List of Quality Assurance Tools and Techniques

by Engr. Kh. Mashiur Rahman | Nov 9, 2013 | QC QA

What is Quality Assurance?

Quality assurance -QA is consists of quality measuring system by quality equipment when production process is completed. Here, we have described some quality assurance system of dyeing and finishing unit

Quality Assurance Tools and Techniques:

Various types of machineries and equipment are used by quality assurance analyst or quality manager during testing. Following equipment’s are the main instruments for testing of quality assurance. All of the qc tool is not contrived by same manufacturing companies. Various qc tool manufacturing companies certified by iso 9001 are liable to provide such types of equipment’s for the textile factory. ISO 9001 standard qc tool or quality assurance tester list for quality assurance is given in this post

List of Quality Equipment :

List of quality equipment is shorted here-

• Crock meter
• Electric Balance
• Other software quality assurance
• Abrasion Tester
• Day light box
• GSM Tester
• Online fabric inspection
• Packing equipment
• GSM Cutter
• Fabric Inspection Machine
• PH meter
• Doubling equipments
• Storage equipment
• Spectrophotometer
• Data color Software
• Mini dyeing machine
• Iron
• Quality assurance tester
• Cloth Measuring Tape

 QA and QC Test:  

• Fastness to water spotting test
• Fastness to perspiration test
• Tear strength test
• Fastness to actual laundering test
• Fastness to sea water test
• Pilling resistance test
• Thermal stability test
• Crease resistance test
• Fastness to washing test
• Fastness to light test
• Fastness to heat test
• Seam slippage test
• Width test
• Tensile strength test
• Threads per inch test
• Fabric weight test
• Fastness to chlorinated water test
• Abrasion resistance test
• Stretch ability & growth recovery test
• Smoothness appearance test

Some Online Quality assurance tools and techniques :

Applicable test: The applicable QA test for pretreatment performance is as follows-

• Pick up percentage test.
• Barium activity number of mercerized fabric.
• pH test.
• Absorbency test.
• Size test.
• Whiteness test.
• Desized wash test.

Test procedure: Pick up percentage test:The pick percentage test procedure is as follows-

• Machine / solution used :N/A
• Machine / solution manufactured by:N/A
• Person responsible:QA checker or inspector
• Frequency:After change of padder, every month following maintenance and/or whenever required.
• Procedure 1 :Make 3 polythene bag (previously weight denoted BL, BA, BR) L, C and R thus will be use to hold the sample taken during the pickup check. L, C & R represent the position from where the sample is taken. Looking down the machine from the face end in the same direction as the fabric is running, left hand side of the machine will designed as L, center C & right hand side is R.
• Procedure 2:Stop the machine when seam level the nip of the padder and cut three samples from the fabric each approximately 3 square inch.
• Procedure 3 :Place the sample into the bag and seal the bag tightly to prevent the moisture loss. Then weigh each of the bag with the sample inside and record the weight (WL, WC, WR).
• Procedure 4 :Take the sample out of the bags. Dry the entire sample and the bag on an oven.
• Procedure 5 :When dried take the bag out of the oven and allow them to cool, then take the sample out of the oven and immediately place them in a correct bag.
• Procedure 6 :Aloe further cooling of the samples (for 5 min) and reweight the bag with the sample inside and record the weight (DL, DC, DL)
• Procedure 7 :Performance standard:Singe & Desize = (80-100) %, Scour & Bleach = (110-120)%, Mercerized    =  (90-100)%,  Stenter              =   (50-70) %
• Procedure 8 :In case of non conformity :Inform mechanical maintenance personnel / relevant area in charge for corrective action.

Barium activity number of mercerized fabric test: The procedure for barium activity number test on mercerized cloth is given bellow-

• Machine / solution used :N/A
• Machine / solution manufactured by:N/A
• Person responsible:QA lab assistant
• Frequency:As and when required
• Procedure Take one unmercerized sample and 3 more sample from left, center and right so that the sample weight is approximately 5 gm. Check the pH if the value is not natural than washed the sample with 10 g/l natural soap and 2 g/l soda ash.boi the sample for one hour and checked the pH of washed liquid. Than dry the sample.
• Procedure    After drying take accurately 2 gm portion of each of the sample and cut them into 3mm square. Place the cut portion in 250 ml volumetric flask. Add 30 ml of 0.25 N barium hydroxide solutions in each of flask and keep them for 2 hours. Stir the content at some interval.
• Procedure    After 2 hours pipette out 10 ml of solution from the flask and titrate with 1 N HCl. Not down the reading.
• Performance standard:128-140
• In case of non conformity :Inform mechanical maintenance personnel / relevant area in charge for corrective action.

pH test:  The details of pH test procedue is given bellow-

• Machine / solution used :Universal indicator solution, flame able liquid, mixable with water, color scale range for pH 4-10
• Machine / solution manufactured by:E-Merck (India) LTd.
• Person responsible:QA lab assistant
• Frequency:Every thousand meter
• Procedure :2-3 drop of water are spayed over the fabric, and then added 1-2 drop of pH solution over it. The resulted color is than compared with the scale. Performance standard:pH 7-8 for reactive. pH ≤ 7 for disperse.
• In case of non conformity :Hot wash

Absorbency test:

• Machine / solution used :N/A
• Machine / solution manufactured by:N/A
• Person responsible:QA lab assistant
• Frequency:Every thousand meter
• Procedure :A full width mercerized fabric is taken. 3 samples are cut from that piece, one from left, one from right and one from center. The size of the sample is (1.3-2.5) cm. Each of the sample is up to 5 cm showing every single cm. the samples are than dipped in the solution (0.5 gm reactive dyes is dissolve in 200 cc water) for 1 min. generally one or less than one cm is dipped in the solution and it is expected that the minimum performance standard.
• Performance standard:Minimum 3 cm
• In case of non conformity :adding with wetting agent or rewash or rebleach.

