt to occur at the time of returning of the looper. Chain-off thread does not come out smoothly.

– 27 –

o When removing the top cover for

adjustment or the like, sealant is peeled off. As a result, oil leakage will be caused.

(11) Adjusting the needle guard

Standard Adjustment

1. Standard position of the rear needle guard (1) Lateral position of rear needle guard

It is the standard that the lateral position of rear needle guard is the position where the rear needle guard receives the needle in the range of B.

(2) Position of the height of the rear needle guard

It is the standard that ridge line A of rear needle guard enters in the needle eyelet of right needle when the needle bar is in its lower dead position.

Details of section A

Ridge line

Needle eyelet

(3) Pressing amount of the rear needle guard

When the top end of looper comes from the extreme right position to the center of right needle, the clearance provided between the needle and the top end of looper becomes 0 to 0.05 mm. Make rear needle guard lightly touch the right needle and the pressing amount of the top end of needle becomes

0.1 to 0.2 mm. It is the standard for the middle needle that when the top end of looper comes to the center of middle needle, the clearance provided between the middle needle and the top end of looper becomes 0 to 0.05 mm and the pressing amount of the top end of the needle is such an amount that rear needle guard lightly touches the middle needle.

0 to

0.05m m

0 to

0.05m m

– 28 –

0.1 to 0.2mm

Adjustment Procedure

Results of Improper Adjustment

1. Loosen setscrew in the rear needle guard holder and perform the adjustment in the lateral direction.

2. Loosen setscrew in the rear needle guard and perform adjustment in the height direction and the direction of rotation.

3. After the adjustment, tighten setscrews and .

(Caution) After the adjustment, check by manual turning whether

the top end of looper does not come in contact with the needle.

o When the pressing amount of

rear needle guard is small, needle deflection increases and stitch skipping, thread breakage, needle breakage and worn-out of the top end of looper will be caused.

– 29 –

(11) Adjusting the needle guard

Standard Adjustment

For MF-7700D-U10

(4) Timing of the rear needle guard

The standard position of rear needle guard cam is the position where timing mark in rear needle guard cam aligns with the center of the notch of looper longitudinal cam .

To align

2. Front needle guard (1) It is the standard that the clearance provided between front needle guard and the needle is 0.1 to 0.3 mm.

0.1 to 0.3mm

– 30 –

Adjustment Procedure

Results of Improper Adjustment

For MF-7700D-U10

4. Remove the bed top cover.

Loosen two setscrews in rear needle guard cam and adjust

the timing.

When moving the cam in direction, timing is advanced, and when

moving in direction, it is retarded.

Pulley side

—

1. Loosen setscrew in the front needle guard and adjust the clearance.

Adjust so that the clearance provided between the needle and front

needle guard is 0.1 to 0.3 mm when looper moves from the extreme right position to the left and passes the rear side of the respective needles and fix the front needle guard with setscrew .

* Place front needle guard as near as the needle to such an extent

that needle thread passes smoothly in accordance with kind and thickness of thread.

o The cam is excessively changed

from the standard position, needle breakage or stitch skipping will be caused.

o When the front needle guard and

the needle come excessively near, stitch skipping or needle breakage will be caused.

(Caution) Check by manual turning whether the needle is pinched

with front needle guard and the rear needle guard.

– 31 –

(12)Installing cover of the looper and needle guard after adjusting

Standard Adjustment

1. Installing bed top cover

– 32 –

Adjustment Procedure

Results of Improper Adjustment

1. When the adjustment of (10) Locus and longitudinal motion of the looper or (11) Adjusting the needle guard has been performed, apply sealant to section A and install bed top cover .

oWhen removing bed top cover

for adjustment or the like, sealant is peeled off and oil leakage will be caused.

– 33 –

(13)Adjusting the feed dog

Standard Adjustment

1. Height of the feed dog It is the standard that the height of feed dogs (main feed dog and differential feed dog ) is 1 mm from the top surface of the throat plate when feed dogs and are in the highest position.

2. Tilt of the feed dog It is the standard that the tilt of feed dogs and is flush with throat plate when feed dogs and are in the highest position.

Flush

1mm

– 34 –

Adjustment Procedure

Results of Improper Adjustment

1. Loosen setscrew in the differential feed dog and setscrew in the main feed dog, and adjust the height.

(1) Adjust the top surface of throat plate and the height of the rear

end of main feed dog to 1 mm when feed dogs and come to the highest position, and fix the main feed dog with setscrew in the main feed dog.

(2) For the height of differential feed dog , adjust the height of front

end of main feed dog and rear end of differential feed dog

, and fix the differential feed dog with setscrew in the differential

feed dog.

2. Adjusting the tilt of the feed dog

(1) Remove rubber plug in the cover located in the rear of the bed

and loosen the setscrew in the feed tilt adjustment shaft located in the rear with a hexagonal wrench key of 2.5 mm.

(2) When turning feed dog tilt adjustment shaft to the right or left, the

top ends of feed dogs and move up or down and the tilt of feed dogs and can be adjusted.

(Caution) After the adjustment check the height of feed dogs

and .

o When the position of the feed

dog is high, stitch skipping, defective chain-off, return of feed, etc. will be caused. Throat plate comes in contact with feed dog and damage of components or abnormal noise will be caused.

o When the position of the feed

dog is low, the stitch length becomes short when the sewing is finished and performance of getting over the overlapped section is deteriorated.

o When the position of the feed

dog is excessively low, looper and feed dog may come in contact with each other.

oWhen the tilt of the feed dog is

raised toward you, performance of catching material is improved.

oWhen the tilt of the feed dog is

lowered toward you, it is effective in irregular stitches and puckering.

– 35 –

(13)Adjusting the feed dog

Standard Adjustment

3. Lateral position of the feed dog It is the standard of the lateral position of the feed dog that the left and right clearances A of the feed dog in terms of the slots of the throat plate are parallel and equal.

– 36 –

Adjustment Procedure

Results of Improper Adjustment

3. Adjusting the lateral position of the feed dog (1) Remove the bed top cover and remove setscrews in rocking bar

guide 2 .

(Caution) When setting the feed motion amount to 3.6 mm (max.)

and the differential feed ratio to 1 : 1 before the adjustment, the adjustment at the time of assembling can be performed with ease.

(2) Loosen setscrew in the feed tilt adjustment shaft and setscrew

in the feed tilt eccentric shaft . Move feed tilt eccentric shaft by approximately 2mm in the left direction shaft, move feed tilt Adjustment shaft by approximately 2mm in the right direction, and open a clearance to the right and left of square block .

(Caution) When moving feed tilt eccentric shaft , lower

downward differential lever pin with differential feed ratio change lever . Edge of feed tilt eccentric shaft comes in contact with the pin and a clearance can not be made.

(3) When loosening setscrew in the differential feed lever and

setscrew in the main feed lever, adjustment of the rocking bar in the lateral direction can be performed.

