Sink marks defect on injection molding using different raw materials

• Main Author: Mohd Nazri, Noordin
• Format: Undergraduates Project Papers
• Language: English
• Published: 2009
• Subjects: TP Chemical technology
• Online Access: http://umpir.ump.edu.my/id/eprint/1139/1/Mohd_Nazri_Noordin.pdf; http://umpir.ump.edu.my/id/eprint/1139/
• Institution: Universiti Malaysia Pahang

The quality of an injection molded part is affected by material properties, mold geometry, process conditions and etc. Obtaining optimum parameters is the key problem to improve the part quality. Sink marks is one of several important flaws of injection molded parts. In this project, numerical simulation is combined with Taguchi design-of-experiment (DOE) technique to investigate the influence of parameters on sink marks of the injection molded part and optimization of parameter settings in injection molding process. The Acrylonitrile Butadiene Styrene (ABS) and polyethylene (PE) materials were used to analyze the sink marks. An orthogonal array based on the Taguchi’s method and Analysis of Variance (ANOVA) was conducted to observe the sink marks of injection molded parts, and to allocate the significant of each factor that contribute to sink marks. Four factors were consisting of packing pressure, mold temperature, melt temperature and packing time. These factors were found to be the principal factors affecting the sink marks of the injection molded parts. It was found that optimum parameters for ABS material are packing pressure at 375 MPa, mold temperature at 400c, melt temperature at 2000c and packing time and packing time 1s. While for PE material, the optimum parameter was found are packing pressure at 75 MPa ,mold temperature at 700c, Melt temperature at 1900c and packing time at 1.5s.