Now showing 1 - 10 of 24
  • Publication
    Effect of tool engagement on cutting force for different step over in milling aisi p20 tool steel
    ( 2021-01-01) ;
    Mohamed N.I.
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    Saravanan R.
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    Azmi H.
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    ;
    In mold production, end milling with tool path strategies is required for the process known as pocket operation. Different step overs involve depending on the type of tool path strategy used. Thus, different engagement will occur and leads to fluctuation of cutting force due to different step over during the process. However, most of study before focused on the effect of cutting speed, feed rate and depth of cut only in machining AISI P20. Thus, in this study, step over will be considered as one of the factor to improve machining force. The objective of this study are to evaluate the effect of cutting parameters and step over on cutting force and to study the behavior of cutting force for different tool engagement. A series of milling operation was carried out by varying cutting speed and feed rate. However, the depth of cut was set to 0.25 mm for each run. Step over with 100%, 75% and 50% were selected in this study. L27 Taguchi and S/N ratio were used to determine the significant factors that influence the result. Within the range of cutting parameters selected, feed rate were found to be the most significant parameters that influence cutting force. The highest cutting force found for 100% step over compared to 75% and 50% step over. According to the result, cutting force increased as the step over increased. In can be concluded that, step over is one of the important cutting parameter that affected machining output.
  • Publication
    Investigation on delamination factor (Fd) of kenaf fibre reinforced plastic composite materials under drilling process
    Natural Fibre Reinforced Plastic Composite material that the Kenaf Fibre are used to reinforce to the polymer matrix to improve its mechanical properties. It is environmentally friendly and low cost as compare to non-biodegradable material. It is also widely used in Aerospace, Automotive and Furniture industry. Drilling process plays an important role in fabrication in these industries. However, some defects often occur on the Natural Fibre Reinforced Plastic Composite during drilling process. The major damage is delamination that are found on the surface of the composite in drilling process. This damage reduces the mechanical properties of the composite. Therefore, the objective of this study is to investigate and minimize the delamination by using Response Surface Methodology (RSM). Cutting speed and feed rate are found significant to delamination in this study. The higher the previous researchers investigate the cutting speed with low feed rate, the lower the delamination. Therefore, the conclusion of this study is high cutting speed with low feed rate improve the mechanical quality of composite.
  • Publication
    Machinability of nickel-titanium shape memory alloys under dry and chilled air cutting conditions
    ( 2023-06-01) ;
    Mativenga P.T.
    Nickel-titanium (NiTi) shape memory alloys (SMAs) undergo phase transformation between austenitic and martensitic phases in response to applied thermal or mechanical stress, resulting in unique properties and applications. However, machinability often becomes challenging due to property and temperature sensitivity attributes. The use of chilled air to influence machinability in macro-milling was investigated in this study. Other than that, differential scanning calorimetry (DSC) was used to determine the temperature of phase transformation. The results showed that milling with chilled air and minimal lubrication significantly improved machining performance by reducing tool wear and burr formation. Moreover, surface quality has also improved significantly. A notable discovery is that the machining process can change the critical conditions for phase transition, enabling new performance capability of tuning material hysteresis.
  • Publication
    Tribological Behaviour of Graphene Nanoparticles as an Additive in Vegetable Based Oil
    ( 2024-04-19)
    Noor N.Z.M.
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    Zain M.Z.M.
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    Friction between cutting tool and workpiece generates heat, which can shorten tool life and impair the quality of machined parts. Thus, the use of appropriate lubricants is required to mitigate these issues. In this research, the use of different weight concentration of graphene nanoparticles (0.1 %, 0.5 % and 1.0 %) to augment commercially available vegetable-based oil, LB3000 was investigated using tribological test. Their performances were evaluated in form of the coefficient of friction, wear scar diameter, kinematic viscosity and thermal conductivity. Higher concentration of graphene was found to be more effective in terms of lowering coefficients of friction, reducing wear scar diameter, and improving kinematic viscosity and thermal conductivity. This study clearly demonstrates that a suitable combination of graphene nanoparticles in oil can improve tribological behaviour as well as lubrication performance.
  • Publication
    Effect of milling parameter and fiber pull-out on machinability kenaf fiber reinforced plastic composite materials
    ( 2021-01-01)
    Azmi H.
    ;
    Haron C.H.C.
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    ; ;
    Lih T.C.
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    Yuzairi A.R.
    ;
    Sanusi H.
    Milling surface quality normally depends on the value of surface roughness and delamination factor. The milling parameters, which are cutting tool geometry and fiber pull-out, are the major factors affecting the value of surface roughness and delamination factor in milling kenaf fiber reinforced plastic composite. The objectives of this research are to study the effects of milling parameters, to evaluate the fiber behavior, and to determine the optimum conditions for a range of milling parameters in order to minimize surface roughness (Ra) and delamination factor (Fd) using response surface methodology (RSM). RSM with central composite design (CCD) approach was used to conduct a non-sequential experiment and analyzed the data from the measurements of surface roughness and delamination factor. This study focused on the investigation of relationship between the milling parameters and their effects on kenaf reinforced plastic composite materials during cutting process. Kenaf composite panels were fabricated using vacuum assisted resin transfer molding (VARTM) method that was pressurized below 15 psi using a vacuum pressure. The results showed that the optimum parameters for better surface roughness and delamination factor were cutting speed of 16 Vm/min, feed rate of 0.1 mm/tooth, and depth of cut of 2.0 mm. The feed rate and cutting speed are expected to be the biggest contributors to surface roughness and delamination factor. Finally, different cutting tool geometries also influenced the fiber pull-out that affect surface roughness and delamination factor in milling kenaf fiber reinforce plastic composite materials.
