Quality is non-negotiable and must be built in the garment. A lot has been said about quality and industry in general is aware about its importance. According to Mausmi Ambastha, the correct measures can pave the way to improved quality levels that most factories strive to achieve.
Mausmi, Founder and COO of ThreadSol, has several years of experience as a consultant with industry expertise in Sewing, Merchandising, Inventory Control and Supply Chain Management.
Right First Time/First Time Right
The goal should be to spend time and energy only while creating a product and not wasted on repair or rework. This time spent on rectification is borne by the company and hence the margin on that product is reduced.
Number of good products produced: Total number of products passed without any repair, rework or rejection.
Number of total products produced: Total number of products produced/inspected in the line. This will include all goods including scrapped, reworked and rejects. Care should be taken to count the repaired products only once. This can be applied at every inspection point or at the end of each process, thereby evaluating the quality level of that department.
Example: In factory XYZ, if end-line inspection table inspected 450 garments in a day and found 50 garments that needed repair or were rejected, then the value of Right First Time at mid-line is 450-50= 400. 400/450 X 100 = 88.89%.
Percentage defective level
Percentage defective level is also known as defect percentage. It is the basic measure of quality percentage that most factories use at the end-line and in the finishing department.
This can be calculated on an hourly, daily, line wise or on complete order basis. Factories measure defect percentage on an hourly basis to continuously monitor quality. The lower the defect percentage, the better the quality. This can be measured at any inspection point.
Example: Percentage defective level for previous example is (100-88.9) = 11.1%.
Defects per Hundred Units (DHU)
DHU is the ratio of number of defects per lot or sample, expressed as a percentage. It is possible that one garment may have more than one defect. Each defect is counted separately as every defect represents additional workload of repair and rework.
This is a very important measure of quality on the production floor and analysis of this data can also highlight quality bottlenecks.
Example: In the previous example, out of the 50 garments that were rejected out of the 450 inspected, there were 20 garments which had 3 defects each, 20 garments which had 2 defects each and 10 garments had 1 defect each. Total defects in 450 garments were 110. Therefore, DHU is 110 X 100/450 = 24.4%.
AQL (Acceptable Quality Level)
An acceptable quality level is an inspection standard describing the maximum number of defects that could be considered acceptable during the random sampling in an inspection. An AQL table determines two key elements:
a) Number of samples to be inspected
b) The limit between acceptability and refusal, when it comes to defective products
Defects found during inspection are sometimes classified into three levels: critical, major and minor. Different companies maintain different interpretations of each type of defect. In order to avoid argument, buyers and sellers agree on an AQL standard, which they use as a reference during pre-shipment inspection to evaluate quality.
Before using AQL tables, three things must be determined:
Lot size, Inspection level, AQL level for both major and minor defects.
“I want no more than 1.5% defective items in the whole order quantity”, meaning the AQL is 1.5 for both major and minor defects. Critical defects often have zero tolerance.
Example: Buyer for factory XYZ follows ‘general inspection level II’ and AQL 1.5 for both major and minor defects. For a lot size of 450 pieces, a sample size of 50 pieces should be taken and if 3 or more defects are found, the shipment is rejected.