Разговор о «изгибе и повороте» печатной платы от IPC-6012E

Q: Разговор о «изгибе и повороте» печатной платы от IPC-6012E

<img style="display: block; margin-left: auto; margin-right: auto;" src="https://www.explus.com.tw/upload_files/Knowledge/Based%20on%203-4-3%20%E2%80%9CBow%20and%20Twist%E2%80%9D%20in%20IPC-6012%2C%20what%E2%80%99s%20the%20acceptance%20criteria%20in%20terms%20of%20%20PCB%20warpage%20for%20printed%20circuit%20board%20that%20use%20for%20surface%20mount%20components.png" alt="" width="523" height="438" /> Defined in IPC-6012E 3.4.3 Bow and Twist , unless otherwise specified in the procurement document, when designed in accordance with IPC-2221, the printed board shall have a maximum bow and twist of 0.75% for printed boards that use surface mount components and 1.5% for all other printed boards. In other word, PCB warpage under 0.75% are accepted according to IPC standard. Can twisted or bowed board be corrected (bent back) manually? No, if bending the PCB manually might worsen PCB warpage. Does PCB mounting process be affected by PCB warpage? Basically, PCB assembly supplier refer to IPC-6012E standard as well, if client has special requirement, they will produce carrier to support the PCB during the process. Also, SMT equipment, in the MOUNTING section, must have a splint design on the conveying track. So if the warpage within standard, the PCB could be mounted without problem.

Question

Accepted Answer

Defined in IPC-6012E 3.4.3 Bow and Twist, unless otherwise specified in the procurement document, when designed in accordance with IPC-2221, the printed board shall have a maximum bow and twist of 0.75% for printed boards that use surface mount components and 1.5% for all other printed boards. In other word, PCB warpage under 0.75% are accepted according to IPC standard.

Can twisted or bowed board be corrected (bent back) manually?
No, if bending the PCB manually might worsen PCB warpage.

Does PCB mounting process be affected by PCB warpage?
Basically, PCB assembly supplier refer to IPC-6012E standard as well, if client has special requirement, they will produce carrier to support the PCB during the process. Also, SMT equipment, in the MOUNTING section, must have a splint design on the conveying track. So if the warpage within standard, the PCB could be mounted without problem.