Mohd Fauzi Ismail

Effects of Cutting Edge Truncation on Ultrasonically Assisted Grinding

Dies for injection molded parts require high-quality surface finishes in terms of both appearance and integrity. Manual finishing by skilled workers is required to produce such surfaces, but this takes several days. To minimize the amount of polishing required, a new finishing technique that employs ultrasonically assisted diamond grinding was proposed in a previous report. Cutting edge truncation prior to grinding is required to produce a mirror surface. In this study, the effect of cutting edge truncation was investigated and the relationships between the ground surface roughness and the cutting torque and the thrust force were considered to optimize the grinding conditions for mirror surface finishing.

Influence of steel fibres on friction behaviours with respect to speed, pressure and temperature

Purpose This study aims to investigate the effect of different volume percentage (Vol.%) of steel fibre on the pressure, surface temperature and speed sensitivity behaviour during braking process as known brake effectiveness and to propose the best steel fibre Vol.% in the formulation. Design/methodology/approach Three brake pads composed of three different steel fibre volume percentages were fabricated through powder metallurgy route. Selecting one sample as based formulations, steel fibre (Vol.%) was decreased and increased by 50 per cent in the other two samples, respectively. The other ingredients are proportionally increased and decreased accordingly to the base formulation. The samples were tested for determining their hardness, porosity and coefficient of friction (COF) using Rockwell hardness tester, hot bath and brake inertia dynamometer, respectively. Findings Test results indicated that Sample T1 which composed of 9 Vol.% of steel fibre had the lowest COF and was sensitive to applied pressure, surface temperature and speed. The samples which composed of 18 and 27 Vol.% of steel fibre were having the same trend of COF and were sensitive to surface temperature and speed. Sample T which composed of 18 Vol.% of steel fibre had lower brake pad and disc lost as compared to Sample T2 which composed of 27 Vol.%. Mechanical properties did not show any significant correlation with COF sensitivity with temperature, speed and pressure. Originality/value The sample with 18 Vol.% of steel fibre was found to be the best formulation which produced acceptable COF; less sensitive to temperature, pressure and speed during braking process; and better wear resistance of brake pad as well as the rotor.

Feature Identification and Filtering for Engine Misfire Detection (EMD) Using Zirconia Oxygen Sensor

Vehicles as transportation are popular and mainly use among peoples around the world for various kind of purpose either personal or not. Over hundreds of year internal combustion engines widely used because of high efficiency and low maintenance compare to new technology which are using cells of battery. Nevertheless, emission cause of incomplete combustion such engine misfire normally occurs as well. For instances, some mechanical, sensors or actuators failure and environmental condition contribute to the engine misfire. The importance of engine misfire detection (EMD) is to ensure engine emissions not harmful to the environments and avoid damage of catalytic converter. By using low cost narrowband oxygen sensor to acquire air to fuel ratio (AFR) signal behavior under misfire condition and analyst by digital signal processing method using Discrete Fourier Transform (DFT) algorithm for Digital Butterworth Filter designation is discussed in this paper.

Evaluation of Outlier Specific Correction Procedure for Areal Surface Texture

Surface texture data measured by optical type profilometer such as confocal microscope often contains outliers which may disturb the characterization of the surface texture. This paper evaluates an outlier specific correction procedure (OSCP) for areal surface texture data which can removes the outliers without affecting normal data points. The outliers are identified based on the median of its relative height to neighbouring data points within the detection window. The application of OSCP to areal topography data measured by confocal laser scanning microscope is compared to Gaussian filter and median filter. The result shows that, OSPC is better in outlier correction without affecting normal data points but there is a room of improvement.

