assqc
DESCRIPTION
ASSQCStudy MaterialSem IVTRANSCRIPT
-
Session 1,2
What is quality
Quality related terms & Definitions
Ref: Managing Quality in the apparel Industry-Mehta and Bharadwaj:Chapter 1
Quality Assurance for Textiles and Apparel-Sara J. Kadolph ;Chapter 2
-
How do we define quality?
-
Traditional definitions of Quality
Fitness for use- Joseph Juran
Conformance to requirements-Philip Crosby
-
Quality defined "Quality" is defined as that combination of design
and properties of materials of a product which are
needed for the intended end use and level of the
market in which it is sold.
"Requisite Quality" is defined as the design and
composition of a product, which has been
thoroughly proved by adequate development
work, in order to establish its reliability under the
conditions to which it will be subjected in use and
to avoid producing too high a grade of product for
the intended market.
-
Quality Defined A holistic definition of Quality can be
Quality is a dynamic state associated with products, services, people ,processes and environments that meets or exceeds expectations (Goetsch and Davis 1994)
Can have a (Garvin) Product perspective,
Producer's perspective or
Consumer's perspective
Value perspective
-
product
In this view, quality is determined as a
precise and measurable variable and
difference in quality reflects differences in
the quality of some ingredient or attitude
seen to be possessed by a product. In this
view quality and quantity has direct relation
-
customer
In this view, definitions are based on the
premise that solely the user determined
quality. Individual customers are assumed
to have different wants or needs and goods
that best satisfy the preference are the one
they regarded, as having the highest
perceived quality. Quality is fitness for use
that this view also reflects a highly
personalized and subjective view
-
manufacturing This view focuses on manufacturing and engineering practices. It
emphasis
conformance to specified requirements. The higher the degree that
meets specified
requirements the higher the quality. This view seeks to ensure that the
deviations from
standards set design specifications are minimized.
To achieve the quality of conformance means improving in the design
of the
Equipment
Materials
Supervision
Control
Training
-
Value based
The base for this view is physiological
understanding of the meaning of value.
Consequently, customers have been
conditioned to accept that the quality of
product is determined by the price. There
fore price and quality have a direct relation
ship
-
Dimensions of quality
Positioning of a company based on Garvin`s Model
1. Performance
2. Features
3. Reliability
4. Conformance
5. Durability
6. Serviceability
7. Aesthetics
8. Perceived quality
-
Dimensions of quality1.Performance: (will the product do the intended (planed or proposed) job). Potential costumer usually evaluate a product to
determine if it will perform certain specific functions and
determine how well it perform them.Example: producing document case leather bag, for what purpose does is bag produced, does the bag has multi function pocket?
2.Reliability: (how often does the product fail?) different products
may need repair over their service life. The leather machineries
should be also reliable so as to increase productivity Example: when we produce the leather garment, it needs higher attention during stitching. Because the nature of the needle is like
cuter edge type and stitch the component by cutting the part. So re
stitching is not done, means no repair and only rejection.
-
Dimensions of quality3.Durability: (how long does the product last?).This is the effective
service life of the product customer obviously want products that
performed satisfactorily over a long period of time.
4.Serviceability: (how easy is it to repair the product?). There are
many industries where the customers view of quality is directly
influenced by how quickly and economically a repair or routine
maintenance activity can be accomplished.
Example: planned maintenance of stitching machine.
5. Aesthetics: what does the product look like?). this is the visual
appeal of the product, often taking into account factors such as style,
color, shape, packaging alternatives and other sensory features.
6.Features :( what does the product do? ). Usually customer associate
high quality with products that have added features: that is, those that
has features beyond the basic performance of the competition
-
Helena M de Klerk and Stephina J Lubbe;Journal of Family Ecology and Consumer Sciences, Vol 32, 2004
-
Quality in the garment Industry
Still at inspection level AQL
Quality is inspected into the product.
A few firms are attempting SPC.
Still a long way to go to finally reach global
quality standards
-
Why improve quality?
FOB is getting lesser
Delivery time is getting lesser
Costs are increasing.
We need to keep providing better service to hold the buyers attention.
Provide indisputable quality
Provide indisputable quality at better costs.
-
Importance of QUALITY
The consumer quality expectations have gone up
Consumer is too busy to come back and complain
Consumer is not interested to take special care of
the product
Consumer spending on apparel has reduced
Stringent consumer protection laws
Stores cannot afford a dissatisfied customer
Working with non-quality vendors is costly
-
Terms related to quality Quality Assurance
1. All those planned and systematic actions
necessary to provide adequate confidence that a
product or service will satisfy given requirements
for quality.
2. The establishment and maintenance of ALL
activities and functions concerned with the
attainment of requisite quality"
-
Terms related to quality Quality Control
1.The operational techniques and the activities used to
fulfill the requirements of quality is called quality
control. It is the regulatory process through which we
measure actual quality performance, compare it with
quality goals and act on the difference.
2. The systems required for programming and coordinating
the efforts of the various groups in an organization to
maintain the requisite quality" As such Quality Control is
seen as the agent of Quality Assurance or Total Quality
Control
-
Quality related terms
Quality Management -That aspect of the
overall management function that
determines and implements the quality
policy.
Quality System -The organizational
structure, responsibilities, procedures,
processes and resources for implementing
quality management
-
Session 3,4
What is Quality Standard and Quality
Grade
Different textile and apparel
standards
Ref:Managing Quality in the apparel Industry-
Mehta and Bharadwaj-Chapter 14
Quality Assurance for Textiles and Apparel-
Sara J. Kadolph-Chapter 3
-
Standards
Standard a set of characteristics or
procedures that provide a basis for resource
and production decisions.
Standardization - is the process of
developing and applying rules for a
consistent and uniform approach to a
specific activity for the benefit and with the
cooperation of all concerned.
-
Standards-uses1. Used to define weights and measures
2. Used to set forth practices and expectations in the field.
3. Used to describe the characteristics of a product in a precise and consistent fashion.
4. Used to describe a minimum level of performance and safety.
5. Used to convey information about a product or material in a consistent manner.
6. Enhances efficiency standardization of parts, processes and products enables economies of scale in production.
7. Standardization leads to enhanced competition.
-
Types/Levels of standards
Company Standards-describe general
characteristics or features of a product or service
or they describe a required level of performance.
Useful for the design, purchase, development and
production departments as they may be developed
by the company itself or adopt other organization's
standards for its specific purpose.
-
Types/Levels of standards
Industry standards reflect consensus
among companies in an industry or among
individual members of a profession.
Developed by trade associations or
professional bodies.
-
Levels/Types of standards
Voluntary standards- allows individuals or companies to determine on their own whether to adopt a standard.
ASTM one of the largest voluntary standards development system in the world
Mandatory standards adoption is required by law or regulation. Mostly related to health or safety issues.
-
Comparison between Various U.S. Drawstring Standards
Neck area Prohibitions-
ASTM Standard (F1816-97) a Voluntary
national standard:
No drawstrings in the hood and neck area of
certain childrens clothing. Only childrens upper
outerwear. Sizes 2t to 12.
Wisconsin Law(ATCP 139)-a State regulation:
No drawstrings in the hood and neck area of all
childrens clothing. All childrens clothing. Sizes
0 to 16.
