JUKI MF-7500 Series User manual

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ENGLISH
INSTRUCTION MANUAL
MF-7500

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CONTENTS
Ⅰ. SPECIFICATIONS .........................................................................................................1
Ⅱ. CONFIGURATION OF THE MACHINE COMPONENTS ..............................................2
Ⅲ.
INSTALLATION......................................................................................................................3
1. Installing the machine head onto the table................................................................................ 3
2.Selecting the motor pulley and the belt....................................................................................... 7
3.Installing the motor ....................................................................................................................... 7
4.Setting the belt............................................................................................................................... 7
5.Installing the belt cover................................................................................................................. 8
6.Installing the chain ........................................................................................................................ 8
7.Installing the thread guide............................................................................................................ 8
8.Installing the needle bar thread take-up cover ........................................................................... 9
Ⅳ. LUBRICATION AND OILING ........................................................................................9
1.Lubricating oil................................................................................................................................ 9
2.Oiling............................................................................................................................................. 10
3.Silicon oil lubricating unit........................................................................................................... 10
Ⅴ. OPERATION................................................................................................................11
1.Needle........................................................................................................................................... 11
2.Attaching the needle ................................................................................................................... 11
3.Threading the machine head...................................................................................................... 12
4.Adjusting the stitch length ......................................................................................................... 13
5.Adjusting the differential feed ratio ........................................................................................... 13
6. Adjusting the presser foot pressure ..................................................................................................14
7.Adjusting the thread tension...................................................................................................... 14
Ⅵ.
ADJUSTING THE SEWING MACHINE......................................................................................15
1.Adjusting the silicon container thread guide............................................................................ 15
2.Adjusting the needle bar thread take-up thread receiver ........................................................ 15
3.Adjusting the rocking thread take-up........................................................................................ 16
4.Adjusting the spreader thread guide......................................................................................... 16
5.Adjusting the looper thread cam................................................................................................ 16
6.Adjusting the looper thread cam eyelet .................................................................................... 17
7.Adjusting the looper.................................................................................................................... 17
8.Adjusting the height of the needle............................................................................................. 18
9.Adjusting the rear needle guard................................................................................................. 18
10.Relation between the rocking thread take-up timing and the needle thread loop ................ 19
(1) Adjustment by means of the crank ............................................................................................. 19
(2) Adjustment by the eccentric cam................................................................................................ 19
11.Adjusting the height of the feed dog ......................................................................................... 20
12.Installing position of the spreader............................................................................................. 20
13.Adjusting the spreader thread guide and the needle clamp thread guide............................. 21
14.Adjusting the front needle guard............................................................................................... 21
15.
Adjusting the presser foot lift ......................................................................................................22
16.Adjusting the micro-lifter............................................................................................................ 22
17.Adjusting the feed locus............................................................................................................. 23
(1) Changing the feed driving movement......................................................................................... 23
(2) Changing the feed rock movement ............................................................................................ 24
(3) Restoring to the standard adjustment ........................................................................................ 24
18.Adjustment value of balloon ...................................................................................................... 25
19. Adjustment of the feed dog in longitudinal direction ............................................................. 27
(1) Longitudinal position of the feed dog.......................................................................................... 27
(2) For C11....................................................................................................................................... 28
Ⅶ.
MAINTENANCE ...................................................................................................................29
1. Cleaning the sewing machine ................................................................................................... 29
2. Replacing the lubricating oil...................................................................................................... 29
3. Inspecing and replacing the oil lter ........................................................................................ 29

– 1 –– 1 –‒ 1 ‒
Model name High-speed, at-bed coverstitch machine
Model MF-7500 series
Stitch type ISO standard 406, 407, 602, and 605
Example of application Hemming and covering for knits and general knitted fabrics
Sewing speed Max. 6,500 sti/min (at the time of intermittent operation) V-belt type
6,000 sti/min (at the time of intermittent operation) Direct-drive type
Factory-set sewing speed at the time of shipment.
4,500 sti/min (at the time of intermittent operation)
Needle gauge 3-needle ... 4.8 mm, 5.6 mm, and 6.4 mm
2-needle ... 3.2 mm and 4.0 mm
Differential feed ratio 1 : 0.7 to 1 : 2 (stitch length : less than 2.5 mm)
Micro-differential feed adjustment mechanism is provided. (Micro-adjustment)
Stitch length 1.2 mm to 3.6 mm (can be adjusted up to 4.4 mm)
Needle UY128GAS #9S to #12S (standard #10S)
Needle bar stroke 31mm (or 33 mm when changing over the eccentric pin)
Dimensions (Height) 451 x (Width) 515 x (Length) 263
Weight 46kg
Lift of presser foot 8 mm (needle gauge : 5.6 mm without top covering), and 5 mm (with top covering)
Micro-lifter mechanism is provided.
Feed adjustment method Main feed ... dial type stitch pitch adjustment method
Differential feed ... lever adjustment method (micro-adjustment mechanism is provided.)
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 Semi-submerged type
Noise
- Equivalent continuous emission sound pressure level (LpA) at the workstation :
A-weighted value of 76.5 dB; (Includes KpA = 2.5 dB); according to ISO 10821- C.6.2 -ISO 11204
GR2 at 4,500 sti/min.
󰴸. SPECIFICATIONS

