Raja Izamshah

Effects of End Mill Helix Angle on Accuracy for Machining Thin-Rib Aerospace Component

Accuracy of machined component is one of the challenging tasks for manufacturer. In the aerospace industry, machining process is widely used for fabrication of unitized-monolithic component that contains a thin-walled structure. During machining, the cutting forces cause deflection to the thin-wall section, leading to dimensional form errors that cause the finished part to be out of specification or failure. Most of the existing research for machining thin-wall component only concentrated on the process planning and the effects of cutter geometric feature is often neglected. Tool geometric feature has a direct influence on the cutting performance and should not be neglected in the machining consideration. This paper reports on the effect of helix angle on the magnitude of wall deflection. The established effects will be used for the development of high performance cutting tool for specifically machining thin-wall component.

Effect of Injection Moulding Machine Parameters on the Warpage by Applying Taguchi Method

The application of Taguchi method to reduce warpage in an injection moulding process is studied. The objective of this paper is to analyze the effect of injection moulding parameters, i.e., injection time, packing time, melt temperature and mould temperature, on the warpage defect in dumbbell plastics part. Optical comparator horizontal type was used to measure the difference of warpage value on each part. L9 orthogonal array with 3 replications was done with 27 totals of specimens. The result collected was optimized using Taguchi method and percentage of contribution was calculated using analysis of variance (ANOVA). According to the analysis, it is found that the significant factors affected warpage are injection time (32.01%), packing time (29.73%), mould temperature (24.39%) and melt temperature (13.87%). The optimum parameters for minimizing the warpage were injection time (1s), packing time (5s), melt temperature (270 °C) and the mould temperature (21 °C). By using Taguchi method and ANOVA analysis, optimum parameters and the percentage of contribution of parameters can be obtained. Thus, it shows that design of experiment method is the good quality tools to get the best quality for production.

Determination on the Effect of Cutter Geometrical Feature for Machining Polyetheretherketone (PEEK) Using Taguchi Methods

This paper details the application of Taguchi method to determine the effect of cutter geometrical features for machining Polyetheretherketones (PEEK) thermoplastic. The planned experiment was conducted by using Taguchi’s orthogonal array taking into account the ball nose geometrical parameters such as helix angle, rake angle, clearance angle and number of flute. The measured response is the machined surface roughness, which is important for the component functionality. In addition, ANOVA was used to validate the percentage contribution of each factor. The obtained results reveals that, less number of flutes is the main factor contributed towards fine surface roughness for this thermoplastic. Fewer flutes provide a smooth flow of chip ejection and minimize the friction on the cutting zone which is vital for polymeric material such as PEEK. High helix and rake angles also influence the machined surface roughness as both angles provide optimum shearing force to produced better surface finishing. However, it is found that clearance angle is less significant on roughness since the function of clearance angle is to control the process damping and stability. The main conclusion of this study is that there is significant effect on the cutter geometrical feature on machining performance and thus conclude the need of special design cutter for effectively machining PEEK plastic.

The Effect of EDM Die-Sinking Parameters on Material Characteristic for Aluminium Composite Using Tungsten Copper Electrode

The machining ability of electrical discharge machining (EDM) die-sinking on aluminium LM6 (Al-Sil2) as a new material is investigated.The objective of this paper is to determine the relationship between the machining parameters which are pulse-on time, pulse-off time and peak current on the material characteristics such as material removal rate (MRR), electrode wear rate (EWR) and surface roughness (Ra). Tungsten copper tool of diameter 10mm was chosen as an electrode. Design of experiment using Taguchi method was used to develop experimental matrix and optimize the MRR, EWR and Ra. The analysis was done using the Minitab software. It is found that the current and pulse on time are significantly affected the MRR, EWR and Ra while pulse off time and voltage are less significant factor that affected the responses. From the Taguchi method, the best setting of optimum value was obtained. Thus, it shows that Taguchi method is the best quality tools that can be applied for production.

An Experimental Study of Different Thermal Boxes Heated by Solar Thermal Radiation for Hot Water System at Night

This research is related to thermal efficient water heating system, specifically to improve the water heating system that exists nowadays. The goal of this research is to improve the current water heating system by using solar heat as the energy source to heat the water. The focus is to improve the thermal efficiency by adding different thermal boxes as the absorber bed. By implementing the black body and radiation concept, the air trapped in the box is heated. The trapped air then increases the collisions between the molecules and directly increases the temperature inside the box, higher than the outside environment. Based on a daytime experimental result revealed steel thermal box is better to be used for tropical weather like Malaysia.