JUKI MO-623N User manual

MO-623N
1-Needle, 3-Thread Overlock Sewing Machine
IMPORTANT:
Read all safety regulations carefully and under-stand
them before using your sewing machine. Retain this in-
struction manual for future reference.
INSTRUCTION MANUAL
EN

“IMPORTANT SAFETY INSTRUCTIONS”
When using an electrical appliance, basic safety precautions should always be followed, including
the following: Read all instructions before using this sewing machine.
“DANGER ____ To reduce the risk of electric shock:”
1. The appliance should never be left unattended when plugged in.
2.
Always unplug this appliance from the electric outlet immediately after using and before cleaning.
3. Always unplug before re-lamping. Replace bulb with same type rated 10W(220V).
“WARNING ____ To reduce the risk of burns, re, electric shock, or injury to persons:”
1. Do not use the appliance as a toy. Caution is advised when the appliance is used by children, or
near children. This sewing machine can be used by children aged from 8 years and above and
persons with reduced physical, sensory or mental capabilities or lack of experience and knowl-
edge if they have been given supervision or instruction concerning use of the sewing machine
in a safe way and understand the hazards involved. Children shall not play with the sewing
machine. Cleaning and user maintenance shall not be made by children without supervision.
2. Use this appliance only for its intended use as described in this manual. Use only attachments
recommended by the manufacturer as contained in this manual.
3. Never operate this appliance if it has a damaged cord or plug, if it is not working properly, if it
has been dropped or damaged, or dropped into water. Return the appliance to the nearest au-
thorized dealer or service center for examination, repair, electrical or mechanical adjustment.
4. Never operate the appliance with any air openings blocked. Keep ventilation openings of the
sewing machine and foot control free from the accumulation of lint, dust, and loose cloth.
5.
Keep ngers away from all moving parts. Special care is required around the sewing machine needle.
6. Always use the proper stitch plate. The wrong plate can cause the needle to break.
7. Do not use bent needles.
8. Do not pull or push fabric while stitching. It may deect the needle causing it to break.
9.
Do not carry out sewing with a marking pin stuck in the material since doing so can cause knife/needle
breakage. In addition, do not attempt to cut anything other than fabric and thread with the upper/lower knives.
10. Switch the sewing machine o󰀨 “O” when making any adjustments in the needle area, such as
threading needle, changing needle, threading looper, or changing presser foot and the like.
11. Always unplug the machine from the electrical outlet when removing covers, when covers are
opened to thread the loopers, when lubricating or when making any other user servicing adjust-
ments mentioned in the instruction manual.
12. Never drop or insert any object into any opening.
13. Do not use outdoors.
14.
Do not operate where aerosol (spray) products are being used or where oxygen is being administered.
15. To disconnect, turn all controls to the o󰀨 “O” position, then remove plug from outlet.
16. Do not unplug by pulling on cord. To unplug, grasp the plug, not the cord.
17. Basically, the machine should be disconnected from the electricity supply when not in use.
18. If the supply cord is damaged, it must be replaced by the manufacturer, its service agent or sim-
ilarly qualied persons in order to avoid a hazard.
19. (Except USA/Canada) This machine is provided with double insulation.
Use only identical replacement parts. See instructions for servicing Double-Insulated machine.
“SERVICING DOUBLE-INSULATED PRODUCTS
(Except USA / Canada)”
In a double-insulated product, two systems of insulation are provided instead of grounding. No
grounding means is provided on a double-insulated product nor should a means for grounding be
added to the product. Servicing a double-insulated product requires extreme care and knowledge
of the system and should only be done by qualied service personnel. Replacement parts for a
double-insulated product must be identical to those parts in the product. A double-insulated product
is marked with the words DOUBLE INSULATION or DOUBLE INSULATED.
The symbol may also be marked on the product.
“SAVE THESE INSTRUCTIONS”
“This overlock sewing machine is intended for household use only.”
1

Danger warn-
ing which is not
specied
There is a risk
of electrical
shock
There is a
risk of re
There is a risk
of injury to
hands, etc.
Prohibited mat-
ter which is not
specied
Disassembly/
alteration is
prohibited
Do not place
ngers
under the
needle
Do not pour
oil, etc.
Generally re-
quired behavior
Disconnect
the power
plug
Congratulations on your purchase of a JUKI sewing machine.
Please be sure to read safety precautions in “To use the sewing machine safely” in the Instruction
Manual before use to fully understand the functions and operating procedures of the sewing
machine so as to use the sewing machine for a long time.
After you have read the Instruction Manual, please be sure to keep it together with the warranty so
that you can read it whenever necessary.
To use the sewing machine safely
Marks and pictographs included in the Instruction Manual and shown on the sewing machine are
used so as to ensure safe operation of the sewing machine and to prevent possible risk of injury to
the user and other people.
Warning marks are used for di󰀨erent purposes as described below.
WARNING Indicates that there is a possible risk of death or serious injury if this mark is ignored and the sewing machine
is used in a wrong manner.
CAUTION
Indicates the operation, etc. which can cause a possible risk of personal injury and/or physical damage if this mark
is ignored and the sewing machine is used in a wrong manner.
Pictographs mean the following:
2

