The advantages of FRP flower pots such as durability and beauty have become the choice of outdoor flower pots. Do you know these operation procedures for the SMC molding process of FRP flower pots?
(1) Preparation of FRP flower pot before pressing: preheating and preforming of molding material, estimation of charging amount, selection of release agent ① Pre-heating and pre-molding of the molding material: Pre-heating the molding material before pressing is called pre-heating. The purpose is to improve the process performance of the material, such as increasing fluidity, facilitating mold loading and reducing the shrinkage of the product; at the same time, increasing the temperature of the molding material. It can shorten the curing time and reduce the molding pressure. The glass fiber reinforced plastic flower pots that have been pressed by the preheated molding material have improved physical and chemical properties and dimensional stability. ②Estimation of the loading amount: In order to improve the production efficiency and ensure the size of the glass steel flower pots Need to make accurate estimates of charge. Generally, a rough estimate is made in advance, and then an accurate charge is found after several pressure tests. The loading amount is equal to the density of the molded FRP flower pot multiplied by the volume of the FRP flower pot, plus 3% -5% loss of volatiles and burrs.
③ Selection of release agents: There are two types of release agents used in molding: internal release agents and external release agents. Oils, oleic acid, stearic acid, etc. are commonly used for phenolic molding materials. Silicone grease or silicone are mostly used for epoxy and epoxy phenolic molding materials. When meeting the demoulding requirements, it should be used as little as possible and painted uniformly, so as not to reduce the surface quality of the glass fiber reinforced plastic flowerpot.
(2) FRP flowerpot pressing: During the molding process, the material macroscopically undergoes three phases of viscous flow, gelation and hardening. At the micro level, the molecular chain changes from a linear to a network body structure. This change is conditional on a certain temperature, pressure and time. The compression system of the molding process includes a temperature system and a pressure system.
① Temperature system: The temperature system includes molding temperature, heating speed, maximum temperature, constant temperature, cooling and post-curing temperature. The molding temperature depends on the curing system of the resin paste, the thickness of the FRP flower pot, the production efficiency, and the complexity of the FRP flower pot. The molding temperature must ensure the smooth initiation and cross-linking reaction of the curing system and complete curing.
② Stress system: Stress system. It mainly includes molding pressure, pressurization timing, and gas release. The molding pressure varies with the degree of thickening of the material, the feeding area, the structure, shape and size of the product.
③ Curing time: The curing time (also called holding time) of the SMC at the molding temperature is related to its properties and curing system, molding temperature, product thickness and color, etc.