-
Levels/Types of standards
International standards-standards are used internationally to facilitate trade and technology transfer among nations
Goal is to Enhance product quality and reliability at reasonable
prices
Improve health and safety and environmental protection
Reduce hazards
Produce greater compatibility of goods and services
Simplify and improve product and service usability
Increase distribution efficiency
-
Different standardizing bodies ( refer Sara Kadolph; Mehta and Bhardwaj)
ASQC- American Society for Quality control
ASQC_TNT- American society for quality control-textiles and needle trade division
ASTM- American Society for Testing and Materials
AATCC-American association of textile chemists and colorists
ANSI-American national standards Institution
ISO- International organization for standardization
BSI- British Standards Institute
BIS- Bureau of Indian Standards.
AQC of AAMA Apparel Quality committee of American Apparel Manufacturer's Association.
-
Grade
The process of assigning a numerical value
based on the number, size,and severity of
defects observed during a visual inspection;
the symbol, number, or letter used for any
step in a multistep standard reference scale
for a quality characteristic.
-
Session 5,6
What is Quality Specification
Concept of Tolerances
Ref: Quality Assurance for Textiles and Apparel-
Sara J. Kadolph-Chapter 3 and 10
-
Specifications
Is a precise statement of a set of
requirements to be satisfied by a material,
product, system or service that indicates the
procedures for determining whether each of
the requirements is satisfied.
Requirements- are non negotiable.they need
to be met for the specs to be satisfied.
-
Specifications
Specs describe requirements- in terms
and/or numerical values.
Minimum is the least or lowest acceptable
value for any given parameter or dimension
Tolerance - describes the range of
acceptable values.
Not all specs will include tolerances
-
Types of specifications
Open- allows for consideration of multiple
vendors and includes a description of the
character and /or performance desired in the
product or material to be purchased.
Closed specifies the exact material,
component, or product by manufacturer or
vendor and includes style numbers, trade
names or other such specific identities.
-
Application of specifications.1. Used to describe the materials ,procedures,
dimensions and performance for a particular product or style.
2. Reflect the standard- co. standards, costs, customer needs and expectations and implementation abilities.
3. Used as a communication tool- for production, for suppliers and for customer.
4. To negotiate bids and contracts
5. Used for purchasing materials for production
6. Used as a determinant for quality.
-
*Fabric Yardage / Width
*Hand feel / Quality
*Color / Print
*Fabric Weight
*Wash & Dry Shrinkage
*Color Fastness
* What percent of goods inspected prior to cutting?
* Are shade controlled and segregated by lots at storage stage?
* Use of a light box?
* Spectrophotometer?
* What is the light source used?
* Is there pre-testing on the shrinkage prior cutting?
* How is the pre-testing done?
* Records on shade bands?
SPECIFICATION GUIDELINES FOR PIECE GOODS INSPECTION
-
Garment spec sheets Specification sheets provide important
details to ensure the correct execution of
patterns into finished garments.
Spec sheets help to produce accurate
samples, which improves turnaround time
and simplifies communication during all
stages of manufacturing and quality control.
Spec sheets include detailed technical
diagrams, construction notes, finished
garment measurements, fabric yields and
material and trim details.
-
Session7,8
Assignment 1- assigned on 20.08.10;
To be submitted on 27.8.10;
time- 3 hrs(2 sessions) ;
marks -20
-
Assignment 1- 20 marks
Prepare a garment specification sheet for a
garment of choice, inspect the garment and
record the inspection report in the prescribed
format.
Individual assignment
Criteria of evaluation
Selection of garment- 3 marks
Specification sheet-7 marks
Inspection report 10 marks O
-
Session 9,10
Fabric Inspection ;Defects
Testing
Ref:Managing Quality in the apparel Industry-
Mehta and Bharadwaj-Chapter 2,Pages 14-20 and pg 75-77
and Chapter 3
-
Fabric- defects
Woven- Knitted- Broken end Barre
Broken Pick Birdseye
Coarse end/Pick Coarse yarn
Color Fly Yarn Dropped stitches
Double end/double pick Fine yarn
End out Missing Yarn
Mispick Needle Line
Hole Run
Shade Bar Tucking Defect
Slub .
Thick and Thin Places
..
-
Fabric
Inspection And Grading
4 point system
10 point system
Graniteville 78 system
-
Fabric grading
4 point system 10 point system Graniteville 78
Allows max. 4 penalty
points to one linear yard
Allows max.10 points
per linear yard
Max.no.of points
per linear yard=
fabric width /9
width in inches.
Points for only length
wise defects and holes
Warp as well as filling
defects carry pointsLength of defect is
counted-can be weft
or warp
Not sensitive to width
of fabric
Sensitive to width of
fabric
Sensitive to width
of fabric
Total defect points per
100square yards should
not exceed 40
If no. of penalty points
are
-
4 point system
Size of defects (Inches) Assigned Points
3 inches or less 1
Over 3 but not over 6 2
Over 6 but not over 9 3
Over 9 inches 4
All textiles are evaluated on a square yard computation. The formula used to determine the point count level of a roll of fabric is as follows:
Total Points x 3,600 = Points per 100 yard2
Inspected Yards x Cuttable Fabric Width (in)-----------------------------------------------------------------------------------------------------------------------------------------------------
10 point system
Size of Defect (Inches) Warp Assigned Points
1 inch or less 1
1 to 5 inches 3
5 to 10 inches 5
10 to 36 inches 10
Size of Defect (Inches) Weft Assigned Points
1 inch or less 1
1 to 5 inches 3
5 inches to half width 5
Large than half width 10
-
Fabric Check ListDivision/Season: Style:
Fabric Pattern#: Type
Fabric Supplier: Roll #:
Piece Length:
1)General Appearance (against weaving/dyeing/ printing standard): ________
2)Construction:Check against hand standard): ________
3)Width( as specified in contract): ________
4)Piece length (as per tag and packing list): ________
5)Design/Pattern and colors/shades (as per approved strike off or lab dip): ________
-Any repeat variation ________
6)MAJOR DEFECTS1-Centre to Selvedge variation _________
2- End to End shading _________
3-Broken or missing ends/Picks _________
4-Torn ,Wavy, Folded or Tight Selvedges _________
5- Coarse Yarn in Warp or Weft _________
6- Holes _________
7-Double or multiple ends/picks _________
8-Loom stop marks _________
10-Noticeable Shade or filling bars _________
11-Noticeable Dead Crease mark/line _________
12-Noticeable Dye Streaks and stains through the roll _________
13- Bowing or skewing _________
14- Reed marks _________
15-Foreigh matter/soiled yarn _________
16-Neps _________
17-Oil Stains _________
18----------- ________
-
Gap standards for Piece goods Inspection
-
Testing
The analysis and evaluation of a material or
product to assess its characteristics, quality
or performance.
Test method- is a definitive procedure for
the identification, measurement, and
evaluation of one or more qualities,
characteristics or properties of a material,
product, system or service that produces a
test result.
-
Testing of fabrics Precision: the degree of agreement within a
set of observations or test results obtained by using a test method.
Accuracy: the degree of agreement between the true value of the property being tested ( an accepted standard value) and the average of many observations made according to the test method, preferably by many observers.
Reliability
-
Testing conditions
Standard Humidity and temperature
conditions to be maintained-
Relative humidity-65+2%
Temperature 21+1oC(70+ 2oF)
Min. 4 hrs in standard test conditions to
reach equilibrium
-
Testing of fabrics Fabric Strength Yarn Count, Yarn Twist, Fabric
construction, Fabric weight and width.
Yarn Slippage
Color fastness- to light, washing, rubbing, sunlight,
perspiration, chlorine ,dry cleaning, heat etc.
