After a partial soldering process of two THD contacts the base material has discoloured. It had been exposed to excessive heat due to unsuitable process parameter. Since the discolourating is only slight and no delamination of the base material has taken place, this defect is tolerable. The process parameter have to be adapted to solve the problems at hand, however.
- excessive heat (processing fault)
The discolourating of the base material can be traced back to delamination (separation of layers in the compound). It has been caused by poor production quality of the base material which only shows after the soldering process. But mechanical stress can also lead to this defect.
- deficiencies in the quality of the base material
- Excessive thermal / mechanical stress