Saiful Bahri Mohamed

Determining Optimum Electro Discharge Machining Parameters for Drilling of a Small Hole by Utilizing Taguchi Method

Electro discharge machining (EDM) is a process that uses an electric sparks to generate the high temperature and melt the workpiece. One of the EDM process is drilling. In EDM drilling, an electro thermal mechanism is introduced between the electrode and work piece to create the hole. The hole size is dependent on the diameters of electrode used during the drilling process. The present study performs Taguchi method to investigate the optimal process parameters for high-speed EDM super drill machine that is used to make a small hole. The workpiece used is made from titanium alloy (Ti-6: ASTM B348 Grade 5) and the copper electrode is 2.0 mm in diameter. In this experiment, the process parameters that were selected to be optimised are: current pulse off, maximum current and standard voltage levels. An orthogonal array L9 were employed to analyze the hole enlargement and material removal rate (MRR) depending on 2.0 mm diameter hole penetration. The optimum EDM parameters for hole making process was established and verified with the acquired results.

Machining Parameters Optimization for Trimming Operation in a Milling Machine Using Two Level Factorial Design

Trimming process using Solid Carbide, 4 flute endmill of 8mm diameter tool on stacks of multidirectional CFRP/Al-2024 in a CNC Milling machine was experimentally investigated. The machining parameters considered were spindle speed (N), feed rate (fr) and depth of cut (dc). The aims were to analyze the influence factors and the interaction of these parameters with respect to surface quality produced. A Two Level Factorial Design method was used to plan systematic experiments. The influence factors and the interaction between these parameters are analyzed and the optimum machining parameters for minimizing the surface roughness is determined. The analysis of variance (ANOVA) shows that dc and fr are the most significant parameters to the overall performance of surface quality. Surface roughness of CFRP is found to be 1.778 µm and Al2024 is found to be 0.983 µm at the setting of N = 1860 rpm, fr = 620 mm/min and dc = 0.12 mm respectively. The validation test shows deviation of predicted to actual value surface roughness is 7.87% for CFRP and 6.61 % for Al2024.

Sustainable manufacturing practices in Malaysian palm oil mills: Priority and current performance

Purpose The purpose of this paper is to investigate the implementation of sustainable manufacturing practices in Malaysian palm oil mills (POMs) by comparing the status of their current achievements and the levels of priority placed on their practices. Design/methodology/approach A questionnaire survey was used to collect data about 20 sustainable manufacturing practices from 51 POMs located in Malaysia. A five-point Likert scale was considered for recording variations in priorities and current practices with regard to sustainable manufacturing. A Cronbach’s α reliability test and a binomial test were undertaken to assess the internal consistency and the validity of the survey data. Spearman’s ρ correlation analysis was employed to determine the linear correlation between each of the sustainability practices identified. Factor analysis was conducted to reduce the number of sustainable manufacturing practices based on factor loading and to derive a clustering of these factors. Findings The results showed that employees’ well-being has the highest level in terms of both priority and current achievement. However, for other sustainable manufacturing practices, there was a difference where the current achievement of these practices in the Malaysian POMs was seen to be slightly lower than the priority given to them. Strong correlation of significant value was observed between the minimization of production waste and pollution prevention practices. From factor analysis, 15 practices of high factor loading were grouped into a proactive sustainability strategy and a preventive sustainability strategy. Research limitations/implications The study was still relatively exploratory. Future studies could investigate the barriers to the implementation of sustainable manufacturing practices at Malaysian POMs. The sample, which consisted of 51 Malaysian POMs, represented an important sector of the Malaysian economy. Reliance on stated, rather than revealed, preferences may limit the implications of the analysis undertaken for this study, but it does represent a major step forward in understanding the past in what was a highly recommended sector for investigation due to the paucity of extant data. A more broadly based, random sample of POMs from other countries would provide a better understanding of issues related to sustainable manufacturing practices. Practical implications The results of this study can be used by practitioners to adjust the sustainable manufacturing practices currently applied and further studies may go on to examine the reasons and implications for discrepancies between priorities and desired sustainability goals in more detail. Originality/value The survey conducted about sustainable manufacturing practices amongst Malaysian POMs was focussed on the three dimensions of sustainability, namely, the economic, environmental, and social elements involved.

The Effects of Cutting Parameters on Surface Texture of Hybrid Composite CFRP/AL2024

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 (Ra) 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.

Cutting Parameters and the Machinability Performance

Optimizing cutting parameters is very significant to obtain good machined surface and meet engineering specifications. It is also can save energy, reduce waste, save processing time, and increase tool life.

Learning from the Carbon Fiber-Reinforced Plastic Project

Design-Expert V9 software was used to predict the cutting parameters that had an important effect for a particular response. Since the surface roughness for CFRP and Al2024 was recorded as two different responses, the analysis was conducted separately. The obtained results from the experiment are listed in Table 4.1 which is then used for further analysis using Design-Expert V9 software. The input variables were spindle speed, feed rate, and depth of cut; meanwhile, the responses were surface roughness for CFRP and Al2024. The analysis began with the analysis of CFRP machined surface and then followed by Al2024 machined surface.

Composite Materials and Types of Machining

A composite material is a composition of two or more constituent materials to form an overall structure which significantly better in terms of mechanical or chemical properties than the sum of individual material.

Teachers’ Feedback on the Development of Virtual Speaking Buddy (VirSbud) Application

This study aims at identifying the ideal characteristics of a virtual speaking buddy (VirSbud), as perceived by the teachers, so that the current VirSbud application can be further developed to meet the users’ expectation. Employing a qualitative approach, an in-depth group interviews was conducted with five English language teachers teaching in Standard Three (nine-year-old pupils). Prior to the interview, the teachers used the application as a teaching aid for eight weeks. The interview reveals the ideal characteristics of an application for virtual speaking buddy. The teachers expected a more sophisticated application which enables online participation, two different interfaces accessible by learners and teachers, looping in the prompts given to the learners, and the use of voice recognition which enables automatic response to the learners. The findings point towards the need of semi-formal learning, instead of formal and informal learning, in developing learners’ speaking skills with the teachers being virtually present at a distance.

Edge Trimming Analysis for Surface Quality of Hybrid Composite - CFRP/Al2024

The application of hybrid composite materials has increased due to their strength and light weight ratio. Edge trimming of these materials was extremely difficult due to the anisotropic and non-homogeneous structures of CFRP and ductile nature of aluminium. This research was focused on edge trimming process via down milling operation. Three cutting parameters were examined namely spindle speed, feed rate and depth of cut. The extension of two level full factorial design, Centre Composite Design (CCD) was used to plan systematic experimental methodology. The analysis of the influence and the interaction factors associated to surface quality was studied. The objective was to obtain machined surface quality of CFRP/Al2024 between 0.4 µm to 0.6 µm. The depth of cut was the most significant factor for Al2014 and meanwhile the spindle speed and feed rate were significant factors of CFRP. The validation experiment was conducted at optimum level of recommendation control factors setting to compare the deviation of predicted value from actual/measured value. Surface roughness of CFRP was found to be at 0.594 micron at the setting of spindle speed, 11750 rpm, feed rate, 750 mm/min and depth of cut, 0.255 mm. For Al2024, the surface roughness was found to be at 0.32 micron.

Down Milling Cutting Parameters Optimization Utilizing the Two Level Full Factorial Design Approach

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 (fr) and depth of cut (dc). 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.