PCB Tech - Introduction to the first piece process of pcba processing

The first piece of PCBA processing is produced because the previous technology and equipment are not as mature as they are now. The factory often has poor batches, repairs, and even scrapping during the production process. The first piece is the product that will need to be processed in batches. The first PCBA board that needs to be strictly inspected or tested at the start of production. First article inspection is to inspect, confirm, and test the first product. The first inspection is to find the problems that affect the quality of the product as early as possible in the production process, and to prevent batch defects or scrap. The first piece of SMT patch is an important means to control the product production process in advance, and it is also a very good method to control the quality of the product process. It is also an effective and necessary way for companies to ensure product quality and improve economic benefits. One of the indispensable processing links.

1. Data requirements for the first inspection of PCBA processing

a. First, the three parties of the production department, engineering department, and quality department need to confirm the correctness of the information, that is, to ensure that the information is correct, there are correct samples to refer to, and it is best that the customer provides physical samples. Such as: product drawings, process documents, BOM, PCBA things, technical documents such as special process requirements, etc. If there is any discrepancy, feedback and confirmation with the customer are required.

First confirmation

2. The key node of the first inspection of PCBA processing

a. The first piece in the order, that is, the first board and the first panel, but generally the first piece will have two panels attached, one for SMT model, one for functional testing and full-function testing.

b. When the production goes to work or shifts, the purpose of the first panel produced on the shift is to check the quality of the shift to prevent the mistakes of the shift from being left on the shift.

c. ECN changes, such as: Replacing more than 15 pieces needs to re-attach the glue board for quality measurement, do the first piece test, and the first piece of the mass production order can be carried out simultaneously with the production, without affecting the production efficiency.

d. Process changes, such as program re-optimization, station changes, and replacement of more than five feeders, need to re-paste cardboard for quality measurement. The first piece test can be performed simultaneously with the production without affecting the production efficiency.

3. Matters needing attention in the first inspection of PCBA processing

a. Take protective measures, such as electrostatic protection, and the information is correct.

b. Whether the position, polarity, angle, etc. of the mounted components meet the requirements of the technical documents.

c. Whether the quality of the incoming components is qualified, such as: component color, component size, positive and negative poles, etc.

d. Whether the welding quality of components meets the requirements of customers or related technical documents.

e. The inspector shall mark the first piece that has passed the inspection according to the regulations, and keep it until the batch of products is completed.

f. The first article inspection must be timely to avoid reducing production efficiency.

g. If the first piece has not passed the inspection, no further processing or operation is allowed.

4. The first inspection mechanism of PCBA processing is interlocking

a. Self-inspection: Engineers conduct self-inspection on the first product they produce, mainly led by on-site engineers. Engineers can conduct self-inspection based on the above confirmed information, and the focus is on the orientation of the components and the placement effect.

b. Mutual inspection: After the engineer inspects, the operator conducts mutual inspection, the focus is to check the BOM and drawings, whether there is a shortage of materials, etc., and immediately notify the production engineer to resolve any objections.

c. Full inspection: After qualified, it will be sent to quality inspectors for full inspection. Generally, multimeters or ECR bridges are used. Large-scale factories basically use bridges. The focus is on component measurement and component orientation. If there are BGA devices, X-ray inspection is required to determine the soldering effect of the internal solder balls. Inspect the product according to the customer’s original BOM, special processing requirements, samples, etc., confirm whether the first product produced meets customer requirements, determine whether the product meets the requirements of the production technical documents, and determine whether the production conditions and process parameters are qualified for mass production Product evaluation. The PCBA samples that have passed the "three inspections" are retained until the end of batch production.

d. The basis of the three-inspection system is the first piece, and the comparison standard of the first piece is the sample and guidance document agreed upon in advance by the factory and the customer. The correctness of the sample includes the correctness of the material and the correctness of the welding. For the consistency of customer guidance documents and samples, the document takes precedence. If there is no document, the sample shall prevail. At any time, you can follow this basic principle. This is a protection for the foundry and a responsibility for the customer. The purpose is to ensure and improve the quality of the goods, and avoid the occurrence of quality losses caused by the mistakes of both parties.

Summarize:

The long-term practical experience of PCBA processing proves that the first inspection system is an effective measure to discover problems as early as possible and prevent batches of products from being scrapped. Through the first article inspection, a series of systemic problems such as severe wear of the fixture or installation and positioning errors, poor accuracy of measuring instruments, misreading of drawings, feeding or formula errors, etc. can be found, so that corrective or improvement measures can be taken in advance. In short, its main purpose It is to discover the system factors that affect product quality in the PCB processing and production process as soon as possible, and to prevent batches of unqualified products or batches of products being scrapped.