The Analysis of Intake Manifold Air Stream Velocity on Different Material Roughness

Intake manifold is a crucial part in an engine that acts as a medium for air flow to mix with the fuel before entering the combustion chamber. For years, cast iron and aluminium were the primary materials chosen for fabrication of an intake manifold before plastic based material was introduced to the field. However, there is lack of research involving the usage of plastic as the intake manifold material. In this paper, the effects of internal surface roughness variations (Cast iron, aluminium and plastic) inside the intake manifold were studied. Three dimensional, intake manifold model was developed to simulate the airflow. The study emphasized on the airflow velocity inside the intake manifold. The study showed that the surface roughness influenced the air flow velocity near the intake manifold outlet. The plastic based intake manifold exhibited the highest air stream velocity (near the intake manifold outlet) at 477.770 m/s. This value is 0.60% and 0.40% higher than those produced by the cast iron and aluminium intake manifold, respectively.

Friction and Wear Characteristics of Cu-Based P/M Brake Friction Materials with Addition of Fe and C

Cu-based powder metallurgy friction materials were prepared by varying of Fe and C (% weight) in the friction components. The samples were compacted under the load of 24 metric tonnes and sintered at a temperature of 950 °C for 45 minutes. The friction and wear characteristics the materials developed were studied using Chase machine. The results show that Fe and C have different friction and wear characteristics. The friction coefficient of Cu-30%Fe-15%C sample maintained to be high and slightly increased after the drum temperature of 350°C and subsequently stable throughout tests. The friction of Cu-20%Fe-10%C stable until the drum temperature of 450°C and then its start to decay slightly until the end of the test. On the hand, the friction of Cu-10%Fe-5%C start to decay after sliding a few minutes at the drum temperature of 230°C. Thus, it could be postulated that the friction coefficient increased with increasing weight percentage of Fe and C in the friction components. However, the volume loss shows that there is no direct correlation with the Fe and C content. The volume loss of Cu-10%Fe-5%C was higher than the two samples which had the lowest hardness. On the hand, the volume loss of the Cu-30%Fe-15%C was slightly higher than Cu20%Fe-10%C as result of higher porosity and lower hardness. Wear mechanisms of abrasion, adhesion and thermal were observed to be operated during sliding process.

Hand-arm vibration analysis of palm oil fruit harvester machine

The objective of this study is to determine the vibration value of Palm Oil Harvester Machine or CANTAS motorized cutter profile. The CANTAS machines have been divided into twelve nodes and hand arm vibration measurements are taken for idle and full throttle operation. Three cutting heads provided by MPOB have been measured for comparison purposes. The hand-arm vibration values for Type A Cutting head achieves (3.89±1.10) m/s2 for idle condition and (10.71±2.88) m/s2 for full throttle condition. Meanwhile Type B Cutting Head achieves (3.63±0.87) m/s2 for idle condition and (11.22±1.74) m/s2 for full throttle condition. Type C of Cutting Head yields (3.51±0.82) m/s2 for idle condition and (15.54±3.81) m/s2 for full throttle condition along the structure. The results also shows which points depicted highest vibration level during idle (no operation, ideally from tree to tree) and full throttle (overuse operation). These values present the maximum and minimum vibration levels that will be received by the user in daily usage of the machine. design in reducing vibration to the hand-arm of the user.

Surface Reversal Method for Cylindrical Tool Characterization

Cutting edges protrusion properties for cutting tools have significant effect of grinding surface finish and its characterization is crucial in understanding tool-work interaction. Existing definition of reference datum in surface topography analysis is not suitable for abrasive tool cutting edges protrusion characterization in relation to tool-work interaction. This paper proposed Surface Reversal Method for the reference datum determination in the characterization of cutting edge protrusion on flat end face of cylindrical cutting tool meant for vertical grinding. Fabricated cylindrical artefact is used to test the theory, accompanied with a specially made fixture. Performance of the proposed method is evaluated based on the repeatability of step height measurement on the topography component and inclination of the reference datum which extracted from primary surface measured by laser confocal scanning microscope. The proposed method provides better datum definition than conventional method for height measurement of the abrasive tool topography in relation to the tool-work interaction.