Precautions for each stage of SMT production
Mar 02, 2023
1. Precautions for production in SMT trial production stage:
The batch size is generally below 100PCS, and it has never been produced before. The key point is to verify the mass production of the model. The SMT production of such a model must pay attention to the following:
 
Precautions for production in SMT trial production stage
 
1. SMT preparation:
A. After learning from the PMC or the procurement department that a certain model is ready for trial investment, you must know the person in charge of the development of the model and the person in charge of the biotechnology model in order to obtain relevant resources and help in the future;
B. Borrowing a sample machine: I need to have a simple understanding of the relevant functions of the produced model, and it is best to have a good product finished machine with full-function tests several times;
C. Know all the post-welding components of the machine, plan the post-welding process, evaluate the post-welding operation and post-welding precautions;
D. Understand the use of test fixtures (the first trial production often does not have test fixtures), plan test items and processes;
E. Understand the component layout of the entire PCB, and evaluate the production considerations for the characteristics of certain components;
F. The SMT materials that need to be prepared for biotechnology include "component location diagram", "BOM table" and "schematic diagram". These materials must be in the same version as the PCB produced;
G. It is best to prepare a sample before departure;
 
 
 
2. Confirmation of materials in the SMT factory: material preparation and delivery are powerless to intervene, but several confirmations should be made after sending out, and it is best to confirm with the development engineer:
A. First understand the material preparation situation. Whether the materials are in order will determine the production arrangement. If the materials are not in order, they must be immediately reported to the factory;
B. Confirmation of key materials, such as the version and material number of FW IC, BGA, PCB board and other main materials; BOM must be checked for material confirmation;
C. The IQC and material personnel of the general manufacturer will also check the materials. If there are any inconsistent materials, they should check with the development engineer immediately;
 
3. First article confirmation:
A. Confirm the first piece of patch, pay attention to the direction and specifications of the main components, check the first piece record of the SMT manufacturer, and check the sample at the same time;
B. After the PCB has passed the furnace, it is necessary to check the tin eating situation of each component and the temperature resistance of the components;
C. It is best to do the first piece of post-welding by yourself, and the development engineer will confirm it; at this time, start preparing for the post-welding process and post-welding SOP;
D. If there is a test fixture, test the first piece by yourself, the development engineer confirms the test items, and begins to prepare the test items and test the SOP;
 
4. Problem tracking and confirmation:
Record and sort out the problems that occurred during the entire production process, including all problems in the SMT process such as data, materials, patch, post-welding, testing, maintenance, etc., and summarize them into a problem tracking report, and promptly communicate with the person in charge of SMT production and development The department engineer confirmed the problem point.
5. Information feedback: After the SMT is completed, the problem should be fed back to the relevant personnel,
A. Feedback the SMT problem points to the person in charge of the biotechnology machine for review and improvement;
B. Collect the SMT problems found in the trial investment in the factory, and feed back to the person in charge of SMT;
C. Feedback the improvement of the trial investment problem to the person in charge of SMT;
D. Track the improvement of problem points.
 
 
 
2. Production precautions in the first mass production stage of SMT
It refers to the model that has been mass-produced after trial production and improvement. Some models are also trial-run and mass-produced at the same time. Generally, the batch size is more than 100. The following should be noted in the same production:
 
 
 
1. SMT preparation:
A. Understand the production arrangement with the purchaser;
B. SMD data preparation (schematic diagram, SMD image, BOM table, FW, driver, burning tool)
C. Understand the basic functions of the model, formulate the test process and test items;
D. Understand the post-soldering components of PCBA, formulate the post-soldering process (try to prepare sop), and clarify the post-soldering precautions;
E. Master the method of strong burning FW of the model;
F. Formulate the process requirements and production precautions of the entire PCBA;
G. Clarify the status of the test fixture, make sure that the test fixture is OK, try to find a sample test;
H. Understand the accessories and equipment needed for testing, special equipment needs to be proposed in advance, and test accessories should be prepared in advance;
I. Prepare the template;
 
2. Confirmation of materials and information:
A. First understand the material preparation situation. Whether the materials are in order will determine the production arrangement. If the materials are not in order, they must be immediately reported to the factory;
B. Confirmation of key materials, such as the version and material number of FW IC, BGA, PCB board and other main materials; BOM must be checked for material confirmation;
C. The IQC and material personnel of the general manufacturer will also check the materials. If there are any inconsistent materials, they should check with the development engineer immediately;
D. Materials that have been changed after trial delivery;
 
3. First article confirmation:
A. Confirm the first piece of patch, pay attention to the direction and specifications of the main components, check the first piece record of the SMT manufacturer, and check the sample at the same time;
B. After the PCB has passed the furnace, it is necessary to check the tin consumption of each component and understand the furnace temperature curve (can be retained);
C. Guide the post-welding operation of the first piece, confirm that all post-welding components are correct and must meet the process requirements, and check the SOP of the corresponding post-welding station;
D. Guide the test function test according to the test process to ensure that all the main functions of the PCB are tested;
 
4. Analysis and confirmation of defective products:
A. Understand the pass-through rate of the test, confirm and record the main adverse phenomena and causes;
B, SMT operation problems are immediately fed forward, requiring immediate control of the front-end;
C, due to immediate feedback on material issues, confirm whether it can be produced and how to produce it, it is best to take pictures and keep it on file;
 
5. Information feedback:
A, SMT production problems are reported back to the person in charge of the biotechnology machine, reminding attention;
B. Collect assembly problem points in the factory, feed back to the person in charge, and ask for improvement;
 
 
3. Production precautions in SMT mass production stage
A certain model has been mass-produced by the same manufacturer for many times, and the process and process are familiar. At some point, the following items should be paid attention to:
1. Confirmation of test fixtures: confirm the condition of test fixtures and test accessories before production; collect previous problem points;
 
 
 
2. Confirmation of special materials: confirm the abnormal materials before production, and confirm the materials once;
 
3. First article confirmation:
A. Do a simple understanding and test of the first article, and check the relevant first article records;
B. Check whether the previous problem occurs again and whether it is improved;
C. Confirm whether the previous process and process need to be improved;
 
4. Analysis and confirmation of defective products;
Do a simple analysis of defective products, understand the distribution of main defects and the main causes of defects, and try to improve;
 
5. Information feedback
A, SMT production problems are fed back to the person in charge of the biotechnology machine to remind attention;
Collect assembly problem points in factory B, feed back to the person in charge, and ask for improvement;