*This is an anonymized case study. No customer or product is identified.*
The assumption
Many people assume wirebond inspection just means: measure the wire height. Reality is messier.
What actually goes wrong
Wirebonds introduce:
- Reflection issues from curved metal surfaces.
- Material variation between parts.
- Shape variation in the bond loops.
- Focus challenges across the height of the loop.
Approach
A combination of 2D appearance checks and 3D height measurement worked better than either alone: 2D to locate and screen, 3D to measure loop height and detect shape defects.
Lessons learned
The reflective, curved geometry meant that lighting and focus dominated the result far more than the height-measurement algorithm itself.