1. Molding process: The mold cost is relatively high. T […]
1. Molding process: The mold cost is relatively high. The advantage is that it can accurately ensure the thickness and size of the composite material. It has two smooth surface components. The components that usually use the molding process include flight control parts, helicopter rotors, sports equipment and Medical bed board, etc. In the molding process, a certain amount of interference is given to the foam core material. During the mold clamping and curing process, the interference provides back pressure to the curing of the panel.
The compressive creep resistance of PMI foam is the prerequisite and guarantee for the transformation of interference into back pressure. The back pressure can be adjusted according to the resin content of the ply, curing system, and panel thickness by setting the appropriate amount of interference. Meet the requirements of curing pressure.
2. Autoclave process: It is a hard mold on one side and a soft mold on the other side (vacuum bag). The solidified composite material laminate is pressurized by vacuuming and pressurizing in the autoclave. If the co-curing process is adopted, that is, the curing of the carbon fiber conforming material panel and the bonding of the sandwich structure core material and the panel are completed at one time. The void of PMI foam is smaller than that of honeycomb, and it can provide enough support for the curing of the panel, and it will not have the telegraph effect like the honeycomb structure panel.
3. RTM process: Liquid resin injection is a relatively new optimized manufacturing process. With the help of RTM (Resin Transfer Molding) technology, high-performance sandwich structural components are produced. At present, it is to simplify the production process, reduce manufacturing costs, and save raw materials. The price is relatively low, and the cloth with good covering performance can be used to achieve mass production, and the components can greatly achieve the effect of using high-quality prepregs.
If the voids of the honeycombs are sealed to prevent low-viscosity injection resin from flowing into the voids of the honeycombs, honeycombs can also be selected as the sandwich material in the RTM manufacturing process. However, usually if the RTM process is used to produce the material for the sandwich structure, the foam core material is generally used, which is the same as the autoclave process. The core material also needs to have good compression creep resistance and meet the requirements of resin injection pressure and injection temperature.