TABLE OF CONTENTS
PAGE
I.
PURPOSE OF GUIDE
LS - 1II.
FACTORIES PRODUCT SAFETY TASK FORCE
COORDINATOR GUIDE & PROCEDURES
LOCKSTITCH BUTTONING MACHINES OPERATING & CONTROL PROCEDURES
1. Button Attachment Control Procedures and LS - 2 ~ 4 Maintenance Program
2. Cause and Corrective Action For Buttoning LS – 5 ~ 6 Problems
3. Lockstitch Button Sewing Machine Suppliers LS – 7 ~ 9
4. Button Attachment Statistical Process Control LS - 10 Procedure
III. FORMS (to be completed by Field QA & Product Safety Officers) :
1. Buttons Attachment Strength Test LS – 11 ~ 12 (Pre-production Control)
a) Blank Form LS – 12a
b) Sample LS – 12b
2. Lockstitch Button Attachment Capacity and SOP Check LS - 13
a) Blank Form LS – 13a
b) Sample LS – 13b
3. Check Record of Even Attachment Tension for Bobbin LS - 14 Thread
I. Purpose of Guide
The purpose of the Lockstitch Buttoning Machines Operating & Control
Procedures is to ensure that sewn-on buttons on each garment will last a
life time. It completely provide guides to ensure all the buttons are
securely attached on the garments and avoid buttons falling off. It does
provide control measure in helping the factory understand the proper
maintenance program.
The Guide also consists of the following sections :
a) Button Attachment Control Procedures & Maintenance Program
b) Cause & Corrective Action for Buttoning Problems
c) Lockstitch Button Sewing Machine Suppliers
II.
FACTORIES PRODUCT SAFETY TASK FORCE
COORDINATOR GUIDE & PROCEDURE
LOCKSTITCH BUTTONING MACHINES OPERATING &
CONTROL PROCEDURES
1. Button Attachment Control Procedures and Maintenance Program
Buttons
All buttons must meet the following minimum performance requirements:
Two Hole Two or Four Hole Two or Four Hole
Ligne Size <14 14-21 > 22
Minimum Thickness
1.65mm/0.065in. 1.65mm/0.0625in 2.0mm/0.0750in.
Center/Breaking Strength
7.7 kg / 17lbs. 7.7kg / 17 lbs. 10 kg / 22 lbs.
Machine
Vendor must clean button attachment machines on a daily basis to avoid any fluff, which could snag the thread and cause missing stitches/passes.
Bobbin
Vendor must clean bobbin area on machine to remove fluff and dirt twice a day (4 hourly) :
• During lunch break
• Before a shift change or before a worker finishes work for the day
Needle Size
The correct needle size must be used. Needle size prefer #11 to #16 is the best for button attachment.
Needle size selection is also a key point to note and in recommending a particular needle size to be used, the vendor need to take into consideration the garment construction, fabrication, and number of ply being used to apply to the garment.
Condition of Needle
A faulty needle is one of the primary causes of button attachment defects. A faulty needle must be replaced before production can be allowed to continue. Examples of faulty needles are:
a) No bent needle b) No tipped needle
Operator need to change the buttoning needle at least twice a day, to Ensure the needle is in good condition.
Faulty Needle Check
An operator can check whether a needle is bent or tipped by rolling it on an even smooth surface. If a needle will not roll smoothly on the surface, it is defective and must be changed immediately before production continues.
Thread Tension
Thread tension must be adjusted in a right position. a) not too loosen
b) not too tighten
Thread tension must be properly adjusted as it may cause missing stitches (i.e. 2 holes instead of 4 holes).
Note : Always adjust bobbin thread tension first.
No sewing operator is allowed to do any adjusting on the machine. All adjustment must be made by the mechanic or technician.
Button Attachment
• All buttons must be attached using a lockstitch buttoning machine.
• Button must in a complete stitch pattern.
• 100% check of complete stitch pattern for baby and kids.
• Only polyester or polyester/cotton wrap threads are to be used. 100% cotton thread should be used for current dye programs only, when buttons are attached prior to dyeing.
• All buttons must withstand a direct pull force of 17 lbs. for 10 seconds.
• Lockstitch buttoning characterized by 2 “Rabbit Ears” and Knot on back side, prefer 1/4” thread length and must not be trimmed off.
Missing Stitches/ Security & Tension Check
On the machine, the thread remaining on the needle must not be too short, the minimum length being at least 3” long. This will prevent the thread from slipping out of the needle eyelet at the start of sewing or sewing from the middle of the predetermined stitches.
