Papers by Author: A. Mohd

Abstract: The direction of feeding the work piece and cutter rotation determines the type of machining mode either it is up milling or down milling. Each of this machining mode affects the quality of machined surface produced. This paper described the experimental design of down milling operation on a stack of multidirectional CFRP/Al2024. Three cutting parameters were considered namely, spindle speed (N), feed rate (f_r) and depth of cut (d_c). Two level full factorial design was utilized to plan systematic experimental methodology. The analysis of variance (ANOVA) was used to analyse the influence and the interaction factors associated to surface quality. The results show that the depth of cut is the most significant factor for Al2024, and for CFRP the spindle speed and feed rate are significant. Surface roughness of CFRP is found to be at 0.594 μm at the setting of N = 11750 rpm, fr = 750 mm/min and dc = 0.255 mm. Meanwhile for Al2024, the surface roughness is found to be at 0.32 μm. The validation test showed average deviation of predicted to actual value surface roughness is 3.11% for CFRP and 3.43% for Al2024.

Abstract: The use of hybrid composite materials has increased due to their special mechanical and physical properties. However, machining of these materials is extremely difficult due to non-homogeneous, anisotropic and highly abrasive characteristics. The performance of machined surface quality of CFRP/Al2024 was described using two level factorial methodology. This research aims to study the interaction effects and significant factors of cutting parameters on the surface quality and optimise the cutting parameter for the surface quality of CFRP/Al2024 1μm to 2μm. The trimming process test was performed under dry conditions using burr tools 6mm diameter of end mills. The factors investigated were spindle speed (N), feed rate (fr) and depth of cut (dc), meanwhile profile roughness parameters (R_a) of CFRP and Al2024 were the response variables. Results show that the best estimated value of fr should be 500 mm/min to 530 mm/min, N is between and 2313.870 rpm to 2336.042 rpm. For both responses, N is the most significant effect followed by fr and dc.

Abstract: The application of simulation software packages for mould design and injection moulding process is becoming importance to optimizing the moulding quality and satisfy market needs. This paper presents the simulation of mould filling and packing for various polymer resin types. The filling and packing pressure phases for different type of polymer resins as well as the flow behaviour of molten resin in the mould cavity were investigated. Three common polymer resins which are amorphous and crystalline thermoplastics were used. Cylinder component cups with variation of wall thicknesses were designed. Two-cavity prototype moulds for cylindrical shape component were constructed by using AutoCAD 2006 including assembly and part drawings. The 3D model was produced by using Autodesk Inventor Professional. The result successfully revealed that polyamide resin required shorter time for filling the cavity and less pressure compared to PS and ABS.