Size test:

• Machine / solution used :Lodin solution
• Machine / solution manufactured by:N/A
• Person responsible:QA lab assistant
• Frequency:Every thousand meter
• Procedure :1. Preparation of iodine solution-  Dissolved 10 gm of potassium iodide in 100 ml of water, add 0.65 gm of iodine and shack till complete dissolution. Fill with water with 800 ml mark and then with ethanol up to 1 liter.
• Application: Put a drop of the solution take 1 ml solution and dissolve in 99 ml of distill water. Drop method-    Take 0.1 N iodine solution and dissolved on 99 ml of distill water
• Application 2: Put a drop of the solution on the fabric and compare the color with the scale.
• Performance standard:6 min (degree of desizing)
• In case of non conformity :Re-scouring

Whiteness test:

• Machine / solution used :Spectrophotometer
• Machine / solution manufactured by:Date color international
• Person responsible:QA lab assistant
• Frequency:Every 100 meter
• Procedure :Measure the whiteness and compare the result.
• Performance standard:Whiteness chart is given bellow-
• In case of non conformity :Re-bleaching

Width test:

• Machine / solution used :Measuring tape
• Machine / solution manufactured by:N/A
• Person responsible:QA lab assistant
• Frequency:Every thousand meter
• Procedure :Manual measurement
• Performance standard:In case of mercerizing CVC / PC (142, 144) cm, cotton (144-148) cm, otherwise as per customer specification.
• In case of non conformity :Stretching.

Desized wash test:

• Machine / solution used :Dyeing padder
• Machine / solution manufactured by:Werner Mathis AG Switzerland
• Person responsible:QA lab assistant
• Frequency:Every yarn dyed fabric
• Procedure :Take one square feet sample. Use desizing recipe and pad the sample fabric under the following condition. Temperature 70°C, pH 7 padder pressure 2.5 bar, batching time 12 hr. Hot wash the padded sample with water at 90 °C for 2 min. Dry. Take a part of the dried sample and padded with 0.5 g/l OBA at room temperature with padder pressure being 2.5 bar. Dry again.     Prepare the desized washed sample sheet (with greige fabric, desized washed fabric and the OBA treated one). Finally compare the sheet with the original swatch (if the fabric is soft finished)
• Performance standard:Match with original.
• In case of non conformity:During processing, after washing checked the shade if it does not match go for topping.
• Applicable test for solid dyed fabric are as follows- Shade check, Listing, Wash fastness, Crocking fastness.

Shade check:

• Machine :Spectrophotometer
• Machine manufactured by :Data color international.
• Person responsible:QA lab assistant
• Frequency:Every thousand
• Procedure :1.Collect sample from dyeing after every thousand meter. 2. Measure the sample by spectrophotometer. 3. Print out the result. 4. Make shade continuity card. 5.           Samples are also compared visually with approved lab dip.
• Performance standard:E value 1.0-1.5
• In case of non conformity:Inform QA executive who take the following necessary action:

Listing:

• Machine / solution used :N/A
• Machine / solution manufactured by:N/A
• Person responsible:QA lab assistant
• Frequency:Every thousand meter
• Procedure :1.A full width sample is cut into 7 pieces and sewed in the following manner and checked with one another in the light specified by the customer. A full width sample is cut into5 pieces and sewed in the following manner and checked with one another in the light specified by the customer.
• In case of non conformity :If listing problem occur, the responsible person in production should be informed generally increasing or decreasing padder pressure solved the problem.

Wash fastness test (for dark shade only):

• Machine used :Gyro wash
• Machine manufactured by:James . H . Heals and company, England
• Person responsible:QA lab assistant
• Frequency:Every order
• Procedure :Method BS 1006 ref:C06 C2S
• Performance standard:For color change – 4C
• For color staining- 4S
• In case of non conformity :Re wash

Crock fastness (for dark shade only):

• Machine used :Crock meter
• Machine manufactured by:Na
• Person responsible:QA lab assistant
• Frequency:Every order
• Procedure :Method BS 1006 ref: X 12
• In case of non conformity :Re-wash or spiral finish with softener which improve crock fastness

7 QC Tools :

Quality assurance and quality control also maintain 7 qc tools  techniques. The techniques are listed below-

1. Cause and effect diagram
2. Pareto chart
3. Scatter diagram
4. Stratification
5. Check sheet
6. Control chart
7. Histogram

Engr. Kh. Mashiur Rahman, Garments Auto Machine Technologist, Web: www.autogarment.com, Email: autogarments@gmail.com, Cell: +88 01 792 52 53 54