Dimensional Changes In Fabrics Due To Laundering, Dry-
cleaning, Steaming, Pressing
Bow and Skewness
Fabric Thickness
Pilling
Abrasion Resistance
-
Testing of fabrics
Each individual to conduct testing of fabrics in the F&T testing lab and record the following in the log book:
1The test being conducted
2.The standard used
3.The test requirements
4.Method of testing and
5.The instrument used
6. Any special instructions/ conditions for the test.
-
Session 11-14
Testing at lab
-
Session 15
Trims DefectsRef: Mehta and Bharadwaj-Chapter 3
-
Trims Defects
Sewing threads-
Imperfections in the yarn
Finish
Color
Package density
Winding
Yardage
-
Trims defects -ZippersTo check for-
Dimensions
Locks at ends and tab-
to be securely attached
Color of tape
Tape quality- no
wrinkling/puckering
Fading of color on
washing or ironing
Deformities due to
washing/ironing
Kinds of defects-
Ratcheting
Shear
Slider distortion
Sewing
Bottom stop
Hump
Popping
Wrongly placed closures at zip
end
Chemical degradation
Design problems
-
Trim Defects
Buttons
Clear holes
Uniform thickness
Color
Laundering/ironing/dry
cleaning pressures
No cracked edges or
sharp edges at holes
Uniform distance of
holes
Buckles
Sharp edges
Color/material-
appropriate for use
Snap Fasteners
Close properly
Metal quality
No sharp edges after
attaching
-
Testing of TrimsZippers Durability of finish of zippers to laundering
Colorfastness of zippers to laundering
Colorfastness of zippers to light
Colorfastness of zippers to crocking
Colorfastness of zippers to laundering
Durability of finish of zippers to dry cleaning
Resistance of zippers to salt spray (fog)
Measuring of zipper dimensions
Strength tests of zippers
Operability of zippers
-
Testing of Trims
Buttons
Impact Resistance
Shape
Uniformity
Resistance to Unsnapping - Snap Fasteners
Hook and loop fasteners
peel strength
sheer strength
shrinkage,
color fastness
-
Testing of Trims
Elastic-
Resistance to degradation (becoming loose,
losing elasticity) due to laundering
Elastic Limit Testing
Fusible Interlining
Bond Strength
Shrinkage and Stretch
Delamination and Strike back
-
Testing of Trims
Sewing threads Friction testing
Colorfastness test & abrasion resistance
Yarn number testing
Twist balance
Shrinkage
Strength and Elongation
Twist
Evenness
Diameter (Thickness)
-
Mid term
-
Post mid term session 17,18
Procedures practiced for Quality
Control and Assurance
(Cutting,Fusing)
Ref:Managing Quality in the apparel Industry-
Mehta and Bharadwaj-Page 34-42
-
Cutting room Quality procedures
-
Cutting Deptt.-activities
Fabric inspection
Pattern making
Marker planning
Spreading
Cutting
Bundling
Ticketing
Fusing
-
Pattern
Basic block + seam allowances = working patterns
working patterns are graded= full set patterns
Full set patterns adjusted for fabric characteristics e.g shrinkage factors= production patterns
Each graded paper pattern must have the following information written on it-size,cut,grain line and name of component part.
-
Requirements of Marker Planning
1) Nature of the fabric and desired result in
the finished garment-
pattern alignment to grain
design characteristics of finished style
pattern style
2) Requirements of quality in cutting
knife clearance
pattern count
appropriate labeling
3)Requirements of Production Planning
-
Factors affecting Marker Planning
Fabric Characteristics
Differences in face & back.
Lengthwise /crosswise symmetry
Need for matching the design
Length of design repeat
Fabric width
Characteristics of Pattern pieces
As number of garment sizes on marker increases the fabric utilization becomes better.
-
Marker making Check ListDivision/Season: Style:
Fabric Pattern# and Swatch: Roll #:
Piece Length:
Width of Piece Goods:
Fabric properties- Directional/Non-Directional
.
-
Cutting -Spreading
Factors affecting spreading
form or nature of the material package
Direction of the material surface w.r.t the
cutting table surface
Direction of surface nap or design w.r.t
the ends of the spread.
-
Cutting -Spreading Process of Spreading- requirements
Splice points to be marked- to avoid fabric flaws
Shades to be sorted out
Ply direction
Stability of the lay
Alignment of plies- length and width
Ply tension
Static elimination
Distortion of spread
Fusion of plies
-
Cutting-requirements
Precision of cut
Clean edges-
no fraying or jagged edges
Unscorched , Unfused surface-appropriate cutting
equipment;
shape of the part and
condition of the knife
Support of the lay
Consistent cutting
Depth of spread
no. of plies and the thickness of ply
Density of material-fabric weight-fibre;yarn size and count
-
Cutting-requirements
Quality criteria-
Knife Clearance
Accuracy of cut-
marker precision
stability of the lay
proper cutting sequence
Cutting pitch
Choice of appropriate cutting knife
Condition of knife blade
-
1. Temperature-Need an optimum ``glue-line
temperature or ``interface temperature``. Once this
temperature is reached the bonding will occur.
At the correct temperature, the resin changes from a
dry solid to a viscous liquid which penetrates the
fibers by suitable application of pressure. After
cooling this re-solidifies and bonding occurs thus.
If the temperature is not reached- fusing will not
take place as resin will not polymerize.
If the temperature is exceeded-can have problems of
`strike-back'; adhesive migration and low bond
strength can be experienced.
Fusing- process parameters
-
2.Time-The function of the time element is to compensate for the delay in the transmission of heat from the source to the fusible agent. It is simply the time duration the composite should be exposed to heat. This time component relates to-
The time when the 2 plates of the press actually meet with the correct specific pressure or the time for which the assemblies are actually in the heating zone if a continuous press is used.
The type of interlining used i.e whether it has a low or high melt adhesive system or if it has a light or heavy weight substrate.
The type of application for which the fusible is to be used
The nature of the shell fabric being used.
The type of fusing equipment employed.
Fusing - process parameters
-
Fusing - process parameters3.Pressure - pressure is necessary to ensure
that intimate contact is effected between fusible interlining and the shell fabric.
Adequate heat transfer takes place
Controlled even penetration of the of the adhesive takes place into the fibers.
Pressure is normally recommended depending on the viscous or flow property of the glue.
4.Cooling cooling is very necessary for the bonding to take place after the fusing process is over
-
Fusing - process parameters Sequence of the process parameters-
first heat should be applied to raise the temperature of the interlining-fabric composite to the glue-line temperature.
Pressure is then applied to enable the adhesive dots of interlining to penetrate the base fabric.
Heat and pressure should not be applied together as this may result in flattening of adhesive dots and resulting unnecessary stiffness in the fused fabric due to increasing area of contact between fabric and interlining.
Flattening of adhesive dots also result in less penetration of adhesive onto the base fabric thus reducing the peel-bond strength.
Cooling after the final pressure.
-
Fusing Performance parameters also depend on-
material and weight of the substrate and
fiber content- cotton and rayon give softer hand
feel;polyester and nylon are used for their strength,
stability and resiliency.Blends of fibers are very
common.wool and hair fibers may be used to provide
resiliency and shape retention and used in wool piece
goods.
resin application methods - commonly used- others include-
scatter coating preformed systems
dry dot printed coating extrusion laminating
paste coating & emulsion coating
-
Fusing -Quality parameters
Quality problems associated with fusing
Strike back
Strike through
Shrinkage
Delamination
Color change
Bubbling
Boardiness
-
Session 19,20
Understanding quality procedures in
sampling
Different stages of samples
-
Product development process
-
Proto Sample
Fit sample
Size set sample
Sealor/sealed sample
Pre production sample/
pilot run sample
TOP sample
Shipment sample
Sampling process
Photo Samples/Salesman Samples
-
Sampling Process Once the merchandiser/designer approve the proto sample
then specs are corrected and fit sample is made.
