Mohd Hadzley

The Effect of Pressure on Warpage of Dumbbell Plastic Part in Injection Moulding Machine

The optimization of processing parameters on warpage of polypropylene (PP) in the application of injection moulding machine was studied. The appropriate parameters were adjusted to reduce the warpage defect on the tensile test specimen of dumbbell. The type of injection moulding machine used in this research is Arburg 420C 800-250C. Four parameters that have been investigated; injection pressure, clamping pressure, back pressure and holding pressure. A concept of design of experiment (DOE) has been applied using Taguchi method to determine the suitable parameters. To measure the warpage of the dumbbell, digital height gauge was used to measure the flatness of the part surface. According the analysis of variance (ANOVA), the most significant factor that effect the warpage was holding pressure by 57.82%, followed with back pressure by 25.75%, clamping pressure by 16.27% and injection pressure by 0.16%. It is found that the optimum parameters setting that have been obtained were injection pressure at 950 bar, clamping pressure at 600 kN, holding pressure at 700 bar and back pressure at 75 bar. The depreciation value of warpage minimum index in this experiment was decreased by 4.6% after confirmation run.

Cutter Path Strategies for Shoulder Milling of Thin Deflecting Walls

The main problem associate with the machining of thin-wall component is the wall deflection which resulting in dimensional surface error that leads to part rejection. The magnitude of wall deflection is induced by the cutting force generated during the material removal process which is governed mainly from the selection of cutter path strategies. Therefore, it is necessary to judge the machining performance of a different cutter path prior to actual machining. In this paper, the machining accuracy of three cutter path strategies namely waterline-step, overlapping-step and tree wise-steps for machining thin-wall component were investigated. It was found that there is a variation in wall accuracy for different cutter path strategies. Based on the experimental results waterline cutter path produced the least surface error followed by overlapping and tree-wise steps.

The Effect of Binder on Mechanical Properties of Kenaf Fibre/Polypropylene Composites Using Full Factorial Method

The effect of maleated polypropylene (MAPP) as binder on the mechanical properties of kenaf fibre/polypropylene (KF/PP) composites is studied. Ratios between kenaf fibre and PP having 10:90, 30:70 and 50:50 in weight ratio were selected. Further, MAPP having 1, 3 and 5 percent in percentage of weight ratio was mixed in KF/PP composites. Hot press machine was used to produce tensile test samples of KF/PP composites. The mechanical properties that are tensile strength, tensile modulus and elongation at break of KF-PP composites were obtained from tensile test result. It is found that the tensile strength and tensile modulus increase with increasing the kenaf fibre loading and higher percentage of MAPP. Further, the elongation at break for KF/PP composites shows lower result when increasing of kenaf fibre loading. However, when percentage of MAPP added in KF/PP composites increases, the elongation at break increased slightly. Thus, result shows that kenaf fibre/PP composites with binder were better in tensile strength, tensile modulus however the elongation at break shows weak result unless the binder was added.

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.

Analysis of Tool Performance during Ball-end Milling of Aluminium Alloy 6061-T6

This article presents the tool wear mechanism when machining Aluminium alloy 6061-T6 with PVD coated carbide under dry cutting condition. Cutting parameters selected were cutting speed, Vc = 115-145 m/min; feed rate fz = 0.15-0.2 mm/tooth and depth of cut, ap = 0.5-0.75 mm. The result showed the tool life of PVD TiAlN ranged from 11 to 97 min. Full factorial approach was employed to exhibit relationship between parameter input and output. From the analysis, cutting speed was found to be the most significant factor for tool performance followed by feed rate and depth of cut. It was also found that most of failure modes occurred were notch wear and flaking near those found near depth of cut line.

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.

Optimization of Cutter Geometry Features to Minimise Cutting Force on Machining Polyetheretherketone (PEEK) Engineering Plastic

Machining of thermoplastic material poses several challenges due to its low melting temperature and high thermal expansion which directly related to cutting force. Thus, controlling the cutting force and temperature is desirable for machining polyetheretherketone (PEEK). The cutting force is dependent on friction and shearing action produced by the tool. It is indicated the cutting force is significantly affected by tool cutter geometry. This paper aims to control the cutting force by optimizing the cutter geometries especially rake, clearance and helix angle on machining PEEK. The two –flutes of solid carbide ball nose end mills were used to conduct the experiments and the cutting force acquired was measured using piezoelectric dynamometer. Response Surface Methodology (RSM) approach was applied to design and analyse the optimal combination of tool geometry feature for machining PEEK. Based on obtained results, the best optimal values of tool geometry which contribute to minimum of cutting force were 17° rake angle, 26° of helix angle and 10° of clearance angle. The best control of tool geometry ultimately improves the cutting performance and reduces defect caused by high cutting forces.

Multi Objective Optimization of Cutting Parameters in Machining Cellulose Based Hybrid Composites

Cellulose based hybrid composites are gaining popularity in the growing green communities. With extensive studies and increasing applications for future advancement, the need for an accurate and reliable guidance in machining this type of composites has increased enormously. Smooth and defect free machined surface are always the ultimate objectives. The present work deals with the study of machining parameters (i.e. spindle speed, feed rate and depth of cut) and their effects on machining performance (i.e. surface roughness and delamination) to establish an optimized setup of machining parameters in achieving multi objective machining performance. Cellulose based hybrid composites consist of jute (a bast fiber) and glass fiber embedded in polyester resins. Response Surface Methodology (RSM) using Box-Behnken Design (BBD) was chosen as the design of experiment approach for this study. Based on that experimental approach, 17 experimental runs were conducted. Mathematical model for each response was developed based on the experimental data. Adequacy of the models were analyzed statistically using Analysis of Variance (ANOVA) in determining the significant input variables and possible interactions. The multi objective optimization was performed through numerical optimization, and the predicted results were validated. The agreement between the experimental and selected solution was found to be strong, between 95% to 96%, thus validating the solution as the optimal machining condition. The findings suggest that feed rate was the main factor affecting surface roughness and delamination .

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.