In a previous discussion, WorkingBear identified potential root causes for screw boss cracking after mold-in screw nut insertion. Following a complaint from the field, we asked EMS and the plastic injection supplier to double-check their inventory and found that approximately 1% of the plastic case had cracked on the screw bosses due to inner stress during the mold-in screw nut insert process, without any additional force or screwdriver. However, the defect rate increased to 30% after the screws were fastened into the plastic case.
As an engineer in the electronics manufacturing industry, have you ever encountered the need to rework a printed circuit board (PCB) to remove the solder mask? If so, how did you approach this problem?
The company’s approach to establishing and maintaining long-term working relationships involves creating and monitoring mutual performance expectations and measurements. The use of performance metrics, constructive feedback, and prompt corrective action by both the supplier and customer is essential for achieving continuous process improvement.
Improving the solderability of BGA (Ball Grid Array) packages is always a big challenge for the SMT (Surface Mount Technology) process. Fine pitch BGAs (with a ball pitch less than 0.8mm) are particularly difficult to solder onto the PCB. Additionally, inspecting the soldering result is challenging because the solder joints are hidden under the BGA body, and sometimes even 2D X-Ray inspection is insufficient. (5Dx or angle rotation X-Ray might be able to inspect BGA soldering quality, but these methods are expensive.)