Corrections on the fit sample lead to a graded size specs and size set
Photo samples/salesman samples in correct design/color and sample size are submitted next
Pre production sample (PPS)/pilot run sample is sent with the bulk fabric and all trims in correct placement with the required after treatment and packaging to make the buyer aware of the shipment which is expected from bulk.
A counter sample or sealed sample is sent along with all corrections made , in correct construction and correct trims with any special instructions from the buyer to the production for production reference.
-
Sewing room Quality procedures
Quality Assurance for Textiles and Apparel-Sara J. Kadolph-Page
375,
Managing Quality in the apparel Industry-Mehta and Bhardwaj
Ch 2
-
Type of Sample Size Material Stages at which it is sent PurposePrototype Samples Average Nearest substitute of fabric At which suppliers are still trying to confirm the
style and trying to get an order
To finalize Fit, construction, and converting sketch/design into
garment.
Salesman samples Average Exactly same fabric After approval of prototype, still trying to get
order from buyer
To know the opinion of the store owners whether the style would sell
in the market or not, and the demand of that product.Helps to book
colorwise-size wise quantities
Fit sample Average Could be substitute if not available. Made after order is booked. Refining a fit & construction from either prototype or salesman
sample, and/or make changes to these samples as required in the
design.
Size-set samples All sizes Exactly same fabric, trims and other value
added work
After fit and construction of average size is
approved.
The purpose is to check the actual approval for production of all the
sizes and also to approve the desired value added work (like printing,
embroidary etc.) to be done on the garment.
Sealer's sample Average Exactly same fabric, trims and other value
added work
After Size-set for the style has been approved. This sample sealed for the bulk i.e. manufacturer will have to make the
exact pieces for bulk.
Pre-production
sample/Advertisement/Photosh
oot sample
Average Exactly same When the initial yardage of bulk fabric is
received.
This is made for advertisement, making catalogue, photoshoot or only
for buyer's referance that how the garment will look like finally.
Top of production Average Exactly same During the execution of production order. To see whether the bulk pieces are coming out alright or not, whether
the quality and construction is matching to the sealer sample or not.
Vendor always tries to select the best quality pieces to send as TOPs.
Shipment samples Average Exactly same Before sending the shipment to the buyer's
warehouse.
Shipment sample is a representative of bulk reaching buyer's
warehouse/DC. It goes from vendor to buyer's office, to buyer's
warehouse/distribution centre and finally to Store. Shipment sample
need to be in correct colour, trims, packing etc.aganist which DC will
check the bulk quantity received.
-
Q.A in sewing department
Two aspects-
1. Operator training as related to quality -operators
to be
1. Aware of the quality standards of the organization
2. Aware of the quality parameters with regards to the
product's fit ,appearance and construction
3. Aware of what constitutes a defect and how to avoid
it.
4. Aware of the correct usage of the fabric and trims
being used.
-
Q.A in sewing department
2. Setting quality standards for sewing
operations
Written quality specs for each operation
spi
Seam type, stitch type, machine type
Matching and/or balancing requirements
Sketch and /or Sample of quality standard
for each operation
Tolerances if any
-
Sewing defects
Needle hole damage
Feed damage
Skipped stitches
Thread break
Broken/joint stitches
Seam grin
Seam pucker
Pleated seam
Wrong spi
Uneven stitch density
Oil spots/stains
Poorly formed stitches
-
Sewing defects
1. Needle damage
Causes holes, picked threads, ruptured threads
or other damages to the fabric.
Caused by wrong size or type of needle, blunt
needle, needle point damaged, needle heat or
machine needle feeding.
Can be remedied by changing the needle or
adjusting the feed mechanism.
-
Sewing defects
2. Feed Damage-
Causes damage on the fabric surface or on seam
Caused by incorrect type of teeth, excessive pressure by foot,improper alignment of feed dog and presser foot, damaged throat plate or excessive machine speed
Remedied by adjusting the feed dog teeth,pressure of the foot,or changing the damaged throat plate
-
Sewing defects
3. Skipped stitches-
Causes excessively long stitches of two or
more stitch lengths during the stitch cycle
Caused by the hook irregularly failing to pick
up the loop of thread from the needle`s eye .
Can be remedied by adjusting the type of
needle, length of needle, bobbin hook
position,matching thread to needle
-
Sewing defects
4. Thread breaks-
Caused by too thick a thread for the needle,too thin a thread for the needle, needle heat,operator working unrhythmically or tight tensions
Remedied by adjusting the correct thread size to needle size, adjusting the machine tension, operator training and using a treated thread to counter needle heat.
-
Sewing defects
5. Broken stitches
Cause unseemly seam appearance and less strength of the seam
Caused by wrong stitch type,too tight tensions,a badly formed joint in the seam where the second line of stitches run over the first and crack it, sharp feeds and too great a pressure
Can be remedied by adjusting the feed dog position and pressure,adjusting the tension,selecting the correct stitch type for the seam.
-
Sewing defects
6. Seam grin-
Causes the seam stitch line to be seen and
seam to open up when pressure is applied
Caused by too loose a tension or too large a
stitch length or the wrong type of stitch.
Can be remedied by adjusting the stitch
density, stitch tension or the stitch type.
-
Sewing defects
7. Seam pucker-
Causes the seam to appear wrinkled
Caused by differential fabric stretch,differential fabric dimensional instability,due to extension in sewing thread, due to sewing thread shrinkage,due to structural jamming, due to mismatched patterns
Remedied by using special feed systems,using dimensionally stable fabric,adjusting tension settings or changing thread type,matching performance of thread to fabric,fabric design change or sewing at bias and proper cutting respectively.
-
Sewing defects
8. Staggered stitches-
Causes poor appearance of the seam
Caused by yarns in the fabric deflecting
needle away from the straight line of
stitching,faulty feed motion,incorrect needle
Remedied by stitching on a slightly bias angle
where the fabric is hard woven,adjusting the
feed mechanismor changing the needle.
-
Sewing defects
9. Improperly formed stitches-
Causes reduced stretch in the stitch line,causes needle thread to show on the underside or bobbin thread to be visible on top
Caused by poor tension,incorrectly adjusted stitch timing or improperly fitting machine components
Remedied by adjusting the feed mechanism, stitch timing,tension
-
Sewing defects
10. Variable stitch density
Caused by insufficient foot pressure, slippery
or sticky surface of fabric
Remedied by increasing the pressure or using
specialized feed systems.
