Study On The Equipment Of The Liquid Composite Molding And Technology Development

Resin transfer molding developed rapidly these years, which is a composite material liquid molding technology, and it is the most important techniques for fiber reinforced plastics. In the process, resin is injected into the closed mold and infiltrate the reinforce materials, then solidify. There are four steps in this process: (1) Lay the fiber. The fiber can either be weaved into the product's shape in one time or laid into the mold layer by layer, or both. (2) Resin injection. Resin and activator are mixed in the motionless mixer before injecting by the former of the injector. (3) Resin solidify. Heating the mold cavity so as to solidify the resin. (4) Product takes off from the mold. When the resin is solidified, opening the mold and getting the part. Comparing with other processing for composite, there are many advantages in RTM. The mold of RTM is closed, so the quantity of styrene volatilization is small. It can improve the working condition and satisfy the standard of harmful gas ejection. In this paper, combining the automobile bumper RTM process, the molding theory, molding equipment, mold design, technological design are researched.1. Study on the rheology theory for RTMThe resin filling process of RTM is analyzed, including the preparing phase, resin flow phase and resin solidify phase. Some measure means and measure equipments for the resin permeability and penetrate ratio. Study on the mathematic model for resin filling process, including conservation of momentum equation, conservation of mass equation and conservation of energy equation.2. Study on the development of LCM molding equipmentFocused on the automobile roof, develop a set of specialized LCM equipment, the principle study is the selction and development of pump system. According to the working principle of peneumatic pump system research the manual and aoto control of the injection, introduct key assembly, inject vavle and static miaxer as well ae the operation of the equipment. 3. Mold design for automobile roof by RTMCombining the flat theory, the thickness of mold board is analyzed. Design for the mold injector port, air vent, design for mold layer structure and strengthen structure, design for airproof structure, all are optimized. In the end, the mold material is selected: ethylene ester mold pastern cloth made in the USA, which has good qualities: high thermal distortion temperature, good tenacity, high rigidity, there isn't even tiny crack in the condition of repeating heat shock, it can reach mirror surface by fine polishing. In the structure layer, medium solidify temperature and low shrink epoxy system is chosen, and adding excellent new type curing agent.4. Techniques experiment study for automobile roof by RTMThe structure of roof is designed, and parent materials and reinforced materials for bumper are chosen too. Combining the simulation result, the molding conditions are determined primarily and experiment is done. The product quality is improved by adjusting injection pressure, filling time, etc. In the end, the bumper's mechanical property is analyzed, the result shows that: in some filling temperature range, the product impact strength rises stably along with the filling temperature. The fiber volume fraction and distribution affect the product tensile strength highly. For the RTM products with continue long fiber felt, the molding process will form defects such as air bubbles, dry points, because of the asymmetry distributing of the fiber, all of these will affect the strength of the product.