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SMT patch processing control and quality inspection process
PCBA Tech
SMT patch processing control and quality inspection process

SMT patch processing control and quality inspection process

2021-11-07
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Author:Downs

1. SMT patch processing and production process control

In SMT chip processing and production, the loss of solder paste, chip glue, and electronic components should be managed by quota as one of the key process control contents. SMT patch production can directly interfere with the quality of products, so it is necessary to control factors such as processing process parameters, processes, personnel, equipment, materials, processing testing, and workshop environment.

Key posts should have a clear post responsibility system. The operators of the patch processing should be strictly trained and assessed, and hold a certificate to work. The smt patch processing plant should have a set of formal production management methods, such as the implementation of first article inspection, self-inspection, mutual inspection and inspector inspection system. Those who fail to pass the inspection of the previous process cannot be transferred to the next process.

1. Product batch management. The nonconforming product control procedures shall clearly stipulate the isolation, identification, recording, review and handling of nonconforming products. Usually SMA should not be repaired more than three times, and electronic components should not be repaired more than twice.

2. Maintenance and maintenance of smt patch production equipment. The key equipment should be inspected regularly by full-time maintenance personnel, so that the equipment is always in good condition, the equipment status is tracked and monitored, problems are found in time, corrective and preventive measures are taken, and maintenance and repair are carried out in a timely manner.

pcb board

3. Production environment

① Water and electricity supply.

②Environmental requirements of SMT chip processing production line-temperature, humidity, noise, cleanliness.

③SMT patch processing site (including electronic component library) anti-static system.

④The entry and exit system, equipment operating procedures, and processing disciplines of the SMT chip processing production line.

4. The production site shall be reasonably set up and the identification shall be correct; the warehouse materials and work-in-process shall be classified and stored, neatly stacked, and the ledger shall be consistent.

5. Civilized production. Including: clean, no debris; civilized operation, no savage and disorderly operation behavior. On-site management must have systems, inspections, assessments, and records, and conduct daily "6S" (organization, rectification, cleaning, cleaning, quality, and service) activities.

Second, the process of SMT patch processing quality inspection

What are the quality inspection procedures for SMT patch processing? In order to connect SMT patch processing with one-time compliance rate and high reliability quality policy, it is necessary to design the printed circuit board scheme, electronic devices, materials, processing technology, machinery and equipment, The management system, etc. are manipulated. Among them, process management based on precautions is particularly important in the patch processing manufacturing industry. In each step of the entire process of patch processing, production, effective inspection methods must be followed to prevent various shortcomings and safety hazards before proceeding to the next process.

The quality inspection of patch processing includes quality inspection, processing technology inspection and surface assembly board inspection. Product quality problems discovered during the entire process of testing can be corrected in accordance with the repair status. The repair cost of unqualified products found in quality inspection, solder paste packaging printing and pre-welding grinding is relatively low, and the harm to the credibility of electronic equipment is relatively small.

But the repair of unqualified products after electric welding is completely different. As post-welding maintenance requires re-welding and welding from the beginning after desoldering, in addition to working hours and raw materials, electronic devices and circuit boards will also be destroyed. According to the analysis of shortcomings, the whole process of quality inspection of SMT patch processing can reduce the failure rate, reduce the cost of repair and repair, and prevent quality damage from the root cause.

SMD processing and electric welding welding inspection are all-round inspections of welding products. Generally, the points that need to be tested are: check whether the welding surface is smooth, whether there are holes, etc.; whether the welding is half-moon-shaped, whether there is more or less tin, whether there are defects such as tombstones, moving parts, missing parts, and tin beads. Whether each component has a different level of defects; check whether there are short-circuit faults, on-offs and other shortcomings during electric welding, and check the color change of the surface of the printed circuit board.

In the entire process of SMT processing, to ensure the quality of the electric soldering of the printed circuit board, it is necessary to pay attention to the effectiveness of the main parameters of the reflow oven processing process from beginning to end. If the basic parameters are not good, the welding quality of the printed circuit board cannot be guaranteed. Therefore, under all normal conditions, the temperature control must be checked twice a day, and the ultra-low temperature checked once. Only gradually improve the temperature profile of welded products and set the temperature profile of welded products to guarantee the quality of processed products.