Inspection method for defects in automotive stamping parts
Stamping parts are widely used, such as in the electronics industry, machinery industry, furniture industry, automotive industry, etc.! So how are defects in stamping parts used in the automotive industry detected? Let's share with you.
1. Cracking
Inspection method: visual Evaluation criteria:
Class A defects: cracks that can be noticed by untrained users. Stamping parts with such defects are unacceptable to users. Stamping parts must be frozen immediately after discovery.
Class B defects: visible and identifiable fine cracks. Stamping parts with such defects are unacceptable in areas Ⅰ and Ⅱ. Other areas are allowed to be repaired by welding, but the repaired parts are not easily noticed by customers and must meet the repair standards of stamping parts.
Class C defects: ambiguous defects that are confirmed after careful inspection. Stampings with such defects are repaired by welding inside zone II, zone III, and zone IV, but the repaired parts are not easily found by customers and must meet the repair standards of stampings.
2. Strain, coarse grains, and hidden scratches
Inspection method: visual Evaluation criteria:
Class A defects: Strain, coarse grains, and hidden scratches that can be noticed by users without training. Stampings with such defects are unacceptable to users and must be frozen immediately after discovery.
Class B defects: visible and identifiable minor strains, coarse grains, and hidden scratches. Stampings with such defects are acceptable in zone IV.
Class C defects: slight strains, coarse grains, and hidden scratches. Stampings with such defects are acceptable in zones III and IV.
3. Depression
Inspection method: visual inspection, oilstone grinding, touch, oiling Evaluation criteria:
Class A defects: defects that cannot be accepted by users. Users without training can also notice them. After such depressions are found, the stamping parts must be frozen immediately. Stamping parts with Class A depressions are not allowed to exist in any area.
Class B defects: It is an unpleasant defect. It is a tangible depression that can be touched and seen on the outer surface of the stamping parts. Such depressions are not allowed on the outer surface of the stamping parts in areas I and II.
Class C defects: defects that need to be corrected. Most of these depressions are in ambiguous situations and can only be seen after oilstone grinding. Stamping parts with such depressions are acceptable.
4. Waves
Inspection methods: visual inspection, oilstone grinding, touch, oiling Evaluation criteria:
Class A defects: This type of wave can be noticed by untrained users in areas Ⅰ and Ⅱ of stamping parts, and users cannot accept it. After discovery, the stamping parts must be frozen immediately.
Class B defects: This type of wave is an unpleasant defect. The waves that can be touched and seen in areas Ⅰ and Ⅱ of stamping parts need to be repaired.
Class C defects: It is a defect that needs to be corrected. Most of these waves are in an ambiguous situation and can only be seen after oilstone grinding. Stampings with this type of wave are acceptable.
5. Uneven and missing flanges and trimmings
Inspection method: visual inspection, touch Evaluation criteria:
Class A defects: Any uneven and missing flanges and trimmings of inner and outer covers that affect the quality of undercuts and uneven and missing weld overlaps, thus affecting the quality of welding, are unacceptable. Stampings must be frozen immediately after discovery.
Class B defects: Uneven and missing flanges and trimmings that are visible and can be determined to have no effect on undercuts, weld overlaps and welding quality. Stampings with such defects are acceptable in Zones III and IV inside Zone II.
Class C defects: Slight unevenness and missing flanges and trimmings have no effect on the quality of undercuts and overlaps, and stampings with such defects are acceptable.
6. Burrs: (cutting edges, punching holes)
Inspection method: visual Evaluation criteria:
Class A defects: large burrs that seriously affect the fit of welded laps and punching holes for positioning and assembly of stamped parts, and are prone to personal injury. Stamped parts with this defect are not allowed to exist and must be repaired.
Class B defects: medium burrs that have a slight impact on the fit of welded laps and punching holes for positioning and assembly of stamped parts. Stamped parts with this defect are not allowed to exist in areas I and II.
Class C defects: smaller burrs. Stamped parts with this defect are allowed to exist without affecting the quality of the vehicle.
7. Pulling and scratches
Inspection method: visual Evaluation criteria:
Class A defects: pulling and scratches that seriously affect the surface quality and potentially cause the punching of stamped parts. Stamped parts with this defect are not allowed to exist.
Class B defects: visible and identifiable burrs and scratches. Stampings with such defects are allowed to exist in Zone IV.