Note : The above reason is the cause for missing or skipped stitches on one side of a button.
To overcome the problem of skipped or missed stitches and evenness of thread tension, this simple procedure must adopted by every operator:
• When a bobbin case is refilled with thread, perform the first (1st) button attachment on a piece of interlining before going into actual production.
• When the bobbin thread in the bobbin case is depleted, the last button sewn from the depleted bobbin must always be removed from the garment.
• Record of P.O #, Style #, date and time of procedure must be clearly recorded and kept as part of standard operating procedures.
2. Cause and Corrective Action For Buttoning Problems
Problem Cause Corrective action
1. The needle thread slips out of the needle eyelet at the start of sewing. 2. The machine starts
sewing from the middle of the predetermined stitches for sewing a button.
A) The needle thread remaining on the needle is too short.
B) The material used flaps. C) The wiper does not
catch the thread.
• Decrease the tension of the thread tension controller.
• Adjust the timing to release the tension disc of the thread tension controller.
• Apply the needle hole guide with a higher boss.
• Apply the button clamp jaw levers with a
thinner plate.
• Correct the spring of the wiper properly. 3. The needle often
breaks
A) The needle hits against the button in the area around the holes.
B) The tip/point/ball of the needle hole guide comes in contact with the recess of the feed plate.
C) The needle used is too thin.
D) The knotting mechanism comes in contact with the needle.
• Adjust the position of the button clamp jaw levers so that the needle enters the center of the holes in the button.
• Adjust the position of the feed plate to
prevent it from coming in contact with the boss of the needle hole guide. If the sewing size specified is too large, use the feed plate for medium-sized buttons or that for large buttons.
• Change the needle of another count
according to the sewing product to be sewn or the holes in button to be attached.
• Adjust the timing of the knot-tying
mechanism or its stroke so that the knot-tying plate does not come in contact with the needle.
4. The finished state of the stitches sewn on the underside of the material is extremely poor.
A) The needle thread remaining on the needle is too long.
B) The wiper clamps the thread with an excessive clamping force.
C) The bobbin thread tension is too loose. D) When using buttons
with round sole, tangled stitches may result on the wrong side of the material.
• Increase the tension of the tension
controller (thread discs).
• Adjust the timing to release the tension disc of the tension controller.
• Decrease the pressure of the spring of the wiper.
• Use the exclusive bobbin case (provide With an idling prevention spring)
2. Cause and Corrective Action For Buttoning Problems (cont)
Problem Cause Corrective action
2. The knot-tying
mechanism fails to secure the end of the thread with consistency.
A) The timing of knot-tying mechanism is not correct, or its stroke is not proper.
B) The needle hits against the button in the area around the holes.
C) The tension of the tension controller is too high.
D) At the time of stop-motion, the tension disc is not released.
E) The needle is caught in the reinforcement interlining.
• Adjust the timing of the knot-tying
mechanism or its stroke so that knot-tying plate does not come in contact with the needle.
• Adjust The position of the button clamp jaw levers so that the needle enters the center of the holes in the button.
• Decrease the tension of the tension
controllers.
• Adjust so that the tension disc is released at the time of stop-motion.
• Use a thinner needle.
3. The button is not
attached on the predetermined position on the garments.
A) The button clamp jaw levers do not securely clamp the button.
B) The pressure of the leaf spring of the button clamp jaw levers is excessive.
C) When using a button with round sole, the thread enters the section between the sole of the button and the surface of the boss of the needle hole guide. As a result, the button fails to be smoothly moved during sewing.
• Adjust so that the button clamp jaw levers securely clamp the button.
• Correct the leaf spring of the button clamp jaw levers so that the spring pressure is decreased.
• Replace the button clamp jaw levers with
3. Lockstitch Button Sewing Machine Suppliers
1) BROTHER
a) Model # LK3 - B438E
- B438 with a ‘E’, is an electronic lockstitch button sewer machine.
- No button feeder is available for model # LK3 - B438E.
- It can be used for attaching buttons with 2, 3 or 4 holes, and has
22 different types of built in programs available.
- For different types of buttons, the desired program can be selected
by using a switch on the control panel.
- Backtack sewing method help to prevents the thread from pulling
out at the sewing start and unraveling at the sewing end.
* Please take note for model without an ‘E’ behind the number, is a
Mechanism lockstitch button sewer machine (model # LK3-B438).
b) Model # LK - B448E/BA-16
– B448E with a ‘E/BA-16’, is an electronic lockstitch button
sewer with auto button feeder machine.
– It can be used for attaching buttons with 2, 3 and 4 holes, and
has 22 different types of built in programs available.