-
Seaming defects
Incorrect width of inlay
Incorrect shape of sewing line
Insecure back stitch
Twisted seam
Mismatched checks/stripes
Reversed garment parts
Wrong seam type
Wrong shade of thread
Extraneous part caught in seam
-
Assembly defects
Finished components not correct to
size/shape/symmetry
Components/parts wrongly positioned
Garment parts pleated/twisted/showing
bubbles/fullness
Parts shaded
Wrong one way direction
Mismatched trimming
-
Pressing and finishing defects
burnt or scorched garments
water spots or stains
gloss or change in color
flattened nap or surface
broken/damaged trims
incorrectly formed crease
garments not thoroughly dried
lining defects- creases, shine marks, pleats
shrinkage/elongation due to heat moisture or incorrect
pressing
-
Inspection
Quality Assurance for Textiles and Apparel-Sara J. Kadolph
Chapters 11-13,
Managing Quality in the apparel Industry-Mehta and Bharadwaj
;Chapter 2 Page 42-74,
-
Act-
if positive results-
action is taken to replicate
the process improvements
across the board
standardization necessary here
if negative results-
plan stage is revisited
and cycle is repeated
Deming`s PDCA cycle
Plan
Check
Act Do
Check-
results of DO stage analyzed
desired objectives met or not
Planning-
what the customer
needs and wants
determine process
goals thru this
examine current process
in view of these goals
Do
implementation of this plan
implemented as a test
case in controlled setting
-
Inspection Loop
Inspection
Detection of defects
Feedback of the defects
to appropriate
personnelDetermination of
causes of defects
Correction of defects
-
Inspectors- Requirements1. Technical knowledge about the job
2. Good vision and color perception
3. Attention to detail
4. Thoroughness in procedure
5. Self-directed
6. Ability to take decisions without bias
7. Ability to work in a team
8. Reasonable knowledge of mats
9. Interest in maintaining the company's reputation for quality merchandise
10. Ability to communicate clearly- verbally and in written form
-
Inspection or audit
The visual examination or review of materials, product components and finished products on the basis of their adherence to some established set of standards ,specifications or requirements.
Can have inspection at different stages of the process- in-process inspection
Or at the end of the process- end process or final inspection.
-
Types Of Inspections- based on
stage in the production process
Inspection
At Source At arrival In ProcessFinished
Goods Vendor
Raw
Material
Fabric
Trims
Acc to
Dept
Acc to
Process
Stability
Setup
Patrol
Spreading
& Cutting
Sewing
Finishing
-
TYPES OF INSPECTION Material inspection
Inspection at the raw material stage.
Source inspection Inspection at the suppliers place including materials, components,
products or documents
In-process inspection Visual inspection of all parts, components and materials during the
production process
In-coming goods inspection Inspection done for goods outsourced
Vendor inspection Inspection done to check vendors facility and operations.
Product inspection Inspection done to ensure whether the product meets the required
standards and specification
-
Inspection or audit1. Raw Material Inspection
Fabric Inspection
length,
width,
quality level (visual and testing) and
Uniformity requirements
Trims Inspection
Interlinings Inspection.
2. In-Process Inspection
Spreading
Cutting
Sewing
Fusing and Printing Operation
Pressing and Finishing Operation
-
Inline Inspection quality parameters
Spreading- Ply alignment, Ply tension, Fabric characteristics
and variations,
Splicing requirements and points,
width and length variation
Type of spread Marking
No. of pattern parts, grain line, pattern alignment, marker width, notches
Cutting- Frayed edges, pattern precision, notches, drills count
Embroidery/Printing Placement, wrong color, wrong print, measurements, missing parts
-
TYPES OF INSPECTION IN
APPAREL INDUSTRY INLINE INSPECTION
Self inspection/no external inspection
100% inspection
Random inspection
FINAL INSPECTION
100% inspection
Spot checking
Arbitrary inspection
Statistical or acceptance sampling
-
In-Process inspection Procedure Complete operational flow chart
Determine Inspection Points
Determine whether 100% or random sampling required.
Amount to be inspected in random sampling depends on-
Kind of Product
Quality policy of the company
Buyer requirements
Other factors such as time, financial constraints, labor restrictions etc.
-
Operation breakdown and flow
chart
-
Men's Tunic Shirt
-
In-Process inspection- Random
Sampling Procedure e.g.
1.Should audit complete finished bundle
2. Inspect every 4th bundle of every operator/operation based on the quality parameters of buyer's AQL or company standards
3. If bundle is rejected, then return the bundle to the operator and inspect the next 3 bundles.
4. If 3 bundles are o.k then go back to inspecting every 4th bundle
-
INLINE INSPECTION FOR
CONTINUOUS PRODUCTION
Inspection done using statistical sampling plans called
Continuous Sampling Plans (CSP)
Combination of 100% inspection and statistical sampling
Example:
100% inspection till a specified number of pieces are found
acceptable
Inspection of only fraction of the pieces produced
If a defective piece is found, revert to first step and follow
same procedure
* Specified number depends upon Accepted Outgoing Quality Level (AOQL)
-
122
Continuous Sampling Plan
Inspect 100%
i
Consecutive
acceptable
units
Inspect fraction f
of the units
Defect
found in
sample
NO
YES NO
YESFLOW OF
THE CSP-1
PLAN
-
In-Line Inspection
In-line inspection should be conducted at least once a shipment.
The checking criteria may be as below:
To check the fabric quality in terms of color shade, hand feel and printed patterns against the standards.
To check the measurements of semi-products against the size specification. When checking this, fabric shrinkage, stretch ability and other factors that may affect the measurement during manufacturing process must be taken into consideration.
-
In-Line Inspection
To check all trimmings in terms of color, function and shape against the approved trim cards, which include labels, hangtags, embroidery, prints, zippers, buckles, etc.
To check the construction in terms of styling and workmanship against the sealed sample.
As the non-conforming products are found, the maker should be pushed taking an immediate corrective action in order to have an immediate improvement
-
Classification Of Defects Critical Defect -A defect is defined as a defect that is
1)resulting in hazardous or unsafe conditions for individual using it or (2) Prevent performance of the tactical function of a major end item.
The critical defects can be
1)Loose components, i.e. buttons, snaps, stones or other miscellaneous parts or any extraneous element is found within a product (insect, part of accessory).;
2) Any items, which have sharp point, sharp edge, or potentially dangerous components, which can cause injury .i.e. broken needles, staples, snaps, rivets, wire and pins;
3) Drawstrings at head or neck for baby or kids products; and
4) Threads or trim which are excessively long or loose which could present a choking hazard to a baby or child if they become entangled.
-
Classification Of Defects
Major Defect -A defect is defined as a
major defect that results in failure, or
reduces materially ,the usability of the unit
of product for its intended purpose.
The major defects can be holes, broken
seam, obvious stains permanent in nature,
etc.
-
Classification Of Defects
Minor Defect -A defect is defined as minor
defect that is not likely to reduce the
usability of the product, but nevertheless
may negatively influence the sales.
The minor defects can be untrimmed
thread-ends, slight dirt in a non- noticeable
zone which can be removed, etc.
-
Product/defect Zones
Garment Zones- Areas which according to their visibility levels to the customer are accorded a status and the acceptance or rejection of the defect is prioritized according to the area or zone in which it occurs.
Based on the kind of defects occurring in specific zones, decisions are taken to accept or reject the product.
-
Product zones ref sara k.
Zone 1or A- areas with high visibility that are likely to be viewed at close distance at time of purchase. Shirts fronts till waist, back till a/h, bottoms- front; flared skirt- till low hip
Zone 2 or B- areas which are not visibly dominant but are visible in normal use. front waist area, back from A/h to 10 cm above hem , bottoms- back.
Zone 3 or C- areas normally hidden in everyday use but could be visible on occasions. shirt side seams , hem area, bottoms- hem of a long skirt full trouser-between knee and hem area, inseam area.
-
Garment Defect Zones
-
How to measure
Blazer/Jacket/Vest/Coat
-
A.Across chest - Measure straight across front at narrowest point between armhole seams. (Garment must
be fastened)
B.Chest/bust- Measure straight across front body, 1" below armhole, from edge to edge
C.Bottom/sweep - Measure along the bottom edge of garment.
