The production process of FR-4 material mainly includes the following steps:
Raw material preparation
Electronic grade fiberglass cloth is selected, which has the characteristics of high strength, good insulation, and dimensional stability. Simultaneously prepare epoxy resin, which is a thermosetting resin that can provide good adhesion, heat resistance, and chemical stability
dipping
Immerse the glass fiber cloth in epoxy resin to allow the resin to fully penetrate the gaps between the fiber cloth and the fibers, ensuring that each fiber is evenly wrapped by the resin. This process requires strict control of parameters such as resin viscosity, impregnation time, and temperature to ensure impregnation effect and material properties
Pre formed
The impregnated glass fiber cloth is subjected to preliminary drying in an oven or heating device to partially cure the resin, forming a prepreg with certain hardness and shape stability. Prepreg is an intermediate product that can be cut and layered as needed
Stacking
Stack multiple layers of prepreg according to design requirements and place copper foil in appropriate positions. Copper foil is used as a conductive layer to form circuit patterns. When stacking, attention should be paid to the alignment and flatness between each layer to avoid defects such as misalignment or bubbles
Hot pressing forming
Put the stacked material into a hot press machine, and under the action of high temperature and high pressure, further cure the epoxy resin and tightly bond it with glass fiber cloth and copper foil to form a sturdy FR-4 board. The control of parameters such as hot pressing temperature, pressure, and time is crucial for the performance of the board. Generally, the temperature is between 150 ℃ -200 ℃, the pressure is between 2MPa-5MPa, and the time depends on the thickness and number of layers of the board
Post processing
The FR-4 sheet after hot pressing needs to undergo post-treatment processes such as cooling, demolding, and cutting to obtain the desired size and shape. Surface treatment can also be carried out, such as grinding, polishing, etc., to improve surface smoothness and flatness, meeting the requirements of different application scenarios
Quality inspection
Finally, the FR-4 board undergoes quality inspection, including visual inspection, dimensional accuracy measurement, electrical performance testing, mechanical performance testing, etc. Only after passing the inspection can the board be put into the market as a qualified product
