What are the precautions for carbon fiber sheet compression molding to affect performance?

Carbon fiber sheet generally adopts the production process of compression molding, which is a molding method under the catalysis of pressure, temperature, and time. The main purpose is to allow the resin in the carbon fiber prepreg to fully flow into the mold cavity, and to compact the carbon fiber prepreg layers to make it perform better after molding. 3G Carbon, as a company that provides customized carbon fiber products for enterprises, this article will explain to you the main points that affect carbon fiber board compression molding.

1. Prepreg compaction operation in carbon fiber board compression molding

When the carbon fiber sheet is molded and produced, it needs to be laminated with prepreg. During the laying, air will enter between the layers of the carbon fiber prepreg, and defects will appear when the carbon fiber sheet is formed. The high probability is that there will be voids. In the case of delamination, after the paving is completed and heated, the resin melting will cause the air in the interlayer to be unable to discharge. After the sheet is formed, bulging and delamination are prone to occur.

In order to avoid the occurrence of this situation, it is necessary to perform compaction after the paving is completed. In addition to laminating several layers, it can be compacted with a roller, including when stacking the material, the carbon fiber prepreg can be compacted first. To a certain extent, it solves the problem of air ingress when paving materials. In addition, it is necessary to control the heating rate during compression molding. Too fast heating rate and too high temperature will cause the internal and external curing degree to be different, and it will also cause the internal compaction.

2. Time control influence of molding process

After the carbon fiber sheet is placed in the hot press, the molding time will also affect the performance of the carbon fiber board, and the curing time of the carbon fiber sheet will affect the flatness of the board. If the temperature is raised to the required maximum temperature prematurely for fast curing, the resin overflow will cause the carbon fiber board to have a low resin content, resulting in a decrease in the shear performance of the carbon fiber board. Excessive molding time will reduce the dimensional accuracy of the plate after the resin is solidified. In addition, if the resin content is high, it will also cause the bending strength of the plate to decrease.

3. The influence of the temperature control of the molding process

When the carbon fiber sheet is formed, it needs to be pressurized and heated when passing through the hot press. The temperature during heating should also be paid attention to. Since the hot press is an open type, it is compared with the temperature control of the autoclave. It’s a bit difficult. In the process of compression molding, the heating speed of the hot press depends on the temperature of the mold. For example, when the mold temperature is high, the heating speed of the hot press is relatively slow, but when the mold temperature is low, the heating speed is It is faster. In the molding process, if the heating speed is fast, it will easily cause the surface resin matrix to melt faster and solidify earlier, which will reduce the shear strength and cause white spots on the surface of the product. Control is very important.