– 2 –– 2 –‒ 2 ‒
󰴹. CONFIGURATION OF THE MACHINE COMPONENTS
󰿿Presser spring regulator 󱢵Eye guard cover
󱀀Needle bar thread take-up cover 󱢶Throat plate
󱀁Oil circulation inspection windows 󱢷Needle tip silicon oil lubricating unit
󱀂Oil hole cap 󱢸Differential lock nut
󱀃Micro-lifter 󱢹Micro-adjustment knob
󱀄Needle thread silicon oil lubricating unit 󱢺Finger guard
󱀅Thread guide No. 1 󱢻Rocking thread take-up
󱀆Upper pulley 󱢼Front cover
󱀇Thread tension nut 󱢽Needle bar thread take-up thread receiver
󱢳Oil gauge 󱢾Silicon container thread guide
󱢴Feed regulating knob 󱢿Belt cover
󰿿
󱀀
󱀁󱀂
󱀃
󱀄󱀅
󱀆
󱀇
󱢳
󱢴
󱢵
󱢶
󱢷
󱢺
󱢻
󱢿
󱢼
󱢾
󱢽
󱢹
󱢸

– 3 –– 3 –‒ 3 ‒
[For the V-belt type]
Attach the supporting board and the rubber seats as shown
in the illustration and properly install the sewing machine.
󰿿 Bolt
󱀀 Spacer
󱀁 Washer
󱀂 Spring washer
󱀃 Nut
󱀄 Supporting board
󱀅 Spring pin
󱀆 Rubber cushion (Black) × 3
󱀇 Rubber cushion (Gray) × 1
1. Installing the machine head onto the table
Semi-submerged type
WARNING :
Do not insert the power plug of the motor into the receptacle until all works have been completed. There
is a danger of injury by being caught in the machine.
WARNING :
The weight of the sewing machine is more than 46 kg. Be sure to perform the work with two persons or
more in case of unpacking, transportation or installation.
󰴺.
INSTALLATION
[For the direct-drive type]
Attach the supporting board and the rubber seats as shown
in the illustration and properly install the sewing machine.
󰿿 Bolt
󱀀 Spacer
󱀁 Washer
󱀂 Spring washer
󱀃 Nut
󱀄 Supporting board
󱀅 Spring pin
󱀆 Rubber cushion (Black) × 2
󱀇 Rubber cushion (Gray) × 2
󰿿
󱀀
󱀁
󱀂
󱀃
󱀄
󱀅
󱀆
󱀇
󰿿
󱀀
󱀁
󱀂
󱀃
󱀄
󱀅
󱀇
󱀆
Semi-submerged type

– 4 –– 4 –‒ 4 ‒
Part No. Part name Q'ty
󰿿40072505 Dust-proof rubber (Gray) 1
󱀀13155403 Dust-proof rubber (Black) 3
■Installing the rubber cushion
Install the gray dust-proof rubber to section A only.
[For the V-belt type]
Part No. Part name Q'ty
󰿿40072505 Dust-proof rubber (Gray) 2
󱀀13155403 Dust-proof rubber (Black) 2
[For the direct-drive type]
󰿿

󱀀
󱀀
󱀀
󰿿

– 5 –– 5 –‒ 5 ‒
DRAWING OF TABLE (SEMI-SUBMERGED TYPE) For the V-belt type
󱤨
4x ø 3.4 on the bottom surface, depth 20
(Drill a hole at the time of set-up.) 󱤩4x10.5 hole, depth 26, spot facing depth 3.5 󱤪2x ø 3.4 on the bottom surface, depth 10 (Drill a hole at the time of set-up.) 󱤫Drilled hole 17 󱤬Installing position of drawer stopper (on the reverse side)
Z-Z(4 locations)
Y-Y(3 locations)X-X
󱤨
󱤩
󱤪
󱤫
󱤬

