Optimization of injection⁃molding process of screw rotor based on response surface method

doi:10.19491/j.issn.1001-9278.2024.06.014

Abstract

Abstract:

Aiming at the problems in the complicated process and the difficulty to control the precision of traditional metal type screw rotor， a new injection⁃molding method with a screw rotor was proposed to replace the metal type rotor with a plastic material. The Moldflow software was used to analyze the injection molding of the tooth surface of the screw rotor using glass⁃fiber⁃reinforced nylon as a raw material. The depth of shrinkage and warping deformation were taken as quality criteria to screen and analyze 7 process parameters affecting the molding quality of plastic parts， and 3 process parameters that had the greatest impact on the 2 quality standards were determined. A response surface experiment was designed through the BBD experiment. The influence of injection process parameters such as melt temperature， holding time， and holding pressure on the shrinkage depth and warp deformation was studied. A polynomial regression response model for minimum shrinkage depth and warp deformation was obtained. Using regression model， the optimal combination of process parameters was determined to be a melt temperature of 281.0 ℃， a pressure holding time of 18.7 s， and a pressure holding pressure of 115.7 MPa. The results indicated that the values obtained from the numerical simulation and prediction with the model were similar along with errors of 3.75 % and 0.53 %， respectively.

Key words: screw rotor, response surface method, indentation depth, buckling deformation

CLC Number:

TQ320.66⁺2

YIN Dashuai, ZHAO Yongqiang, HEI Ganggang, LI Zhibin. Optimization of injection⁃molding process of screw rotor based on response surface method[J]. China Plastics, 2024, 38(6): 90-97.

Figures/Tables 23

References 18

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工艺性能	数值
推荐模具表面温度/℃	80
推荐熔体温度/℃	290
推荐模具温度范围/℃	80~120
推荐熔体温度范围/℃	280~300
绝对最大熔体温度/℃	300
顶出温度/℃	215
最大剪切应力/MPa	0.5
最大剪切速率/s^-1	60 000

工艺性能	数值
推荐模具表面温度/℃	80
推荐熔体温度/℃	290
推荐模具温度范围/℃	80~120
推荐熔体温度范围/℃	280~300
绝对最大熔体温度/℃	300
顶出温度/℃	215
最大剪切应力/MPa	0.5
最大剪切速率/s^-1	60 000

方案编号	注射时间/ s	熔体温度/ ℃	保压时间/ s	开模时间/ s	注射压力/MPa	模具表面温度/ ℃	保压压力/ MPa	缩痕深度/ mm	翘曲变形总量/ mm
1	3	280	16	4	115	80	80	0.698	0.622
2	4	280	16	6	115	120	120	0.667	0.616
3	4	300	24	4	125	80	80	0.795	0.658
4	4	300	24	6	125	120	120	0.851	0.655
5	6	280	16	4	125	80	80	0.708	0.669
6	6	280	16	6	125	120	120	0.65	0.652
7	6	300	24	4	115	80	80	0.758	0.640
8	6	300	24	6	115	120	120	0.809	0.647

方案编号	注射时间/ s	熔体温度/ ℃	保压时间/ s	开模时间/ s	注射压力/MPa	模具表面温度/ ℃	保压压力/ MPa	缩痕深度/ mm	翘曲变形总量/ mm
1	3	280	16	4	115	80	80	0.698	0.622
2	4	280	16	6	115	120	120	0.667	0.616
3	4	300	24	4	125	80	80	0.795	0.658
4	4	300	24	6	125	120	120	0.851	0.655
5	6	280	16	4	125	80	80	0.708	0.669
6	6	280	16	6	125	120	120	0.65	0.652
7	6	300	24	4	115	80	80	0.758	0.640
8	6	300	24	6	115	120	120	0.809	0.647

因子	对缩痕深度影响的百分比/%	对翘曲变形影响的百分比/%
注射时间	3.91	13.32
熔体温度	30.14	28.53
开模时间	3.02	2.04
速度/压力切换（由注射压力）	5.14	5.15
持续时间（保压时间）	22.88	17.20
模具表面温度	5.43	8.32
保压压力	29.48	25.45