(4) Loosen setscrew in rocking bar guide 1 and adjust main feed

rocking bar and differential feed rocking bar to the right and left so that the clearances of the feed dog in terms of the slots of the throat plate are parallel and equal with feed dog and throat plate attached. When the equal clearances are set, tighten setscrew to fix rocking bar guide 1 , attach rocking bar guide 2 and guide setscrews , and fix the rocking bar so that it is put between the setscrews.

(5) Bring feed tilt adjustment shaft and feed tilt eccentric shaft to

their home positions to get rid of the right and left clearances of square block .

(6) After adjusting the lateral position of the feed dog, loosen setscrew

in the thrust collar , remove the thrust of the shaft with thrust collar

and fix the thrust collar with the setscrew.

(Caution) 1. After fixing, check the lateral play of the rocking bar

by moving the feed dog to the right or left. At the same time, move the rocking bar to and fro and check whether it moves smoothly.

2. For the fixing of setscrew in the differential feed lever and setscrew in the main feed lever, refer to the longitudinal adjustment value of the feed dog.

3. When fixing setscrew in the feed tilt adjustment shaft, check the tilt of the feed dog and when fixing setscrew in the feed tilt eccentric shaft, there should be no lateral play of square block .

o When the lateral position of the

feed dog is incorrect, worn-out of throat plate and feed dog will be caused.

o Heating or abnormal noise will

occur.

o The feed components will wear

out early , or the looseness will be caused.

– 37 –

(13)Adjusting the feed dog

Standard Adjustment

4. Longitudinal position of the feed dog (1) Position of the main feed dog : it is the standard that the position where the clearance from the edge of the

slot of the throat plate to the front face of the main feed dog is 0.6±0.2 mm at the position where the main feed dog travels to the extreme front position (operator’s side) when feed momentum is set to 3.6 mm (maximum).

(2) Position of the differential feed dog : it is the standard that the position where the clearance provided

between main feed dog and differential feed dog is 1.6±0.2 mm when the differential feed ratio is set to 1 : 1 after adjusting the position of the main feed dog.

0.6±0.2mm 1.6±0.2mm

5. For C10

– 38 –

0.6±0.2mm

±0.2mm

Adjustment Procedure

Results of Improper Adjustment

4. Longitudinal position of the feed dog (condition : feed momentum

3.6 mm (maximum))

(1) When fixing setscrew in the main feed lever , adjust the clearance

from the edge of the slot of the throat plate to the front face of the main feed dog to 0.6±0.2 mm when the feed dog travels to the extreme front position (operator’s side), press the main feed lever to the rocking bar side, and fix it with setscrew.

(2) When fixing setscrew in the differential feed lever, set the

differential feed ratio to 1 : 1, adjust the clearance provided between the main feed dog and the differential feed dog to 1.6±0.2 mm, press the differential feed lever to the rocking bar side, and fix it with setscrew.

(Caution) When the adjustment value changes greatly, feed dog

or throat plate will be broken.

o When the fixing position of the

main feed lever slips greatly out of position, abnormal noise or abrasion will be caused.

o When the fixing position of the

differential feed lever slips greatly out of position, abnormal noise or abrasion will be caused.

5. For C10 Front and rear positions of the feed dog

(1) When the main feed dog has a pitch of 3.6mm, the clearance

between the most advanced position of feed (worker side) and the throat plate shall be 0.6 ± 0.2mm.

(2) When the differential feed dog has a pitch of 2.5mm and the

differential feed ratio is 1:1 at that time, the clearance between the main feed dog and the differential feed dog shall be 1 ± 0.2mm.

– 39 –

(14)Adjusting the feed relation

Standard Adjustment

1. Changing the stitch length It is possible for the standard stitch length to adjust up to 1.2 to 3.6 mm. Turning feed adjust knob clockwise increases the stitch length and turning it counterclockwise decreases the stitch length.

2. Changing the differential feed ratio Differential feed ratio is 1 : 0.7 to 1 : 2 (stitch length : less than 2.5 mm).

Gathering

Stretching

– 40 –

Adjustment Procedure

Results of Improper Adjustment

1. When making the stitch length more than 3.6 mm, loosen setscrew of the feed adjustment stopper pin, turn feed adjust knob

clockwise, and adjust the stitch length. By turning feed adjust knob

, pin is pushed out. Fix pin with setscrew in the feed

adjustment stopper pin after adjusting the stitch length.

Maximum stitch length is 4.4 mm.

o When the stitch length is set to

more than 3.6 mm, the contact of main feed dog, differential feed dog and throat plate occurs due to the adjustment in case of the standard position of the feed dog. Additionally machine the feed dog to satisfy the need.

o When using the machine with the

stitch length of more than 2.5 mm and the maximum differential feed ratio, turn the machine by hand and check whether there is any contact with feed dog and throat plate. In addition, when more gathering is necessary , grind the differential feed dog.

2. Loosen differential lock nut and raise lever to increase the

differential feed ratio (shrinkage in stitched material cloth). When the lever is lowered, the differential feed ratio becomes small (elongation in stitched material cloth).

Fine adjustment of the differential feed ratio can be performed with

micro-adjust knob .

When engraved marker of the differential feed lever is aligned with

the long engraved marker line on the dial plate, the momentum of the main feed dog and the differential feed dog becomes almost 1 : 1.

(Caution) For some stitch lengths and differential feed ratios,

improper adjustments may give rise to breakage as a result of contact between feed dogs or between feed dog and throat plate.

– 41 –

(15)Adjusting the presser foot

Standard Adjustment

1. Height of the presser foot Height of the presser foot has to be the position the presser foot does not come in contact with other components at the position where lifter lever is lowered and comes in contact with height adjustment screw .

Dimension A 8 mm in case of needle gauge 5.6 mm without top covering

5 mm in case of needle gauge 5.6 mm with top covering

2. Position of the thrust collar (1) Clearance provided between thrust collar and presser shaft bushing is 0.1 mm at the position where

lifter lever is lowered and comes in contact with height adjustment screw .

0.1mm

Throat plate

3. Position of the lifter connecting plate

(1) Adjust the clearance provided between lifter connecting plate and hinge screw to 0.5 mm when the

presser foot is lowered in the state that the feed dog comes down below the throat plate.

(2) Adjust so that the needle enters in the center of needle entry of the presser foot and fix the presser foot with

setscrew in the presser bracket.

0.5mm

– 42 –

Center of needle entry

Adjustment Procedure

Results of Improper Adjustment

1. Adjusting the height of the presser foot Loosen adjustment nut . Lower lifter lever , adjust height

adjustment screw , and fix nut at the position where the presser foot does not come in contact with other components.

2. Adjusting the thrust collar Loosen setscrew in the thrust collar and adjust the clearance. When the height of the presser foot is changed, Be sure to perform

the adjustment of the clearance of thrust collar and check the clearance.

