The quality control of sweater processing workshop runs through the entire production process from raw material input to finished product output, aiming to ensure that each sweater meets the established quality standards. The following is a detailed quality control process:
- Raw material inspection
Purchase acceptance: After the raw materials arrive, the quality control personnel first check the delivery note and purchase order to ensure that the types, specifications and quantities of wool yarn and accessories (such as buttons, zippers, etc.) are accurate.
Appearance inspection: Perform appearance inspection on the wool yarn to check whether there are problems such as color difference, uneven thickness, knots, impurities, etc. For accessories, check whether the buttons are damaged and whether the zipper is smooth.
Physical performance testing: Take some wool yarn samples to test their physical performance indicators such as strength, elasticity, shrinkage, etc. These indicators must meet the product design requirements. For example, the wool yarn used to make thick winter sweaters should have sufficient warmth retention and good elastic recovery.
Chemical performance testing: Test for chemical substances that may affect human health or product quality, such as formaldehyde and heavy metal content in dyes. The test results must comply with relevant national and industry standards to ensure consumer safety. Only raw materials that have passed the above comprehensive inspections are allowed to enter the production workshop. - Knitting process quality control
First piece inspection: When each sweater starts to be knitted, the operator makes the first product. Quality control personnel conduct a detailed inspection of the knitting needles, patterns, and sizes of the first sweater based on the design drawings and process requirements. If problems are found, adjust the knitting equipment parameters or operating methods in time to avoid batch errors.
Inspection: During the knitting process, quality control personnel conduct regular inspections. Observe whether the operator’s knitting techniques are standardized, check whether the knitting equipment is operating normally, and ensure that the knitting density is uniform, there are no missing needles, no wrong needles, etc. For areas with complex patterns or special needles, increase the frequency of inspections.
Semi-finished product sampling inspection: Random sampling inspections of knitted semi-finished products (such as front and back pieces, sleeves, etc.) are carried out according to a certain proportion. In addition to checking the size, needles, etc., it is also necessary to check whether the edges of the semi-finished products are neat and whether there are signs of de-threading. If unqualified products are found, immediately trace the source of the problem, take corresponding corrective measures, and review the semi-finished products that have been produced. - Sewing process quality control
Sewing process confirmation: Before starting sewing, the quality control personnel confirm whether the sewing process meets the requirements, such as whether the selection of sewing thread matches the sweater material, and whether the sewing needle method can ensure firmness and smooth appearance.
First sewing inspection: A comprehensive inspection of the first sewn sweater is carried out, focusing on the firmness of the sewing parts, the uniformity of the stitches, and whether the overall shape of each component after sewing meets the design. If there are any problems, adjust the sewing process and operation methods in time.
Process inspection: During the sewing process, the quality control personnel conduct regular inspections to check whether the operators sew strictly in accordance with the process requirements to avoid problems such as sewing deviation, missing seams, and skipping. At the same time, check the operating status of the sewing equipment to ensure the normal operation of the equipment and the stability of the sewing quality. - Finishing quality control
Cleaning quality inspection: After the sweater is washed, check the cleaning effect to ensure that the stains are removed cleanly and the sweater is not faded or deformed. At the same time, check whether the residual chemicals in the washing water meet the standards to avoid secondary pollution of the sweater.
Ironing quality inspection: After ironing, check the flatness, glossiness and shaping effect of each part of the sweater. Key parts such as collars, cuffs, and hems should have smooth lines and regular shapes. For sweaters with special styling requirements, ensure that the design effect is achieved after ironing. - Final inspection of finished products
Full inspection or random inspection: According to the order requirements and product characteristics, the finished sweaters are fully inspected or randomly inspected at a certain ratio. Full inspection is suitable for high-quality and high-requirement orders, and random inspection is carried out according to sampling standards.
Appearance inspection: Carefully check whether there are stains, color flowers, damage, hair balls and other problems on the surface of the sweater. Check whether the color of the sweater is uniform and consistent, and whether there is obvious color difference compared with the standard color card. At the same time, check whether the patterns and embroidery on the sweater are clear, complete, and accurate in position.
Size inspection: Use professional measuring tools to measure the key dimensions of the sweater, such as chest circumference, shoulder width, sleeve length, and length, to ensure that they meet the design specifications and the error is within the allowable range.
Physical performance review: Review the physical properties of some finished products, such as shrinkage rate, color fastness, etc., to ensure the stability of product quality.
Functional inspection: For sweaters with special functions, such as zipper sweaters, check whether the zipper is smooth, and button sweaters, check whether the buttons are firm, etc., to ensure that the product functions normally. - Handling of unqualified products
Identification and isolation: Unqualified products found during the inspection process shall be immediately identified and stored separately from qualified products to prevent them from flowing into the next link.
Cause analysis: Organize relevant personnel (such as production personnel, technical personnel, quality control personnel) to analyze unqualified products and find out the reasons for the unqualified products, such as raw material problems, equipment failures, operating errors, unreasonable processes, etc.
Disposal measures: Take corresponding disposal measures according to the reasons for unqualified products and the actual situation of the products. For minor defects, such as a small amount of thread ends and small stains, rework can be performed; for serious defects, such as large weaving defects and serious color differences, scrapping may be required. The reworked products need to be re-inspected until they are qualified.
Preventive measures: Develop and implement preventive measures for the causes of unqualified products to prevent similar problems from happening again. For example, strengthen raw material inspection, provide skills training for operators, optimize production processes, etc. At the same time, evaluate and improve the quality control process and continuously improve the quality control system.