– 6 –– 6 –‒ 6 ‒
DRAWING OF TABLE (SEMI-SUBMERGED TYPE) For the direct-drive type
󱤨
4 x ø 3.4 on the bottom surface, depth 20
(Drill a hole at the time of set-up.) 󱤩4 x10.5 hole, depth 26, spot facing depth 3.5 󱤪2 x ø 3.4 on the bottom surface, depth 10 (Drill a hole at the time of set-up.) 󱤫Drilled hole 17 󱤬Installing position of drawer stopper (on the reverse side)
Z-Z(4 locations)
󱤩
󱤪
󱤫
󱤨
󱤬

– 7 –– 7 –‒ 7 ‒
2. Selecting the motor pulley and the belt
* The table shows the numbers when a 3-phase
2-pole 400 W clutch motor (1 / 2 HP) is used.
* 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.
Use a motor pulley which is adaptable to
this sewing machine. The sewing speed
exceeds the max. sewing speed of this
sewing machine and machine trouble will
be caused unless a motor pulley which is
adaptable to this sewing machine is used.
When you use a new sewing machine, use
the machine at a speed of 4,500 sti/min or
less for the rst 200 hours (approximately
one month). A good result can be obtained
in terms of the durability.
Motor pulley and belt
Speed of
stitch
(sti/min)
50Hz 60Hz
Pulley size Belt size Pulley size Belt size
4,500 ø 100 M-35 ø 85 M-35
4,800 ø 105 M-36 ø 90 M-35
5,000 ø 115 M-36 ø 95 M-35
5,500 ø 125 M-37 ø 105 M-36
5,800 ø 130 M-37 ø 110 M-36
6,000 ø 135 M-37 ø 115 M-37
6,200 ø 140 M-38 ø 120 M-38
6,500 ø 150 M-39 ø 125 M-38
3. Installing the motor
Motor pulley
5.5
mm
10 mm
M type V belt
Use a clutch motor of 3-phase, 2-pole, 400 W (1/2HP).
Use the M type V belt.
1) The motor pulley shifts to the left-hand side when de-
pressing the pedal. At this time, install the motor so
that the centers of motor pulley and lower pulley align
with each other.
* For the installing procedure of the motor pulley, refer to
the Instruction Manual for motor.
Lower pulley
2) Install the motor so that the pulley rotates clockwise.
If the machine pulley rotates in the reverse
direction, nomal lubrication cannot be per-
formed. As a result, machine trouble will
be caused.
4. Setting the belt
WARNING :
When replacing the belt, be sure to turn OFF the power to the motor and ascertain that the motor has
totally stopped rotating before starting the work. There is a danger of injury since hands or clothes may
be caught in the belt.
1) Fit belt 󰿿 to lower pulley 󱀀.
2) Turning upper pulley 󱀁, set the other side of the belt to
motor pulley 󱀂.
3) Adjust the belt tension so that the belt sags 15 to 20
mm when the center of the belt is pressed with an ap-
proximate 10N (1.02 kgf) load.
4) Securely x the belt with lock nut 󱀃 when the belt has
been set.
󰿿
󱀁
󱀂
󱀃
󱀀
15 - 20 mm
If the deection of the belt is excessive
when the sewing machine is operated,
check again the belt tension.
40˚

– 8 –– 8 –‒ 8 ‒
Install belt cover 󱀁 as shown in the illustration.
󰿿and 󱀀 are the xing screws for belt cover 󱀁.
5. Installing the belt cover
WARNING :
Be sure to install the belt cover. If it is not installed, there is a danger of injury since hands or clothes may be caught
in the machine or a danger of damage of the machine since sewing products may be caught in the machine.
1) Hang hook 󱀀 of chain 󰿿 to presser bar lifting lever 󱀁.
2) Hook the other side of the chain 󰿿 to the pedal.
1) Install thread guide No. 1 󰿿 supplied as accessories
on the machine arm with screws (black, screw shank
length 6 mm) 󱀀.
2) Install thread guide 󱀁 on thread guide No. 1 󰿿 with
screw (black, screw shank length 6 mm) 󱀂.
7. Installing the thread guide
󱀁
󱀀
󰿿
󰿿
󱀀
󱀂
󱀁
6. Installing the chain
󰿿
󱀀
󱀁