Mohd Amran Ali

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.

Microstructural evolution and mechanical properties of thixoformed A319 alloys containing variable amounts of magnesium

The effects of Mg content on the microstructure and tensile properties of thixoformed A319 alloys were studied. The samples were thixoformed at 50% liquid content and some of the thixoformed samples were subjected to the T6 heat treatment. The samples were then examined by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) analysis as well as tensile tests. The results showed that magnesium was able to refine the eutectic silicon in the samples. It was also observed that a compact Al9FeMg3Si5 phase was formed when the magnesium content was 1.0% and 1.5%. The results also revealed that as the magnesium content in the alloy increases, the tensile strengths of the thixoformed alloys also increase. The ultimate tensile strength, yield strength and elongation to fracture of the thixoformed A319 heat treated alloy were 298 MPa, 201 MPa and 4.5%, respectively, whereas the values of the thixoformed heat treated alloy with 1.5% Mg content were 325 MPa, 251 MPa and 1.4%, respectively. Thixoformed A319 alloy showed a dimple fracture behaviour, while thixoformed A319 alloys with 1.5% Mg showed a mixed mode fracture behaviour, where dimple and cleavage ruptures were seen on the fracture surface of the samples.

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.

Investigation of tangential force on ball nose rake face during high-speed milling of Inconel 718

Abstract Notch wear and flaking are common tool damage found during end milling. The problems are caused by abrasive wear and excessive cyclic load exerted on cutting tool. This study presents an experimental investigation on the effect of various cutting parameters in high-speed machining of aged Inconel 718 on the tangential force. The effect of cutting speed, feed rate, depth of cut and width of cut on cutting forces had been studied. The cutting parameters were cutting speed, Vc of 100–140 m/min, feed rate, fz of 0.1–0.2 mm/tooth, depth of cut, ap of 0.5–1.0 mm and width of cut, ae of 0.2–1.8 mm. The results show that the width of cut is the main factor in controlling tangential force during end milling, followed by depth of cut and feed rate. These factors controlling the volume of material removed so that larger stress created on the cutter rake face.

Interchangeable core and cavity plates for two-plate family injection mould

This study modified a two-plate family plastic injection mould to become interchangeable by changing the core and cavity plates using an existing mould base. The plastic parts produced in the modified two-plate family plastic injection mould included tensile, hardness, impact and flexural test specimens. The cavities of the plastic parts were machined at the parting surface of core plate. Meanwhile, the feeding systems including runner and gate system were machined at the cavity plate to ensure molten plastic can be injected in the cavity area. Various factors have been considered during the designing and fabricating process. This is to ensure the process of assembly between mould plate and standard mould parts can be done perfectly. The plastic parts in the family mould were successfully injected after mould was completed assembled and mould trial was performed. The plastic parts which had been ejected from the family injection mould are purposely produced for future research to study the mechanical properties of plastic materials.

Performance evaluation of rotary mechanism characteristics by response surface methodology in cylindrical wire electrical discharge turning

Abstract Cylindrical wire electrical discharged turning (CWEDT) is currently used for machining hardened and delicate cylindrical parts due this process neglects the issues in electrode wear and cutting force in removing the materials. Recently, many researchers have focused on investigating the CWEDT machine parameter for obtaining desired machining parts quality. However, the characteristics of the rotary mechanism itself has potential to influences of the parts quality. Therefore, the objective of this study is to evaluate the rotary mechanism characteristics on surface roughness and material removal rate (MRR). The investigation of the characteristics of rotary mechanism consists rotational spindle speed, radial depth of cut, table feed rate, workpiece overhang and spindle direction. Central composite design (CCD) of response surface methodology (RSM) as experimental design that was employed to analyse the result and generated a mathematical prediction model. The experimental results showed the feed rate is the dominating factor for surface roughness and depth of cut is dominating for MRR. The models found significant for the both responses and reliable with experimental result with prediction error less than 7%. The prediction of multi-response optimization values for surface roughness and MRR are 4.525 μm and 19.147 mm3/min, respectively.

Effect of Different Coolant Medium on Warpage Deflection Using Moldflow Insight Analysis

The effect of mould temperature on warpage using water and oil as coolant fluid was studied using flow software analysis. Mould temperature was controlled using two types of coolants; where cold mould was controlled by water and hot mould was controlled by oil. The simulation analysis was performed using flow software analysis Moldflow Plastics Insight (MPI). Taguchi method was used to design the planning matrix and to find the optimum levels of input variables. Then, to find the percentage contribution of input variables on output variables, analysis of variance (ANOVA) was used. It is found that mould temperature controlled by water shows less warpage analysis compared to oil. The minimum and maximum percentage of warpage analysis between cold mould and hot mould are 3.1% and 7.1% respectively. In addition, ANOVA analysis shows that the most significant parameters affected the warpage analysis for both moulds using oil and water are melt temperature (255°C) followed by mould temperature (water 15°C and oil 70°C) and cooling time (water 8s and oil 6s). Thus, it shows that coolant medium used in mould cooling system contributes the quality of plastic parts.

Fatigue Life Analysis of High Performance Motorcycle Disc Brake

This paper presents fatigue life analysis of high performance motorcycle disc brake. The design parameter such as stress, deformation and safety factory that influences the disk brake on a high performance motorcycle were investigated. The simulation of static structural analysis of high performance motorcycle is successfully presented on 3 proposed materials by using ANSYS software. The static structural analysis is performed on the disc brake rotor with these candidate materials. From the analysis, Martensitic stainless steel, Wrought AISI 410 has the lowest value in Von-Mises stress which is 766.9MPa. Furthermore, it is less deformed which is 0.3429mm and has the factor of safety more than 1. Thus, this project proposes Martensitic Wrought AISI 410 stainless steel as the suitable material for disc brake rotor on HONDA GL1500 VALKYRIE motorcycle.

The Effect of EDM Die-Sinking Parameters on Material Characteristic for Aluminum Composite

The machining ability of Electrical Discharge Machining (EDM) die-sinking on material characteristics of LM6 (Al-Sil2) is studied. This is due to the machining process on sharp edge, pocket, deep slot and micro hole cannot be performed by milling and turning machine. The objective of this paper is to determine the relationship between the machining parameters such as pulse on time, pulse off time, peak current and voltage on material removal rate (MRR) that are electrode wear rate (EWR) and surface roughness (Ra). Graphite tool of diameter 15mm was chosen as an electrode. Taguchi method is used as analysis technique to develop experimental matrix that is used to optimize the MRR, EWR and Ra. The analysis was done by using the Minitab software version 16. It is found that the current and pulse off time are significantly effected the MRR, EWR and Ra while pulse on time and voltage are less significant factors 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.

Finite Element Model of Trimming CFRP Aerospace Composites

Carbon Fiber Reinforced Plastics (CFRP) exhibit superior characteristics such as high specific strength, high specific modulus, fatigue strength and endurance. During the manufacture of components from CFRP, it is usually necessary to carry out a post-machining step. Generally, after curing process, the parts will be trimmed in order to meet the required tolerances. Due to the heterogeneous composition and anisotropy of composite materials, machining procedures can damage the material in ways that directly affect its mechanical properties. Currently a costly try and error approach is employed to determine the optimal process conditions. Thus, this study focused on numerical modelling of machining CFRP composites using cross-nick router. A set of machining tests were performed in order to validate the accuracy of the model. Good agreement between simulation and experimental results show the validity of the model in handling real-field problems. The proposed numerical modeling technique can be used as an input in the process planning and decision making levels.