PCBA Defects: 3 Common Issues and How to Prevent Them
2026-05-28
Even good designs can fail if assembly issues aren't caught.
Here are 3 common PCBA defects – and how to stop them before they reach you.
1. Solder Bridges
What it looks like: Solder connects two adjacent pins that should be separate.
What causes it:
- Too much solder paste
- Misaligned stencil
- Component placement off-center
How to prevent:
- Optimize stencil aperture design
- AOI inspection after placement
2. Tombstoning
What it looks like: Small component stands up on one end like a tombstone.
What causes it:
- Uneven heating during reflow
- Pad size mismatch between ends
- Poor solder paste volume
How to prevent:
- Balanced pad design
- Proper reflow profile
- Quality solder paste
3. Cold Solder Joints
What it looks like: Dull, grainy, or cracked solder surface instead of shiny and smooth.
What causes it:
- Insufficient heat during reflow
- Contaminated component lead
- Solder paste expired
How to prevent:
- Reflow temperature verification
- Clean component storage
- Use fresh solder paste
How STG Electronic Prevents These
Defect STG Prevention Method
Solder bridges SPI + AOI inspection
Tombstoning Optimized reflow profile
Cold joints Temperature logging + paste control
Solder bridges SPI + AOI inspection
Tombstoning Optimized reflow profile
Cold joints Temperature logging + paste control
Quick Prevention Checklist
- DFM review before production
- SPI (Solder Paste Inspection)
- AOI after placement
- Reflow temperature profiling
- X-ray for BGA/QFN boards
Ready to Avoid Defects?
Send your Gerber files + BOM → 24hr DFM report + quote
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