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CONTENTS
I. SPECIFICATIONS .............................................................................................................1
II. AT THE BEGINNING ........................................................................................................1
III. INSTALLING THE ACCESSORIES ................................................................................2
1. Installing the air regulator ................................................................................................................... 2
2. Installing the manifold ......................................................................................................................... 2
3. Connecting the cords .......................................................................................................................... 3
4. Setting procedure of the machine head ............................................................................................. 4
IV. AIR PIPING DRAWING ...................................................................................................5
1. Piping of the thread trimmer device ................................................................................................... 5
2. Adjusting the air regulator ................................................................................................................... 5
V. THREADING THE MACHINE HEAD ...............................................................................6
VI. ADJUSTING THE LOOPER THREAD TRIMMER MECHANISM ..................................7
1. Initial position of the looper thread trimmer mechanism ................................................................. 7
VII. INSTALLING THE SS LEVER UNIT .............................................................................8
1. Installing the SS lever unit .................................................................................................................. 8
2. Adjusting the SS lever unit .................................................................................................................. 8
VIII. DRAWING OF THE TABLE ..........................................................................................9
IX. SETTING THE UPPER STOP POSITION OF THE NEEDLE BAR .............................10
X. SETTING THE RAVELING PREVENTION PARAMETER ............................................12
i
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I. SPECIFICATIONS
Model name High-speed, cylinder-bed coverstitch machine
Model MF-7900 series
Stitch type ISO standard 406, 407, 602, and 605
Example of application
Sewing speed Max. 6,000 sti/min (at the time of intermittent operation) Direct-drive type
Needle gauge 3-needle ..... 5.6 mm and 6.4 mm
2-needle ..... 4.0 mm and 4.8 mm
Differential feed ratio 1 : 0.9 to 1 : 1.4 (stitch length : less than 2.5 mm) * Only for H23
Stitch length 0.9 mm to 3.6 mm (can be adjusted up to 4.5 mm)
Needle UY128GAS #9S to #14S (standard #10S)
Needle bar stroke 31mm (33 mm when the eccentric pin is changed over)
Dimensions (Height) 450 x (Width) 456 x (Length) 299
Weight 45 kg (With pneumatic type thread trimmer)
Lift of presser foot 8 mm (needle gauge : 5.6 mm without top covering), and 5 mm (with top covering)
Feed adjustment
method
Looper mechanism Spherical rod drive method
Lubricating system Forced lubrication method by gear pump
Lubricating oil JUKI GENUINE OIL 18
Oil reservoir capacity Oil gauge lower line : 600 cc to upper line : 900 cc
Installation Table-mount type, Semi-submerged type
Noise - Equivalent continuous emission sound pressure level (LpA) at the workstation:
Main feed ............... dial type stitch pitch adjustment method
Differential feed ..... lever adjustment method (micro-adjustment mechanism is provided.)
A-weighted value of 79.5 dB; (Includes KpA = 2.5 dB); according to ISO 10821- C.6.2 -ISO 11204 GR2 at 4,500
sti/min.
For preventing thread from raveling at the end of hemming or other processes
Speed of stitch at the delivery: 4,500 sti/min (at the time of intermittent operation)
(1 : 0.6 to 1 :1 .1, when the differential link hinge screw is changed)
Micro-differential feed adjustment mechanism is provided. (Micro-adjustment)
Micro-lifter mechanism is provided.
II. AT THE BEGINNING
❶
Remove xed band ❶ for transportation before setting
up the sewing machine.
– 1 –
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III. INSTALLING THE ACCESSORIES
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.
1. Installing the air regulator
❷
❶
2. Installing the manifold
1) Install air regulator asm. ❶ under the table with
wood screws ❷.
❶
❷
Install manifold asm. ❶ on the table with wood screw
.
❷
– 2 –
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3. Connecting the cords
❶
A
1) Pass cords ❶ and of the thread-trimming solenoid, reverse feed stitching, motor signal etc. and
the motor cord through the hole A in the table to
route them to the underside of the table.
❻
❾
❺
❽
❸
B
❷
2) Loosen screw B in cover ❷ with a screwdriver to
open the cover.
❼
3) Connect 14P code ❸ coming
from the machine head to connector ❻ (CN36).
4) Insert 3P cord ❾ coming from
the machine head into connector (CN42).
5) Insert presser foot lifter cord 2P
into connector ❼ (CN37).
❹
6) Connect connector ❺ coming
from the motor to connector ❽
(CN30) on the circuit board.
❹
7) Insert pedal sensor cable into connector (CN34).
8) Insert motor fan cord into connector .
9) Insert 8P cord to connector (CN56).
Be sure to securely insert the respective connectors after checking the inserting directions since all connectors have the inserting directions. (When using a type with lock, insert the connectors until they go to the
lock.) The sewing machine is not actuated unless the connectors are inserted properly. In addition, not only
the problem of error warning or the like occurs, but also the sewing machine and the control box are damaged.
[Connecting the connector for the operation panel]
– 3 –
The connector for the operation panel is provided.
Paying attention to the orientation of the connector ,
connect it to connector (CN38) located on the circuit
board. After the insertion, securely lock the connectors
to prevent them from coming off easily.
Be sure to turn OFF the power before connecting the connector.