3. Adjusting the lifter connecting plate For the adjustment of the clearance provided between lifter

connecting plate and hinge screw , loosen setscrew in the lifter lever shaft when the feed dog lowers from the top surface of the throat plate and the bottom face of the presser foot comes in close contact with the throat plate.

o When the position of the presser

foot is too high, it comes in contact with the spreader, and breakage, stitch skipping, etc. will be caused. In addition, the needle tip comes out from the sole of the presser foot. As a result, sewing material is damaged or needle breakage will be caused.

o In case the clearance of thrust

collar is large, when the presser foot gets over the overlapped section, the presser foot comes in contact with other components and will cause the damage.

o When replacing the presser foot

due to the replacement of the gauge or the like, check the clearance provided between thrust collar and lifter connecting plate .

o When the clearance of lifter

connecting plate does not exist, not only feed force is reduced but also components are led to breakage since the presser foot does not come down to the top surface of the throat plate when the feed dog comes down from the top surface of the throat plate.

o When adjusting the lever shaft,

adjust the height of lifter lever .

– 43 –

(16)Adjusting the micro-lifter

Standard Adjustment

1. Micro-lifter Adjust the micro-lifter in accordance with sewing conditions for use.

Major applicable process

1. When twist occurs in the hemming bottom process.

2. When tape is twisted in collecting.

Down

– 44 –

Adjustment Procedure

1. Adjusting the micro-lifter (1) When micro-lifter knob is turned counterclockwise, micro-lifter

stopper lower and comes in contact with presser lifting lever . Then the presser foot goes up. Adjust the height accordance with the sewing conditions.

(2) When micro-lifter knob is turned clockwise, micro-lifter stopper

is raised and comes in contact with presser lifting lever . Then

the presser foot comes down.

(Caution) When the micro-lifter is not used, turn clockwise micro-

lifter knob and fix micro-lifter stopper at the highest position.

Results of Improper Adjustment

– 45 –

(17)Adjusting the looper thread cam

Standard Adjustment

1. Adjust so that thread comes off from the highest place of looper thread cam when needles come down and the top end of left needle aligns with the bottom surface of looper . Then tighten setscrews to fix the looper thread cam.

Theread

To align

2. Preventing thread winding around the looper thread cam Adjust the clearance provided between the top end of section A of looper thread winding prevention plate

and the edge of looper thread cam to approximately 0 to 0.3 mm (the plate should not come in contact

with looper thread cam ).

– 46 –

Adjustment Procedure

Results of Improper Adjustment

1. Loosen setscrews in the looper thread cam and adjust while checking that looper thread comes off from the periphery of the looper thread cam.

(Caution) When setscrews in the looper thread cam are

loosened, looper thread cam moves in the shaft direction as well. Assemble so that the clearances provided between the cam and the thread guide are equal.

Equal clearances

oWhen the position of looper

thread cam slips greatly out of position, stitch skipping or defect of thread tightness on the back of the looper is apt to occur.

2. Adjusting the looper thread winding prevention plate

Adjust the clearance to approximately 0 to 0.3mm, provided between

the top end of Section A of looper thread winding prevention plate

and the edge of looper thread cam . (Loosen setscrews (2 pcs.) of looper thread cam and move them to the right and left to adjust the clearance to 0 to 0.3mm. After that, tighten setscrews (2 pcs.).) Since then, tighten setscrews (2 pcs.) to fix the looper thread winding prevention plate.

o It is effective to adjust as narrow

as possible the clearance provided between the top end of click section (section A) of looper thread winding prevention plate and the edge of looper thread cam

. However, when making them come too near and come in contact with each other, looper thread cam is scratched and winding is caused by this adjustment, instead.

– 47 –

(18)With regard to lubrication

1. Replacing the oil filter Normal lubrication cannot be performed if dust collects in oil filter . Inspect it every 6 months.

Standard Adjustment

2. Oil circulation identification window Make sure that lubricating oil rises to oil circulation identification window during operation. <When using the sewing machine for the first time> Lubricating oil has been taken out at the time of delivery. Be sure to supply lubricating oil before using the sewing machine for the first time.

*Oil used : JUKI MACHINE OIL 18

(Caution) Do not use oil addition agent since

deterioration of lubricating oil or machine trouble will be caused.

Remove oil hole cap and fill the oil reservoir with lubricating oil up to the level between the upper and lower engraved marker lines of oil gauge . <Checking before using the sewing machine>

1) Check oil gauge and make sure that lubricating oil level is between the upper and lower two lines. When lubricating oil level lowers below the lower line, supply lubricating oil.

2) Make sure that lubricating oil comes out from the nozzle of oil circulation identification window when rotating the sewing machine. When lubricating oil does not come out, perform "Inspecting and replacing the oil filter ".

Lubrication

– 48 –

Adjustment Procedure

Results of Improper Adjustment

1. Inspection and replacement Loosen setscrews in the oil filter cap and remove oil filter cap . Draw out oil filter to inspect it. When it is clogged with dust, replace

it with a new one.

After the replacement, fix oil filter cap with setscrews in the oil

filter cap.

(Caution) When removing the oil filter cap , lubricating oil

collected in oil filter will leak out. So, be careful.

2. Oil circulation identification

(1) In case the oil does not come out from oil circulation identification

window even when oil filter is replaced with a new one, remove six setscrews in the oil pan, remove oil pan , and tilt the machine head to the rear up to the position where pipe connecting joint screw

can be removed.

(2) Oil sucked up from gear pump passes oil pipe and enters oil

filter from pipe connecting joint screw . When the lubrication oil does not rise to oil circulation identification window , The hole in pipe connecting joint screw may be clogged with dust. So, check it.

(Caution) When there is any foreign material in oil pan , remove

it.

o In case oil cannot be observed

from oil circulation identification window even when the sewing speed is 2,500 rpm or over, the machine will be in danger of seizure if the operation is continued.

– 49 –

(18)With regard to lubrication

3. Oiling

Standard Adjustment

No oiling

4. Replacing the lubricating oil

– 50 –

Adjustment Procedure

3. Oiling The mechanisms inside the frame such as the needle bar, presser lift and spreader components are lubricated with grease. Never add oil inside the frame.

(Caution) If inside of the frame is oiled, the grease will be expelled,

resulting in mechanical failure.

Results of Improper Adjustment

4. Replacing the lubricating oil In case of the new sewing machine, replace the lubricating oil (JUKI MACHINE OIL 18) with new one after using it for approximately one month. Then replace the lubricating oil every six months. (1) Set a container to receive the lubricating oil under drain screw

. (2) Remove drain screw . The lubrication oil is drained. (3) After the drain, wipe out the oil and attach the drain screw .

– 51 –

(19)Setting for functions of SC-500

Functions can be selected and specified by means of the four setting switches and light emitting diode located inside the front cover of the SC-500.

Specified No. Specified value

Switch for entering specified value changed Down switch (DOWN) and updating setting No. in DOWN direction Up switch (UP) Switch for entering specified value changed and updating setting No. in UP direction

(Caution) 1. Do not perform switch operations other than those described in the following explanations.

