Long Glass Fiber Reinforced Reaction Injection Molding Integration Process

Long fiber reinforced reaction injection molding (LFI), as a process for producing polyurethane (PU) products, has just been applied in our country for few years, and many technology issues have not been resolved. The thesis is based on the actual project "Yangtze Automobile Interior Trim Corporation 16/40 LFI production line". Aiming at the problems exist in the existing production lines, such as the skin cannot fit with the mold, and manual operations are time-consuming, some interrelated theoretical research were studied, then completed the transformation of this production line.The mechanism of vacuum Plastic-absorbing molding were studied. the theoretical model including continuity equation, momentum equation, energy equation and constitutive equation were established. Take a skin part of electrical covering of one carriage as an example, the entire process of simulating vacuum Plastic-absorbing molding in POLYFLOW were researched. The results of the numerical simulation showed that: with the pressure and the load time increase, the forming speed of various parts are different, deep parts and small parts are slower than other parts. In order to get uniform thickness distribution and higher-quality, the number of blister holes could be increased to accelerate the forming speed of those parts; Increasing the fillet radius between the bottom and side wall and enlarging the demoulding gradient can improve the thickness distribution; to the products with large ratio of depth-radial, the prestretching process could improve the thickness distribution. The temperature field of plastic sheet in radiation heat process was researched with ANSYS. The simulation results showed that: the temperature distribution of the sheet cross-section is always uneven in the various stages of heat radiation, the maximum temperature region is at middle, the minimum temperature region is at edge; the degree of the unevenness could be gradually increasing over time; there is a temperature gradient along the thickness direction, through making the sheet natural cooling properly, the temperature gradient can be improved.Finally, on the basis of analysing the the operation and the structural characteristics of the existing production lines, an integrative process transformation solution was proposed. Through transformating it can achieve integration of skin forming, casting, reaction forming, and improve production efficiency and product quality of interior parts.