JUKI LU-2828-7, LU-2828-6 Instruction Manual

LU-2828-7, 2828-6

INSTRUCTION MANUAL

CONTENTS

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

2. INSTALLATION .......................................................................................................... 2

2-1. Installation of the sewing machine ................................................................................... 2

2-2. Installing the belt cover and the belt (LU-2828-6) ............................................................ 5

2-3. Adjusting the belt tension (LU-2828-6) ............................................................................. 6

2-4. Installing the synchronizer (LU-2828-6) ............................................................................ 6

2-5. Adjusting the synchronizer (LU-2828-6) ........................................................................... 7

2-6. Installing the oil shield ....................................................................................................... 8

2-7. Pneumatic components ..................................................................................................... 8

2-8. Wiring the machine head (LU-2828-6) ............................................................................. 10

2-9. Installing the thread stand ............................................................................................... 14

2-10. Installing the thread guide pin ....................................................................................... 14

3. PREPARATION OF THE SEWING MACHINE ........................................................ 15

3-1. Lubrication ........................................................................................................................ 15

3-2. Attaching the needle......................................................................................................... 17

3-3. Attaching and removing the bobbin ............................................................................... 17

3-4. Threading the hook .......................................................................................................... 18

3-5. Winding a bobbin .............................................................................................................. 18

3-6. Threading the machine head ........................................................................................... 19

3-7. How to set the model of the machine head (LU-2828-7) ............................................... 20

3-8.

Adjusting the machine head

(LU-2828-7) .......................................................................... 22

4. ADJUSTING THE SEWING MACHINE ................................................................... 24

4-1. Adjusting the stitch length............................................................................................... 24

4-2. Thread tension .................................................................................................................. 25

4-3. Thread take-up spring ...................................................................................................... 26

4-4. Adjusting the pressure of the presser foot .................................................................... 27

4-5. Needle-to-hook relation .................................................................................................... 28

4-6. Adjusting the hook needle guard .................................................................................... 29

4-7. Adjusting the bobbin case opening lever....................................................................... 29

4-8. Adjusting the moving knife, the counter knife and the bobbin thread clamp............. 30

4-9. Adjusting the thread trimming cam timing..................................................................... 32

4-10. Adjusting the condensation stitch ................................................................................ 33

4-11. Adjusting the amount of the alternating vertical movement of the walking foot and

the presser foot ............................................................................................................... 34

5. OPERATION OF THE SEWING MACHINE ............................................................. 34

5-1. Hand lifter .......................................................................................................................... 34

5-2. Resetting the safety clutch .............................................................................................. 34

5-3. Adjusting the automatic presser foot lifter .................................................................... 35

5-4. Fixing the feed adjusting dial .......................................................................................... 36

5-5. Normal-/reverse-feed stitch needle entry points alignment at the time of automatic

reverse feed stitching ..................................................................................................... 37

5-6. Operation switches ........................................................................................................... 38

5-7. Knee switch ....................................................................................................................... 40

5-8. Function setting for the SC-922 (LU-2828-7) .................................................................. 43

6. SEWING SPEED TABLE ......................................................................................... 46

7. TROUBLES IN SEWING AND CORRECTIVE MEASURES ................................... 47

i

1. SPECIFICATIONS

No. Item Application

1 Model LU-2828-7 LU-2828-6

2 Model name 1-needle, unison-feed, lockstitch

machine with automatic thread trimmer

(with 2.7-fold vertical axis hook/needle

thread clamp function/direct drive type)

3 Application Medium- to heavy-weight materials, car seat, furniture

4 Sewing speed Max. 3,000 sti/min

"6. SEWING SPEED TABLE" p.46

(See

5 Needle SCHMETZ 134-35 (Nm 125 to Nm 180) (Standard : Nm 140)

6 Applicable thread size for sewing #30 to #5

7 Applicable thread size to be cut #30 to #5

8 Stitch length Max. 9 mm (forward/reverse feed)

9 Stitch length dial 2-pitch dial

10 Presser foot lift Hand lifter : 10 mm

Automatic presser foot lifter : 20 mm

11 Stitch length adjusting

mechanism

12 Reverse stitch adjusting method Air cylinder type (with touch-back switch)

13 Thread take-up Link thread take-up

14 Needle bar stroke 40 mm

By dial

1-needle, unison-feed, lockstitch

machine with automatic thread trimmer

(with 2.7-fold vertical axis hook/needle

thread clamp function/V belt type)

*1

.)