2. Be sure to re-turn the power switch ON after one second or more has passed. If the power is turned ON immediately after turning it OFF, the sewing machine may not work normally. In this case, turn ON the power again.

How to change over to the function setting mode

(1) Turn OFF the power to the unit. (2) Pressing switch , turn ON the power to the unit. (3) Indication , will be shown on the display. (If the

indication fails to change, re-perform the procedure

1) and 2).

– 52 –

Specified No.

(4) When you want to advance the setting No., press

switch to advance the setting No. When you want to return the setting No., press switch

to return the setting No.

(Caution) 1. When switch (switch ) is held

pressing, the setting No. will return (will advance) continuously.

2. When the setting No. is advanced (returned), the contents which are before by one (after by one) will be changing the contents (up/down switch is touched).

EXAMPLE) CHANGING THE FLICKER REDUCING FUNCTION (SETTING No. 5)

Press switch five times to set the setting No. to “5”. Press switch five times to change the set No. to “5” since the current set value is displayed on LED . (Standard : “0”)

(Caution) Keep pressing switch or switch , and

the setting value can be changes continuously.

(5) When the change has been completed, press switch

or to specify the changed value.

(Caution) 1. When turning OFF the power before

performing this work, the contents which have been changed are not updated.

2. Press switch , and screen display will change to the contents of thew setting No. which is before by one.

3. Press switch , and screen display will change to the contents of next setting No. After completing the operation, turn OFF the power and turn ON the power again to return to the normal operation.

After completing the operation, turn OFF the power and turn ON the power again return to the normal operation.

– 53 –

(20) Adjusting and setting SC-510

1. When SC-510 is used, install the motor referring to the Instruction Manual for SC-510.

2. Installation of the synchronizer

1) Synchronizer can be installed by the method below.

2) Using two setscrews , mount synchronizer fixing plate on the sewing machine. Then, install synchronizer on it.

3) Fix a cord of synchronizer to synchronizer fixing plate by means of cable clip band . Fasten the cord in the illustrated position, using cord clamp and setscrew .

– 54 –

3. Synchronizer adjustments

The synchronizer can be adjusted in the procedures specified below.

WARNING : To protect against possible injury to hands or fingers due to abrupt start of the machine during performing adjustment, perform the adjustment of the stop position under the function setting mode.

1) Loosen screw and remove cover .

2) Turn disk on this side by hand, and adjust the adjusting mark “B” of disk in the rear to edge of disk .

3) Temporarily tighten the synchronizer to the lower main shaft handwheel with screw .

4) When the power is turned ON, the sewing machine turns approximately by one half and stops.

5) Turn OFF the power, and loosen screw .

6) Holding section B of the synchronizer so as not to move, turn the upper main shaft handwheel, and temporarily tighten screw in the position where mark of the handwheel is adjusted to mark on the machine head side.

7) Turn ON the power again and make sure that the sewing machine stops where mark of the handwheel is apart from mark on the machine head side. Then tighten screw .

8) After the adjustment, be sure to attach cover and tighten screw .

9) After the adjustment above has been performed, when the sewing machine stops at the DOWN position, top end C of the looper is located at the position where it has scooped loop D of left needle

thread as shown in the figure.

(Caution) When using the synchronizer as UP/

DOWN stop position type without using the thread trimmer device, change the setting of the function setting No. 74 to “1 (thread trimming )

→→

→ 0 (UP/DOWN po-

→→

sition)”. (Setting procedure of both SC500 and SC-510 is common.) Thread trimmer safety device error occurs unless the setting is changed, and it is impossible to operate the sewing machine. So, be careful.

– 55 –

4. Setting procedure of the machine head

1) Refer to “3-3 Setting for functions of SC-510” in the INSTRUCTION MANUAL for SC-510, and call the function setting No. 95.

2) The type of machine head can be selected by pressing switch (switch ).

3) After determining the type of machine head, by pressing switch (switch ), the step proceeds to 96 or 94, and the display automatically changes to the contents of the setting corresponding with the type of machine head.

(Caution) When the type of machine head is

changed, the contents which have been changed before return to the standard set values.

– 56 –

5. Machine head list

No. Machine head Type Contents

of display

1MF Semi-dry (MF-7700D/7800D) MF.d 4000 4000 2MF (4 needles) MF.S3 3200 4200 3 MF Roller MF.S1 4000 5000 4 MF Knife MF.S2 4500 5500 5 MF-7823/UT25, MF-77∗∗/UT∗∗ MF 4500 6500 6 16 Class U.16 800 800 7 35800 U.358 4000 4000 8 MS-3580 J.358 4000 4500

9 36200 U.362 3300 3300 10 MO∗∗ MO. 1 4000 5500 11 MO∗∗ MO. 2 7000 8000 12 DU-141H du. 14 2000 2000 13 LU-2210 (VR type) LU. 2v 3500 4000 14 DSU-14∗ dsu 2000 2000 15 DSC-24∗ dsc.0 2200 2200 16 LZH-1290 LZH 2000 2000 17 PLC-1660/1610 PL.66 2000 2000 18 PLC-1710/1760-7 PL.70 2500 2500 19 PLC-1760L PL.7L 1800 1800 20 DNU-1541-7 dnU. 5 3000 3000 21 LS-1342-7 LS.13 2500 2500 22 LU-1510N-7 LU.51 3000 3000 23 LU-1510NA LU.5A 2000 2000 24 LU-1560N-7 LU.56 2500 2500 25 LU-1520N-7 LU.52 3000 3000 26 DLN-6390 DLn 4500 5000 27 MH-48∗ MH.81 5500 5500 28 MH-48∗ MH.82 4500 4500 29 MH-1410 MH.14 4000 5000 30 LU-2216 (VR type) LU.26 3000 3000 31 LU-22∗0 (Special) LU.20 3500 4000 32 LU-2212 LU.12 3500 3500 33 LU-2220 LU.22 3500 3500 34 LT-1040 LT 800 800 35 LH-3500 LH.35 3000 3000 36 DDL-8700 dL.87 4000 5000 37 DDL-8700J dL.8J 4000 4000 38 DDL-5600J dL.6J 4000 4000 39 DDL-5600LUR dL.6L 3000 3000 40 ASN-690 ASn 5500 8000

Sewing speed set at the

time of delivery speed (sti/min)

from factory (sti/min)

Max. sewing

—

o Machine head set at the time of delivery

– 57 –

(21)MF-7700D/MF-7800D How to use the timing gauge

(Refer to the Engineer’s Manual for the adjustment procedure)

For MF-7700D

4.5

3.7

4.5

(Part No. 40020268)

1.0

4.9

3.3

4.1

Unit: mm

4.9

8.5

7.8

For MF-7800D

3.9

3.1

3.9

(Part No. 40020269)

1.0

1. Returning amount of the looper

Move the looper to its back end (extreme right position), fit the slit of the gauge to the right needle, and adjust the returning amount so

Align that the end of the gauge is aligned with the blade point of the looper.

