Papers by Author: Abul B.M. Saifullah

Abstract: In an injection moulded part, warpage is the distortion caused by non-uniform shrinkage within the plastic part. When looking critically at the causes of warpage, it is found that several key parameters of the moulding process have some effect on the warpage. However, the two major categories that contribute to warpage include the part design and the mould design. In mould design, the gate location, runner/gate system and cooling system design are the major factors affecting not only the warpage and part quality but also the injection moulding cycle time. This paper presents an investigation of using different cooling system configuration on warpage and shrinkage of an industrial plastic part with the aim of determining which cooling configuration will provide minimum warpage and cycle time. As conventional injection mould cooling design is based on straight drilling, it limits the geometric complexity of the cooling design, especially curved shape cooling channels. Nowadays, new technology of advanced rapid tooling based on solid freeform fabrications can be been used to provide conformal cooling channels in injection moulds. In this paper, several type of cooling channels are analysed to compare the performance in terms of warpage and shrinkage and to determine which configuration is suitable for minimizing warpage. Autodesk Moldflow Insight (AMI) simulation software is applied to examine the results of the cooling performances and warpage analysis.

Abstract: One of the most important aspects of mould design in injection moulding is the provision of suitable and adequate cooling arrangements. Proper cooling channel design in the mould is an important aspect as it affects cycle time and quality of the injection moulded plastic part. A new cooling channel design with copper tube insert can reduce cycle time by optimal and uniform heat transfer in the mould. In this research work a comprehensive FEA transient thermal-structural analysis has been performed with ANSYS simulation software to understand robustness and longevity of an industrial plastic part mould with these cooling channels and compared with conventional straight cooling channels. Autodesk Moldflow Insight (AMI) also has been used to get essential process parameter values for analysis. Result shows that by inserting copper tube in the cooling channels, a mould can increase cooling efficiency and can last for higher number of cycles before fatigue failure, thus increasing production rate.

Abstract: Design of gate location is a crucial factor in achieving product quality in injection moulding. It Influences the manner of plastic flow into the cavity. The optimum gate location improves quality and avoids products defects. This paper presents an investigation for the effects of gate location on product quality in injection moulding. Plastic advisor, simulation software embedded in Pro/Engineer package has been used for flow analysis of plastic product for selected gate locations. It has been shown that optimum gate location improves cooling quality resulting in a better product quality. The previous conventional experiences by individual credited engineers have been considered.

Abstract: Cooling channel design is important in mould designs to achieve shorter cycles, dimensional stability and reduced part stresses. Traditionally, cooling channels have been machined into mould components to avoid interference with the ejection system, coring, cavity and other mould details. Over the years straight drilled cooling channels have given away, in part, to conformal cooling technique often using free form fabrication techniques. This paper presents a study of optimised mould design with conformal cooling channel using finite element analysis. Various configurations of conformal cooling channels have been developed. The part cooling time using the conformal cooling channels and the straight cooling channels in the mould are computed using the Pro/Mechanica Thermal FEA software. Results are presented based on temperature distribution and cooling time using steady state and transient analysis conditions. The results show a reduction in cycle time for the plastic part with conformal cooling channel design.