Effect of cavity surface coating on mold temperature variation and the quality of injection molded parts

被引:63
作者
Chen, Shia-Chung [1 ,2 ,3 ]
Chang, Yi [1 ,2 ]
Chang, Yeon-Pun [1 ]
Chen, Yen-Chen [2 ]
Tseng, Chia-Yen [1 ,2 ]
机构
[1] Chung Yuan Christian Univ, Dept Mech Engn, Chungli 32023, Taiwan
[2] Chung Yuan Christian Univ, R&D Ctr Mold & Molding Technol, Chungli 32023, Taiwan
[3] Chung Yuan Christian Univ, R&D Ctr Membrane Technol, Chungli 32023, Taiwan
关键词
Surface coating; Variable mold temperature control; Interface temperature; Weld line; Tensile strengths; SIMULATION;
D O I
10.1016/j.icheatmasstransfer.2009.06.020
中图分类号
O414.1 [热力学];
学科分类号
摘要
Suiting for high gloss surface of injection molded parts free of painting is a great concern from both environment and cost effective considerations. As a result, variable mold temperature controls to achieve the mentioned goal have been paid great attentions. In this study, TiN and Teflon of various thicknesses were coated on the cavity surface of a tensile bar mold designed with double gate. During the injection molding process, melt-mold interface temperature was analyzed and simulated. In a regular injection molding of ABS resin using P20 as the mold material, the initial melt temperature may drop from 240 degrees C to about 65 degrees C after 0.01 s of contact with the cavity surface when the coolant temperature is 60 degrees C. For a TiN surface coating of 4 mu m, the interface contact temperature was raised to 73.6 degrees C. For a Teflon coating of 22 mu m, the contact surface temperature is as high as 100 degrees C initially (about 25 degrees C higher) and remains above 80 degrees C for about 0.4 s. Teflon coating on the cavity surface eliminates the weld-line marks, improves part surface smoothness and results in better tensile strength for weld line than TiN coating. Moreover, the cooling time was almost not affected. When surface coating is combined with infrared heating, not only the tensile strengths of the weld line were further enhanced but also the heating rate at mold surface is enhanced. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.
引用
收藏
页码:1030 / 1035
页数:6
相关论文
共 9 条
[1]   Simulation of infrared rapid surface heating for injection molding [J].
Chang, Pei-Chi ;
Hwang, Sheng-Jye .
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 2006, 49 (21-22) :3846-3854
[2]  
Chen S. C., 2006, International Polymer Processing, V101, P457
[3]   Simulations and applications of injection-compression molding [J].
Chen, SC ;
Chen, YC ;
Cheng, NT ;
Huang, MS .
JOURNAL OF REINFORCED PLASTICS AND COMPOSITES, 1999, 18 (08) :724-734
[4]   Dynamic mold surface temperature control using induction heating and its effects on the surface appearance of weld line [J].
Chen, Shia-Chung ;
Jong, Wen-Ren ;
Chang, Jen-An .
JOURNAL OF APPLIED POLYMER SCIENCE, 2006, 101 (02) :1174-1180
[5]  
CHEN YC, 2005, THESIS CHUNG YUAN U
[6]   Investigations on the weldline tensile strength of thin-wall injection molded parts [J].
Chien, RD ;
Chen, SC ;
Peng, HS ;
Su, PL ;
Chen, CS .
JOURNAL OF REINFORCED PLASTICS AND COMPOSITES, 2004, 23 (06) :575-588
[7]   3D numerical simulation of transient temperature field for lens mold embedded with heaters [J].
Lin, YW ;
Li, HM ;
Chen, SC ;
Shen, CY .
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER, 2005, 32 (09) :1221-1230
[8]   REDUCING RESIDUAL-STRESSES IN MOLDED PARTS [J].
LIOU, MJ ;
SUH, NP .
POLYMER ENGINEERING AND SCIENCE, 1989, 29 (07) :441-447
[9]   High-frequency proximity heating for injection molding applications [J].
Yao, Donggang ;
Kimerling, Thomas E. ;
Kim, Byung .
POLYMER ENGINEERING AND SCIENCE, 2006, 46 (07) :938-945