15 Amount of the alternate vertical

movement

16 Hook Full-rotary vertical-axis 2.7-fold hook (Latch type)

17 Feed mechanism Box feed

18 Top and bottom feed actuation

mechanism

19 Thread trimming method Cam-driven scissors type

20 Lubrication Automatic lubrication by oil tank (with oil gauge)

21 Lubricating oil JUKI New Defrix Oil No. 1 (equivalent to ISO standard VG7)

22 Bed size 643 mm × 178 mm

23 Space under the arm 347 mm × 127 mm

24 Hand wheel size Outer diameter : ø123 mm

25 Motor/Control box SC-922B -

26 Machine head weight 62 kg

27 Rated power consumption 180VA

28 Noise

*2

- Equivalent continuous emission sound pressure level (LpA) at the workstation:
A-weighted value of 81.0 dB; (Includes KpA = 2.5 dB); according to ISO

1 mm to 9 mm (Alternate vertical dial adjustment type)

Timing belt

or JUKI MACHINE OIL No. 7

10821- C.6.2 - ISO 11204 GR2 at 3,000 sti/min.

- Sound power level (LWA);
A-weighted value of 85.5 dB; (Includes KWA = 2.5 dB); according to ISO
10821- C.6.2 - ISO 3744 GR2 at 3,000 sti/min.

*1 The speed setting according to the amount of the alternating vertical movement of the walking foot and presser

foot is automatically carried out.

*2 The noise level show in the table is the level generated in the case JUKI's control box (SC-922) is used.

– 1 –

2. INSTALLATION

2-1. Installation of the sewing machine

1) Carry the sewing machine with two persons.

Do not hold the pulley and the reverse feed
lever.

2) Do not put protruding articles such as the

screwdriver and the like at the location where

the sewing machine is placed.

❸

❷

Sheet B

Sheet C

❹

❶

Sheet A

❸

3) Attaching the hinge seats and the support rub-

bers of the machine head

Place sheets A and B (standard: three pieces)

and C (standard: one piece) between hinge seat

and machine head support rubbers ❷ and ❸.

❶

Then, x them on the table with nail ❹.

There are two different machine head support

rubbers ❸; i.e., the rubber for the right and that

for the left. Be sure to check the types of the

support rubbers before xing them.

Sheets A and B (eight pieces each) and
sheets C (four pieces) are supplied with the
machine as accessories.
For the sheets A and B, three sheets are
to be used as standard for each mounting
position. For the sheet C, one sheet is to be
used as standard. (The state shown in the

left gure)

The sheets A, B and C are used for adjust­ing the height of the top surface of the bed.
Use one more sheet to increase the height,
or use only one sheet to decrease it.

– 2 –

Operator’s side

❺

Align

Table

Align

4) Attaching the oil pan

Fix the oil pan ❺ supplied with the machine on

the table by tightening ten wood screws.

Top surface

Multi-layered part

❻

5) Attach a lter ❻ to the oil pan ❺ as shown in

the gure.

Install lter ❻ so that its multi-layered part is

brought to the right side as observed from you.

❼

❺

6) Install hinge ❼ on the bed with screw ❽.

Engage the hinge with the rubber hinge of the

table. Then, place the machine head on the

machine head support rubber.

❽

– 3 –

❾

󱢷

❺

7) Securely attach head support rod ❾ until its rib

is closely pressed against the table.

8) Put reux pipe 󱢳 in the oil reservoir A of oil

pan ❺. Secure the pipe in groove 󱢴.

9) Fix lter 󱢵 and lter clamp 󱢶 with tting 󱢷.

󱢶

󱢻

󱢳

󱢴

󱢼

󱢽

󱢺

󱢹

󱢸

A

󱢵

10) Mount spacers 󱢸 supplied with the machine

head on the frame.

11) Install bracket 󱢺 on CP panel 󱢹 with screws 󱢻

supplied with the panel.