D.Total body length from high point of shoulder- Measure from shoulder seam at neck straight down to the
bottom edge of garment.
E.Shoulder seam- -Measure from neck seam along shoulder to armhole seam.
F.Armhole (curved)- -Measure from the joint point of shoulder seam at armhole to joint point of underarm
seam at armhole, following the shape of curve line
G.Armhole (straight)- -Measure straight from the joint point of shoulder seam at armhole to joint point of
underarm seam at armhole.
H.Upper arm(1 " below armhole)- - measure straight across sleeve seam, parallel to sleeve opening.
I.Sleeve length from shoulder- -Measure from joint of shoulder seam at sleeve to bottom edge of sleeve
J.Sleeve length from centre back- -Measure from centre back neck seam across to shoulder seam, down to
bottom edge of sleeve.
K.Sleeve (2" above cuff)- -Measure 2" above cuff or finished edge, straight across sleeve (from edge to
edge).
L.Sleeve opening- -Measure along the edge of sleeve
M.Across shoulder- -Measure straight across back from shoulder/sleeve seam to shoulder/sleeve seam.
N.Across back - Measure straight across back at narrowest point between armhole seams
O.Centre back length - Measure from centre back neck seam, straight across to the bottom edge of garment.
P.Neck opening - Measure along neck seam from centre front to centre back.
Q.Flap width - Measure along the top of flap (from edge to edge).
R.Flap depth - Measure from centre of top edge of flap to bottom edge
S.Welt pocket opening - Measure along the welt pocket opening (from edge to edge).
T.Chest pocket from neck point - Measure from high point of shoulder seam at neck to top of flap or welt.
-
Jeans/Pants/Shorts/Skirt
-
Jeans/Pants/Shorts/Skirt
-
Woven Bottom - Jeans/Pants/Shorts/SkirtA. Waist relaxed
B. High hip
C. Low hip
D. Thigh
E. Knee
F. Leg opening
G. Inseam
H. Outseam
I. Front rise
J. Back rise
K. Back pocket width
L. Back pocket depth
M. Front pocket opening
N. Centre back length
(for skirts )
O. Sweep
(for skirts only)
A. Measure along the centre of waistband. (Garment must be fastened)
B. Measure across hip at specified distance (usually 4" at centre front and side seams) below waist seam.
C. Measure across hip at specified distance (usually 8" at centre front and side seams) below waist seam.
D. Fold garment with inseams matching. Measure across the garment from front crease to back crease at bottom of crotch seams.
E. Fold garment with inseams matching. Specify distance (inches or cm) below crotch seam along inseam. Measure straight across leg from front crease to back crease at indicated point.
F. Measure along the bottom of leg.
G. Fold garment with inseams matching. Measure from cross of crotch seam straight along to the bottom of leg.
H. Fold garment with inseams matching. Measure straight along seam line from bottom of waistband to bottom of leg opening.
I. Measure from waist seam to crotch seam. If there is no waist seam, measure from top of the pants to crotch seam.
J. Measure from waist seam to crotch seam. If there is no waist seam, measure from top of the pants to crotch seam.
K. Measure along the pocket opening (from edge to edge).
L. Measure from top edge down to bottom edge at centre of pocket
M. Measure along pocket edge from waist seam to side seam, following the shape of curve line.
N. Measure waistband seam to the bottom hem. If there is no waistband, measure from the top of skirt to the bottom hem.
O. Measure along the bottom edge of hem.
-
Blouse/Shirt
-
Woven Top - Woven Shirt/BlouseA.Across chest
B. Chest/bust
C. Bottom/sweep
D. Total body length from high point of shoulder
E. Shoulder seam
F.Armhole (straight)
G. Upper arm
H. Sleeve (2" above cuff)
I. Cuff opening
J. Sleeve opening
K. Sleeve length from shoulder
L. Sleeve length from centre back
M. Across shoulder
N. Across back
O. Centre back length
P. Neck opening
Q. Neck opening inside
R. Front neck depth
S. Collar point to point
T. Neck circumference
U. Chest pocket from neck point
V. Chest pocket from centre front
A. Measure straight across front at narrowest point between armhole seams. (Garment must be fastened)
B. Measure straight across front body, 1" below armhole, from edge to edge
C. Measure along the bottom edge of garment
D. Measure from shoulder seam at neck straight down to the bottom edge of garment
E. Measure from neck seam along shoulder to armhole seam.
F. Measure straight from joint of shoulder seam at armhole to joint point of underarm seam at armhole.
G. (1" below armhole), measure straight across sleeve seam, parallel to sleeve opening.
H. Measure 2" above cuff or finished edge, straight across sleeve (from edge to edge), all pleats open.
I. Measure at middle of cuff across sleeve from fold to fold with cuff closed
J. Measure along the edge of sleeve.
K. Measure from shoulder/sleeve seam along top to bottom edge of sleeve
L. Measure from centre back neck seam across to shoulder seam, down to bottom edge of sleeve (Include cuff).
M. Measure straight across back from shoulder/sleeve seam to shoulder/sleeve seam.
N. Measure straight across back at narrowest point between armhole seams
O. Measure from centre back neck seam, straight across to the bottom edge of garment.
P. Measure along neck seam from centre front to centre back.
Q. Measure from inside edge of collar straight across to opposite inside edge of collar.
R. Create an imaginary line across neck at high point shoulder. Measure at centre front from the imaginary line to front neck seam.
S. Measure along the outer edge of top collar from point to point.
T. Measure from centre of button to the end of buttonhole along middle of collar band.
U. Measure from high point of shoulder seam at neck to top of pocket.
V. Measure from centre front to edge of pocket.
-
Knit Top
-
Knit topA. Chest/bust
B. Bottom/sweep
C. Upper arm
D. Sleeve opening
E. Armhole (curved)
F. Total body length from high point of shoulder
G. Sleeve length from shoulder
H. Sleeve length from centre back
I. Across shoulder
J. Neck opening inside
K. Front neck depth
L. Chest pocket from neck point
M. Chest pocket from centre front
N. Minimum neck stretch
A. Measure straight across front body, I" below armhole, from edge to edge.
B. Measure along the bottom edge of garment
C. (1" below armhole), measure straight across sleeve seam, parallel to sleeve opening.
D. Measure along the edge of sleeve.
E. Measure from the joint point of shoulder seam at armhole to the Joint point of underarm seam at armhole, following the shape of curve line.
F. Measure from shoulder seam at neck straight down to the bottom edge of garment
G. Measure from joint of shoulder seam at sleeve to bottom edge of sleeve.
H. Measure from centre back neck seam across to shoulder seam, down to bottom edge of sleeve.
I. Measure straight across back from shoulder/sleeve seam to shoulder/sleeve seam.
J. Measure from inside edge of collar straight across to opposite inside edge of collar.
K. Create an imaginary line across neck at high point shoulder. Measure at centre front from the imaginary line to front neck seam.
L. Measure from high point of shoulder at neck to top of pocket.
M. Measure from centre front to edge of pocket.
N. Stretch neck, do not overextend. Measure straight across the neck opening at neck seam inside edge to edge.
-
Final Inspection
It is the last inspection done before the buyer inspection
All the buyer specifications are checked for-
1. Form Fit checking
2. Sewing- needle damages, sewing defects, assembly defects, quality of seam, placement of labels, cleanliness , correct trims
3. Measurements
4. Final handfeel and look
5. Packing and packaging
-
Final Inspection
Final inspection can be conducted under the
following conditions :
The quantity in carton boxes must be at least up
to 80% of the total shipped quantity.
