{"id":14826,"date":"2022-07-21T06:00:35","date_gmt":"2022-07-21T06:00:35","guid":{"rendered":"https:\/\/pj4iaixa9m.wpdns.site\/?p=14826"},"modified":"2022-07-25T07:40:49","modified_gmt":"2022-07-25T07:40:49","slug":"inspection-methods-and-defect-evaluation-criteria-for-stamping-parts","status":"publish","type":"post","link":"https:\/\/www.harslepress.com\/vi\/inspection-methods-and-defect-evaluation-criteria-for-stamping-parts\/","title":{"rendered":"Ph\u01b0\u01a1ng ph\u00e1p ki\u1ec3m tra v\u00e0 ti\u00eau ch\u00ed \u0111\u00e1nh gi\u00e1 khuy\u1ebft t\u1eadt \u0111\u1ed1i v\u1edbi c\u00e1c b\u1ed9 ph\u1eadn d\u1eadp"},"content":{"rendered":"\n

<\/span>Estimated reading time: <\/span>11<\/span> minutes<\/span><\/p>\n\n\n\n

Stamping<\/a> Parts Inspection Method<\/strong><\/h3>\n\n\n\n

1. Touch Inspection<\/strong><\/h4>\n\n\n\n

It is to wipe the surface of the outer cover with clean gauze. The inspector needs to wear touch gloves and touch the surface of the stamping part along the longitudinal direction of the stamping part. This inspection method depends on the experience of the inspector. If necessary, the detected suspicious area can be polished with a whetstone and verified, but this method can be regarded as an effective rapid inspection method.<\/p>\n\n\n\n

2. Whetstone Grinding<\/strong><\/h4>\n\n\n\n

First, wipe the surface of the outer cover with clean gauze, then polish it with a whetstone (20\u00d720\u00d7100mm or larger), use a relatively small whetstone (for example 8 \u00d7100mm semi-circular whetstone) for grinding.<\/p>\n\n\n\n

The choice of whetstone particle size depends on the surface condition (e.g. roughness, galvanizing, etc.). Fine-grained Whetstone is recommended. The direction of whetstone grinding is basically carried out in the longitudinal direction, and it fits well with the surface of the stamping parts, and some special places can also supplement the horizontal grinding.<\/p>\n\n\n\n

\"Figure
Figure 1 Punching machine<\/figcaption><\/figure>\n\n\n\n

3. Flexible Gauze Polishing<\/strong><\/h4>\n\n\n\n

Wipe the surface of the outer cover clean with clean gauze. Use a flexible sand mesh to close to the surface of the stamping part and grind it to the entire surface in the longitudinal direction, and any pitting and indentation will be easily found.<\/p>\n\n\n\n

4. Oil Inspection<\/strong><\/h4>\n\n\n\n

Wipe the surface of the outer cover clean with clean gauze. Then use a clean brush to apply oil evenly to the entire outer surface of the stamping in the same direction. Put the oiled stamping parts under strong light for inspection. It is recommended to erect the stamping parts on the body position. This method allows tiny pits, slumps, and ripples on stamping parts to be easily found.<\/p>\n\n\n\n

5. Visual Inspection<\/strong><\/h4>\n\n\n\n

Visual inspection is mainly used to find the abnormal appearances and visible defects of stamping parts.<\/p>\n\n\n\n

6. Inspection Tool<\/strong><\/h4>\n\n\n\n

Put the stamping parts into the inspection tool, and test the stamping parts according to the operational requirements of the inspection tool manual.<\/p>\n\n\n\n

\"Figure
Figure 2 Multiple inspections of stamping parts<\/figcaption><\/figure>\n\n\n\n

Stamping<\/a> Defect Evaluation Criteria<\/strong><\/h3>\n\n\n\n
  • Cracking<\/strong><\/li><\/ul>\n\n\n\n

    Inspection method: Visual inspection.<\/p>\n\n\n\n

    Evaluation criteria:<\/p>\n\n\n\n

    Class A defects: These are cracks that can be noticed by an untrained user. Stamping parts with such defects is unacceptable to users, and the stamping parts must be frozen immediately after discovery.<\/p>\n\n\n\n

    Class B defects: visible and determinable fine cracks. Such defective stampings are unacceptable in areas I and II. Repair welding and repairing are allowed in other areas, but the repaired parts are not easy for customers to notice and must Meet the rework standard of stamping parts.<\/p>\n\n\n\n