– 58 –

7700D and 7800D are different in the returning amount even when the needle gauge is the same. Use the gauge on which 7700 is stamped for 7700 or that on which 7800 is stamped for 7800.

MF-7700D

Needle gauge

3.2 4.9 4 4.5

4.8 4.1

5.6 3.7

6.4 3.3

MF-7800D

3.2 4.3 4 3.9

4.8 3.5

5.6 3.1

6.4 2.7

2. Height of the needle bar

Bring the needle bar to the upper dead point of its stroke, fit the gauge from the top surface of the

Align

throat plate to the top end of the left needle, and adjust the height of the needle bar so that the end of the gauge is aligned with the tip of the needle.

7700D and 7800D are different in the height. Use the gauge on which 7700 is stamped for 7700 and that on which 7800 is stamped for 7800. Height of the needle bar varies in accordance with the needle gauges. For the details, refer to the Engineer’s Manual.

MF-7700D Top surface of throat

plate standard

Needle gauge

5.6 8.5

MF-7800D Top surface of throat

plate standard

Needle gauge

5.6 7.8

2.7

Unit: mm

Right needle

Returning amount

Right needle

Left needle height

4.3

3.5

4.3

standard

3. Spreader

(1) Height of the spreader

Insert the timing gauge between the top surface of the throat plate and the bottom surface of the spreader. 7700D and 7800D are different in the height. Use the gauge on which 7700 is stamped for 7700 and that on which 7800 is stamped for 7800.

Spreader

(3) Clearance between the needle and the

spreader

Insert the gauge between the left needle and the spreader when the spreader starts to return from the extreme left position to the right and comes nearest to the left needle, and adjust the clearance.

(5) Clearance between the fixed thread guide

and the needle clamp thread guide

Bring the needle bar to the lowest position of its stroke, insert two pieces of the gauge between the fixed thread guide and the

needle clamp thread guide, and adjust the height of the needle clamp thread guide.

(2) Protruding amount of the spreader

When the spreader travels to its front end (extreme left position), fit the left needle to the slit of the gauge, and adjust the lateral position so that the top end of the thread guide of the spreader is aligned with the end of the gauge.

Aligh

Throat plate

(4) Clearance between the spreader and

the fixed thread guide

Insert the gauge between the spreader and the fixed thread guide, and adjust the height of the fixed thread guide.

4. Height of the feed dog

Bring the feed dog to its highest position, put the gauge from the upper part of the feed dog and adjust the height.

6. E10/MD10

(1) Specifications (E10)

Model MF-7700D-E10 Class name Elastic tape attachment with fabric trimmer Max. sewing speed 4,000sti/min (4,000 sti/min with MD)

Needdle

gauge

Differential feed ratio 1: 0.7 to 1 : 1 Stitch length 0.9 to 3.6mm (Adjustable to 4.5mm)

3-needle 5.6mm, 6.4mm 2-needle 4.0mm

(2) Specifications (MD10)

Model MD10 Class name Mechanical metering device Max. sewing speed 4,000 sti/min

Needdle

gauge

Tape width 50mm (standard)/80mm * Amount of tape feeding 0.9 to 3.5mm

*Changeover scheduled

3-needle 5.6mm, 6.4mm 2-needle 4.0mm

– 59 –

(3) Adjusting the needle guard

For MF-7700D-E10

1. Most advanced position of the needle guard

E10/MD10

Standard Adjustment

Present status (E10) 195 °

(E10) 180 °

Screw position is used as a mark.

– 60 –

E10/MD10

Adjustment Procedure

For MF-7700D-E10

195° Present status (E10) Position where the root of rod for looper front-rear motion almost coincides with the center of first screw of the balancer when the rear needle guard is in the most advanced position.

180° (E10) Position where the oil hole of rear needle guard rod almost coincides with the rear end of first screw of the balancer when the rear needle guard is in the most advanced position.

Results of Improper Adjustment

– 61 –

(4) Adjustment of knife

Standard Adjustment

1. Adjustment procedure of the knife pressure

Strong

Weak

E10/MD10

2. Adjustment procedure of knife cutting position

Body part

Left needle

Right needle

Elastic tape

Cutting position

– 62 –

E10/MD10

Adjustment Procedure

1. Adjustment procedure of the knife pressure

The fabric trimmer pressure or the pressing force to mesh with the counter knife should be made as small as possible within the range where the material cloth can be cut smoothly. The knife pressure can be made stronger when setscrew of thrust collar A is loosened and the spring is pressed to the right and tightened.

Results of Improper Adjustment

o Too weak knife pressure may

cause the knife to be displaced due to the presence of the step section or the like, and the cut section does not become parallel to the stitches.

oToo strong knife pressure may

cause the fixed knife to be abraded sooner.

2. Adjustment procedure of knife cutting position

Adjust the distance between the right needle and the cutting position as described below. (1) Loosen setscrew and turn adjusting screw to adjust fabric

trimmer and fixed knife to the right and left. The fabric trimmer and fixed knife move to the left when adjusting screw is turned clockwise. They move to the right

when the adjusting screw is turned counterclockwise. (2) Tighten setscrew after adjustments. (3) After the adjustment, perform the adjustment of the knife

pressure again.

– 63 –

Standard Adjustment

3. Adjustment procedure of engagement amount of knives

0.5mm Lowest knife position

E10/MD10

4. Replacement procedure of fabric trimmer and fixed knife

Processed plane A

– 64 –

E10/MD10

Adjustment Procedure

3. Adjustment procedure of engagement amount of knives

(1) Loosen setscrew where fabric trimmer stays in the lowest

position so that fabric trimmer can be moved vertically.

(2) Adjust the amount of fabric trimmer and fixed knife

engagement to about 0.5mm from the tip of the fabric trimmer

and tighten setscrew . At that time, sliding arm should be positioned somewhat toward the left side so that it does not come in contact with square block cover .

Results of Improper Adjustment

o If the amount of engagement is

insufficient, the cutting amount becomes smaller compared with the feeding amount. As a result, finished stitches become ugly.

o If the amount of engagement is

excessive, the amount of abrasion becomes large at the fixed knife.

4. Replacement procedure of fabric trimmer and fixed knife

To replace fabric trimmer , remove setscrew , guard , and

setscrew . When mounting it again, press it against the processed plane A and stop it there.

For the replacement of fixed knife , loosen screw and remove

the old fixed knife .

– 65 –

(5) Presser adjustments

E10/MD10

Standard Adjustment

– 66 –

E10/MD10

Adjustment Procedure

1. Adjustment procedure of front-up amount of the presser foot

When sewing a thick rubber sheet or the like together, fabric can be smoothly fed by raising the front of presser foot . Loosen nut , turn setscrews to the right (clockwise), and raise the front of presser foot for adjustment.

2. Adjustment procedure of the position of the tape guide

Loosen setscrew , and move tape guide base to the right and left to adjust the position of the tape.

