Category Archives: Quality

What purpose of alloy metal of Cu, Ag, Zn, Sb, Bi added to solder paste?

Tin (Sn) based solder is still the best material for PCB (Printed Circuit Board) assembly in the modern industry today. The only difference is the lead (Pb) free from the solder base due to environmental concerns. The melting point of … Continue reading

Both solder joint bridging and open solder joint happen at same BGA?

Is that possible for both solder joint bridging and open solder joint defect occur in the same BGA (Ball Grid Array) or CSP (Chip Scale Package) device? It is rare to observe both solder joint bridging and open solder joint … Continue reading

Increase solder paste volume will improve the MLCC capacitor broken?

Recently WorkingBear got complaint from R&D and ask increase the solder paste volume on the MLCC (Multi-Layer Ceramic Capacitor)  component pads to improve the capacitor broken issue. R&D said he had verified that the capacitor’s footprint in the board design … Continue reading

Trouble Shooting Guide for Plastic Injection

Trouble Suggested Remedies (Solutions) DIMENSIONAL PROBLEMS   Shot-to-shot dimensional variations Increase injection pressure Maintain uniform pad (cushion) Repair leaking back flow value if pad cannot be maintained Increase screw forward time Maintain uniform cycle Eliminate un-melted particles (see below) Use … Continue reading

Case study for the mold-in insert screw boss broken

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 … Continue reading