Research On Removing Fusion Line Of Injection Moulding

The plastics injecting products as one of the main structure parts of the modern industrial products, have already been widely used in a lot of fields of all trades and professions. Because of the complexity of forming process, the products of moulding are extremely apt to produce various kinds of defects, especially the existence of fusion line defect has universality. As one of the common appearance defects of injecting the products, it not only influences the appearance quality of the products, and make the electroplate process produce colour difference .It also produce an influence and damage on the mechanics performance of the products to the intensity of the products when being serious to make, bring the potential hazard to normal use of the products,influence products quality, arise from serious waste of material and energy ,etc.How to dispel or weaken the fusion line's defects which is formed in the moulding process and improve the quality of the products is one of the import subjects for research of the mold design and manufacturing field.This subject combining research of removing fusion line which is a project from natural science foundation of ningbo, according to the produce practice of double-barrel of washing machine from niguang group of ningbo .after having consulted much domestic and international materials about injection moulding.This dissertation introduces the injection moulding's development,the development trend in our country and foreign countries and the eliminating resolvent of fusion line at the present time.The dissertation still points out the mark of welding produces mechanism.and points out eliminating fusion line with sequential valve gating control.The implementation of this project can not only make our kow more about the mark of welding produces mechanism.also is helpful for eliminating fusionline,improve the quality of the surface of the prodcut,but also avoid a lot of losing, sequential, it will enhance the credit standing .We explained the sequence controlling system of double-barrel of washing mechine.Analyse the reason and result why fusion line produces .and design sequence controlling system base on it.the dissertation includes the mechanism of fusion line,the condition of fusion line produce.In the dissertation , I optimize the timing of sequence controlling by genetic algorithm.The dissertation also describe the mould plastic and filling the course melting body rheology analysis of the mould. Point out plastic fusibility belong s to the fluid which is glotinous , no-Newton and no-compressible. The fusibility has the flow course of free surface and non-isothermal instant state when it conduct the movement of filling-moulding Depict simply the physical course of fusibility filling moulding.Utilize viscidity hydrodynamics and spread the basic equation of calorifics especially, is it that equation set up to fill by power rate mould melting body model is it is it is it is it flow dish and type flow rheology nature of course to become to melt to analyse to come function have to use.We introduce the development trend and the composition of hot runner,analyse thermal current dishes of system compare routine flow dishes of system pros and cons at the economy and technology. The dissertation discuss why fusion line produces and analyse the condition which influence the fusion line. Analyse the reason and result why fusion line produces by effect of"sandwich"proved that fusion line is two different state of melting body flow each other material , energy exchange complete and different from melting and flowing originally transition. Then wo use moldflow to analyse these conditions. Then, we built the restraint conditions , length and location function base on genetic algorithm. And then wo use it to optimize the timing of sequence conrolling syetem, at last, we design sequence controlling system.We explains the sequence controlling system of double–barrel of wahsingmechine. This chapter is the most imporant part in this paper. Introduce the theory of sequence controlling system.Sequence controlling system can avoid the fusion line or reduce it. Or displace it onto subordinate faces of the products. For standard runner system, it doesn't have injection gate valve, can't control the movement of the melt body in injection gate, so this system can be applied only in hot runner. Theremore,it is also very expensive.