● Do not wipe the sewing machine with solvent
such as thinner.
When the sewing
machine is soiled, put a
small quantity of neutral
detergent on a piece of
soft cloth and carefully
wipe o󰀨 the sewing
machine with it.
● Be sure to use the sewing machine in the
temperature range from 5ºC to 40ºC.
If the temperature is excessively low, the
machine can fail to operate normally.
WARNING
For the combination of the material and the thread and needle, in particular, refer to the explanation
table in “Replacement of the needle”.
If the needle or thread does not match the material used such as in the case that an extra heavy-
weight material (e.g., denim) is sewn with a thin needle (#11 or higher), the needle can break result-
ing in an unexpected personal injury.
Other precautions
● Do not put the sewing machine under the
direct sunlight or in a humid place.
Be aware that the following state can take place since the sewing machine incorporates semi-con-
ductor electronic parts and precise electronic circuits.
* The operating temperature of the sewing machine is between 5ºC and 40ºC. Do not use the
sewing machine under the direct sunlight, near the burning things such as a stove and candle, or
in a humid place. By so doing, the temperature in the interior portion of the sewing machine can
rise or the coating of the power cord can melt, causing re or electrical shock.
LED light
・
Rated Voltage: 9V
・
Maximum power consumption: 1.3W
3

Safety instructions ········································1-3
Contents························································4
Details of the machine···································5-6
• Accessories·················································6
Assembling thread stand ··································7
Preparing the machine ·····································8
Operation and function ································ 9-13
Threading ··············································· 14-17
Trial sewing ·················································18
Adjusting the thread tension ····························19
Sewing in tape··············································20
Roll hemming ·········································· 21-22
Thread breakage during sewing ·······················23
Securing seams ············································24
Maintenance ················································25
Trouble shooting guide ···································26
Specications ···············································27
Optional accessories······································28
Contents
4

View with looper cover open
Details of the machine
Details of the machine
CAUTION :
Be sure to turn o󰀨 the power switch before opening
the looper cover.
1. Looper cover
2. Looper cover opening handle
3. Chip guard cover
4. Cloth plate
5. Throat plate
6. Presser foot
7. Lower looper thread tension dial
8. Upper looper thread tension dial
9. Needle thread tension dial
10. Thread take-up cover
11. Thread guide plate
12. Presser foot adjusting screw
13. LED light
14. Power/light switch
15. Handwheel (pulley)
16. Machine socket
17. Spool holder
18. Anti-vibration cone
19. Spool holder pin
20. Retractable support rod
21. Thread guide
22. Open thread guide
23. Presser loot lifter
24. Urethane sheets
1. Upper looper
2. Upper knife
3. Lower knife
4. Overlock width selection knob
5. Lower looper
6. Lower knife setscrew
5

Accessories
View with cloth plate open
Details of the machine
1. Lower knife adjusting knob
2. Stitch length adjusting knob
1. Foot controller
2. Nets
3. Spool caps
4. Tweezers
5. Cleaning brush
6. Looper threader
7. Needles in the needle box
8. Small screwdriver
9. Oiler
10. Accessory bag
11. Dust cover
6

Assembling thread stand
Raise the support rod fully.
Turn the thread stand until it engages the positioning stopper (A)
with a click.
For overlock spools
For large spools
If large industrial spools are used, position the anti-vibration cone
upside down on the spool holder pin, i.e. with the wider edge at the
top.
Notch
For small house-use spools
When using house-use spools, remove the anti-vibration cones.
Place a spool on the spool holder with its notch downward and push
the spool caps on with the rounded outside edge at the bottom.
7

Preparing the machine
Attaching the foot controller
On/O󰀨 of the power/light switch
The power/light switch is conveniently placed on the handwheel
side of the machine in front of the socket.
・ Off (A)
・ On with light (B)
CAUTION :
Be sure to turn OFF the power switch before plugging/un-
plugging the controller.
1. Plug foot controller into machine socket.
2. Plug foot controller into power supply socket.
3. Lay your foot on the foot controller.
Step on the foot controller strongly (deeply), and the sewing
speed increases.
Step on the foot controller lightly (shallowly), and the sewing
speed decreases.
CAUTION :
Perform these following steps when you are not using your sew-
ing machine:
1. Be sure to turn OFF the power switch.
2. Be sure to remove the power plug from the wall outlet.
3. Do not place a thing on the foot controller.
8

