Performance requirements for reflow soldering equipment
Reflow soldering equipment has a heating circuit inside. Once heated to a high enough temperature, it is blown onto the circuit board where the part is affixed, causing the solder on both sides of the part to melt and adhere to the motherboard. The reflow process is more than just a temperature process. In order to guarantee the basic temperature process characteristics, it must be supported by adequate equipment performance. Therefore, it is necessary to achieve an integrated control of equipment performance, temperature and SPC (Statistical Process Control).
The basic process of reflow equipment tuning is as follows:
Many factories commission third-party certification bodies (such as esamber certification centers) to perform equipment performance calibration, certification, and alignment. Some workers have set up a standby maintenance team to configure their own specialized equipment for performance calibration.
The main aspects to be confirmed are as follows:
1. When the hot air flow rate is between 4.5-6.5 kl/cm-2.min, the best results; when the hot air flow rate is too small, it is easy to have thermal compensation and insufficient thermal efficiency; when the hot air flow rate is too large, it is easy to have deviation, BGA-tin connection and other welding defects. It can be adjusted by adjusting the frequency of the hot air motor.
2. No-load and full-load capacity. No-load and full-load temperature difference does not exceed 3℃. Reflow soldering working principle.
3. Confirmation of chain speed accuracy and stability. The deviation of chain speed should not exceed 1%.
4. Make sure the track is parallel to prevent the plywood from falling off. Plywood easily lead to the bottom of the board off, PCB bending, tin catching and other problems, and off the damage is more obvious.
5. SPC control of reflow soldering equipment performance.
Related test tools include reflow soldering process performance tester, track parallelism tester, etc.
Only on the basis of testing for temperature control, to ensure the basic performance of reflow soldering equipment and product temperature profile of the sample test. In addition, although the furnace temperature profile is tested, it can only represent the current situation and cannot represent the temperature profile of all products to be produced. Due to the instability of the furnace with poor process performance, poor load capacity and insufficient convection of hot air, instability can occur during the temperature rise process. Therefore, before adjusting the temperature process, it is necessary to test and confirm the performance of the equipment, implement optimization improvements, configure the model rationally and optimize the production capacity.
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