SMT processing is an abbreviation for the process of soldering components on a PCB circuit board through a placement machine and a reflow soldering machine. Whether the components can work normally, whether the final circuit board can guarantee normal work and function depends on this. Therefore, process control measurements must be implemented before SMT processing to optimize PCBA processing and assembly. This will ensure that costly errors will not be discovered in the future, reduce product failure rates, and protect the reputation of SMT chip processing plants.

The process control of PCB assembly mainly involves the implementation of some robust processes in the printing, mounting and reflow stages.

Let us dive into some details of assembly SMT welding defects. The success of solder paste printing determines whether the overall quality can meet expectations. Therefore, we need to understand and evaluate the quality abnormalities that may affect the process in detail.

Before SMT proofing, the following items must be checked:

1. What PCB needs to be tested

1. Whether the PCB light board is deformed and the surface is smooth;

2. Whether there is oxidation on the circuit board pads;

3. Whether the copper coating on the circuit board is exposed;

4. Whether the PCB has been baked for the specified time.

2. What should be checked before solder paste printing

1. The plates cannot be stacked vertically, and no collision between the plates;

2. Whether the positioning hole is consistent with the template opening;

3. Whether the solder paste is thawed in advance at room temperature;

4. Whether the selection of solder paste is correct and whether it has expired;

5. Whether the SPI solder paste detector has calibration data;

6. Whether the steel mesh and mold are cleaned, and whether there is flux residue on the surface;

7. Whether to conduct warpage test on steel mesh;

8. Whether the parameters of the scraper are calibrated and adjusted.

Shenzhen Leicas Precision Manufacturing and Processing Advantages

1. Highly professional: The company focuses on processing samples, small and medium batches, and promises to deliver goods within 3-5 working days after the materials are confirmed.

2. Professional equipment: The company's equipment is advanced equipment tailored for sample and small and medium batch production, which can be attached to 0201, BGA pitch 0.3MM, QFN, CSP, CON and other components.

3. Professional technology: 100% of technical backbones have more than 5 years of work experience, and 85% of frontline operators have more than 3 years of work experience.

4. The company implements the 5S and 6σ concepts in its daily operations, and has at least 7 checks from incoming materials to shipments. Our company promises to pass AOI optical inspection if the quantity reaches 100PCS.

5. The company promises that the welding through rate is over 99%. If the customer finds welding defects, the company promises to repair it free of charge.

PCBA proofing process

1. Customer orders

Customers place orders according to their actual needs, PCBA processing plants, and put forward specific requirements. The processing plant will evaluate its own capabilities to see if it can complete the order. If the manufacturer determines that it can complete the order within the expected time, then the two parties will negotiate to determine the production details.

2. Customers provide production materials

After the customer decides to place an order, he provides a series of documents and checklists to the PCBA processing plant, such as PCB electronic files, coordinate files, and BOM lists required for production, which are all required.

3. Procurement of raw materials

PCBA processing plants purchase relevant raw materials from designated suppliers according to the documents provided by customers.

4. Incoming Material Inspection

Before PCBA processing, all raw materials to be used are subjected to strict quality inspection to ensure that they are qualified and put into production.

5. PCBA production

During PCBA processing, in order to ensure the quality of production, whether it is patch or solder production, manufacturers need to strictly control the furnace temperature.

6. PCBA test

The PCBA processing plant conducts strict product testing, and the PCB boards that pass the test are delivered to the customer.

7. Packaging after sale

After PCBA processing is completed, the product is packaged and then delivered to the customer to complete the entire PCBA processing work.