Operation and function
CAUTION :
Moving parts - To reduce risk of injury, switch machine off (“O”)
before servicing and when opening looper cover, cloth plate,
close before using.
Handwheel (Pulley)
The handwheel turns toward you.
・ Upon completion of threading, at sewing start or sewing end, be
sure to turn the handwheel toward you.
Opening and closing the looper cover
Opening : To open the looper cover, pull the looper cover opening
handle to the right, and tilt the looper cover toward you.
Closing : To close the looper cover, push up the looper cover,
press it lightly to the right. The looper cover closes auto-
matically.
Opening and closing the cloth plate
Opening : Press the cloth plate toward outside.
Closing : Push the cloth plate toward the sewing machine.
9

Operation and function
Presser foot lifter (To raise the presser foot by the presser foot
lifter)
A : For regular sewing operation (sewing a medium-weight materi-
al), raise the presser foot to position (A) illustrated in the figure.
B : When you sew a heavy-weight material, raise the presser foot
to position (B) illustrated in the figure, to provide more space
between presser foot and throat plate.
Changing the presser foot
Switch the machine o󰀨 (power switch”O”)
WARNING :
When using the extra lift (B), do not run the machine or turn
the handwheel.
1. Raise the presser foot.
2. Turn the handwheel until the needle is fully raised.
3. Press point (C) ilustrated in the figure, and the presser foot
will be released.
4. To release the presser foot, raise the presser foot lifting lever
to its highest position (B). Then you can release the presser
foot easily.
5. To attach the presser foot, place it so that the presser foot
pin (D) comes exactly under the groove in the holder. Lower
the presser foot lifting lever and the presser foot will engage
automatically.
10

Stitch length adjusting knob (to adjust the stitch length)
Stitch length is adjustable within the range from 1 to 4 while sewing.
To adjust the stitch length, turn the stitch length adjusting knob and
move the knob upwards or downwards.
・ For normal overlocking stitches set the stitch length adjusting
knob at 2 to 3.
Releasing the upper knife
Operation and function
1. Turn the handwheel until the upper knife is fully raised. Open
the looper cover.
2. Press the part indicated as (A) in the figure toward the right
until it will go no further.
3. Keep pressing (A) and turn the knob on the right side in the
direction of the arrow.
4. Turn the knob until the knife reaches position (B) .
Switch the machine o󰀨 (power switch”O”)
11

Operation and function
Lower knife adjusting knob (adjusting the lower knife position
for cutting width)
Switch the machine o󰀨 (power switch”O”)
Turn the lower knife adjusting knob by pressing part (A) in the fig-
ure.
Reduce cutting width (knife moves to the left) if the edges of fabrics
curl up
Increase the cutting width (knife moves to the right) if the loops are
too loose
Overlocking width selection knob (For overlocking or roll
hemming)
Turn the handwheel until the needles are fully raised
For overlocking
Push the overlocking width selection knob back so that it aligns with
the rear red marking on the throat plate.
For roll hemming
1. Pull the overlocking width selection knob forward so that it
aligns with the front red marking on the throat plate.
2. Set the lower knife adjusting knob at “1 ~ 2”.
12

Operation and function
Flat side of a needle
Applying the needle attaching hole (A) of
the cleaning brush will help replace the
needle ease.
Changing the needle
Switch the machine o󰀨 (power switch”O”)
1. Turn the handwheel until the needle is fully raised.
2. Before changing the needle, lower or remove the presser
foot.
3. Using a small screwdriver, loosen the needle setscrew and
remove the needle.
4. Insert the needle with the flat side away from you into the
needle clamp, making sure it is inserted as far up as possible.
Tighten the needle clamp setscrew securely.
Types of needle Thickness
Needle used: 130/705H No. 75/11 or 90/1 4
* When you buy the needles for the sewing machine, select the
above type of the needles.
Decrease Increase Presser foot pressure adjusting screw
Pressure of the presser foot has been factory-adjusted properly.
Therefore you do not need to adjust it except when sewing a spe-
cial material.
・To increase the pressure of
the presser foot
: For heavy-weight materials such
as denim, tweed, or hard linen
・To decrease the pressure
of the presser foot
: For light-weight materials such as
georgette, lawn, or tricot
(B): The place where the lower part of control cap aligns with the
upper face of cover.
13

