Optimization Of Parametric For Injection Molding Of Plastics Chair

As an important forming technique to produce plastic product, Plastic mould injection can produce the product with complex shape and high degree of accuracy. However, Plastic mould injection is a rather complicated physical process. Under press propulsion, Non-Newtonian fluid passes runner and gate to fill cavity. Firstly, because of heat transfer to the mould, melt is rapidly cooled. Secondly, due to the quantity of heat produced by high-rate shearing, melt solidification, volume contraction, molecule orientation and possible crystallization may occurre. Therefore, previons mould injection technique utilized trial-and-error method to determine mould injection parameters. However, This method generates lots of problems, such as long production cycle, low production efficiency and instability of quality. To solve these problems, researchers developed mould-flow analysis technigue, such as Mould injection CAE technology. By using basic theory of flow rheological dynamics and heat transfer, Mould injection CAE technology set up flow and heat transfer physical-mathematic model of plastic melt in die cavity. The model can utilize numerical calculation theory to construct the solution method. By using computer graphics to visualized simulate the dynamical filling and cooling process, the model would quantitative analyze the status parameter in moulding process (such as pressure, temperature, velocity etc.).In this research, Plastic toy chair was defined to the basic research object and Taiwan PP 6361 was prepared to experimental material. We discussed the case of a die with one cavity and a die with two cavities. By using mould-flow analysis software Moldflow, plastic toy chair was analyzed by CAE and defined the optimum definite element model and deformation parameter. To obtain the reasonable result, the thesis set four type of side length in element lattice(2.6mm,3.0mm,3.4mm,3.8mm) and discuss the element model. Then the result shows that the large density of element lattice cannot obtain the best effect, lattice repair and product structure also should be considered. The size of optimal lattice is 3.4mm. To obtain the balance fill, by using MoldFlow and recursive trial-and-error method, this research obtained geometric parameter and position of running system in two states, respectively, and attained equilibrium fill. By setting every parameter to several values and comparing with each other, it is known that a small amount of enhancement to injection pressure can greatly improve the dwell pressure and mode locked pressure, when inject nearly mold shell product. Therefore, it is helpless to improve running quality by enhancing injection pressure. Selecting the reasonable mold temperature and plastic melt temperature is the best way to improve the product quality.Otherwise, for the second situation, configuration of cooling water pipe has the great effect to injection mounding. The configuration of cooling water pipe can not only affect the fill balance, but also greatly affect the distribution of temperature field and product distortion. For mold with different cavities, cooling water pipe should be discuss with other deformation parameter to get optimum result.