3. Adjustment of tape guide width

According to the tape width, loosen screw and adjust tape guide

to the right and left.

4. Adjustment of fabric presser

According to the knife cutting position, loosen screw for adjustment so that hook knife can enter knife guide .

Results of Improper Adjustment

– 67 –

(6) Method of lubrication

1. Lubrication to bearings

E10/MD10

Standard Adjustment

Left side

2. Lubrication to clutches

Right side

– 68 –

E10/MD10

Adjustment Procedure

1. Lubrication to bearings

• At the time of shipment from the factory, grease is applied to bearings.

(1) Remove screws and from both end sections of the shaft and

feed the attached grease sufficiently.

(2) After grease replenishment, mount screws and on both end

sections of the shaft.

Results of Improper Adjustment

2. Lubrication to clutches

• At the time of shipment from the factory, grease is applied to clutches.

(1) Remove the Phillips screw (+) from the clutch A section where

grease is specified.

(2) Replenish the specified grease through the A section.

At that time, keep on feeding the new grease until it comes out of the B section.

(3) After replenishment, attach the screw (+) to the clutch A section.

(Cautions)1. Greasing to the clutch should be carried out at the

intervals of 100 hours of working based on general standard practice.

2. At the time of delivery or starting operation after replenishment, a surplus grease may leak out of the clutch through of the B section. In such a case, wipe off the leaking grease. (Appropriate grease: JUKI Part No. 13525506)

– 69 –

(7) Adjustment of the amount of feeding

Standard Adjustment

1. Adjustment of the amount of feeding with a cam

E10/MD10

For tape feeding of 0.6 to 1.5mm

(Shipment from the factory)

For tape feeding of 1.4 to 3.3mm

– 70 –

E10/MD10

Adjustment Procedure

By adjusting eccentric cam B , the amount of tape feed, 0.6 to 1.5mm (at the time of shipment from the factory), can be adjusted within the range of 1.4 to 3.3mm. (1) Remove the pulley cover and the pulley. (2) Loosen two screws at eccentric cam B .

For tape feeding of 0.6 to 1.5mm:

Where the notch of eccentric cam B comes in contact with the right side of screw , fix eccentric cam B by tightening its screw.

For tape feeding of 1.4 to 3.3mm:

Where the notch of eccentric cam B comes in contact with the left side of screw , fix eccentric cam B by tightening two screws.

Results of Improper Adjustment

– 71 –

(8) Adjustments for heavy material sewing

Standard Adjustment

1. Standard adjustments

E10/MD10

Engraved line B

Engraved marking dot

Standard adjustments (Shipment from the factory)

2. Adjustments for heavy materials (3.5mm or above)

Engraved marking dot

Engraved line A

Adjustments for heavy materials (3.5mm or above)

– 72 –

E10/MD10

Adjustment Procedure

1. Standard adjustments

For standard adjustments, the status is that engraved line B meets the engraved marking dot. (Shipment from the factory)

Results of Improper Adjustment

2. Adjustments for heavy materials (3.5mm or above)

These adjustments are applicable where heavy materials of 3.5mm or above are processed by joining fabrics and tapes. (Standard adjustments have been finished at the time of shipment from the factory.) Adjustments are carried out as specified below. (1) Remove the pulley cover and the pulley. (2) Loosen two setscrews of eccentric cam A and two

setscrews of eccentric cam B .

(3) Adjust engraved line A of eccentric cam A to the engraved

marking dot that is located on shaft . Then, tighten setscrews

and that have been loosened as per (2) above.

– 73 –

(9) Mounting position of the eccentric cam

Standard Adjustment

E10/MD10

– 74 –

E10/MD10

Adjustment Procedure

Mounting position of the eccentric cam

(1) Assume the state that eccentric cam B is kept contact with the

section of eccentric cam A , as illustrated.

(2) Tighten screws and (2 pcs. each) of eccentric cams A and

B , respectively as illustrated, so that clearances B and C among washer , pointer , and rod are equally maintained under the condition that butterfly nut is tightened.

(Caution) Try to turn the pulley by hand after adjustments and

confirm that it can be moved smoothly.

Results of Improper Adjustment

– 75 –

MEMO

– 76 –

7. MF-7724DU10D60 (4 needles)

(1) Specifications

Model name Semi-dry head, flat-bed top and bottom coverstitch machine Model MF-7724D Stitch type ISO standard 607 Example of application Lap seam to knits and jersey products Max. sewing speed 4,000 sti/min (at the time of intermittent operation)

Needle gauge 4-needle .............6.0 mm

Differential feed ratio

Stitch length 1.2mm to delivery adjustment 2.5 mm (can be adjusted up to 4.4 mm) Needle SMX1014B #9S to #12S (Standard #10S) Needle bar stroke 31 mm (Standard) Dimensions (Height) 451 x (Width) 515 x (Length) 265 Weight 46kg

Lift of presser foot

Feed adjustment method

Looper mechanism Spherical rod drive method Lubricating system Forced lubrication method by gear pump Lubricating oil JUKI MACHINE OIL 18 (Equivalent to ISO VG18) Oil reservoir capacity Oil gauge lower line : 600 cm3 to upper line : 900 cm Installation Semi-submerged type

1 : 0.7 to 1 : 2 (stitch length : less than 2.5 mm) Micro-differential feed adjustment mechanism is provided. (Micro-adjustment)

5 mm (with top covering) Micro-lifter mechanism is provided.

Main feed ................dial type stitch pitch adjustment method

Differential feed .......

lever adjustment method (micro-adjustment mechanism is provided.)

(2) Needle

Japan No. 9 10 11 12 German No. 65 70 75 80

The needle used for this sewing machine is SM1014B. For the needle No., select a proper needle in accordance with the sewing conditions.

– 77 –

(3) Standard adjustments

1) Needle mounting

1. Attaching the needle

MF-7724DU10D60

Standard Adjustment

GOOD

Scart

– 78 –

MF-7724DU10D60

Adjustment Procedure

1) Loosen setscrew and needle with a screwdriver.

2) Hold the new needle with its scart made to face the rear and insert it to the end of the hole of needle clamp .

3) Securely tighten setscrew of the needle .

Results of Improper Adjustment

o If needle is not entered

completely, this can be a cause of stitch skipping.

– 79 –

2) Threading the machine head

MF-7724DU10D60

Standard Adjustment

When covering thread is excessively loosened = When covering thread is excessively loosened even after passing B =

When covering thread is excessively tense =

Broken line E when using more stretchable thread

When using more stretchable thread

– 80 –

MF-7724DU10D60

Adjustment Procedure

1. When motion of thread is very rough, and stable seams can not be

obtained, there are cases where the condition can be improved by the following threading. (1) Wind thread around 1st thread guide .

(2) Wind thread around the thread tension thread guide .

Results of Improper Adjustment

o When threading is not properly

performed, not only sewing trouble occurs, but also needle breakage is caused. So, be careful.

