M. Azuddin

Observation of Polypropylene (PP) Melt Flow on Microchannel Using Polymethyl Methacrylate (PMMA) Mold

The flow of melted plastic in microparts is an interesting area to discover. Many studies have being conducted to understand the phenomena of polymer flow in microplastic parts. One type of study is the visualization of melted polymer flow. This work focuses on the observation of the micro-flow of melted Polypropylene (PP) using transparent polymethyl methacrylate (PMMA) mold. A PMMA mold with 0.5, 0.8, and 1.0 mm diameter channels were fabricated and injected with melted PP using a custom made vertical plastic injection molding machine. The flow of the melted PP can be clearly seen through the PMMA transparent mold. The result of the experimental are compared with a result from finite element analysis (FEA) software, MoldFlow Part Advisor. The result shows a good agreement for 1.0 and 0.8 mm channels, but not for the 0.5 mm. It can be concluded that, the analysis software is not capable of predicting the flow for 0.5 mm channel and less.

Process Development and Product Quality of Micro-Metal Powder Injection Molding

Injection molding has been found to be an efficient and cost-effective manufacturing technique for the production of a wide variety of parts and components at both macro- and microscale. This is attributed to the application of robust design and process development. However, every manufacturing technique is challenged by quality issues and part defects, but tackled by continuous improvement framework(s). This systematic monitoring and control approach of dimensional accuracy, mechanical properties, and surface quality of the finished part strongly depend on process conditions at different production stage. Therefore, the aim of this study is to review process development of micro-metal injection molding; focusing on critical factors influencing part quality and optimization of process parameters. The critical factors that influenced the finished part quality are part design, mold design, material selection, machine, and process conditions. Optimizing mold temperature, melt temperature, injection speed, injection pressure, cooling time, packing, and holding parameters improve the quality of the molded part. This trend of process development of injection molding gave rise to a broad scope of applications with brighter future potentials for the next decades, particularly for medical and electronics applications.

1.15 Micro Plastic Part Filling Capabilities through Simulation and Experiment: A Case Study on Micro Gear Shape

Micro plastic molding is a new niche area in injection molding industry and growing faster due to its huge application in various sectors. This reflects the increased interest from researchers to produce high precision micro plastic parts. The challenge in micro molding is on part design, tooling, molding machine, part inspection, and plastic materials. The present study starts with the design and fabrication of injection molding machine that is suitable for micro molding application, with the provision of a window for flow behavior observation. The works continue with exploring the flow behavior in various shapes and sizes of micro channel. A modified cross viscosity model has been formulated to identify the filling capability of straight, reverse ‘T’ and cross ‘+’ shape micro channel with various sizes. The results obtained from Moldflow simulation, ANSYS CFX, and actual experiments at different mold and melt temperatures are compared. ANSYS CFX gave similar results with that of experiments by modification of the cross viscosity model. In conclusion, this study proposes a modified ‘cross viscosity model’ to be used in ANSYS CFX simulation package which is capable of analyzing a specific micro part in micro injection molding.

Influence of electromagnetic field on metal cutting in turning operation of AISI 1018 low carbon steel

The effects of magnetic field on the machining force and tool wear in turning operation has been investigated. AISI 1018 low carbon steel used during machining as it is generally used in industry. The present and absent of the magnetic field during machining in dry condition was studied, and has been analysed. Taguchi approach has been used when designing the experiment. The results shown in this study related to the machining force and tool wear. The experimental results shown that when magnetic field has been applied, the machining force in turning operation such as radial force (Fr ), feed force (Ff ), and cutting force (Fc ) gave higher results as compared to the absent of magnetic field. As for the tool wear, the results shown that the tool life is getting longer when the magnetic field has been applied which has been proven by the previous studies done before.