Root Cause of Escape :
1. IQC were sampling check may be not found problem.
2. IPQC (printing process) were check dimension & appearance of 1st / middle / final piece may be couldn't found defect. But production inspector were dimension check 1 : 20 pcs and visual 100% check not found defect. Suspect as human error.
3. OQC (gluing process) also check dimension & appearance of 1st / middle / final piece may be couldn't found defect. But production inspector were appearance 100% check not found defect. Suspect as human error.