(Caution) Even when wooly thread or the like is used, stitches

will become more stable when the thread is passed through bobbin thread minor tension .

Engraved line

– 81 –

3) Adjusting the rocking thread take-up

MF-7724DU10D60

Standard Adjustment

1. Length of the rocking thread take-up

(1) It is the standard that the length of rocking thread take-up from the center of the shaft of rocking thread

take-up support arm to the thread hole face of rocking thread take-up is 90 mm.

90mm

2. Position of the rocking thread take-up

– 82 –

MF-7724DU10D60

Adjustment Procedure

1. Length of the rocking thread take-up

(1) Loosen setscrews move rocking thread take-up to the right

and left, adjust so that 90 mm is given from the thread hole to the center of rocking thread take-up shaft , and fix setscrews as shown in the figure.

2. Position of the rocking thread take-up

(1) Align the center of thread hole of rocking thread take-up with the

upper end plane of cover when the rocking thread take-up is at its lowest position, and fix the cover with screw .

(Caution) When adjusting the position of rocking thread take-up

Results of Improper Adjustment

o When length of rocking thread

take-up is lengthened, needle thread is tightened.

(Caution) When lengthening

rocking thread take-up

, check whether it comes in contact with the thread take-up cover.

o When length of rocking thread

take-up is shortened, needle thread is loosened.

o When installing position of

rocking thread take-up is raised, needle thread is loosened when the needle bar thread takeup is used, and needle thread is tightened when the needle bar thread take-up is not used.

– 83 –

4) Adjusting the position of the needle thread guide rod

MF-7724DU10D60

Standard Adjustment

1. Position of the needle thread guide rod

(1) It is the standard that the height of needle thread guide rods is the position where the dimensions from

the top surface of needle thread guide base to the bottom end of the hole are as follows.

Needle thread guide rods ABCD Standard seams 17mm 22mm 28mm 31mm

Extreme right position

2. Adjusting the position of needle thread guide base and silicon container thread guide

(1) It is the standard that the height of silicon container thread guide (refer to 2. CONFIGURATION OF THE

MACHINE COMPONENTS) is the position where the height from the center of setscrew to the bottom end of thread hole is 12 mm.

(2) Move the lateral position of needle thread guide base fully to the right of slot (43 mm).

(43mm)

12mm

Extreme right position

– 84 –

MF-7724DU10D60

Adjustment Procedure

1. Position of the needle thread guide rod

(1) Loosen setscrews and adjust so that the heights of the respective

needle thread guide rods are the dimensions as shown in the illustration. Then tighten screws to fix the thread guide rods.

(Caution) 1. Move the lateral position of needle thread guide base

fully to the right of slot.

2. When adjusting the height of needle thread guide rods , install the rods so that the thread holes are parallel to the thread holes of silicon container thread guide so that excessive resistance is not applied to threads.

Results of Improper Adjustment

oWhen needle thread guide rod is

raised, needle thread is loosened.

o When needle thread guide rod is

lowered, needle thread is tightened.

2. Adjusting the position of needle thread guide base and silicon container thread guide

(1) Loosen setscrews , adjust so that 12 mm is given from the center

of the upper setscrews to the top surface of thread guide, and tighten the thread guide with setscrews . Loosen setscrews and adjust the position from the center of setscrews to the center of needle thread guide rod to the extreme right position (43 mm). Then tighten setscrews to fix the thread guide rod.

o When silicon container thread

guide is raised, needle thread is loosened.

o When silicon container thread

guide is lowered, needle thread is tightened.

o When needle thread guide base

is moved to the left, needle

thread is loosened.

– 85 –

5) Adjusting the rocking thread take-up thread receiver

Standard Adjustment

1. Position of the needle bar thread take-up thread receiver (in case of standard seams)

5mm

MF-7724DU10D60

Front needle thread

– 86 –

MF-7724DU10D60

Adjustment Procedure

(1) Loosen four setscrews in the needle thread receiver plate, and

adjust the height. Adjust the left medium needle only to 5 mm and securely tighten the setscrews . Align the height of the other needle thread receiving plates with the needle thread receiving base and fix. The size of needle thread loop can be changed by adjusting the height according to the kinds of needle thread.

Results of Improper Adjustment

o When the needle bar thread take-

up thread receiver is raised, loop becomes large.

o When the needle bar thread take-

up thread receiver is excessively raised.

(2) Bring the needle bar to its lowest position, loosen setscrew to

adjust so that the needle thread comes is contact with the thread receiver of the front needle thread, and fix the thread receiver with setscrew .

– 87 –

6) Adjusting the looper

1. Right and left looper positions

3.5mm

2. Front and rear looper positions

0 to 0.05mm

MF-7724DU10D60

Standard Adjustment

7) Adjusting the height of the needle

Standard Adjustment

1. Equally adjust clearance A between needles and needle holes in the throat plate.

2. When the needle is in the highest dead point, the height from top surface A of the throat plate to the top end of left needle is

8.9 mm.

8.9mm

– 88 –

MF-7724DU10D60

Adjustment Procedure

1. Right and left looper positions

Clearance between looper and the center of right needle (looper return amount) is 3.5 mm. Loosen clamp screw and adjust looper supporting arm to the right and left.

2. Front and rear looper positions

Adjust so that the clearance between blade point of the looper and left medium needle is 0 to 0.05 mm when the top end of looper passes 4 needles from the right extreme point. Turn adjusting screw to adjust the longitudinal position. Turn clockwise to move the looper supporting arm to the rear side and counterclockwise to move it to the front side. After the adjustment, tighten clamp screw to fix the looper.

* The blade point of the looper comes in contact with the right-

hand needle when rear needle guard does not work. So, be careful.

Results of Improper Adjustment

o When the returning amount is

small, loop of needle thread is small and stitch skipping or thread breakage will be caused. In addition, thread tangling will be caused.

Adjustment Procedure

After adjusting the height of needle and the clearance between the needle and the needle hole of throat plate, tighten needle bar bracket setscrew

and attach rubber cap .

– 89 –

Results of Improper Adjustment

oA large difference in needle bar

height will be a cause of stitch skipping, needle breakage, thread breakage, and so on.

8) Adjusting the rear needle guard

MF-7724DU10D60

Standard Adjustment

0 to

0.05mm

0 to 0.05mm

0.1 to 0.2mm

A (0±0.2mm)

9) Adjusting the looper thread cam

Standard Adjustment

Adjust so that thread comes off from the highest place of looper thread cam when needles come down and the top end of left needle aligns with the bottom surface of looper . Then tighten screws to fix the looper thread cam.

Thread

Uniform clearance

– 90 –

MF-7724DU10D60

Adjustment Procedure

Adjust the lateral position of rear needle guard so that it receives the needle within the range of B when the needle is in its lowest position. (1) When the blade point of looper comes to the right end left needle,

adjust the height with setscrew so that the top end of left needle aligns 0±0.2 mm with the edge line A.

