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About precautions for each stage of SMT production
PCBA Tech
About precautions for each stage of SMT production

About precautions for each stage of SMT production

2021-11-06
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Author:Downs

According to the mass production situation of the model, SMT can generally be divided into the following three situations, and the relevant work focuses also have similarities and differences:

1. Precautions during the trial production phase of SMT:

The batch is generally below 100PCS, and it has never been produced before. The focus is on verifying the mass production of the model. The SMT production of such a model must pay attention to the following things:

1. SMT preparation:

A. After learning from the PMC or the purchasing office that a certain model is ready for trial launch, 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. Borrow a prototype: I need to have a simple understanding of the related functions of the machine produced, and I have a good product to test the full function of the finished machine several times;

C. Understand all post-welding components of the model, plan post-welding procedures, evaluate post-welding operations and pre-welding precautions;

D. Understand the use of test fixtures (there are often no test fixtures for the first trial production), and plan test items and procedures;

E. Understand the layout of the entire PCB components, and evaluate the characteristics of certain components for production considerations;

F. The SMT materials that biotechnology needs to prepare include "component location map", "BOM table" and "principle diagram". These materials must be the same version as the PCB produced;

pcb board

G. It is best to prepare a sample before departure;

2. Confirmation of materials in SMT factory: The preparation and distribution of materials cannot interfere with the biotechnology, but several confirmations should be made after sending out. It is best to confirm with the development engineer:

A. First understand the situation of material preparation, whether the material is complete will determine the production arrangement, and if the material is not complete, it should be reported to the factory immediately;

B. Confirmation of key materials, such as the version and material number of major materials such as FW IC, BGA, PCB board, etc.; material confirmation must check the BOM;

C. Generally, the manufacturer’s IQC and material staff will also check the materials. If there are any inconsistent materials, they should immediately check with the development engineer;

3. First article confirmation:

A. Confirm the first piece of the 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 furnace, the PCB needs to look at the tin consumption of each component and the temperature resistance of the components;

C. It is best to work on the first post-welding part by yourself, and the development engineer confirms; at this time, start to prepare the post-welding process and post-welding SOP;

D. If there is a test fixture, test the first piece by yourself, and the development engineer confirms the test item, and begins to prepare the test item and test SOP;

4. Problem tracking and confirmation:

Record and sort out the problem points that occurred in the entire production process, including all the problems in the SMT process such as data, materials, placement, post welding, testing, maintenance, etc., and summarize them into a problem point tracking report, and timely contact the SMT production leader and development The department engineer confirms the problem.

5. Information feedback: After the SMT is completed, the problem should be reported to the relevant personnel,

A. Feedback the SMT problem points to the person in charge of the biotechnology model for review and improvement;

B. Collect the SMT problem points found in the trial investment in the factory and feed it 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. Precautions for SMT's first mass production stage

Refers to models that are mass-produced after trial production and improvement. There are also some models that are trial-commissioned and mass-produced at the same time. Generally, the batch size is more than 100. In the same production, you need to pay attention to the following:

1. SMT preparation:

A. Understand production arrangements with purchasers;

B. Preparation of patch data (schematic diagram, patch map, bom table, FW, driver, burning tool)

C. Understand the basic functions of the model, formulate test procedures and test items;

D. Understand the post-welding components of PCBA, formulate post-welding procedures (try to prepare sop), and clarify the precautions for post-welding;

E. Master the method of burning FW for the machine type;

F. Develop process requirements and production precautions for the entire PCBA;

G. Clarify the condition of the test fixture, make sure that the test fixture is OK, try to find a sample for test;

H. Understand the accessories and equipment required for the test, special equipment needs to be proposed in advance, and test accessories are prepared in advance;

I. Prepare a model;

2. Confirmation of materials and data:

A. First understand the situation of material preparation, whether the material is complete will determine the production arrangement, and if the material is not complete, it should be reported to the factory immediately;

B. Confirmation of key materials, such as the version and material number of major materials such as FW IC, BGA, PCB board, etc.; material confirmation must check the BOM;

C. Generally, the manufacturer’s IQC and material staff will also check the materials. If there are any inconsistent materials, they should immediately check with the development engineer;

D. Materials that have changed after trial investment;

3. First article confirmation:

A. Confirm the first piece of the 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 furnace, the PCB needs to look at the tin consumption of each component and understand the furnace temperature curve (can be retained);

C. Instruct the first post-welding operation, 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. Follow the test process to guide the test function test to ensure that all the main functions of the PCB are tested;

4. Analysis and confirmation of defective products:

A. Understand the straight-through rate of the test, confirm the main undesirable phenomena and causes and record them;

B, SMT operation problems are immediately forwarded feedback, requiring immediate control of the previous stage;

C. For material problems, feedback immediately to confirm whether it can be produced and how to produce it. It is best to take photos and keep files;

5. Information feedback:

A, SMT production problem points are reported back to the person in charge of biotechnology models to remind them;

B. Collection of assembly problems in the factory, feedback to the person in charge, and request for improvement;

Three, SMT mass production stage production precautions

A certain model has been mass-produced by the same manufacturer many times, and the process and flow are relatively familiar. In some cases, the following matters should be paid attention to:

1. Confirmation of test fixtures: confirm the conditions of test fixtures and test accessories before production; collection of previous problems;

2. Special material confirmation: confirm the abnormal material before production, and confirm the material once;

3. First article confirmation:

A, make a simple understanding and test of the first article, and check the related first article records;

B. Check whether the previous problem occurs again and whether the hand 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 main defective distribution and the main causes, and try to improve;

5. Information feedback

A, SMT production problem points are reported back to the person in charge of biotechnology models to remind them;

Collection of assembly problems in factory B, feedback to the person in charge, and request for improvement