关键词: 挤出吹塑；型坯壁厚；Catmull-Rom样条；优化设计

Abstract:

The parison thickness for extrusion blow molding has direct effects on the manufacturing cost of hollow plastic parts. A new method of computer aided design for parison thickness was presented based on Catmull-Rom spline, which used geometric continuity of the Catmull-Rom spline, and operated curves by a set of control vertices and a set of shape parameter values. In order to satisfy the requirements of good continuity and fast-respondability of the parison thickness controlling, a new algorithm of adaptive data sampling based on curvature was proposed. Based on elasticity finite elements method analysis, the parison inflation in the plastics extrusion blow molding was simulated, and the optimal shape of parison thickness had achieved. Experimental results indicate that this technology makes it easier to edit and revise the values of parison thickness, and can obtain values of superior quality and performance. Human-machine interface software of the parison thickness control system was developed, and applied in the extrusion blow production activity. The results show the utility of this technology. 

Key words: extrusion blow molding, parison thickness, Catmull-Rom spline, optimum design