We use the international famous brand of raw materials and make inspection standard according to the International Standard and customer requirements. We keep monitoring suppliers continuous improvement activities and build long-term partnership with all suppliers.

 

In-Process Quality Control

Good products come from good manufacturing but not inspection. We have standard manufacturing process and detailed work instructions for each operation station in production line to make sure that operation standard are implemented correctly.

 

 

Final Quality Control

We inspect and control strictly the outgoing products quality according to the international standards and customer standards, follow up the quality performance of products after sales and take rapid and effective improvement actions when there are any abnormal quality feedbacks.

 

**************PCB quality control*******************

In order to ensure the production quality of PCB boards, manufacturers have gone through a variety of inspection methods during the production process, and each inspection method will target different PCB board defects.

 

1. PCB size and appearance inspection

The content of PCB size inspection mainly includes the directness of processing holes, spacing and tolerances, PCB edge dimensions, etc. The content of appearance defect inspection mainly includes: the alignment of the solder mask and the pad; whether the solder mask has abnormal conditions such as impurities, peeling, wrinkles, etc.; whether the reference mark is qualified; whether the width of the circuit conductor (line width) and spacing are consistent Requirements; Whether the multilayer board is peeled off, etc. In practical applications, special equipment for PCB appearance testing is often used for testing. Typical equipment is mainly composed of computers, automatic workbenches, and image processing systems. This system can detect the inner and outer layers of multilayer boards, single/dual panels, and base map films; it can detect broken lines, overlapping lines, scratches, pinholes, line widths, rough edges, and large Area defects, etc.

2. PCB solderability test

The solderability test of PCB focuses on the test of pads and plated through holes. Standards such as IPC-S-804 stipulate the solderability test method of PCB, which includes edge dipping test, rotary dipping test, wave dipping test and solder Bead test etc.

 

3. PCB solder mask integrity test

 

Dry film solder mask and optical imaging solder mask are generally used on PCBs. These two solder masks have high resolution and immobility. Dry film solder mask is laminated on the PCB under pressure and heat. It requires a clean PCB surface and an effective lamination process. This kind of solder mask tin-lead alloy has poor surface adhesion, and under the impact of thermal stress generated by reflow soldering, peeling and fracture of the PCB surface often occur. This kind of solder mask is also brittle, and may cause micro-cracks under the influence of heat and mechanical force during leveling. In addition, physical and chemical damage may also occur under the action of cleaning agents. In order to find out these potential defects of dry film solder mask, strict thermal stress test should be carried out on PCB during incoming material inspection. When the solder mask peeling is not observed during the test, the PCB test piece can be immersed in water after the test, and the capillary action of the water between the solder mask and the PCB surface can be used to observe the solder mask peeling. The PCB specimen can also be immersed in the SMA cleaning agent after the test to observe whether it has physical and chemical effects with the solvent.

 

4. PCB internal defect detection

 

The internal defect detection of PCB generally adopts microsection technology, and the specific detection method is clearly stipulated in relevant standards such as IPC-TM-650. The main inspection items for microsection inspection include the thickness of copper and tin-lead alloy coatings, the alignment of the internal conductors of the multilayer board, the laminated voids and the copper cracks.

 

 

**************PCBA quality control****************

What is the main quality control of PCBA processing

 

PCBA processing technology involves a series of processes such as PCB board manufacturing, PCBA incoming purchase and inspection, SMT chip processing, plug-in processing, program firing, testing, and aging. Both the supply chain and the manufacturing chain are long. Any defect in any link will cause a large number of PCBA boards to be unqualified, leading to serious consequences. In this case, the quality control of PCBA chip processing is a very important quality assurance in electronic processing, so what is the main quality control of PCBA processing?

 

It is especially important to hold a pre-production meeting after receiving the PCBA processing order. Mainly analyze the PCB process flow, and submit a manufacturability report (DFM) according to the different requirements of customers. Many small manufacturers do not take this seriously, but tend to do so. It is not only prone to poor quality problems due to poor PCB design, but also requires a lot of rework and maintenance work.

 

2. Procurement and inspection of PCBA components

To strictly control the procurement channels of parts and components, goods must be purchased from major merchants and original factories to avoid the use of second-hand materials and counterfeit materials. In addition, it is necessary to set up a special PCBA incoming material inspection post to strictly check the following items to ensure that the components are free of faults.

PCB: Check the temperature test of the reflow oven, there is no fly wire through hole clogging or ink leakage, board bending, etc.

 

IC: Check whether the screen printing is exactly the same as the BOM, and store at constant temperature and humidity.

Other commonly used materials: check screen printing, appearance, power measurement, etc.

3. SMT assembly

The solder paste printing and reflow oven temperature control system is the focus of assembly, which requires the use of laser stencils with higher quality requirements and better processing requirements. According to the requirements of PCB, some steel mesh holes or u-shaped holes need to be added or reduced, and steel mesh can only be made according to process requirements. The temperature control of the reflow oven is very important for the wetting of the solder paste and the firmness of the stencil welding, and can be adjusted according to the normal SOP operation guide.

In addition, strict implementation of AOI testing can greatly reduce the adverse effects caused by human factors. Substitution processing

In the process of plug-in assembly, the mold design of wave soldering is the key. How to use molds to improve product yield is a process that PE engineers must continue to practice and summarize.

5. Program launch

In the previous DFM report, customers can be advised to set some test points (test points) on the PCB to test the circuit continuity of the PCBA processing circuit after all the parts are soldered on the PCB. If possible, you can ask the customer to provide a program, burn the program to the main control IC through the burner, and test various touch actions more intuitively, thereby verifying the functional integrity of the entire PCBA.

6. PCBA processing board test

For orders with PCBA test requirements, the main test content includes ICT (circuit test), FCT (functional test), burn test (aging test), temperature and humidity test, drop test, etc.