button attachment sop

Lockstitch Buttoning Machines Operating & Control Procedures

PRODUCT SAFETY HANDBOOK 1999

TABLE OF CONTENTS

PAGE

I. PURPOSE OF GUIDE LS - 1

II. FACTORIES PRODUCT SAFETY TASK FORCECOORDINATOR GUIDE & PROCEDURES

LOCKSTITCH BUTTONING MACHINES OPERATING & CONTROLPROCEDURES

1. Button Attachment Control Procedures and LS - 2 ~ 4Maintenance Program

2. Cause and Corrective Action For Buttoning LS – 5 ~ 6Problems

3. Lockstitch Button Sewing Machine Suppliers LS – 7 ~ 9

4. Button Attachment Statistical Process Control LS - 10Procedure

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 – 12ab) Sample LS – 12b

2. Lockstitch Button Attachment Capacity and SOP Check LS - 13


3. Check Record of Even Attachment Tension for Bobbin LS - 14Thread



PRODUCT SAFETY HANDBOOK 1999LS - 1

I. Purpose of Guide

The purpose of the Lockstitch Buttoning Machines Operating & ControlProcedures is to ensure that sewn-on buttons on each garment will last alife time. It completely provide guides to ensure all the buttons aresecurely attached on the garments and avoid buttons falling off. It doesprovide control measure in helping the factory understand the propermaintenance program.

The Guide also consists of the following sections :a) Button Attachment Control Procedures & Maintenance Programb) Cause & Corrective Action for Buttoning Problemsc) Lockstitch Button Sewing Machine Suppliersd) Button Attachment Statistical Process Control Charts



II. FACTORIES PRODUCT SAFETY TASK FORCECOORDINATOR GUIDE & PROCEDURE

LOCKSTITCH BUTTONING MACHINES OPERATING &CONTROL PROCEDURES

1. Button Attachment Control Procedures and Maintenance Program

ButtonsAll buttons must meet the following minimum performance requirements:

Two Hole Two or Four Hole Two or Four HoleLigne Size <14 14-21 > 22MinimumThickness

1.65mm/0.065in. 1.65mm/0.0625in 2.0mm/0.0750in.

Center/BreakingStrength

7.7 kg / 17lbs. 7.7kg / 17 lbs. 10 kg / 22 lbs.

MachineVendor must clean button attachment machines on a daily basis to avoid any fluff,which could snag the thread and cause missing stitches/passes.

BobbinVendor must clean bobbin area on machine to remove fluff and dirt twice a day (4hourly) :• During lunch break• Before a shift change or before a worker finishes work for the day

Needle SizeThe correct needle size must be used. Needle size prefer #11 to #16 is the best forbutton attachment.

Needle size selection is also a key point to note and in recommending a particularneedle size to be used, the vendor need to take into consideration the garmentconstruction, fabrication, and number of ply being used to apply to the garment.



Condition of NeedleA faulty needle is one of the primary causes of button attachment defects. A faultyneedle must be replaced before production can be allowed to continue. Examplesof faulty needles are:

a) No bent needleb) No tipped needle

Operator need to change the buttoning needle at least twice a day, toEnsure the needle is in good condition.

Faulty Needle CheckAn operator can check whether a needle is bent or tipped by rolling it on an evensmooth surface. If a needle will not roll smoothly on the surface, it is defective andmust be changed immediately before production continues.

Thread TensionThread tension must be adjusted in a right position.a) not too loosenb) not too tightenThread tension must be properly adjusted as it may cause missing stitches (i.e. 2holes 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 areattached 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.• Button attachment must be attached with a minimum of 16 passes.



Missing Stitches/ Security & Tension CheckOn the machine, the thread remaining on the needle must not be too short, theminimum length being at least 3” long. This will prevent the thread from slippingout of the needle eyelet at the start of sewing or sewing from the middle of thepredetermined stitches.Note : The above reason is the cause for missing or skipped stitches on one side ofa button.

To overcome the problem of skipped or missed stitches and evenness of threadtension, this simple procedure must adopted by every operator:

• When a bobbin case is refilled with thread, perform the first (1st) buttonattachment on a piece of interlining before going into actual production.

• When the bobbin thread in the bobbin case is depleted, the last button sewnfrom 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 action1. The needle thread

slips out of theneedle eyelet at thestart of sewing.

2. The machine startssewing from themiddle of thepredeterminedstitches for sewinga button.

A) The needle threadremaining on the needleis too short.

B) The material used flaps.

C) The wiper does notcatch the thread.

• Decrease the tension of the thread tensioncontroller.

• Adjust the timing to release the tension discof the thread tension controller.

• Apply the needle hole guide with a higherboss.

• Apply the button clamp jaw levers with athinner plate.

• Correct the spring of the wiper properly.

3. The needle oftenbreaks

A) The needle hits againstthe button in the areaaround the holes.

B) The tip/point/ball of theneedle hole guide comesin contact with therecess of the feed plate.

C) The needle used is toothin.

D) The knotting mechanismcomes in contact withthe needle.

• Adjust the position of the button clamp jawlevers so that the needle enters the center ofthe holes in the button.

• Adjust the position of the feed plate toprevent it from coming in contact with theboss of the needle hole guide. If the sewingsize specified is too large, use the feed platefor medium-sized buttons or that for largebuttons.

• Change the needle of another countaccording to the sewing product to be sewnor the holes in button to be attached.

• Adjust the timing of the knot-tyingmechanism or its stroke so that the knot-tying plate does not come in contact withthe needle.