The sewing or assembly process must be
finished for the balance quantity (20% of the
total shipped quantity).
-
Final Inspection
Types of final inspection
No inspection
100%inspection
spot checking
arbitrary sampling
statistical sampling
-
Final Inspection
Spot checking - inspection of random shipments. Some shipments are inspected while others are not at all inspected
Arbitrary sampling - a certain percentage of shipment is inspected and the accept or reject decision is based on the inspection.
A major drawback is that either too little or too much is inspected.
-
Final Inspection
Statistical sampling-is a system based on the theory that a given amount of samples drawn at random from the production lot will reflect the percent defective in the lot with certain tolerance limits for the percent defectives and within certain limits of probability.
Acceptance sampling plans are used in statistical sampling as a tool to determine the lot acceptance or rejection of the lot
-
Acceptance Sampling System
SAMPLING PLANS AND
PROCEDURES
FOR
INSPECTION BY ATTRIBUTES
ANSI/ASQ Z1.4-2003
(ISO 2859-1)
(MIL-STD 105E)
-
History Standard military sampling procedures for inspection by attributes were
developed during World War II. Army Ordnance tables and procedures were
generated in the early 1940's and these grew into the Army Service Forces
tables. At the end of the war, the Navy also worked on a set of tables.
In the meanwhile, the Statistical Research Group at Columbia University
performed research and outputted many outstanding results on attribute
sampling plans. These three streams combined in 1950 into a standard called
MIL-STD. 105A. It has since been modified from time to time and issued as
105B, 195C and 105D. MIL-STD. 105D was issued by the U.S. government in
1963.
In 1971, it was adopted by the American National Standards Institute as ANSI
Standard Z1.4 and in 1974 it was adopted (with minor changes) by the
International Organization for Standardization as ISO Std. 2859.
The latest revision is MIL-STD 105E and was issued in 1989, and was
cancelled in February 1995 to reduce cost through the elimination of
duplication. ANSI/ASQ Z1.4 is nearly identical to MIL-STD 105E.
-
Acceptance Sampling System
Acceptance sampling is used to determine whether to accept or reject a lot of material that has already been produced.
A lot is defined as a quantity of product accumulated under uniform conditions. For example, from one production line or machine.
-
Acceptance Sampling System
Importance
Acceptance sampling
Do not provide any direct form of quality
improvement.
Not to inspect quality into the products, but
rather as an audit tool to ensure that the output of a
process conforms to requirements.
-
Acceptance Sampling System
Aim
To induce a supplier to maintain a process average at least as good as the specified Acceptable Quality Limit (AQL), whilst at the same time providing an upper limit for the risk to the consumer of accepting the occasional poor lot.
-
Acceptance Sampling System
Why not use 100% Inspection?
6 situations where 100% inspection is often not practical:
When testing is destructive
When inspection costs are extremely high
When time or technology limitations are constraints
When lot sizes are very large and the probability of inspection error is very high
When supplier quality history is good enough to justify less than 100% inspection
When potential liability risks are high enough to warrant some form of continuous monitoring
-
Acceptance Sampling SystemAdvantage
Less expensive because of less inspection.
There is less handling of the products.
It is applicable to destructive testing.
Fewer personnel are involved in inspection activities.
It often greatly reduces the amount of inspection error.
The rejection of entire lots often provides a stronger motivation to the supplier for quality improvement.
-
Acceptance Sampling SystemDisadvantage
Risk of accepting bad lots and rejecting good
lots.
Less information is usually generated.
Acceptance sampling requires planning and
documentation of the acceptance sampling
procedure whereas 100% inspection does not.
-
Acceptance Sampling System >>>
Accept the lots Reject the lots
Acceptable O.K. Producers Risk
RejectableConsumers
RiskO.K.
Decision
Quality
Risk
-
Acceptance Sampling System
Definitions & Terminology
Sampling Plan: A sampling plan indicates the number of units of
products from each lot or batch which are to be inspected (sample
size or series of sample sizes) and the criteria for determining the
acceptability of the lot or batch (acceptance and rejection numbers)
Inspection by Attributes: Inspection by attributes is inspection
whereby either the unit of the product is classified simply as
conforming or nonconforming (Good or Bad), or the number of
nonconformities in the unit of products is counted, with respect to a
given requirement or set of requirements.
-
Acceptance Sampling
Attribute sampling is usually based on Poisson statistics, where sample size and acceptance number (maximum number of BAD units in the sample) are specified.
This generates an Operating Characteristic (OC) that is a plot of the probability of lot acceptance (or confidence level) vs. percent defective in the total lot from which the sample was randomly selected which take the form of Acceptance sampling charts or tables.
-
Acceptance Sampling System
Definitions & Terminology
Acceptable Quality Limit (AQL): The AQL is the quality level
that is the worst tolerable process average when a continuing series
of lots is submitted for acceptance sampling. (ANSI/ASQ Z1.4-
2003)
Also defined as- the maximum percentage defective that for the
purpose of sampling inspection can be considered satisfactory as a
process average.
-
Acceptance Sampling System
Definitions & Terminology
Inspection Level. The inspection level determines the relationship between the lot size and the sample size.
3 general inspection level I , II, III
Level II is designated as normal and will be used unless another inspection level is specified.
Level I requires about half the amount of inspection of inspection as level II, and is used when reduced sampling cost are required and a lower level of discrimination can be tolerated.
Level III requires about twice the amount of inspection as level II, and is used when more discrimination is needed.
4 special inspection levels S1, S2, S3, S4
Use special inspection level when sample size must be kept small and larger sampling risks can be tolerated.
-
Acceptance Sampling SystemThree Types of Sampling Plans
Single Sampling Plan.
Double Sampling Plan.
Multiple Sampling Plan.
