Papers by Author: Mohd Fazuri Abdullah

Abstract: This paper presents the comparative study between the strain signal and its edited signal. In this study, a fatigue strain loading was measured on an automobile coil spring, and the purpose to analyse this component is because it been identified as one of the critical component in an automobile. The strain signal editing process was performed by removing low amplitude cycles contained in the original signal using the short-time Fourier transform (STFT) method. This low amplitude cycles were eliminated based on the cut-off level of the signal energy distribution in the time representation. The original and edited strain signals were then analysed for predicting the fatigue damage of the coil spring. A comparison study of the fatigue damage and the most damaged zone obtained from the strain signal and the edited strain signal was also carried out. It was found that, the prediction of the fatigue damage and the most damages zone for both signals was same. Hence, the shortened signal can be used in the laboratory fatigue testing for the purposes of accelerated fatigue testing.

Abstract: In this paper, injection molding parameters are optimized using the L18 Taguchi orthogonal array for mechanical strength and surface quality of the green part. The feedstock used consists of stainless steel powder (SS316L) with the powder loading of 63 vol. %, 63.5 vol. % & 64 vol. %. The binder compositions used are polyethelene glycol (PEG-73 wt.%), polymethyl methacrilate (PMMA-25 wt.%) and stearic acid (4 wt.%). Mould temperature, injection temperature, injection pressure, injection time, holding time and powder loading ware selected as signal factors using Taghuci’s method based on literature, where these parameters were significant in MIM. Results showed that the optimum parameters are: mold temperature at 650C, injection temperature at1450C, injection pressure at 650 bar, injection flow rate at 20 m3/s, holding time at 5 s and powder loading of 64 vol.%. Analysis of Variance (ANOVA) result shown that mold temperature is the most influence in order to produce good green part’s surface quality while powder loading give the best result for green part’s strength.

Abstract: The comparison of binder system between PP/ palm stearin and PE/ palm stearin both mixed with palm stearin were studied based on the rheological properties to (MIM) process. The microstructure of distribution and dispersion studied using scanning electron microscope (SEM) to observe the pattern of the attached binder with stainless steel powder. The types of binder system used were palm stearin with Polypropylene (PP) and Polyethylene (PE). The powder loading for stainless steel 316L with average size of 20µm used was determined at 66 vol %. The palm stearin was the main significant factor for both viscosity and sensitivity of the feedstock behavior. Less content of palm stearin reduce the viscosity of the feedstock in the range of 100-10000 Pa.s and less influence on changing towards temperature and pressure. As the percentage of addition of palm stearin increase, the feedstock becomes less viscous with high sensitivity. PP and PE feedstock shows dilatant and pseudoplastic flow behavior respectively. PE homogenously coated each of stainless during morphology observation. Meanwhile poor distribution of PP can be observed from SEM observation at 1000x magnification.

Abstract: During performing Computer assisted Total Knee surgery, surgeons have difficulties in orientation of cutting block before sawing procedure. The objectives of this study are develop design approach and fabrication of prototype, which able to eliminate stated difficulties. Thus, improve performance and cycle time of total knee surgery. Benchmarking with commercial product had been conducted, two designs of jig system were proposed. Selection of design was conducted using Pugh method. Two designs were compared based on specific requirements, in order to get the most acceptable design. Pugh method analysis shown that the second design give more advantages in handling, easy to operate, least cost in manufacture, and reduction of time in doing the total knee replacement than the first design. Prototype jig assembly consist of arm, base and cutting block were fabricated by rapid protyping for feasibility analysis. Then, simulation of fabrication by machining process was conducted through Mastercam Mill V8. All component were able to fabricated through machining. A prototype of jig system was fabricated using stainless steel typed SS316L, and evaluation of cutting procedure with saw bone confirmed that the second design is fulfill the objectives of this study.

Abstract: The effects of different cutting parameters, insert nose radius, cutting speed and feed rates on the surface quality of the stainless steel to be use in medical application. Stainless steel AISI 316 had been machined with three different nose radiuses (0.4 mm 0.8 mm, and 1.2mm), three different cutting speeds (100, 130, 170 m/min) and feed rates (0.1, 0.125, 0.16 mm/rev) while depth of cut keep constant at (0.4 mm). It is seen that the insert nose radius, feed rates, and cutting speed have different effect on the surface roughness. The minimum average surface roughness (0.225µm) has been measured using the nose radius insert (1.2 mm) at lowest feed rate (0.1 mm/rev). The highest surface roughness (1.838µm) has been measured with nose radius insert (0.4 mm) at highest feed rate (0.16 mm/rev). The analysis of ANOVA showed the cutting speed is not dominant in processing for the fine surface finish compared with feed rate and nose radius. Conclusion, surface roughness is decreasing with decreasing of the feed rate. High nose radius produce better surface finish than small nose radius because of the maximum uncut chip thickness decreases with increase of nose radius.