Deeply Analyze the PCBA IQC Inspection Process and Unveil a New Chapter in Quality Control



Author: Jack Wang

I. Raw Material Inspection (IQC Inspection)

In the PCBA production process, the quality inspection of raw materials is the first step to ensure the quality of the final product. This step mainly includes the following aspects:

1. Incoming Inspection: All electronic components and raw materials need to be carefully checked for specifications, models, place of origin and other information to ensure that they are completely consistent with the list provided by the customer. Especially for integrated chips, details such as their size and pin pitch should also be checked to ensure there are no errors.

2. Tin Loading Test: This test mainly examines the tin wetting condition of IC pins and electronic components to determine whether there are problems such as oxidation. If the tin wetting is poor, there may be false soldering or empty soldering during the soldering process.

3. PCB Board Inspection: The quality of the PCB board directly affects the performance of the final product. We need to check whether there are problems such as deformation, scratches, and circuit damage on the PCB board to ensure a smooth appearance and avoid problems in subsequent soldering.

4. Tin Wetting Inspection of PCB Board: Humidity will affect the tin wetting effect of the PCB board. A low tin wetting rate will lead to uneven soldering. Therefore, it is necessary to ensure that the tin wetting rate of the PCB board meets the requirements.

5. Buried Hole Position Inspection: The diameter of the buried hole must be determined according to the size of the electronic component. If the hole diameter is not appropriate, it may cause the component to fail or fall off.

II. Solder Paste Management

Solder paste is an indispensable material in PCBA processing, and its use and storage have strict requirements:

- Storage Temperature: Solder paste is usually stored in an environment of 0°C to 10°C, and the temperature difference should not exceed 1°C. It needs to be thawed before use, which takes about 4 hours.

- Usage Principle: Solder paste follows the principle of "first in, first out". When using it, it is necessary to make good marks, and the remaining part needs to be recycled. However, the number of recycling times should not exceed twice. Otherwise, it needs to be returned to the supplier for processing.

- Stirring: Before use, it needs to be stirred with an automatic stirring device for 5 minutes to prevent air from entering and generating bubbles, which will affect the soldering quality.

III. Stencil and Squeegee Control

Stencils and squeegees are important tools in the SMT chip mounting process, and their quality directly affects the soldering effect:

- Stencil Specifications: Usually, the size of the stencil is 37cm×47cm, and the bearing capacity is between 50-60MP. When storing, the temperature should be controlled at 25°C to prevent the stencil from becoming brittle and damaged.

- Squeegee Usage: The working angle of the squeegee is 45 degrees. Generally, it needs to be replaced after being used 20,000 times. Otherwise, the thickness of the stencil will become smaller, affecting the tin scraping effect.

IV. SMT Mounter Adjustment and First QC

During the SMT chip mounting process, we need to adjust the coordinates of the mounter according to the documents provided by the customer to ensure the accuracy of component placement. After the chip mounting is completed, the quality inspection personnel will check the first sample. Only after confirming that there are no problems such as missing chips and flying chips can mass production be carried out.

V. Reflow Soldering Control and Second QC

The temperature setting of the reflow soldering needs to be adjusted according to the material of the PCBA board (such as single-layer board, double-layer board, etc.). The PCB materials of Jianxiang Sheng perform excellently during the reflow soldering process, being able to withstand high temperatures and maintain stability to ensure the soldering quality. After the soldering is completed, the quality inspection personnel will conduct a second inspection of the first sample to check whether there are problems such as unmelted tin, yellowing of components, or empty soldering. Only after confirming that there are no errors can production continue.

VI. Third QC Inspection

After the PCBA finished product is completed, the quality control department will conduct a sampling inspection to ensure that all products meet the quality standards. Only by passing this final checkpoint can the product be delivered to the customer.

Every step of PCBA production is inseparable from strict quality control. From the inspection of raw materials to the final testing of the finished product, every single link must be treated with great care and cannot be taken lightly.

Relying on years of industry experience and high-quality PCB materials, PCBMASTER offers customers comprehensive support ranging from raw materials to finished products, ensuring the quality and reliability of the final products.

Author: Jack Wang