    Class C defects: ambiguous defects determined after careful inspection. The stamping parts of such defects are repaired and repaired in Zone II, Zone III, and Zone IV, but the repaired parts are not easy to be found by customers and must meet the requirements of stamping parts. Repair standard.<\/p>\n\n\n\n

    \"Figure
    Figure 3 Stamping crack<\/figcaption><\/figure>\n\n\n\n
    • Strain, Coarse Grain, Dark Injury<\/strong><\/li><\/ul>\n\n\n\n

      Inspection method: Visual inspection.<\/p>\n\n\n\n

      Evaluation criteria:<\/p>\n\n\n\n

      Class A defects: Strain, coarse grain, and dark damage that can be noticed by untrained users. Stamping parts with such defects is unacceptable to users, and the stamping parts must be frozen immediately after discovery.<\/p>\n\n\n\n

      Class B defects: visible and determinable fine strains, coarse grains, and dark injuries. Stampings with such defects are acceptable in Zone IV.<\/p>\n\n\n\n

      Class C defects: that is, slight strain, coarse grain, and dark damage. Stampings with such defects are acceptable in Zones III and IV.<\/p>\n\n\n\n

      • Depressed Pond<\/strong><\/li><\/ul>\n\n\n\n

        Inspection methods: visual inspection, oil stone grinding, touch, and oiling.<\/p>\n\n\n\n

        Evaluation criteria:<\/p>\n\n\n\n

        Class A Defects: Defects that are unacceptable to users and can be noticed by untrained users. The stamping parts must be frozen immediately after such slumps are found, and the stamping parts of Class A stagnant ponds are not allowed to exist in any area.<\/p>\n\n\n\n

        Class B defect: It is an unpleasant defect. It is a definite slump that can be felt and visible on the outer surface of the stamping part. Such types of defects are not allowed on the outer surface of the stamping parts I and II. Depressed pond.<\/p>\n\n\n\n

        Class C defects: defects that need to be corrected. Most of these slumps are in ambiguous situations and can only be seen after the oil stone is polished. Stamping parts of this type of deflated pond are acceptable.<\/p>\n\n\n\n

        \"Figure
        Figure 4 Punching machine<\/figcaption><\/figure>\n\n\n\n
        • Waves<\/strong><\/li><\/ul>\n\n\n\n

          Inspection methods: visual inspection, oil stone grinding, touch, and oiling.<\/p>\n\n\n\n

          Evaluation criteria:<\/p>\n\n\n\n

          Class A defects: Such waves can be noticed by untrained users in areas I and II of stamping parts, and are unacceptable defects by users. Stampings must be frozen immediately upon discovery.<\/p>\n\n\n\n

          Class B defect: This type of wave is an unpleasant defect, and the determinable wave that can be felt and seen in the stamping parts I and II areas needs to be repaired.<\/p>\n\n\n\n

          Type C defects: Defects that need to be corrected. Most of these waves are in ambiguous situations and can only be seen after the oil stone is polished. Such wavy stampings are acceptable.<\/p>\n\n\n\n

          • Flanging, Uneven Trimming, And Shortage<\/strong><\/li><\/ul>\n\n\n\n

            Inspection method: visual, touch.<\/p>\n\n\n\n

            Evaluation criteria:<\/p>\n\n\n\n

            Class A defects: It is unacceptable for any unevenness and shortage of flanging and trimming of the inner and outer covers, which affects the quality of undercuts and the unevenness and shortage of welding laps, thereby affecting the quality of welding. Stampings must be frozen immediately upon discovery.<\/p>\n\n\n\n

            Class B Defects: Visible and identifiable flanging, trimming irregularities, and shortages that have no effect on undercuts, weld laps, and weld quality. Stamping parts with such defects is acceptable in Zone II, III, and IV.<\/p>\n\n\n\n

            Class C defects: slight flanging, unevenness, and shortage of trimming have no effect on the quality of undercut and lap welding, and stamping parts with such defects are acceptable.<\/p>\n\n\n\n

            \"Figure
            Figure 5 Uneven punching and trimming<\/figcaption><\/figure>\n\n\n\n
            • Trimming, Punching Burr<\/strong><\/li><\/ul>\n\n\n\n

