注射模冷却系统的计算机模拟

Computer Simulation of Cooling System for Injection Molding

冷却系统的计算机模拟是相当有效的工具,它在注射模具设计中的应用有广泛的前途.本文作了注射模的冷却分析,建立了冷却分析的数学模型,推导了传热有限元理论计算,并对具体实例进行了传热有限元计算机程序的编写.本程序的有限元法在分析注射模热行为中得到了发展,程序应用了二次等参数单元,且能自动地进行单元划分,显示模具截面内的等温线预测图.由此本程序优化冷却管道的布置,选择最有效的冷却剂温度和准确预测最短冷却时间,从而达到提高传热的速率和平衡整个模具内的传热.

At present,the design of cooling system for injection molds is pri-marily based on the designers' experience.Since the cooling process invo-lves the longest time in the overall injection molding cycles,and especiallywhen the heat flow from the mold is not balanced,differential shrinkagecan occur,resulting in residual stress and/or warping of the moulded parts.Therefore the analysis of the thermal behaviour of the mold is important sothat a rational design of the cooling system can be achieved.This paperuses the steady state and unsteady state mathematical models in thermal con-duction with the convevtive heat transfer boundary conditions at the cooln-ing channel.This computer program wich is based on the finite elementmethod has been developed for analyzing the thermal behaviour of the in-jection mold.The program makes use of the quardratic isoparamentric ele-ment and automatically numbers the elements to show the predicted isothermsresult of the cross-section of the model.Accordingly,it can optimize thelocation of the cooling lines in the mold to select the most effective coolanttemperature and accurately predict the minimum cooling time,etc.Thus im-provements can be obtained in(1)accelerating the rate of heat transfer,and(2)balancing heat transfer throughout the mold.