  • Publication
    Experimental investigation on the microdefects formation due to the electrical discharge coating process: A fractional factorial design
    Electrical discharge coating (EDC) is a well-known technique among researchers for modification of metallic surfaces. This process is capable of producing a hard coating layer, biocompatible and high corrosion resistance at low operating cost. Unfortunately, the process develops unfavourable microcracks and porosity on the substrate surface attributed by heat generation. Thus, in this study, the effect of several parameters to the microdefects' formation was investigated through an experimental work based on fractional factorial design. This work was conducted on a nickel-titanium (NiTi) shape memory alloy by varying the EDC parameters, namely; polarity, discharge duration, peak current, pulse interval, gap voltage and additive Ti nano powder concentration in deionized water (DI water). ANOVA results exhibited that the discharge duration has dominated the microcracks and porosity fraction on the substrate surface due to the impact of high intensity of discharge energy. Although, the Ti nano powder mixed in the DI water had capability to reduce the microcracks formation, the porosity fraction during at high gap voltage setting was elevated with the Ti nano powder mixed.
  • Publication
    Optimisation of cutting performance in drilling of aluminium alloy 7075 involving chilled air cooling under Taguchi method
    (Semarak Ilmu Publishing, 2025)
    Muhammad Hisyamuddin Rosli
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    ; ;
    Muhammad Zikry Zainuddin
    ;
    Adel Ali Azawqari
    The use of lightweight Aluminium Alloy 7075 (AA7075) in aerospace and automotive industries is increasing due to its exceptional properties, such as high strength, good fatigue resistance, and excellent strength-to-weight ratio. However, this alloy is difficult to machine due to high ductility and heat generation during cutting. Cutting fluids are commonly used to deal with these problems, although they raise environmental concerns. The research aims to enhance drilling efficiency for AA7075, considering environmental impacts, through a greener method, a chilled air system. Their impact on tool wear and cutting force was evaluated through spindle speed, feed rate, and nozzle types by adopting the Taguchi method. Chisel edge wear was discovered to be a major contributor to tool wear. Lower feed rate and slower spindle speed using dual nozzle yielded better tool wear and cutting force performance. These findings provide feasible recommendations for industry practitioners seeking to employ eco-friendly chilled air systems to achieve optimal drilling efficiency for this type of material.
  • Publication
    Enhancement on the surface quality in machining of aluminum alloy using graphene nanoparticles
    Aluminum alloys are popularly used in the aerospace industry due to their lightweight and high strength-to-weight ratio. However, cutting these alloys can result in various machinability issues such as tool wear, built-up edges, and material adherence on the cutting tool. To address these issues and minimize the use of lubricants, researchers are exploring alternative greener techniques. One such technique is the use of nano lubrication technology. In this research, the consequence of three cutting techniques - dry cutting, minimum quantity lubrication (MQL), and MQL dispersed with graphene nanoparticles - was experimentally studied to assess their impact on hole quality, surface roughness, and the number of holes drilled. The findings showed that the addition of graphene nanoparticles improved roughness quality, reduced tool wear, and increased the number of holes drilled, but had less impact on hole accuracy. This study highlights the importance of nanoparticles in enhancing the machinability of aluminum alloys and offers promising avenues for future research in this area.
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  • Publication
    Machining of Cobalt Chromium Molybdenum (CoCrMo) Alloys: A Review
    ( 2021-01-01)
    Saravanan R.
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    Murad N.M.
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    Cobalt chromium molybdenum (CoCrMo) alloys are not only broadly applied in engineering fields but also in manufacturing of surgical implants components and medical devices due to its outstanding properties of wear resistance and great biocompatibility as demanding in the vivo environment. However, these alloys classified as difficult to cut materials as it presents several characteristics such as high hardness, low thermal conductivity, high wear resistance and strain hardening which contribute to its poor machinability. Although these CoCrMo alloys are theoretically similar to titanium alloy in terms of properties but the studies on machining of CoCrMo alloys still insufficient. This paper provides a review on machining aspects of cobalt chromium molybdenum (CoCrMo) alloys including the properties and machinability, cutting fluid methods and tool material selection for these alloys.
      7  33
  • Publication
    Effect of Inclined Angle in Trimming of Ultra-high Strength Steel Sheets Having Inclined and Curved Shapes
    Trimming the scrap portion of ultra-high strength steel (UHSS) components poses a significant challenge due to the inherent high strength and hardness characteristics of the material. For UHSS components with a higher geometric complexity such consisting of inclined and curved sections, sharp tilt, and small bend radius, the large trimming load results in poor sheared quality and shape defects, which commonly happen in these areas. This research investigated the effects of applying a small inclination angle to the punch in the trimming of the UHSS parts having an inclined and curved shape. The inclined punch was modified to four sets of different degrees of inclination i.e., 1°, 3°, 5°, and 10°. A comparative analysis of the trimming load, trimming energy, sheared edge quality and shape defects was conducted between these modified punches and the normal punch for their effectiveness in the trimming operation. Results showed that the application of inclination angle significantly decreased the trimming load, reduced the trimming energy, and improved the sheared edge surface quality, as well as prevented the shape defects at the inclined and curved zones as compared to the outcomes produced when trimming using the normal punch. The study suggested that the change to the punch geometry is an effective option to improve the performance of the process as well as the quality of the part, particularly in trimming the high-strength components having complex shapes.
      4  42