Parameter Optimization On Hybrid Micro Wire Electrical Discharge Turning

Micro-machining is expected to play an important role in today's manufacturing technology. However, the traditional down-scaling process creates challenges relating to process stability and materials behaviour especially for small difficult-to-machine made materials. Therefore, a suitable material removal process to perform micro-machining on cylindrical components is spark erosion process. In this study, the new hybrid micro-machining process is developed. This process is synonym with the name of wire electrical discharged turning (WEDT) which incorporates a turning process of rotating workpiece to continuous travelling electrode wire in electrical discharged conditions produced by wire electrical discharge machine. The objective of this research is to develop and evaluate the advance machinery and equipment for rotary axis mechanism that is being used to rotate the workpieces. The research focuses on optimizing the process parameter of hybrid WEDT for micro-machining straight shaft cylindrical component made of Ti6Al4V as materials. The issues pertaining to hybrid WEDT process on surface roughness (Ra) in the past have been explored comprehensively. The rotary axis mechanism that works well with WEDM machine has been successfully developed and the micro turning operations has been performed. The parameter optimization consideration on Ra begins with two stage screening. Firstly, the suitable combination parameter and its range is properly selected. Then, the selection of appropriate parameters and range is further screened by Taguchi orthogonal array L12. From the 11 process parameters that consist of electrical, non-electrical and rotary axis mechanism characteristics, only four has been selected to perform optimization by response surface methodology (RSM) which are intensity of pulse, voltage open, wire tension and rotational spindle speed. The other parameters are fixed at best level to produce low Ra value which is identified by Alicona Infinite Focus microscope (IFM). The optimal Ra that is produced by experiment through desirability approach is as much as 4.0143 μm with relative error as much as 5.9% compared to the prediction. The parameter and its level are pulse intensity of 8 Notch, wire tension of 14.8 Newton, voltage of 7 Notch and rotational spindle speed of 2390 rev/min. The machined parts surface is being deteriorated accordingly to the violent energy density generated by high pulse intensity and voltage, low wire tension and spindle speed

Enhancing the Productivity of Wire Electrical Discharge Machining Toward Sustainable Production by using Artificial Neural Network Modelling

Sustainability plays an important role in manufacturing industries through economically-sound processes that able to minimize negative environmental impacts while having the social benefits. In this present study, the modeling of wire electrical discharge machining (WEDM) cutting process using an artificial neural network (ANN) for prediction has been carried out with a focus on sustainable production. The objective was to develop an ANN model for prediction of two sustainable measures which were material removal rate (as an economic aspect) and surface roughness (as a social aspect) of titanium alloy with ten input parameters. By concerning environmental pollution due to its intrinsic characteristics such as liquid wastes, the water-based dielectric fluid has been used in this study which represents an environmental aspect in sustainability. For this purpose, a feed-forward backpropagation ANN was developed and trained using the minimal experimental data. The other empirical modelling techniques (statistics based) are less in flexibility and prediction accuracy. The minimal, vague data and nonlinear complex input-output relationship make this ANN model simple and perfects method in the manufacturing environment as well as in this study. The results showed good agreement with the experimental data confirming the effectiveness of the ANN approach in the modeling of material removal rate and surface roughness of this cutting process

Experimental Analysis On Parameters Affecting The Material Removal Rate In Wire Electrical Discharge Turning Using The Taguchi Method

Wire electrical discharge turning (WEDT) allows success in the machining of advanced materials, particularly for the cylindrical shape components used in the metrology, medical and aerospace field. Using WEDT technology, the micro dimension of geometrical features can be machined without constraints on difficult-to-machine electrically conductive materials. The high precision with large aspect ratio machining capability make WEDT valuable. The correct machining parameter selection is the most important aspect to take into consideration when machining by WEDT. Therefore, the purpose of this study was to rank, determine and optimise the machining parameters that affect the material removal rate (MRR) in WEDT process. As WEDT has as much as eleven control parameters in this study, representing a large number of machining, the Taguchi L-12 orthogonal array was used to obtain the required data with a minimum number of experiments. By using similar experimental data, the regression equation was developed to represent as fitness function for optimisation by genetic algorithm (GA). It was found that by selecting the fast feed of workpiece to machining zone, the faster material was removed and moreover, it dominated other machining parameters. The optimised parameters yield 1.398 mm³/min as the maximum value predicted for MRR recommended by GA