4. The finished stateof the stitches sewnon the underside ofthe material isextremely poor.

A) The needle threadremaining on the needleis too long.

B) The wiper clamps thethread with an excessiveclamping force.

C) The bobbin threadtension is too loose.

D) When using buttonswith round sole, tangledstitches may result onthe wrong side of thematerial.

• Increase the tension of the tensioncontroller (thread discs).

• Adjust the timing to release the tension discof the tension controller.

• Decrease the pressure of the spring of thewiper.

• Use the exclusive bobbin case (provideWith an idling prevention spring)



2. Cause and Corrective Action For Buttoning Problems (cont)

Problem Cause Corrective action2. The knot-tying

mechanism fails tosecure the end ofthe thread withconsistency.

A) The timing of knot-tyingmechanism is notcorrect, or its stroke isnot proper.

B) The needle hits againstthe button in the areaaround the holes.

C) The tension of thetension controller is toohigh.

D) At the time of stop-motion, the tension discis not released.

E) The needle is caught inthe reinforcementinterlining.

• Adjust the timing of the knot-tyingmechanism or its stroke so that knot-tyingplate does not come in contact with theneedle.

• Adjust The position of the button clamp jawlevers so that the needle enters the center ofthe holes in the button.

• Decrease the tension of the tensioncontrollers.

• Adjust so that the tension disc is released atthe time of stop-motion.

• Use a thinner needle.

3. The button is notattached on thepredeterminedposition on thegarments.

A) The button clamp jawlevers do not securelyclamp the button.

B) The pressure of the leafspring of the buttonclamp jaw levers isexcessive.

C) When using a button withround sole, the threadenters the sectionbetween the sole of thebutton and the surface ofthe boss of the needlehole guide. As a result,the button fails to be

smoothly moved during sewing.

• Adjust so that the button clamp jaw leverssecurely clamp the button.

• Correct the leaf spring of the button clampjaw levers so that the spring pressure isdecreased.

• Replace the button clamp jaw levers withthose with a thicker plate.



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 aMechanism 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

with button feeder.



3. Addresses and contact numbers

Juki Corporation

JapanJuki Corporation International Sales Division8-2-1, Kokuryo-Cho, Chofu-ShiTokyo 182, JapanTel: 03(3430) 4001-5Fax: 03(3430) 4909-4914-4984

Hong KongJuki (Hong Kong) Ltd.Units 1901 & 1911 - 12Level 19, Metroplaza Tower II223 Hing Fong RoadKwai Fong, N.T., Hong KongTel: (852) 24237888, 24238608, 24237906 (Parts)Fax: 24237121, 24237151 (Parts)

SingaporeJuki (Singapore) Pte Ltd.159 Sin Ming Road#07-02 Amtech Building,Singapore 575625Tel: 5534388Fax: 5525565



Brother’s Lockstitch Button Sewing Machine Supplier

JapanBrother International Corporation15-1, Naeshiro-cho, Mizuho-ku,Nagoya 467-8561Telephone: 81-52-824-3393Facsimile: 81-52-824-3390

Hong KongBrother Corporation (Asia) LtdSuite 1103,Chinachem Golden Plaza 77 Mody Road,Tsimahatsui East,Kowloon, Hong KongTelephone: 852-2723-4198Facsimile: 852-2723-1776

SingaporeBrother International Singapore Pte LtdNo. 1 Phillip Street #06-00Lippo Centre,Singapore 048692Telephone: 65-538-0311Facsimile: 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 SafetyOfficers) :

1) Lockstitch Button Attachment Strength Test (Pre-productionControl) - 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 thebutton are secured and can withstand a direct pull force of 20lbs. 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 (ButtonAttachment)

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 andquantity 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 ofa button..

Note: All button attachment defects are considered criteriadefect. If one is found during the audit, a 100% re-audit of thewhole production is required.Line supervisor must trained by appropriate button machinesupplier 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 attachedon the garments and avoided button falling off. Additional itis a control measure in helping the factory management totrack the production.





3) Check Record of Even Attachment Tension for BobbinThread - 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 attachedon the garments, as to avoid missing stitch and caused buttonfalling off. Additional it is a control measure in helping thefactory management to track running production.



Product SafetyButton 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 washed Remarks

PS5 LS - 12a 1999

Product SafetyButton Attachment Strength Test - (Pre-production Control)

Vendor: Ponie Garment Factory : Intravest - Malaysia

Garment description Machine model / NumberBabyGap 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 PatternPolyester / 18L Polyester / #180 / 'X' Completed Stitch Pattern

No. of Buttons on garments Stitch Density (no. of stitches)/ needle size3 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

1 X 1 X

2 X 2 X

3 X 3 X Button fell off Button attached on uneven surface

4 X 4 X

5 X Button fell off 5 X Stitches incomplete, no lockstitch

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 washed Remarks

PS5 LS - 12b 1999

Product SafetyLockstitch 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

recordOutput 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.

PS6 LS - 13a 1999

Product SafetyLockstitch 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

recordOutput 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

Production Control - apply 100 % check every two hour. The initial refilled and the ending of each bobbin thread, button must sewn on Interlining.

PS6 LS - 13b 1999

Product SafetyCheck 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




Time: Time: Time: Time:

1 2 3 4






5 6 7 8






9 10 11 12

Stitch Density (Nos. of Stitches) :

PS7 LS - 14a 1999

Product SafetyCheck 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





Time: 10:30 AM Time: 1:00 PM Time: Time:

1 2 3 4






5 6 7 8






9 10 11 12

Stitch Density (Nos. of Stitches) : 16

PS7 LS - 14b 1999

button attachment sop

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