– The adoption of Brother’s unique back tack sewing method
ensures that the thread will not unravel.
– A double-check function for button feeding prevents sewing
operations from continuing when no button has been set.
2) JUKI
a) Model # LK-1903SS
- 1903SS, is an electronic lockstitch button sewer machine.
- It prevents thread fray from the end of sewing.
- The machine provided as standard with 33 kinds of patterns and
the pattern can be changed over by one-touch simple operation.
b) Model # LK - 1903SS / BR-25
- 1903SS with a / BR-25, is an electronic lockstitch button sewer
3. Addresses and contact numbers
Juki Corporation
Japan
Juki Corporation International Sales Division
8-2-1, Kokuryo-Cho, Chofu-Shi
Tokyo 182, Japan
Tel: 03(3430) 4001-5
Fax: 03(3430) 4909-4914-4984
Hong Kong
Juki (Hong Kong) Ltd.
Units 1901 & 1911 - 12
Level 19, Metroplaza Tower II
223 Hing Fong Road
Kwai Fong, N.T., Hong Kong
Tel: (852) 24237888, 24238608, 24237906 (Parts)
Fax: 24237121, 24237151 (Parts)
Singapore
Juki (Singapore) Pte Ltd.
159 Sin Ming Road
#07-02 Amtech Building,
Singapore 575625
Tel: 5534388
Fax: 5525565
Brother’s Lockstitch Button Sewing Machine Supplier
Japan
Brother International Corporation
15-1, Naeshiro-cho, Mizuho-ku,
Nagoya 467-8561
Telephone: 81-52-824-3393
Facsimile: 81-52-824-3390
Hong Kong
Brother Corporation (Asia) Ltd
Suite 1103,
Chinachem Golden Plaza 77 Mody Road,
Tsimahatsui East,
Kowloon, Hong Kong
Telephone: 852-2723-4198
Facsimile: 852-2723-1776
Singapore
Brother International Singapore Pte Ltd
No. 1 Phillip Street #06-00
Lippo Centre,
Singapore 048692
Telephone: 65-538-0311
Facsimile: 65-538-7003, 1020
4. Button Attachment Statistical Process Control Procedure
a) Pre-production Control = Button Attachment Strength Test
* Before wash mock seam
- Apply 5 buttons sewn to a mock seam (before wash)
- Button attachment strength must withstand a direct pull force of
20 Lbs. for 10 seconds.
* After wash mock seam
- Apply 5 buttons sewn to a mock seam (after wash)
- Button attachment strength must withstand a direct pull force of
17 Lbs. for 10 seconds.
III. FORMS (to be completed by Field QA & Product Safety
Officers) :
1) Lockstitch Button Attachment Strength Test (Pre-production
Control) - refer to form LS – 12a
Generated by
Factory authorized staff e.g. Task Force Coordinator
When
Every new order sewed with sewn on button.
Why
The purpose is to ensure the fabric; sewing thread and the
button are secured and can withstand a direct pull force of 20
lbs. for 10 seconds (before wash) and 17lbs. for 10 seconds
(after wash).
1) Lockstitch Button Attachment Strength Test (Pre-production Control)
- refer to form LS – 12a (cont.)
Procedure
•
Please refer to the button attachment statistical process
control procedure for more details.
Production Control = Checked Appearance (Button
Attachment)
Construction review: Appearance and security of button stitching
• A 100% check must be conducted on buttons sewn-on garments.
• The total quantity of production done at every 2-hour interval
must be collected, serial number of machine recorded and
quantity noted before 100% inspection begins.
• Three criteria must be noted during the audit :
• Buttons are sewn with a complete stitch pattern;
• The “Rabbit Ears” and knot are clearly visible on the back
side;
• The first and last button tension check which is
characterized by missing or skipped stitches on one side of
a button..
Note: All button attachment defects are considered criteria
defect. If one is found during the audit, a 100% re-audit of the
whole production is required.
Line supervisor must trained by appropriate button machine
supplier annually.
2) Lockstitch Button Attachment Capacity and SOP Check
– refer to form LS – 13a
Generated by
Factory authorized staff e.g. factory QC.
When
Apply 100% check every two hours per day per order.
Why
The purpose is to ensure all the buttons are security attached
on the garments and avoided button falling off. Additional it
is a control measure in helping the factory management to
track the production.
Procedure
•
Please refer to the button attachment statistical process
control procedure for more details.
3) Check Record of Even Attachment Tension for Bobbin
Thread - refer to form LS – 14a
Generated by
Factory authorized staff e.g. button sewing operator
When
The initial refilled and the ending of each bobbin thread.
