1. Mold preheating: before pressing, open the mold thermostat in advance to preheat the mold, remove moisture and other volatile substances, which can improve the curing speed, shorten the pressing cycle, improve the uniformity of cured products, improve the physical and mechanical properties of products, and improve the fluidity of molding materials.
2. Molding temperature control: during the molding process, the function of the mold tempering furnace mainly includes three processes: mold installation heating, temperature rise rate control and molding insulation. The temperature setting required for the mold depends on the type of material and the quality of the molded material. The forming temperature is closely related to the type of forming material. The setting of the molding temperature depends on the curing system of the resin paste, the thickness of the product, the production efficiency and the complexity of the product structure. The mold temperature control must be kept within a reasonable range, because the mold temperature is too high, the material reaction speed is too fast, and local curing can not fill the mold cavity, resulting in material shortage and bubbles; On the contrary, if the temperature is too low and the heat preservation time of the product is insufficient, incomplete curing defects will occur; If the temperature of the upper and lower molds is uneven, or the temperature of the large mold is inconsistent, the FRP products will warp and deform, affecting the dimensional accuracy.
3. In the curing stage, the temperature stability of the mold temperature machine can completely cure the product and eliminate the internal stress. The European Machinery FRP SMC special mold temperature machine uses heat transfer oil as the heat transfer medium. The maximum temperature can reach 300 ℃, and the temperature control accuracy can be controlled at 0.5 ℃.
4. Cooling process
Only when the mold temperature drops below 60 ℃ during slow forming can the demoulding operation be carried out. Mold temperature machine with natural cooling and forced cooling. The rapid pressing process cannot be used for cooling operation. After heat preservation, the product can be taken out of the mold at the end of the forming temperature, and then necessary auxiliary processing can be carried out to obtain the product.
Generally speaking, the temperature control process of SMC FRP mold mainly includes two aspects, one is mold preheating, the other is mold temperature control during mold forming. The temperature control must ensure that after the resin curing system is started, the cross-linking reaction can proceed smoothly and the curing can be completed.