Class C defects: slight burrs and scratches may result in stampings. Stampings with such defects are allowed to exist in Zones III and IV.
8. Springback
Inspection method: Place on the inspection fixture for inspection Evaluation criteria:
Class A defects: springback that causes serious dimensional matching and welding deformation between stampings. Such defective stampings are not allowed to exist.
Class B defects: large dimensional tolerances, springback that affects dimensional matching and welding deformation between stampings. Such defective stampings are allowed to exist in Zones III and IV.
Class C defects: small dimensional tolerances, springback that has a slight impact on dimensional matching and welding deformation between stampings. Such defective stampings are allowed to exist in Zones I, II, III, and IV.
9. Missed punching
Inspection method: Visual inspection and counting marks with water-soluble markers
Evaluation criteria: Missed punching of any hole on automotive stampings will affect the positioning and assembly of stampings and is unacceptable.
10. Wrinkling
Inspection method: Visual Evaluation criteria:
Class A defects: Severe wrinkling that causes overlapping materials. Stampings with this defect are not allowed.
Class B defects: Visible and tangible wrinkling. Such defects are acceptable in Zone IV
Class C defects: Slight and less obvious wrinkling. Stampings with such defects are acceptable in Zones II, III, and IV.
11. Pockmarks, pits, indentations
Inspection methods: visual inspection, oilstone polishing, touch, oiling Evaluation criteria:
Class A defects: pits are concentrated, and pits are distributed over more than 2/3 of the entire area. After such defects are found in areas I and II, the stamping parts must be frozen immediately.
Class B defects: pits can be seen and touched. Such defects are not allowed to appear in areas I and II.
Class C defects: pits distributed separately can be seen after polishing. In area I, the distance between pits is required to be 300mm or more. Stamping parts with such defects are acceptable.
12. Polishing defects, polishing marks
Inspection methods: visual inspection, oilstone polishing Evaluation criteria:
Class A defects: polished through, clearly visible on the outer surface, and immediately visible to all customers. After such stamping marks are found, the stamping parts must be frozen immediately
Class B defects: can be seen and touched, and can be proved after grinding in the disputed area. Such defects are acceptable in areas III and IV. Class C defects: can be seen after grinding with an oil stone. Stamping parts with such defects are acceptable.
13. Material defects
Inspection method: visual Evaluation criteria:
Class A defects: Material strength does not meet the requirements, traces, overlaps, orange peels, stripes, loose galvanized surface, and galvanized layer peeling left by rolled steel plates. After such stamping marks are found, the stamping parts must be frozen immediately.
Class B defects: Material defects such as obvious traces, overlaps, orange peels, stripes, loose galvanized surface, and galvanized layer peeling left by rolled steel plates. Such defects are acceptable in Zone IV.
Class C defects: Material defects such as ambiguous traces, overlaps, orange peels, stripes, loose galvanized surface, and galvanized layer peeling left by rolled steel plates. Such defects are acceptable in Zones III and IV.
14. Oil pattern
Inspection method: visual, oilstone polishing
Evaluation criteria: No obvious marks are allowed in Zones I and II after oilstone polishing.
15. Bumps and depressions
Inspection methods: visual inspection, touch, oilstone polishing Evaluation criteria:
Class A defects: defects that users cannot accept, and users without training can also notice them. After Class A bumps and depressions are found, the automobile stamping parts must be frozen immediately.
Class B defects: It is an unpleasant defect. It is a tangible bump or depression that can be touched and seen on the outer surface of the stamping. This type of defect is acceptable in Zone IV.
Class C defects: It is a defect that needs to be corrected. Most of these bumps and depressions are in an ambiguous situation and can only be seen after oilstone polishing. This type of defect is acceptable in Zones II, III, and IV.
16. Rust
Inspection method: visual inspection
Evaluation criteria: No degree of rust is allowed on automobile stamping parts.
17. Stamping marks
Inspection method: visual Evaluation criteria:
Class A defects: Stamping marks that are unacceptable to users and can be noticed by untrained users. Stamping parts must be frozen immediately after such stamping marks are found.
Class B defects: Stamping marks that are unpleasant and can be felt and seen on the outer surface of stamping parts. Such defects are not allowed in areas I and II, but are acceptable in areas III and IV if they do not affect the quality of the whole vehicle.
Class C defects: Stamping marks that can only be determined by grinding with oilstone. Automotive stamping parts with such defects are acceptable if they do not affect the quality of the whole vehicle.
