螺杆转速和机筒温度对加工聚丙烯的影响

分析工艺条件对螺杆注射加工聚丙烯的影响.在不同螺杆转速和机筒温度条件下,使用有限元法数值计算螺杆头为35°锥角且带止逆环的注射螺杆流道内熔体的三维非等温流场.分析了熔体的温度、剪切应力、黏度和黏性热.研究结果表明,在塑化过程中,当螺杆转速由45 r/min提高到105 r/min时,熔体的最大流速、剪切应力和黏性热分别增大了1.60,0.41,2.00倍.当机筒温度从573 K降低100 K时,塑化时熔体的最大速度减小了0.011 m/s,熔体的最大剪切应力、黏性热和熔体黏度分别增加了1.13,1.15,6.39倍;注射时熔体的最大流速减小了0.359 m/s,熔体的最大剪切应力、黏度和黏性热分别增大了1.32,2.40,1.87倍.

Influence of the Screw Rotating Speed and Barrel Temperature on Polypropylene Injection

The influence of processing conditions on the polypropylene melt flow in the flow channel of injection screw was analyzed in this paper. The three-dimensional nonisothermal flow fields of polypropylene melt in the flow channel of 35°cone non-return injection screw were simulated under different screw speeds and barrel wall temperatures using the finite element method. The fields of temperature, shear stress, viscosity and viscous heating of the melt were analyzed. Simulation results indicate that when the screw speed increases from 45 r/min to 105 r/min, the maximum velocity, the maximum shear stress, and maximum viscosity heating of the melt respectively increase by 1.60, 0.41 and 2.00 times, respectively, in the plasticizing process. When the barrel temperature decreased by 100K from 573K, the maximum shear stress, the maximum viscosity, and the maximum viscous heating increase by 1.13, 1.15 and 6.39 times, respectively, in the plasticizing process for a maximum velocity decrease of 0.011m/s. The corresponding increases in the maximum shear stress, maximum viscous heating, and the maximum viscosity of the melt are 1.32, 2.40 and 1.87 times, respectively, in the injection process for a maximum velocity decrease of 0.359m/s.