Provisions for each type of sampling plan
1. Normal Inspection
2. Tightened Inspection
3. Reduced Inspection
-
Sampling Procedures for Inspection by
Attributes (MIL-STD 105E, ANSI/ASQ Z1.4)
1. Determine the lot size
2. Choose the inspection level to obtain the desired
sample size code letter
3. Determine the appropriate type of sampling plan to
use (single, double or multiple) and the provision of
the plan (single, tightened or reduced)
4. Enter the appropriate table with the desired AQL and
sample size code letter to find the type of sampling
plan to be used (sample size, acceptance and rejection
number)
-
Sampling Procedures for Inspection by
Attributes (MIL-STD 105E, ANSI/ASQ Z1.4)Sample Size Code Letters
to
to
to
to
to
to
to
to
to
to
to
to
to
to
and
150,001
500,001
Lot or Batch Size
501
1,201
3,201
150,000
500,000
over
2
9
16
26
51
91
8
15
25
50
90
150
3,200
10,000
35,000
500
1,200
151
281
D
10,001
280
35,001
D
D
C
General Inspection LevelSpecial Inspection Level
C
C
B
B
C
D
E
E
E
A
A
A
A
B
B
D
E
C
C
D
H
A
A
A
B
B
B
C
F
G
G
C
E
F
C
D
D
A
B
B
S-3S-2S-1
A
J
J
K
G
G
H
E
E
F
C
C
D
S-4
A
A
B
L
M
N
H
J
K
E
F
G
C
C
D
I
A
A
B
N
P
Q
K
L
M
G
H
J
D
E
F
II
A
B
C
P
Q
R
L
M
N
D
H
J
K
E
F
G
III
B
C
-
Sample
size Sample
code size 0.010 0.015 0.025 0.040 0.065 0.10 0.15 0.25 0.40 0.65 1.0 1.5 2.5 4.0 6.5 10 15 25 40 65 100 150 250 400 650
letter Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re
A 2 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
B 3 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 30 31
C 5 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 30 31 44 45
D 8 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 30 31 44 45
E 13 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 30 31 44 45
F 20 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
G 32 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
H 50 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
J 80 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
K 125 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
L 200 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
M 315 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
N 500 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
P 800 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
Q 1250 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
14 15 21 22
Single Sampling Plan For Normal Inspection ( Master Table)
Acceptable Quality Limit (Normal Inspection)
1 2R 2000 2 3 3 4 5 6 7 8 10 11
Sampling Procedures for Inspection by
Attributes (MIL-STD 105E, ANSI/ASQ Z1.4)
-
Single Sampling Plan
Select sample
Inspect sample
Make decision
The decision to
accept or reject the lot
is made based on the
results of a single
sample
-
Double Sampling Plan
Select sample
Inspect sample
Make decision
If there is not a clear accept/
reject decision from inspection
of the first sample, a second
sample is taken and the
decision is made based on the
results of the combined
samples.Is sample
clear accept
or reject
Resample Inspect Resample
-
Sampling Procedures for Inspection by
Attributes (MIL-STD 105E, ANSI/ASQ Z1.4)
Example:-
A lot containing 12, 000 units is to be inspected using General Inspection Level II to a 2.5% AQL. Single sampling plan is to be used.
-
Sampling Procedures for Inspection by
Attributes (MIL-STD 105E, ANSI/ASQ Z1.4)Sample Size Code Letters
to
to
to
to
to
to
to
to
to
to
to
to
to
to
and
E
III
B
C
D
H
J
K
F
G
L
M
N
P
Q
R
II
A
B
C
D
E
F
G
H
J
K
L
M
N
P
Q
I
A
A
B
C
C
D
E
F
G
H
J
K
L
M
N
S-4
A
A
B
C
C
D
E
E
F
G
G
H
J
J
K
S-3S-2S-1
A
A
B
B
C
E
F
C
D
D
F
G
G
H
A
A
A
B
B
B
C
D
E
C
C
D
E
E
A
A
A
A
B
B
General Inspection LevelSpecial Inspection Level
C
C
B
B
C
D
E
D
D
C
151
281
D
10,001
280
35,001
3,200
10,000
35,000
500
1,200
26
51
91
8
15
25
50
90
150
2
9
16
150,001
500,001
Lot or Batch Size
501
1,201
3,201
150,000
500,000
over
-
Sample
size Sample
code size 0.010 0.015 0.025 0.040 0.065 0.10 0.15 0.25 0.40 0.65 1.0 1.5 2.5 4.0 6.5 10 15 25 40 65 100 150 250 400 650
letter Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re Ac Re
A 2 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
B 3 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 30 31
C 5 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 30 31 44 45
D 8 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 30 31 44 45
E 13 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22 30 31 44 45
F 20 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
G 32 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
H 50 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
J 80 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
K 125 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
L 200 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
M 315 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
N 500 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
P 800 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
Q 1250 0 1 1 2 2 3 3 4 5 6 7 8 10 11 14 15 21 22
7 8 10 11 14 15 21 22
Single Sampling Plan For Normal Inspection ( Master Table)
Acceptable Quality Limit (Normal Inspection)
1 2R 2000 2 3 3 4 5 6
Sampling Procedures for Inspection by
Attributes (MIL-STD 105E, ANSI/ASQ Z1.4)
-
Acceptance Sampling SystemDefinitions & Terminology
Normal Inspection - Used at the start of the inspection activity.
Tightened Inspection - Used when the vendors recent quality
history has deteriorated (acceptance criteria are more stringent
than under normal inspection)
Reduced Inspection - Used when the vendors recent quality
history ahs been exceptionally good (sample sizes are usually
smaller than under normal inspection).
-
Acceptance Sampling SystemSwitching Procedures
-
Assignment 2 Students to select a set of 2 different defective
garments. Each student needs to go through the
garments and list down the defects. All garments
need to be analyzed for all possible cutting room,
sewing room, finishing room and fabric defects
and their possible remedies.
Class assignment to be completed on 1.12.10
and presented to class on 3.12.10 at 10.30 a.m
Students will be marked individually for the
selection of the garment and the analysis of the
defects with their possible prevention method.
-
Buyers Audit criteria
BUYER Manual
-
Generally included areas
Vendor contractual terms
Fabric inspection, inline and final
inspection procedures and formats to be used
Defect criteria and tolerances
Measurement criteria-how to measure
Packing ,labeling, shipping requirements
-
Meaning of AQL
When a consumer designates some specific value of AQL for a
certain nonconformity or group of nonconformities, it indicates to the
supplier that the consumers acceptance sampling plan will accept the
great majority of the lots or batches that the supplier submits, provided the
process average level of percent nonconforming (or nonconformities per
hundred units) that the consumer indicates will be accepted most of the
time by the acceptance sampling procedures to be used. The sampling
plans provided herein are so arranged that the probability of acceptance at
the designated AQL value depends upon sample size, being generally
higher for larger samples than for smaller one, for a given AQL.
The AQL alone does not describe the protection to the consumer
for individual lots and batches, but more directly relates to what might be
expected from a series of lots or batches, provided the steps indicated in
this sampling procedures are taken.
-
Acceptance Sampling System
Definitions & Terminology
Percent nonconforming The percent nonconforming of any
given quantity of units of product is one hundred times the
number of nonconforming units divided by the total number of
units of products, i.e.:
number of nonconforming
number of units inspectedPercent nonconforming = X 100
-
Acceptance Sampling System
Switching Procedures
Normal to Tightened. When normal inspection is in effect,
tightened inspection shall be instituted when 2 out of 5
consecutive lots or batches have been non-acceptable on original
inspection (i.e. ignoring resubmitted lots and batches for this
procedure).
Tightened to Normal. When tightened inspection is in effect,
normal inspection shall be instituted when 5 consecutive lots or
batches have been considered acceptable on original inspection.
-
Acceptance Sampling SystemSwitching Procedures
Normal to Reduced. When normal inspection is in effect, reduced inspection shall be
instituted providing that the following conditions are satisfied:
a. The preceding 10 lots or batches have been on normal inspection and all have been
accepted on original inspection; and
b. the total number of nonconforming units in the samples from the preceding 10 lots
or batches is equal to or less than the applicable number given in the limit number
sampling table. If double or multiple sampling is in use, all samples inspected should
be included, not first samples only ; and
c. Production is at steady rate; and
d. Reduced inspection is considered desirable.
-
Acceptance Sampling SystemSwitching Procedures
Reduced to Normal. When reduced inspection is in effect, normal inspection shall be
instituted if any of the following occur on original inspection:
a. A lot size or batch is rejected; or
b. A lot is consider acceptable under the special procedures for reduced inspection
where the sampling procedure may be terminated without making a decision; or
c. Production becomes irregular or delayed; or
d. Other conditions warrant that normal inspection shall be instituted.
-
Acceptance Sampling System
Switching Procedures
Discontinuation of Inspection. In the event that 5 consecutive
lots remain on the tightened inspection, inspection under the
provisions of this standard should be discontinued pending
action to improve the quality of submitted material.