Why
The purposes are to ensure all the buttons are security attached
on the garments, as to avoid missing stitch and caused button
falling off. Additional it is a control measure in helping the
factory management to track running production.
Procedure
•
Please refer to the button attachment statistical process
control procedure for more details.
Button Attachment Strength Test - (Pre-production Control)
Vendor: Factory:
Garment description Machine model / Number
Gap Style Number / Division Operator
Button Description / Size Type/Size of Thread & Stitch Pattern
No. of Buttons on garments Stitch Density (no. of stitches)/ needle size
Location on garment Fabric Thickness ( no. of plies )
Name of Task Force Coordinator Date
Pass Fail Type of Failure Pass Fail Type of Failure
1 1 2 2 3 3 4 4 5 5 Sample Sample
PRE-PRODUCTION SETTING - apply 10 buttons per style to a mock / faux seam which is same construction as the production
Maintain 20 lbs. for 10 seconds before washed
Maintain 17 lbs. for 10 seconds after
Button Attachment Strength Test - (Pre-production Control)
Vendor: Ponie Garment Factory : Intravest - MalaysiaGarment description Machine model / Number
BabyGap Girl Ctn Jsy Embroidery Collar Slip Dress (GW) LK-1851 / 00189 (Juki)
Gap Style Number / Division Operator 322103 (BGK) Mei
Button Description / Size Type/Size of Thread & Stitch Pattern
Polyester / 18L Polyester / #180 / 'X' Completed Stitch Pattern
No. of Buttons on garments Stitch Density (no. of stitches)/ needle size
3 16 Stitches / # 12
Location on garment Fabric Thickness ( no. of plies )
Half Front Placket 2 Fabric + 1 Interlining
Name of Task Force Coordinator Date
Anna Loh 7/23/1998
Pass Fail Type of Failure Pass Fail Type of Failure
Sample Sample
PRE-PRODUCTION SETTING - apply 10 buttons per style to a mock / faux seam which is same construction as the production
Maintain 20 lbs. for 10 seconds before washed
Maintain 17 lbs. for 10 seconds after
Lockstitch Button Attachment Capacity And SOP Check
Vendor : Factory:
Model No. / Machine No. : Operator :
Task Force Coordinator: Date :
Style No. : Stitch Density (Nos. of stitches) :
Time Complete 2 "Rabbit Ear" Complete Stitch Pattern (Cross or Parallel stitches)
The initial refilled & ending
of bobbin thread record Output TTL Defective Action Taken Output TTL Defective Action Taken Nos. Of Button Production Control - apply 100 % check every two hour. The initial refilled and the ending of each bobbin thread, button must sewn on Interlining.
Lockstitch Button Attachment Capacity And SOP Check
Vendor : Ponie Garment Factory: Intravest -Malaysia
Model No. / Machine No. : LK-1851 / 00189 (Juki) Operator : Mei
Task Force Coordinator: Anna Loh Date : 23 July 98
Style No. : 322103 Stitch Density (Nos. of stitches) : 16
Time Complete 2 "Rabbit Ear" Complete Stitch Pattern (Cross or Parallel stitches)
The initial refilled & ending
of bobbin thread record Output TTL Defective Action Taken Output TTL Defective Action Taken Nos. Of Button
10.30 AM 200 1- Knot on backside too heavy stitches and stitches is too loose
Adjust bobbin thread
tension
200 1-Missing stitches, due
to bobbin depleted
Check bobbin case tension and bobbin thread
2
1.00 PM 200 Nil Nil 200 1- Thread breakage Adjust needle thread or bobbin thread tension and it depends on the type of fabric
construction and the nos. of ply is being used
2
Check Record Of Even Attachment Tension For Bobbin Thread
Vendor : Factory:
Model No. : Machine No.:
Operator : Date :
Style No. :
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Time:
Time:
Time:
Time:
1 2 3 4
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Time:
Time:
Time:
Time:
5 6 7 8
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Time:
Time:
Time:
Time:
9 10 11 12
Check Record Of Even Attachment Tension For Bobbin Thread
Vendor : Ponie Garment Factory: Intravest - Malaysia
Model No. : LK-1851 (Juki) Machine No.: 00189
Operator : Mei Date : 23-Jul-98
Style No. :
322103
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Time: 10:30 AM
Time: 1:00 PM
Time:
Time:
1 2 3 4
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Button attached
for initial refilled
of each bobbin
Time:
Time:
Time:
Time:
5 6 7 8
