Now it is evident that the PCB processing quality of punching, cutting, and drilling is inconsistent; coating adhesion is poor, or the coating is uneven in the metallized hole.
Inspection method: Inspect the incoming materials, test various key mechanical PCB processing operations, and conduct routine analysis after the materials pass through the hole metallization process.
Possible reasons:
1. Changes in material curing, resin content, or plasticizer can affect the quality of drilling, punching, and shearing.
2. Poor techniques in drilling, punching, or shearing result in inconsistent production quality.
3. Excessive preheating cycle time before punching or drilling can adversely affect laminate processing.
4. Aging of materials, particularly phenolic ones, may cause plasticizer migration, making the material more brittle than usual.
Solution:
1. Contact the laminate manufacturer to establish a test that simulates the processing performance requirements for key mechanical PCBs. Avoid using the production mold for the test, as wear and changes to the mold can affect the results. In cases where mechanical PCB processing performance issues arise, only suspect laminate quality if the problem coincides with a change in material batch number.
2. Consult the manufacturing recommendations for various laminate types. Contact the laminate manufacturer to determine the specific drilling speed, feed, bit, and punch temperature for each laminate grade. Note: manufacturers use different resin and substrate mixtures, so their recommendations will vary.
3. Preheat the laminate carefully and identify any overheated areas, such as those under a heating lamp. Follow the first-in, first-out principle when heating materials.
4. Verify with the laminate manufacturer to obtain data on the material’s aging characteristics. Manage inventory to ensure that it consists of predominantly newly produced plates. Be aware of potential overheating during warehouse storage.
**Warpage and Distortion Problems**
Signs: Warping or distortion of the substrate before, during, or after PCB processing is a concern. Post-soldering hole tilt also indicates substrate warpage or distortion.
Inspection Method: Use a float soldering test and conduct incoming material inspections. The 45-degree tilted soldering test is particularly effective.
Possible Reasons:
1. Warping or twisting upon receipt or after sawing and cutting may result from improper lamination, cutting, or an unbalanced laminate structure.
2. Improper storage, especially of paper-based laminates, can lead to warping or deformation if stored upright.
3. Warpage may be caused by unequal copper and iron wall foils, such as 1 ounce on one side and 2 ounces on the other; uneven electroplating layers; or copper stress from special printed board designs.
4. Warpage can occur from improper fixture use or heavy components during soldering operations.
5. PCB processing or soldering may cause hole displacement or tilt due to improper laminate curing or substrate glass cloth stress.
Solutions:
1. Straighten the material or relieve stress in an oven, and perform cutting operations according to the laminate manufacturer’s recommended board angle and heating temperature. Ensure substrates with uneven structures are not used.
2. Store materials flat in loading cardboard boxes or diagonally flat on shelves, generally at an angle of 60 degrees or less from the ground.
3. Contact the laminate manufacturer to avoid unequal copper foils. Analyze plating and stress or redesign the printed board to balance components and copper areas. Avoid vertical wiring layouts that could cause thermal expansion discrepancies.
4. During soldering, especially with paper-based boards, use clamps and balance heavy components with special fixtures if necessary.
5. Consult the laminate manufacturer for recommended post-curing measures. In some cases, a different laminate may be suggested for more stringent or specialized applications.
Inspection method: Inspect the incoming materials, test various key mechanical PCB processing operations, and conduct routine analysis after the materials pass through the hole metallization process.
Possible reasons:
1. Changes in material curing, resin content, or plasticizer can affect the quality of drilling, punching, and shearing.
2. Poor techniques in drilling, punching, or shearing result in inconsistent production quality.
3. Excessive preheating cycle time before punching or drilling can adversely affect laminate processing.
4. Aging of materials, particularly phenolic ones, may cause plasticizer migration, making the material more brittle than usual.
Solution:
1. Contact the laminate manufacturer to establish a test that simulates the processing performance requirements for key mechanical PCBs. Avoid using the production mold for the test, as wear and changes to the mold can affect the results. In cases where mechanical PCB processing performance issues arise, only suspect laminate quality if the problem coincides with a change in material batch number.
2. Consult the manufacturing recommendations for various laminate types. Contact the laminate manufacturer to determine the specific drilling speed, feed, bit, and punch temperature for each laminate grade. Note: manufacturers use different resin and substrate mixtures, so their recommendations will vary.
3. Preheat the laminate carefully and identify any overheated areas, such as those under a heating lamp. Follow the first-in, first-out principle when heating materials.
4. Verify with the laminate manufacturer to obtain data on the material’s aging characteristics. Manage inventory to ensure that it consists of predominantly newly produced plates. Be aware of potential overheating during warehouse storage.
**Warpage and Distortion Problems**
Signs: Warping or distortion of the substrate before, during, or after PCB processing is a concern. Post-soldering hole tilt also indicates substrate warpage or distortion.
Inspection Method: Use a float soldering test and conduct incoming material inspections. The 45-degree tilted soldering test is particularly effective.
Possible Reasons:
1. Warping or twisting upon receipt or after sawing and cutting may result from improper lamination, cutting, or an unbalanced laminate structure.
2. Improper storage, especially of paper-based laminates, can lead to warping or deformation if stored upright.
3. Warpage may be caused by unequal copper and iron wall foils, such as 1 ounce on one side and 2 ounces on the other; uneven electroplating layers; or copper stress from special printed board designs.
4. Warpage can occur from improper fixture use or heavy components during soldering operations.
5. PCB processing or soldering may cause hole displacement or tilt due to improper laminate curing or substrate glass cloth stress.
Solutions:
1. Straighten the material or relieve stress in an oven, and perform cutting operations according to the laminate manufacturer’s recommended board angle and heating temperature. Ensure substrates with uneven structures are not used.
2. Store materials flat in loading cardboard boxes or diagonally flat on shelves, generally at an angle of 60 degrees or less from the ground.
3. Contact the laminate manufacturer to avoid unequal copper foils. Analyze plating and stress or redesign the printed board to balance components and copper areas. Avoid vertical wiring layouts that could cause thermal expansion discrepancies.
4. During soldering, especially with paper-based boards, use clamps and balance heavy components with special fixtures if necessary.
5. Consult the laminate manufacturer for recommended post-curing measures. In some cases, a different laminate may be suggested for more stringent or specialized applications.