              Inspection method: Visual inspection.<\/p>\n\n\n\n

              Evaluation criteria:<\/p>\n\n\n\n

              Class A defects: The punching holes that seriously affect the degree of welding overlap and the positioning and assembly of punching parts, and the thick burrs that are likely to cause personal injury. The stamping parts with this defect are not allowed to exist and must be repaired.<\/p>\n\n\n\n

              Class B defects: Moderate burrs that have a slight effect on the fit of the welding lap and the punching holes for the positioning and assembly of the punching parts. Stamping parts with this defect are not allowed to exist in Zones I and II.<\/p>\n\n\n\n

              Class C defects: small burrs and stamping parts with this defect are allowed to exist without affecting the quality of the whole vehicle.<\/p>\n\n\n\n

              \"Figure
              Figure 6 Punching machine<\/figcaption><\/figure>\n\n\n\n
              • Pulling And Scratching<\/strong><\/li><\/ul>\n\n\n\n

                Inspection method: visual<\/p>\n\n\n\n

                Evaluation criteria:<\/p>\n\n\n\n

                Class A defects: Severely affect the surface quality, and potentially lead to scratches and scratches that can cause the stamping parts to crack. The stamping parts with such defects are not allowed to exist.<\/p>\n\n\n\n

                Class B defects: visible and identifiable scratches and scratches, stampings with such defects are allowed to exist in zone IV.<\/p>\n\n\n\n

                Class C defects: slight scratches and scratches may result in stamping parts, and stamping parts with such defects are allowed to exist in zones III and IV.<\/p>\n\n\n\n

                • R<\/strong>ebound<\/strong><\/strong><\/li><\/ul>\n\n\n\n

                  Inspection method: put it on the inspection tool for inspection.<\/p>\n\n\n\n

                  Evaluation criteria:<\/p>\n\n\n\n

                  Class A defects: cause the size matching between stamping parts and the springback of serious welding deformation, such defective stamping parts are not allowed to exist.<\/p>\n\n\n\n

                  Class B defects: The size is out of tolerance, which affects the size matching between stamping parts and the rebound of welding deformation. Such defective stamping parts are allowed to exist in zones III and IV.<\/p>\n\n\n\n

                  Class C defects: The size excess is small, and it has a slight impact on the size matching between stamping parts and the rebound of welding deformation. Such defective stamping parts are allowed to exist in zones I, II, III, and IV.<\/p>\n\n\n\n

                  \"Figure
                  Figure 7 Stamping springback<\/figcaption><\/figure>\n\n\n\n
                  • Leak Punching<\/strong><\/li><\/ul>\n\n\n\n

                    Inspection method: Visual inspection and count mark with a water-soluble marker.<\/p>\n\n\n\n

                    Evaluation criteria: The leakage of any hole on the stamping part will affect the positioning and assembly of the stamping part, which is not acceptable.<\/p>\n\n\n\n

                    • Wrinkle<\/strong><\/strong><\/li><\/ul>\n\n\n\n

                      Inspection method: Visual inspection.<\/p>\n\n\n\n

                      Evaluation criteria:<\/p>\n\n\n\n

                      Class A defect: serious wrinkling resulting in overlapping of materials, stamping parts with this defect are not allowed to exist.<\/p>\n\n\n\n

                      Class B defects: visible and palpable wrinkles, such defects are acceptable in Zone IV.<\/p>\n\n\n\n

                      Class C defects: slight, less obvious wrinkling, stampings with such defects are acceptable in zones II, III, and IV.<\/p>\n\n\n\n

                      • Pock <\/strong>P<\/strong>oint <\/strong>G<\/strong>roup, <\/strong>P<\/strong>it <\/strong>P<\/strong>oint, <\/strong>I<\/strong>ndentation<\/strong><\/strong><\/li><\/ul>\n\n\n\n

                        Inspection methods: visual inspection, oil stone grinding, touch, and oiling.<\/p>\n\n\n\n

                        Evaluation criteria:<\/p>\n\n\n\n

                        Class A defects: The pits are concentrated, and more than 2\/3 of the entire area has pits. After such defects are found in areas I and II, the stamping parts must be frozen immediately.<\/p>\n\n\n\n

                        Class B defects: pitting can be seen and touched. Such defects are not allowed to appear in Zones I and II.<\/p>\n\n\n\n

                        Class C defects: Pocks can be seen individually distributed after grinding, and the distance between pits in Zone I is required to be 300mm or more. Stampings with such defects are acceptable.<\/p>\n\n\n\n