(2) Make rear needle guard sightly come in contact with the left needle

so that the clearance between left medium needle and top end of the looper keeps 0 to 0.05 mm when top end of the looper comes to the center of left medium needle at the time of moving of top end of the looper to the left from the extreme right position. Perform the adjustment with setscrews and .

(Caution) After the adjustment, check by manual turning whether

the top end of looper does not come in contact with the needle.

Results of Improper Adjustment

o When the pressing amount of

rear needle guard is small, needle deflection increases and stitch skipping, thread breakage, needle breakage and worn-out of the top end of looper will be caused.

Adjustment Procedure

Loosen setscrews in the looper thread cam and adjust while checking that looper thread comes off from the periphery of the looper thread cam.

(Caution) When setscrews in the looper thread cam are

loosened, looper thread cam moves in the shaft direction as well. Assemble so that the clearances provided between the cam and the thread guide are equal.

Results of Improper Adjustment

o When the position of looper

thread cam slips greatly out of position, stitch skipping or defect of thread tightness on the back of the looper is apt to occur.

– 91 –

10) Installing position of the spreader

MF-7724DU10D60

Standard Adjustment

1. Height of the spreader

It is the standard that the height from the top surface of throat plate to the bottom surface of spreader is 7.9 to 8.4 mm.

7.9 to 8.4mm

2. Longitudinal position of the spreader

It is the standard that when spreader returns from the extreme left position to the right and top end A of thread hooking section reaches to the front of left needle, the clearance between the spreader and the left needle is 0.1 to 0.3 mm.

0.1 to 0.3mm

3. Protruding amount

It is the standard that the dimension from the center of left needle to top end B of thread hooking section, when spreader is in the extreme left position, is 4.5 to 5.5 mm.

4. Spreader stroke

It is the standard that the spreader stroke is 17 to 19 mm at the stroke of thread hooking section.

4.5 to 5.5mm 17 to 19mm

*Except for the adjusting values specified above, refer to the adjusting values for standard adjustments.

– 92 –

MF-7724DU10D60

Adjustment Procedure

1. Adjusting the height of the spreader

To adjust the height of spreader , loosen spreader setscrew

for adjustment.

2. Adjusting the longitudinal position of the spreader

Loosen spreader setscrew to adjust the front and rear positions

of spreader .

Results of Improper Adjustment

o Height of the spreader is improper,

stitch skipping of spreader occurs.

o Adjust the height in accordance

with the needle gauge.

3. Protruding amount of the spreader

Loosen setscrew in the spreader folder and adjust the protruding

amount. Adjust aiming the adjustment figure of 5 mm.

4. Adjusting the spreader stroke

The standard position is located where the notch section of spreader

o Even when the protruding amount

is excessive or insufficient, stitch skipping of spreader will be caused.

o When the protruding amount is

insufficient, it will be the cause for left needle not to scoop covering thread at overlapped section.

o When the stroke is increased,

disorder of covering thread stitching will be caused.

o When the stroke is decreased,

stitch skipping of spreader will be caused.

– 93 –

8. UT31

(1) Installation of SC-500

1. Installing procedure of the synchronizer

UT31

Standard Adjustment

2. Installing procedure of the resistor pack (asm.)

3. Installing procedure of the exclusive cord for MF

– 94 –

UT31

Adjustment Procedure

1. Installing procedure of the synchronizer

(1) Using two setscrews , mount synchronizer fixing plate on the

sewing machine. Then, install synchronizer on it.

(2) Fix a cord of synchronizer to synchronizer fixing plate by

means of cable clip band . Fasten the cord in the illustrated position, using cord clamp and setscrew .

2. Installing procedure of the resistor pack (asm.)

Install resistor pack (asm.) on cylinder installing base with setscrew .

Results of Improper Adjustment

3. Installing procedure of the exclusive cord for MF

Connect the exclusive cords for MF to the respective designated connectors as follows.

• Synchronizer cord → CN33

• Resistor pack asm. → CN32

• Thread trimmer sensor cord → CN42

• Thread trimmer code → CN36

• Presser lifter cord → CN37

– 95 –

(2) Change of the setting

1. Automatic presser lifting

FL ON : Auto-lifter device becomes effective. FL OFF : Auto-liffter function does not work.

(Standard at the time of delivery) (Similarly , the presser foot is not automatically lifted when programmed stitching is completed.)

UT31

Standard Adjustment

1. To perform re-turning ON of the power, be sure to perform after the time of one second or more has passed. (If ON/OFF operation of the power is performed quickly , setting may be not changed over well.)

2. Auto-lifter is not actuated unless this function is properly selected.

3. When “FL ON” is selected without installing the auto-lifter device, starting is momentarily delayed at the start of sewing. Be sure to select “FL OFF” when the auto-lifter is not installed.

2. Ineffective setting of the automatic reverse feed stitching

– 96 –

JUKI MF-7700D Series Engineer's Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

PREFACE

CONTENTS

1. SPECIFICATIONS

2. CONFIGURATION OF THE MACHINE COMPONENTS

3. MODEL NUMBERING SYSTEM

(1) MF-7700D Series

(2) MF-7700D Series Thread trimmer

4. MOTOR PULLEY AND BELT

5. ST ANDARD ADJUSTMENT

(1) Threading the machine head

(2) Adjusting the rocking thread take-up

(3) Adjusting the position of the needle thread guide rod

(4) Adjusting the position of the thread receiver

(5) Adjusting the position of the spreader thread guide and spreader thread take-up

(6) Adjusting the spreader

(7) Adjusting the timing relation between the looper and needle bar

(8) Returning amount of the looper

(9) Height of the needle

(10)Locus and longitudinal motion of the looper

(11) Adjusting the needle guard

(12)Installing cover of the looper and needle guard after adjusting

(13)Adjusting the feed dog

(14)Adjusting the feed relation

(15)Adjusting the presser foot

(16)Adjusting the micro-lifter

(17)Adjusting the looper thread cam

(18)With regard to lubrication

(19)Setting for functions of SC-500

(20) Adjusting and setting SC-510

6. E10/MD10

(1) Specifications (E10)

(2) Specifications (MD10)

(3) Adjusting the needle guard

(4) Adjustment of knife

(5) Presser adjustments

(6) Method of lubrication

(7) Adjustment of the amount of feeding

(8) Adjustments for heavy material sewing

(9) Mounting position of the eccentric cam

7. MF-7724DU10D60 (4 needles)

(1) Specifications

(2) Needle

(3) Standard adjustments

1) Needle mounting

2) Threading the machine head

3) Adjusting the rocking thread take-up

4) Adjusting the position of the needle thread guide rod

5) Adjusting the rocking thread take-up thread receiver

6) Adjusting the looper

7) Adjusting the height of the needle

8) Adjusting the rear needle guard

9) Adjusting the looper thread cam

10) Installing position of the spreader

8. UT31

(1) Installation of SC-500

(2) Change of the setting