12) Install bracket 󱢺 on spacer 󱢸 with screws 󱢼

supplied with the machine head and washers

󱢽

supplied with the panel.

Do not use the screws supplied the panel
instead of screws 󱢼 supplied with the ma­chine head.

– 4 –

2-2. Installing the belt cover and the belt (LU-2828-6)

WARNING :

To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.

(Installation procedure)

❶

❺

V-belt

1) Remove belt cover A ❶.

2) Pass the 14P connector which puts cables

together and the air tube through the slotted

hole in the table.

3) Put the V-belt on the sewing machine pulley.

4) Adjust the belt tension.

5) Pass synchronizer support shaft ❷ and washer

through mounting hole in belt cover A ❶ and

❸

x the synchronizer support shaft with washer

and nut ❹.

❸

6) Mount belt cover A ❶.

7) Install belt cover B ❺ on the table.

Be sure to use the sewing machine with

safety devices ❶ and ❺ installed.

Slotted hole in
the table

❶

❸

❷

❸

❶

❹

– 5 –

2-3. Adjusting the belt tension (LU-2828-6)

WARNING :

To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.

15mm

9.8N

Handwheel

Motor pulley

2-4. Installing the synchronizer (LU-2828-6)

Adjust the belt tension with the height of the motor

so that the belt sags 15 mm when the center of V

belt is applied with a 9.8 N load.

WARNING :

To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.

(Installation procedure)

1) Fix synchronizer ange ❶ on the end of the

Synchronizer

❶

main shaft.

2) Fix the synchronizer on synchronizer ange ❶.

3) Fix synchronizer support plate ❷ with setscrew

so as to prevent the synchronizer from

❸

rotating.

Be sure to remove the connector for the
sewing machine for the sake of safety
before checking the upper and lower
positions of the synchronizer.

❷

❸

– 6 –

2-5. Adjusting the synchronizer (LU-2828-6)

WARNING :

To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.

C

Marker line

Marker dot

Adjust the upper stop position (needle-up stop posi-

tion) so that the marker line on belt cover A ❷ aligns

with the marker dot (one) on handwheel ❶(70 °po-

sition).

Adjust the lower stop position (needle-down stop

position) so that the needle bar stops at the position

where the needle bar goes up from the lower dead

point (180 °) by approximately 13 mm (120 °posi-

tion). (The position which is reached by turning the

handwheel from the lower end of the needle bar in

the reverse direction of rotation of the main shaft (di-

rection C))

❷

Marker dot on the handwheel

Upper stop position
(one marker dot)
70 °

❶

Thread trimming
cam alignment
(two marker dots)
275 °

Opener timing adjustment
(three marker dots)
314 °

– 7 –

2-6. Installing the oil shield

WARNING :

To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.

❶

❷

2-7. Pneumatic components

WARNING :

To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.

❺

❷

❸

❼

❻

❷

❾

❽

Install oil shield ❶, supplied with the unit, on the

frame with screws ❷.

(1) Installing the regulator

1) Install regulator (asm.) ❶ on mounting plate

with screw ❷, spring washer ❸ and nut ❹

❺

which are supplied with the unit.

2) Install couplings ❻ and ❼ on regulator ❶.

3) Install mounting plate ❺ on the underside of the

table.

4) Connect ø6 air tube ❽ and ø4 air tube ❾ com-

ing from the sewing machine to coupling ❻.

❶

Decrease Increase

❹

❶

A

❷

(2) Adjusting the air pressure

1) The operating air pressure is 0.5 to 0.55 MPa.

Adjust the air pressure using air pressure

regulating knob ❶ of the lter regulator.

2) In the case uid accumulation is observed in A

section of the lter regulator, turn drain cock ❷

to drain the uid.

– 8 –

❸

(3) Installing the solenoid valve mounting

plate (LU-2828-6)

Install solenoid valve mounting plate asm. ❶ to

the undersurface of the table with screw ❷ and

washer ❸ supplied with the unit.

❷

❶

8 air tube

ø

Solenoid
valve
cable

6 air tube

ø

A

B

❷

❺

❸

❹

❷

❶

(4) Connecting the air tube and the solenoid

valve cable (LU-2828-6)

Connect the air tubes and the solenoid valve

cable to the locations shown below.

