Affiliation:
1. INSA-Lyon LaMCoS UMR5259
2. INSA-Lyon IMP UMR5223
3. INSA-Lyon MATEIS UMR5510
Abstract
Single stage injection blow moulding process, without preform storage and reheat, could be run on a standard injection moulding machine, with the aim of producing short series of specific hollow parts. In this process, the preform is being blow moulded after a short cooling time. Polypropylene (Random copolymer) is a suitable material for this type of process. The preform has to remain sufficiently melted to be blown. This single stage process introduces temperature gradients, molecular orientation, high stretch rates and high cooling rates. These constraints lead to a small processing window, and in practice, the process takes place between the melting temperature and the crystallization temperature. To investigates the mechanical behaviour in conditions as close to the process as possible, we ran a series of experiments: First, Dynamical Mechanical Analysis was performed starting from the solid state at room temperature and ending in the vicinity of the melting temperature. Conversely, oscillatory rheometry was also performed starting this time from the molten state at 200°C and decreasing the temperature down to the vicinity of the crystallization temperature. The influence of the shear rate and of the cooling kinetics on the enhancement of the mechanical properties when starting from the melt is discussed. This enhancement is attributed to the crystallization of the material. The question of the crystallization occurring at such high stretch rates and high cooling rates is open. A viscous Cross model has been proved to be relevant to the problem. Thermal dependence is assumed by an Arrhenius law. The process is simulated through a finite element code (POLYFLOW software) in the Ansys Workbench framework. Thickness measurements using image analysis are performed and comparison with the simulation results is satisfactory.
Publisher
Trans Tech Publications, Ltd.
Subject
Mechanical Engineering,Mechanics of Materials,General Materials Science
Reference16 articles.
1. ANSYS: Ansys polyflow user's guide. release 13 · 0 (2010).
2. Devaux, N.: Influence d'un cisaillement sur les premiers stades de la cristallisation du polypropylène. Thèse de l'Ecole des Mines de Paris (2003).
3. Duffo, P., Monasse, B., Haudin, J.M., G'Sell, C., Dahoun, A.: Rheology of polypropylene in the solid state. Journal of Materials Science 30 (1995).
4. Duval, C.: Polypropylènes (pp). Techniques de l'ingénieur (2004).
5. Groot, J.A.W.M., Giannopapa, C.G., Mattheij, R.M.M.: A computer simulation model for the stretch blow moulding process of polymer containers. ASME 2010 (2010).
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献