Bubble was cause due to impurity inside the laminate, impurity has expand during reflow process
2. Improvement action: Since the testing result showed the root cause of the problem is due to impurity inside. Concerning this quality issue, QA department will apply certain improvement action as below,
1. Deep clean oven, tuyere and racking.
2. Inspecting kraft paper, ensure no impurity on it. If any impurity find, QA stuff will remove immediately.
3.QC department will improve the inspection control.