11c...Acceptable Quality Level

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Knitwear Production Planning

ACCEPTABLE QUALITY LEVEL (AQL)

WHAT IS QUALITY The best money can buy

Meeting a specification or conformance of specification Craftsmanship The degree of excellence that an item possesses

No more than 1% defective lot

User based def:-whatever the costumer says or wants

Producer based def:-meeting specifications to requirementValue based def:- considers cost and price of a product

ISO- degree to which a set of inherent characteristics fulfill requirements

CONSUMERS PERCEPTION OF QUALITY

Price Technology

Psychology Time Orientation

Contractual

Ethical

Testing for packaging quality Report test statistics

End term inspection

No inspection

100% inspection

Constant percentage checking

Random spot checking

Audit sampling

Statistical/acceptance sampling

QUALITY REQUIRED AT EACH STAGEWE HAVE DIVIDED QUALITY PARAMETERS

ACCORDING TO THE FOLLOWING DEPARTMENTS:

YARN

KNITTING

DYEING AND PROCESSEING

Oct 2011 ACCEPTABLE QUALITY LEVEL (AQL)


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SPREADING & CUTTING

PRINTING

EMBROIDERY

SEWING

FINISHING

WHAT IS AQLAcceptable Quality Level is a statistical Tool, which is used to measure the degree of

variance found in a lot using a random sampling method.

By Pradip V. Mehta AQL is the maximum per cent defective that for the purpose ofsampling inspection can be considered satisfactory as a process average

o Generally expressed in %

o Used in apparel industry are 1.5,2.5, 4.0,& 6.5 depending on price and item

o For low price items and childrens wear AQLs of 6.5 and 10.0 may be quite

appropriate

o However, for higher price items AQLs of 1.5 and 4.0 may be appropriate.

HISTORY OF AQLAQL was originally applied by U.S millitary for the testing of bullets during World War

II. If every bullet was tested in advance, no bullets would be left. If on the other handnone were tested, results would be disastrous due to malfunction of the bullets

Based on this, us government issued the standard for sampling procedure and tables for

inspection as:-

In 1963MIL STD-105DIn 1989 modified to MIL-STD 105E

Re-designed in Feb 1995 as ANSI/ASQC Z 1.4



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ANSI/ASQC Z 1.4

STAGES OF AQL SAMPLING Select the appropriate sampling plan

Determine the AQL %

Determine the sampling plans parameters Establish the sample size, accept and reject criteria

Randomly select the parts Inspect each part for the given feature

Accept or reject the remaining parts

SAMPLING PLANSSampling plans are hypothesis tests regarding a product acceptance or rejection

Sampling provides a check on the adequacy of the quality control procedures

1. METHODS OF CHECKING PRODUCTS

No Checking in this no inspection is done, and nothing is known about theproduct until it reaches the hands of costumer

100% inspection in this every unit is inspected, done for very expensive items,done where lives are involved, it is costly,



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TYPES OF SAMPLING PLANS

Constant percentage sampling in this 10% samples are taken from the lot for

inspection, samples for small lots are very small, samples for large lots are toolarge

Random spot checking it is in between no inspection and 100% inspection, usedwhen supplier is certified for providing quality product, used when the processcapability is so good that other method of inspection is not necessary

Audit sampling- it is done on routine basis, quality report is issued for further

improvement

Acceptance sampling-it is based on probability and is widely used samplingtechnique

ACCEPTENCE SAMPLING PLANSingle sampling :-

Lot size is produced for checking Sample size is selected

If the no. of defects in the sample exceed the acceptance no. the entire lot isrejected

If the no. of defects in the sample do not exceed the acceptance no. the entire lot

is accepted

SINGLE SAMPLING CHART



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DOUBLE SAMPLING CHART Lot size (N) is produced for checking Two sample sizes ( n1, n2) and two acceptance numbers ( c1, c2)

are specified First sample of size n1 is taken

If the no. of defects in the first sample size exceeds c2, lot isrejected and second sample size is not taken

If the no. of defects in the first sample size do not exceeds c1, lotis accepted and second sample size is not taken

If the no. of defects in the first sample size is more than c1 butless than or equal to c2, second sample n2 is selected

RANDOM SAMPLING OF CARTON BOX FOR INSPECTION If second sample size n2 is inspected:-

1. If defects in combined first and second sample size do not exceed c2 the lot isaccepted

2. If defects in combined first and second sample size exceed c2 the lot is rejected

Continuous sampling



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It is used where product flow is continuous and not feasible to beformed into lots

Two parameters are specified in this, first is the frequency ofchecking (F) and second is the clearance no. ( I ). Frequency F isexpressed as 1/10,1/20, 1/X etc. and I is a number such as 20 or

50 When inspection begins, the product is checked 100% until (I)parts are to be found defect free. At this time one out of X shallbe inspected. If F=1/10, then one out of 10 parts will be checked.The sampling will continue until a defect is found. When a defectis found, 100% inspection shall be resume and the cycle startsover. When ( I ) parts are to be defect free, the sample 1/X shallstart again

RANDOM SAMPLING OF CARTON BOX FOR INSPECTIONTotal order qty:- 1200 pcs

Black S-150/M-150/L-150/XL-150=600 pcs

White S-150/M-150/L-150/XL-150=600 pcs

S= 300, M= 300, L= 300, XL= 300.

If a carton contains Black, S-10. M-10,L-10,XL-10White, S-10. M-10,L-10,XL-10

sample size for 1200 pcs =80 pcs

Total no. of carton -15

Size wise garments selection=No. of size pcs/total pcs *sample size

300/1200*80=20 pcs /size /color



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WHY IS IT NEEDED

To Minimize Internal Rejections To ship extra 3% shipment To save time, that can be used in other processes

To eliminate Re-work In Finishing

To eliminate financial losses for re-working

To minimize delay in shipments To make goodwill in the business and in the market


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11c...Acceptable Quality Level