Solenoid valve Tube number Cable number

❶

❷

❸

❹- A

❹- B

❺- A

❺- B

4 CN151

8 CN152

6 CN153

10

CN154

9

2

CN155

1

(5) Exhaust tube

Pass ø8 exhaust air tube ❶ through hole ❷ in

the table stand and other relevant hole. Then,

route the air tube downward. If the humidity is

high, water may come out of the air tube.

❶

– 9 –

2-8. Wiring the machine head (LU-2828-6)

WARNING :

Junction cord preparation and wiring to the control box must be carried out by an electrical engineer

without exceptions. Be sure to turn off the power to the sewing machine and wait for ve minutes before

starting the wiring work.
If the pin numbers of the connectors are not correctly connected, errors and breakage of parts and con­trol box can result. Carefully connect the machine-head connectors and the control-box connectors.

(1) Wiring diagram

Details of the connectors wired to the machine head are as described below.
Refer to

out of the pins.

"(2) Details of connectors"

Thread clamp solenoid

Tension release solenoid (upper side)

Tension release solenoid (lower side)

Reverse feed switch

6-gang switch

Alternate up/down limit switch

on the next page for details of connectors ① to ⑤,

-1: CN37A / 2P connector

⑤

Thread clamp solenoid junction cord

-1

and lay-

⑤

: CN158 / 4P connector

①

Alternate up/down limit switch

(lower side)

Alternate up/down limit switch

(upper side)

: CN37 / 2P connector

⑤

Thread clamp solenoid

: CN36 / 14P connector

②

Tension release solenoid (lower side)
Tension release solenoid (upper side)
Thread trimming solenoid
Reverse feed switch
FG (earth cord)
Knee switch

Thread trimming solenoid

Presser bar lifting cylinder solenoid valve: CN151

Reverse feed cylinder solenoid valve: CN152

Alternate up/down cylinder solenoid valve: CN153

Condensation stitch cylinder solenoid valve: CN154

2-pitch cylinder solenoid valve: CN155

2.5-pitch cylinder solenoid valve: CN156

FG (earth cord)

Knee switch

: CN144 / 16P connector

③

6-gang switch

: CN102 / 12P connector

④

Solenoid valve

– 10 –

(2) Details of connectors

This clause explains details of connectors ① to ⑤,

gram. Identify the connector pin number as described below.

Connector

The numeric character indicated
on the connector, as viewed
from the direction of the arrow,
is the connector pin number.

CN158: 4P connector (alternate up/down switch)

①

-1

and layout of the pins shown in the wiring dia-

⑤

10 9 7 6

5 4 3 2 1

You may nd the numeric characters indicat-

ed on the connector when viewing from the

direction of the arrow.

4 3

2 1

Pin No. Part name Color of cable Remarks

1 Alternate up/down limit switch (lower side) White

2 Alternate up/down limit switch (upper side) Red

3 Alternate up/down limit switch (lower side) Black GND

4 Alternate up/down limit switch (upper side) Green GND

* When connecting the connectors to the control box, prepare a junction cord using the below-stated connector pin terminal.
Part number of the target connector: HK034620040 (MOLEX: 5559-04P)
Part number of the target pin terminal: HK034630000 (MOLEX: 5558TL)

– 11 –

CN36: 14P connector (solenoid, switch)

②

9 811 101214 13

2 14 357 6

Pin No. Part name Color of cable Remarks

1 Tension release solenoid (lower side) Black

2 Tension release solenoid (upper side) Black

3

4 Knee switch White

5 Reverse feed switch Black

6

7 Thread trimming solenoid Black

8 Tension release solenoid (lower side) White Power supply (+27 V)

9 Tension release solenoid (upper side) White Power supply (+27 V)

10 FG (earth cord) Green / Yellow FG

11 Knee switch Black GND

12 Reverse feed switch White GND

13

14 Thread trimming solenoid White Power supply (+27 V)

－ － －

－ － －

－ － －

* When connecting the connectors to the control box, prepare a junction cord using the below-stated connector pin terminal.
Part number of the target connector: HK034620140 (MOLEX: 5559-14P)
Part number of the target pin terminal: HK034630000 (MOLEX: 5558TL)