                        • Polishing <\/strong>D<\/strong>efects, <\/strong>P<\/strong>olishing <\/strong>M<\/strong>arks<\/strong><\/strong><\/li><\/ul>\n\n\n\n

                          Inspection method: visual inspection, oil stone grinding.<\/p>\n\n\n\n

                          Evaluation criteria:<\/p>\n\n\n\n

                          Class A Defects: Sanding perforations, clearly visible on the exterior surface, immediately visible to all customers. The stampings must be frozen immediately after such stampings are found.<\/p>\n\n\n\n

                          Class B defects: can be seen, touched, and can be found after grinding in controversial places. Such defects are acceptable in Zones III and IV.<\/p>\n\n\n\n

                          Class C defects: It can be seen after grinding with oil stone that the stamping parts with such defects are acceptable.<\/p>\n\n\n\n

                          • M<\/strong>aterial <\/strong>D<\/strong>efect<\/strong><\/strong><\/li><\/ul>\n\n\n\n

                            Inspection method: Visual inspection.<\/p>\n\n\n\n

                            Evaluation criteria:<\/p>\n\n\n\n

                            Class A defects: material strength does not meet the requirements, traces left by rolled steel, overlapping, orange peel, streaks, loose galvanized surface, peeling of the galvanized layer. The stampings must be frozen immediately after such stampings are found.<\/p>\n\n\n\n

                            Class B defects: obvious traces, overlapping, orange peel, streaks, loose galvanized surface, peeling of galvanized layer left by the rolled steel plate, such defects are acceptable in zone IV.<\/p>\n\n\n\n

                            Class C defects: material defects such as traces, overlapping, orange peel, streaks, loose galvanized surface, and peeling of galvanized layer left by rolled steel sheets are acceptable in zones III and IV.<\/p>\n\n\n\n

                            \"Figure
                            Figure 8 Defects of stamping material<\/figcaption><\/figure>\n\n\n\n
                            • Oil Pattern<\/strong><\/li><\/ul>\n\n\n\n

                              Inspection method: visual inspection, oil stone grinding<\/p>\n\n\n\n

                              Evaluation criteria: No obvious imprints are allowed in areas I and II after being polished by the whetstone.<\/p>\n\n\n\n

                              • Bumps, <\/strong>D<\/strong>epressions<\/strong><\/strong><\/li><\/ul>\n\n\n\n

                                Inspection method: visual inspection, touch, grinding with an oil stone.<\/p>\n\n\n\n

                                Evaluation criteria:<\/p>\n\n\n\n

                                Class A defect: It is a defect that cannot be accepted by the user. Untrained users can also notice that the stamping part must be frozen immediately after Class A bumps and depressions are found.<\/p>\n\n\n\n

                                Class B defect: It is an unpleasant defect, which is a determinable bump and depression that can be touched and seen on the outer surface of the stamping part. Such defects are acceptable in Zone IV.<\/p>\n\n\n\n

                                Type C defects: defects that need to be corrected. Most of these bumps and depressions are ambiguous and can only be seen after the whetstone is polished. Such defects are acceptable in Zones II, III, and IV.<\/p>\n\n\n\n

                                • Rust<\/strong><\/strong><\/li><\/ul>\n\n\n\n

                                  Inspection method: visual<\/p>\n\n\n\n

                                  Evaluation criteria: stamping parts are not allowed to have any degree of corrosion.<\/p>\n\n\n\n

                                  \"Figure
                                  Figure 9 Corrosion of stamping parts<\/figcaption><\/figure>\n\n\n\n
                                  • Punching Printing<\/strong><\/li><\/ul>\n\n\n\n

                                    Inspection method: visual<\/p>\n\n\n\n

                                    Evaluation criteria:<\/p>\n\n\n\n

                                    Class A defects: stampings that cannot be accepted by users and can be noticed by untrained users. After such stampings are found, the stampings must be frozen immediately.<\/p>\n\n\n\n

                                    Class B defect: It is an unpleasant, determinable stamping that is palpable and visible on the outer surface of the stamping. Such defects are not allowed in Zones I and II and are acceptable in Zones III and IV without affecting the quality of the vehicle.<\/p>\n\n\n\n

                                    Class C defects: stamping marks that can only be determined by grinding with a whetstone. Stampings with such defects are acceptable without affecting the quality of the vehicle.<\/p>\n\n\n\n

                                    \n