Inspection standards for injection molded products
1. Inspection environment:
Place the inspected product at a position of 0.8-1 meters under a 40W fluorescent lamp or a 60W ordinary bulb, with a direction of 45-135 degrees and a distance of 30-50 cm between the two eyes. Stay on the visible part of the front for 3-5 seconds and on the other side for 2-3 seconds.
2. Differences in the strictness of product inspection:
Class I products refer to products that do not require painting, such as DVRs, wall box covers, satellite switch rubber brackets, PHLIPS customer antennas and other indoor products with high surface requirements; Class II products refer to products that require painting and indoor antenna products (plastic parts are relatively large, cheap, and exported to some underdeveloped countries and regions such as Africa and South Asia).
3. Distinguish the strictness of different positions of the same product.
3.1. The visible part of surface A during normal operation of the product, such as the top cover, front end, interface, etc. of the product.
3.2. Surface B, which is not common in normal product operation, such as the side of the product.
3.3. Surfaces that are not visible in normal operation, such as the bottom of the product.
3.4. Surface D refers to the non-exposed surface of the product structure, such as the inner surface of the product and the structural part of the inner surface.
4. Classification of non-conforming products
4.1. Fatal defects: Experience and judgment show that it is a non-conforming situation that causes or is unsafe for individuals who use, maintain or rely on the product.
4.2. Serious defects: Not fatal defects, but in order to achieve the intended purpose, it is likely to cause product failure or greatly reduce the efficiency of use.
4.3. Minor defects: Non-conforming situations that cannot significantly reduce the efficiency of product use, but have little impact on the product to achieve the intended purpose.
5. Classification of specific product inspection defects for injection products
5.1. Material defects: Improper use of materials, containing foreign materials, and using a large proportion of nozzle materials without confirmation (serious defects).
5.2. Appearance:
The B and C surfaces of the first-level and second-level products, and the A, B, and C surfaces have no obvious scratches, shrinkage, flow marks, color difference, and white tops (minor defects).
The A surface of Class I products has obvious scratches, shrinkage, material flow lines, color difference, top white, weld lines, and material heads (serious defects) that affect assembly.
Product structure (assembly) defects: defects that cause the product to be unable to be assembled with matching parts and affect use (serious unqualified). For example, the upper and lower covers are seriously misaligned after assembly, the screw threads do not match, the column cracks after the screws are tightened, and the punch rod holes crack.
Product performance defects: defects that cause the product to fail to meet the design function (serious defects). For example: paint peeling, electroplating coating peeling, steel hardness and strength are unqualified, electrical connections are open and short-circuited, and attenuation reflection does not meet the standards.
Packaging defects: may cause product scratches and quality risks or fail to add corresponding packaging material protective films and plastic bags as required (serious defects).
6. General judgment principles
6.1. In the production process of injection molded parts, the concept of "zero defects" is adopted to inspect products, control production, and help workshops analyze the causes of defects. 6.2. The finished injection molded parts produced depend on the customer and product type. If there are slight defects in appearance, it is acceptable if it does not affect assembly.
6.3. As long as the color difference is not wrong, it is acceptable if the color difference of the matching products is not large.
6.4. Defective products that cause poor assembly (cracking of punching rod holes, slipping teeth, burning of locking screw holes, deformation of columns that affect assembly, large joints, fractures, loose fastening, and misalignment) must be rejected.
7. Injection molding inspection skills
7.1. Surface appearance:
The surface is free of burrs, weld marks, bubbles, water marks, deformation, and scratches.
Look at the color difference (pay attention to the combination).
No strain or delamination is allowed at the feed port.
Whether there is a cut edge at the trimming position.
7.2. Structural parts
There should be no blockage of holes, deformation of holes (large or small holes), whitening, and weld marks at the screws and through holes.
There should be no cracks or damage at the joints.
The wire cannot slip or twist.
7.3. Trial installation and spraying.