Rotary Ultrasonic Assisted Machining Of Mould And Die Material

The high strength properties of hardened steel AISI D2 material (~51 HRc) have created problems to the conventional machining process; poor machined surface, high cutting force, extreme machining temperature and rapid tool wear. In order to solve the discrepancies in machining the material, this paper proposed a hybrid machining process technique that combined a high frequency ultrasonic vibration (~20 kHz) with the rotating end mill. An in-house ultrasonic tool holder that fitted the CNC machine spindle was developed to perform the ultrasonic assisted machining process. A set of experimental work was conducted to evaluate the improvement of the ultrasonic vibration in the cutting process. The evaluation included the effects of machining parameter namely cutting speed, feed rate, depth of cut, ultrasonic frequency and vibration amplitude in improving the surface roughness value for machining hardened AISI D2 material. The analytical results demonstrated that the presence of the ultrasonic vibration was able to improve the machined surface roughness in that up to 80% reduction in Ra value was observed as compared to the conventional machining process within the same cutting conditions

Investigation on Improvement of Surface Roughness Using Rotary Ultrasonic Assisted Machining Technique for Hardened Steel Material / Azlan Ramli...[et al.]

Several challenges are faced by manufacturers producing best surface finish especially for the mould and die applications. In general, most of the mould and die material are made from hardened steel (~40-60 HRc). The high strength of these materials reduced the capability of the conventional machining technique. Poor machined surface and high tool wear rate are among the problems associated with the conventional machining of this material. To overcome these problems, this paper proposed a hybrid machining process by adding an ultrasonic transducer to the normal tooling system namely ultrasonic assisted machining (UAM). Experimental work consisted of a comparison between ultrasonic assisted machining and conventional machining for different parameters namely cutting speed, feed rate and machining depth in order to validate the effectiveness of the proposed technique in improving the surface roughness value for machining hardened AISI D2 material. 2 level factorial design with 3 factors was employed as the technique of design of experiment (DOE). The machining test showed that the presence of rotary ultrasonic assisted vibration significantly improved the machined surface roughness with up to 85% reduction in Ra value compared to the conventional machining process with the same cutting conditions. In addition, the macroscopic observation of machined surface showed that the surface produced from ultrasonic machining was uniform with consistent peak to peak value which improved the surface finish

The Effects Of Indentation Loading Force And Number Of Indentations On The Micro Hardness Variation For Inconel 718

The accuracy of the hardness test depends on the effects of variations of the loading force and the number of indentations. The purpose of this study was to compare the micro hardness data of these factors. Aged Inconel 718 with a hardness of 450 HV was used as the specimen in this test. The investigation was carried out by observing the amount of dispersion in a set of hardness data at different loads and number of indentations. The applied loading force ranged from 0.05 to 0.3 Kgf, while the number of indentations was set from 10 to 30. From the result, it was found that increasing the applied load brought the hardness value close to the standard hardness of the material. However, an increase in the number of indentations failed to produce an accurate value

Multi-actuators vehicle collision avoidance system - Experimental validation

The Insurance Institute for Highway Safety (IIHS) of the United States of America in their reports has mentioned that a significant amount of the road mishaps would be preventable if more automated active safety applications are adopted into the vehicle. This includes the incorporation of collision avoidance system. The autonomous intervention by the active steering and braking systems in the hazardous scenario can aid the driver in mitigating the collisions. In this work, a real-time platform of a multi-actuators vehicle collision avoidance system is developed. It is a continuous research scheme to develop a fully autonomous vehicle in Malaysia. The vehicle is a modular platform which can be utilized for different research purposes and is denominated as Intelligent Drive Project (iDrive). The vehicle collision avoidance proposed design is validated in a controlled environment, where the coupled longitudinal and lateral motion control system is expected to provide desired braking and steering actuation in the occurrence of a frontal static obstacle. Results indicate the ability of the platform to yield multi-actuators collision avoidance navigation in the hazardous scenario, thus avoiding the obstacle. The findings of this work are beneficial for the development of a more complex and nonlinear real-time collision avoidance work in the future

Unveiling Limestone Orchid Hotspots in the Karst Hills of Northern Peninsular Malaysia

