Key points control of vacuum laminator
Today, I would like to share with you the key points of vacuum laminating machine when pressing PCB boards. The main points are as follows:
1. Temperature rise curve - the temperature rise rate of the film is recommended to be controlled at 1.5~3 ℃/min when it is in the range of 80~140 ℃ from the open melt flow to the completely non flowing state to obtain the best pressing effect, while the material temperature is recommended to be greater than 40 'when it is above 170 ℃ to make the resin cure complete. This is for general FR-4. If the material used is High Tg material, the cure time shall be subject to the recommendations of each supplier
2. The material temperature difference of each panel on the same layer should be less than 5 ℃. If it exceeds, it means that there is a difference in the heat supply in the hot disk. The hot coal flow must be corrected to confirm whether the pipeline is blocked.
3. The number of overlapping layers in each opening is about 10-11, so there will be a drop in temperature transmission. When the material temperature of the outer layer and the middle layer is 100 ℃↑, the difference should be less than 15 ℃.
4. Set the pressure curve. Use a small pressure for one section of the pressure, that is, let the hot plate just hold, about 100~150psi. When the middle layer material temperature is about 55~60 ℃, it can rise to the main pressure section about 300~400psi. At this time, the outer layer material temperature is about 85~90 ℃, and the time setting is about 10~30 minutes, depending on the material temperature.
5. For cold press conditions, generally the cooling rate should be less than 2.5 ℃/min when it is set above the material temperature Tg, and the cooling rate can be accelerated when the material temperature is below the Tg point, so as to avoid thermal stress residues, and at the same time, the cycle time of cold pressing will not be too long. Generally, the heating conditions and pressure conditions should be set for trial pressing. After taking the actual material temperature as the wiring quantity, fine adjustment can be made according to the actual pressing quality to obtain the best conditions.
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