Jul 10, 2023 
Precaution for the SMT
Preparation before production
1. Non-vacuum packaged PCB, QFP, BGA, IC (customer requires baking) and other components must be baked before going online. Implementation of “SMT Parts Baking Operation Instructions”.
2. The warehouse formulates the “SMT Chip Issue List” based on the “BOM List”.
3. SMT patch receives materials according to the relevant model “SMT patch material delivery list”, and confirms the material model, specification, quantity, and other conditions, the warehouse is responsible for follow-up and replenishment of missing materials, or the customer requires a blank sticker to issue an “empty patch” Sticker”.
4. According to the SMT chip production plan, the project confirms the BOM, process requirements, SMT chip program, fixtures, tools, and other pre-production preparations.
5. The process department and the quality department should provide the corresponding inspection specification documents.
6. SMT elongation should arrange personnel and materials according to relevant documents such as “BOM list”, “Process Requirements”, and “SMT patch station table” corresponding to the corresponding model.
Printing
1. Solder paste and red glue should be warmed up before use, and then they can be used after stirring. The specific operation is based on the “Storage and Use of Solder Paste and Red Glue”. Instructions” implementation, and make corresponding work records.
2. The return temperature and stirring time of solder paste and red glue are recorded in the solder paste/red glue control label and the “Solder Paste and Red Glue Use Record Form”.
3. The use of the solder paste mixer and printing machine shall be implemented by the “Solder Paste Mixer Operation Instructions” and the corresponding printing machine operating instructions.
4. The lead-free and brand must be confirmed before solder paste printing, and the “Registration Form for Use and Replacement of Solder Paste and Red Glue” must be filled out.
Chip processing
1. The SMT operator checks the material number, product name, specification, quantity, etc. according to the “SMT patch station table” and loads it into the FEEDER or tray. The direction of the material needs to be confirmed when it is placed, and the FEEDER or drag Put the disk into the corresponding station, notify IPQC to check, and the SMT operator will check the distance between FEEDER and inform the technician to debug the equipment.
2. IPQC checks all station materials and signs for confirmation according to the “SMT SMT Station Position Table”. Signature confirmation after verification by IPQC.
3. All materials must be confirmed by IPQC when loading or changing materials before starting production.
4. The operation method of the mounter is carried out according to the corresponding “Operation Instructions for Mounter”.
5. The intermediate inspector will conduct a 100% visual inspection of the mounted boards. If the detected defective products are slight (such as component deviation), the visual inspector will repair them by themselves, and if they are seriously defective (such as wrong parts), the operator will For repairs when serious defects are found or the same defect occurs more than 3 times in a row, feedback should be given to the supervisor or technician in time for improvement.
6. IPQC checks the first article according to the relevant process documents and records it in the corresponding column on the “First Article Report”.
7. When the operator has to replace the material, the non-screen printing component must be measured and notified to IPQC for confirmation before production.
Reflow soldering
1. The machine boards that have been visually OK by the inspectors are put into the reflow soldering process for soldering according to the “Furnace Passing Operation Instructions”.
2. In case of reflow soldering with a red light or an alarm, it is forbidden to put it into the machine board. When the reflow soldering alarm is found, the furnace passer should promptly feedback to the SMT technician for improvement.
3. Before passing the furnace, the furnace passer must notify the technician and confirm the furnace temperature.
4. IPQC needs to confirm that the first piece of furnace welding is OK, and then notify the production of the batch furnace after 5-10pcs of samples are passed through the furnace without abnormalities.
Post furnace QC
1. Post-furnace QC conducts an appearance inspection on key positions of the board after reflow soldering according to the “SMT Appearance Inspection Acceptance Standard” and records it in the “QC Daily Report”.
2. If a serious defect is found or the same defect occurs more than 3 times in a row, it should be reported to the line leader in time to request improvement.
Summary of Precaution for the SMT production process
The above content is shared by SZTech-SMT for you about precaution for the SMT. I hope it will be helpful to you. To learn more about SMT chip processing, welcome to visit www.sztech-smt.com
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