CN144: 16P connector (6-gang switch)

③

16

8

Pin No. Part name Color of cable Remarks

1 6-gang switch Orange (red dot 1)

2 6-gang switch Orange (black dot 1) SW1 (DLSW)

3 6-gang switch Gray (red dot 1) SW2 (Automatic reverse feed prohibition switch)

4 6-gang switch Gray (black dot 1) SW3 (One-stitch correction switch)

5 6-gang switch White (red dot 1) SW4 (Pitch changeover switch)

6 6-gang switch White (black dot 1) SW5 (Thread tension changeover switch)

7 6-gang switch Yellow (red dot 1) SW6 (Thread clamp switch)

8 6-gang switch Yellow (black dot 1) GND

9 6-gang switch Pink (red dot 1) LED1 (DLSW LED)

10 6-gang switch Pink (black dot 1) LED2 (Automatic reverse feed prohibition switch LED)

11 6-gang switch Orange (red dot 2) LED3 (One-stitch correction switch LED)

12 6-gang switch Orange (black dot 2) LED4 (Pitch changeover switch LED)

13 6-gang switch Gray (red dot 2) LED5 (Thread tension changeover switch LED)

14 6-gang switch Gray (black dot 2) LED6 (Thread clamp switch LED)

15 6-gang switch White (red dot 2) SW7 (Machine head fall sensor)

16

－ － －

10 912 111315 14

2 14 357 6

+5V * Do not connect the +24V connector. If the +24V

connector is connected to this switch, the LED
burnout can occur.

* When connecting the connectors to the control box, prepare a junction cord using the below-stated connector pin terminal.
Part number of the target connector: HK034620160 (MOLEX: 5559-16P)
Part number of the target pin terminal: HK034630000 (MOLEX: 5558TL)

– 12 –

CN102: 12P connector (Solenoid valve)

④

8 710 91112

2 14 356

Pin No. Part name Color of cable Remarks

1 Solenoid valve (CN151) Black Presser bar lifting cylinder

2 Solenoid valve (CN152) Black Reverse feed cylinder

3 Solenoid valve (CN153) Black Alternate up/down cylinder

4 Solenoid valve (CN154) Black Condensation stitch cylinder

5 Solenoid valve (CN155) Black 2-pitch cylinder

6 Solenoid valve (CN156) Black 2.5-pitch cylinder

7 Solenoid valve (CN151) Red +24V

8 Solenoid valve (CN152) Red +24V

9 Solenoid valve (CN153) Red +24V

10 Solenoid valve (CN154) Red +24V

11 Solenoid valve (CN155) Red +24V

12 Solenoid valve (CN156) Red +24V

* When connecting the connectors to the control box, prepare a junction cord using the below-stated connector pin terminal.
Part number of the target connector: HK034620120 (MOLEX: 5559-12P)
Part number of the target pin terminal: HK034630000 (MOLEX: 5558TL)

CN37: 2P connector (Thread clamp solenoid)

⑤

2

1

Pin No. Part name Color of cable Remarks

1 Thread clamp solenoid Blue

2 Thread clamp solenoid Blue Power supply (+27 V)

* When connecting the connectors to the control box, prepare a junction cord using the below-stated connector pin terminal.
Part number of the target connector: HK034620020 (MOLEX: 5559-02P)
Part number of the target pin terminal: HK034630000 (MOLEX: 5558TL)

-1 CN37A: 2P connector (Thread clamp solenoid junction cord)

⑤

Pin No. Part name Color of cable Remarks

1 Thread clamp solenoid Blue

2 Thread clamp solenoid Blue Power supply (+27 V)

* Thread clamp solenoid junction cord is shipped with assembled in the machine head.

– 13 –

2-9. Installing the thread stand

Assemble the thread stand, set it up on the machine

table using the installation hole in the table and tight-

en nut ❶ gently.

2-10. Installing the thread guide pin

❷

❶

❶

Insert needle thread guide pin ❶ into the corre-

sponding hole in top cover ❷.

– 14 –