Trong du an Flex PCB, nhieu chi phi phat sinh khong den tu gia vat lieu ma den tu viec phat hien loi qua muon. Mot cau han bi bridge, mot linh kien dao cuc, hoac coverlay lech vi tri co the day pilot build vao rework va tre giao hang.
Vi vay, doi voi mua hang va SQE, cau hoi dung khong chi la nha cung cap co may AOI hay khong. Dieu quan trong hon la AOI duoc dat o cong doan nao, mach mem duoc co dinh ra sao, va khi nao phai bo sung electrical test hay X-ray.
"AOI chi tao gia tri khi no chan duoc loi truoc khi loi tro thanh chi phi va anh huong lead time."
— Hommer Zhao, Engineering Director at FlexiPCB
AOI thuc su lam duoc gi
AOI so sanh hinh anh thuc te cua panel hoac assembly voi tai lieu tham chieu ky thuat so. Trong Flex PCB, no bat loi open, short, linh kien thieu, sai cuc tinh, xoay sai, bridge han lo ro va loi canh chinh coverlay hoac stiffener rat tot. Tuy nhien, no khong the thay cho electrical test 100% va cung khong danh gia dang tin cac hidden joints ben duoi BGA hay QFN.
AOI nen nam o dau trong flow
Flow tot nhat la dat AOI sau etching cua bare flex, sau SMT placement va sau reflow. Voi mach mem, fixture co vai tro cuc ky quan trong; neu bo mach khong duoc giu phang va lap lai on dinh, false call se tang nhanh. Co the xem them huong dan quy trinh san xuat Flex PCB va huong dan reliability testing.
| Defect / condition | AOI result | Extra method |
|---|---|---|
| Trace open / nick | Strong on bare flex | Flying probe confirms continuity |
| Copper short / spacing issue | Strong on bare flex | Electrical test for full coverage |
| Missing or wrong component | Strong on assembly | Usually no extra method |
| Visible solder bridge | Strong on assembly | Electrical test still recommended |
| Hidden joint under BGA/QFN | Weak | X-ray |
| Coverlay or stiffener misregistration | Strong to moderate | Dimensional check when tolerance is tight |
Khi nao AOI khong du
Neu san pham co BGA, QFN, hidden joints hoac yeu cau do tin cay cao, AOI mot minh la khong du. Luc do can AOI ket hop electrical test va nhieu truong hop can them X-ray.
Can gui gi truoc khi xin bao gia
- Gerber hoac ODB++, assembly drawing va stackup
- BOM co MPN va package type
- Tep centroid
- So luong prototype, pilot va production
- Bend zones, stiffeners, unsupported tails va muc tieu do day ZIF
- Moi truong su dung, target lead time va compliance target
Day du cac tai lieu nay se giup nha may xac dinh inspection plan ngay tu giai doan bao gia.
FAQ
AOI co du cho moi flex assembly khong?
Khong. AOI manh voi loi nhin thay duoc, nhung khong thay the electrical test.
AOI co dung cho bare flex khong?
Co, va day la mot gate rat co gia tri o giai doan som.
Vi sao Flex PCB co nhieu false call hon?
Vi hinh hoc kem on dinh hon, co warpage cuc bo va bien doi quang hoc.
Khi nao can X-ray?
Khi co hidden joints, BGA, QFN hoac cau truc camera khong nhin thay truc tiep.
Buyer hay bo sot cau hoi nao?
AOI duoc tich hop the nao vao flow cua san pham cu the.
Buoc tiep theo
Neu ban dang bat dau mot chuong trinh moi, hay gui drawing, BOM, quantity, environment, target lead time va compliance target. Dong thoi cho biet co can AOI, flying probe, X-ray, FAI hay traceability hay khong. Chung toi se gui lai DFM feedback, inspection plan va bao gia. Yeu cau bao gia hoac lien he doi ky thuat.