Thread the machine carefully in the correct sequence.
This is important for making beautiful seams.
Preparation
1. Retractable support rod with thread guide must be fully raised.
2. Open the looper cover and cloth plate.
3. Turn the handwheel toward you until the needles are fully raised.
4. Release the upper knife.
Threading sequence
Colored threading illustrations affixed clearly show the threading sequence.
Thread the machine in the following sequence:
Threading aids such as tweezers, needle threader, and looper threader which are provided as accessories will
be very useful in threading work.
Thread guide plate
Slide thread into the two slits to form an S-loop.
Threading
1. Upper looper thread (Blue)
2. Lower looper thread (Red)
3. Needle thread (Green)
Threading the tension dials
To lay the thread correctly between the tension discs, pull the thread
lightly with both hands.
14

Threading (1)
1. Upper looper thread (Blue)
Place the spool on the spool holder pin right under blue marking on
the retractable support rod thread guide.
(1) Bring thread up to the retractable support rod thread guide.
(2,3) Pass the thread through the thread guide plate.
(4) Lay the thread between the thread tension dial discs.
(5,6,7,8,9,10) Thread the thread guides.
(11) Turn the handwheel until the upper looper is fully raised.
Thread upper looper eye.
(12) Pull about 10 cm of the thread out.
Place the thread under the presser foot, and pull the thread
from behind the presser foot.
Use a net for a hard twisted thread.
When a thread coils around the thread guide due to its hard
twist, cover the spools of upper looper and lower looper with
attached nets.
Net
15

Threading (2)
2. Lower looper thread (Red)
Place the spool on the spool holder pin right under red marking on
the retractable support rod thread guide.
(1) Bring the thread up to the retractable support rod thread guide.
(2,3) Pass the thread through the thread guide plate.
(4) Thread the thread tension dial.
(5,6,7,8,9) Thread the thread guides.
(10) Using the looper threader, pass the thread from the right
through to the left of the sewing machine. Turn the handwheel
toward you until the lower looper is in the left-most position.
Insert the thread into the slit on the lower looper.
(11) Using the looper threader, pull the thread through to the right
side again.
Turn the handwheel toward you until the lower looper is in the
right-most position, and thread the looper eye. Pull the thread
up until it lies in the long groove on the lower looper.
(12) Pull about 10 cm of the thread out through the upper looper.
Raise the presser foot, place the thread under it and then
lower the presser foot.
If the lower looper thread is broken or slipped, cut the right-
hand needle thread off at the needle. Then remove the thread.
Thread the looper and then the needle.
16

Threading (3)
3. Needle thread (Green)
Place the spool on the spool holder pin right under the green mark-
ing on the retractable support rod thread guide.
(1) Bring the thread up from the spool to the thread guide the
green thread guide.
(2,3) Thread the thread guide plate.
(4) Thread the thread tension dial.
(5) Thread the thread guide.
(6) Lay the thread in the notch on the thread take-up lever.
(7) Thread the thread guide.
(8,9) Thread the needle thread guides.
(10) Thread the needle. Pull about 10 cm of the thread out from
the needle eye. When threading is completed, lower the upper
knife and close the looper cover and cloth plate.
17

After threading, make a trial sewing.
Be sure to use a double layer of fabric in order to check whether the
seam and thread tension are adequate.
1. Set all of the thread tension dials at “4”.
2. Make sure that the upper knife is lowered (in the cutting posi-
tion).
3. Raise the presser foot.
4. Place the fabric under the presser foot.
5. Lower the presser foot and sew.
6. At the end of the seam, continue sewing to form a 5 to 6 cm long
thread chain.
7. Holding the fabric with one hand, pull the thread chain over the
thread cutter on the presser foot shank.
・ Thread tension dial should be properly adjusted according to
the types of fabrics and threads to be used.
Trial sewing
Thread tension dial
Adjusting the thread tension
Imperfect stitch formation can be corrected by adjusting the set
value (1 to 9) on the thread tension dial.
Types of needle Standard of the thread
tensioner dial
AUpper looper thread tension adjusting dial 3 - 5
BLower looper thread tension adjusting dial 3 - 5
CNeedle thread tension adjusting dial 3 - 5
Turning to the right increases the thread tension.
Turning to the left decreases the thread tension.
When using filament thread or woolly nylon thread, adjust the
thread tension accordingly.
Increase
Decrease
18

Adjusting the thread tension
Adjusting the thread tension
Turn the thread tension dial in the direction of the arrow, and make
a trial sewing.
A - If the upper looper threads meet on the underside of the fabric:
B - If the lower looper thread meet on the upper side of the fabric:
C -If the overlock needle thread forms loops on the underside of the
fabric:
D -The edge of the fabric curls when both upper looper and lower
looper thread tension is too high:
・ Adjustment can be made by setting the lower knife adjusting
knob to the smaller value on the scale.
E - If the fabric puckers during sewing:
19