To date, documentation of the diversity of orchids from the limestone hills in the northern part of Peninsular Malaysia, particularly in the states of Kedah and Perak, is still lacking, with limited literature available. There is indeed an urgent need to fill this knowledge gap, so that proper documentation of the diversity of orchids from this unique karst habitat can be prepared. In this study, a series of 12 months of diversity assessments on five limestone hills in Kedah and Perak has resulted in the discovery of 56 orchid species from 37 genera. From this account, 12 species are new records within Kedah and 2 species are new records within Malaysia, namely Bulbophyllum meson J.J.Verm., Schuit. & de Vogel and Luisia brachystachys (Lindl.) Blume. Three species are endemic to Peninsular Malaysia which are Anoectochilus sanguineus P.T.Ong & P.O’Byrne, Cheirostylis goldschmidtiana Schltr. and Phalaenopsis appendiculata Carr. Findings of two keystone species, the long-lost Cheirostylis goldschmidtiana and the endangered snow-white slipper orchid, Paphiopedilum niveum (Rchb.f.) Stein, have catalyzed the need for a more comprehensive study to unveil the species richness and endemism within a limestone habitat. Heat maps using geographical data produced from ArcGIS software have enabled precise determination of the areas with the highest concentration of orchid diversity. Results from this study have shown that Gunung Fakir Terbang houses the greatest number of orchid species, followed by Gunung Batu Putih and Gunung Baling. Meanwhile, lower species occurrences were recorded from Gunung Pulai and Gunung Pong. However, lack of attention and delayed conservation action on this unique karst habitat would only lead to more habitat loss, leading to the decline of limestone orchid populations. Orchids as well as other plants are threatened by anthropogenic activity such as quarrying and forest clearing for agriculture. Thus, the results of this study will serve as baseline data for future work in documenting and conserving limestone orchids and their karst habitat in northern Peninsular Malaysia

A checklist of vascular plants and uses of some species for livelihood-making in Setiu Wetlands, Terengganu, Malaysia

The Setiu Wetlands, a unique area with nine interconnected habitats, comprises a considerable fraction of the total Peninsular Malaysia’s wetland flora. Although botanical collecting in the area has been active in the past 10 years, only a few studies dealing with the wetland flora have been published. Thus, a detailed checklist of this area is urgently needed to ensure the continuity of its inter-relating flora and fauna, as well as the livelihood of the local people. In this work we conducted a survey of the vascular plant flora of Setiu Wetlands and investigated the most important plants used by the local communities. Our checklist accounts for 406 taxa from 277 genera and 106 families, including 24 (6%) species of ferns and lycophytes, three gymnosperms, 257 (64%) dicotyledons and 122 (30%) monocotyledons. This comprehensive plant checklist will be a primary reference for the management of the newly gazetted Setiu Wetlands State Park covering more than 400 hectares of lands and water bodies

Time to treatment initiation (TTI) and retrospective analysis of antiretroviral therapy (ART) outcomes among HIV-positive Methadone Maintenance Therapy clients In primary health care centres, Kuantan, Pahang.

Introduction: Methadone Maintenance Therapy (MMT) program improves access to antiretroviral therapy (ART) among people who inject drugs (PWID) with HIV-positive status. However, the time to treatment initiation (TTI) and outcomes of ART intervention in this population has scarcely been analysed. Objectives: This study aimed to analyse the TTI and outcomes of ART among MMT clients in primary health care centres in Kuantan, Pahang. Materials and Methods: This is a retrospective evaluation of MMT clients’ records from the year 2006 to 2019. The TTI was calculated from the day of diagnosis to ART initiation. The trends of CD4 counts and viral loads were descriptively evaluated. Cox proportional hazard model was used to analyse the survival and treatment retention rate. Results: A total of 67 MMT clients from six primary health care centres were HIV-positive with 37 clients were started on ART. The mean TTI of ART was 27 months. The clients who were given ART had a median CD4 count of 119 cells/mm3 at baseline and increased to 219 cells/mm3 after six months of ART. Only two patients (5.4%) in the ART group had an unsuppressed viral load. The initiation of ART had reduced the risk of death by 72.8% (hazard ratio = 0.27, p=0.024), and they are 13.1 times more likely to retain in treatment (p<0.01). Conclusion: The TTI of ART was delayed in this population. MMT clients who were given ART have better CD4 and viral loads outcomes, helped reduced death risk and showed higher retention rates in the MMT program