Efficient and effective lubricants have great application prospects in the manufacturing industri... more Efficient and effective lubricants have great application prospects in the manufacturing industries. Minimum quantity lubrication (MQL) machining with low flow rate of nanolubricants is investigated for cooling and lubrication during the process. This paper investigates the characterization of graphene-mixed aluminium oxide (G-Al2O3) hybrid nanomixture spent lubricants for MQL machining purposes. The main advantage of this method is to reduce the disposal lubricants to develop high-performance cooling-lubrication by using nanolubricants of G-Al2O3 nanoparticles in different volume composition ratios at a constant 1.0% volume concentration in a base liquid mixture of 40% spent lubricants. Before conducting the measurements of the nanolubricants’ thermal conductivity and dynamic viscosity, the nanolubricants were homogenous and stable. The tribological performance of all ratios was evaluated by using a four-ball wear tribotester machine. The thermal conductivity peak value for the G-A...
IOP Conference Series: Materials Science and Engineering, 2019
Machining coolant is used in manufacturing industry for lubrication, rusting control and cooling ... more Machining coolant is used in manufacturing industry for lubrication, rusting control and cooling which are crucial in operations such as grinding and cutting process. However, the machining coolant lose efficiency in months due to the thermal degradation and contamination. To recycle the used of machining coolant while enhancing the performance, the mixture of nanofluids (N) based Al2O3 with better thermal properties to synthesize with the recycled machining coolant (RMC). This study suspended Al2O3 nanofluids in four base ratios of recycled machining coolant (i.e. 0:100, 20:80, 40:60 and 60:40) by ultrasonic homogenies. The three main parameters in cooling rate performance and rusting control are thermal conductivity, dynamic viscosity and pH indication, respectively. The thermal conductivity and dynamic viscosity are then measured at temperature range of 30 to 60°C. The highest enhancement of thermal conductivity was evaluated to be 37.9% higher than machining coolant base fluid a...
Journal of Mechanical Engineering and Sciences, 2021
This paper presents a complete and well tested virtual instrument (VI) for computer numerical con... more This paper presents a complete and well tested virtual instrument (VI) for computer numerical control (CNC) machine predictive maintenance. The national instrument (NI) hardware, LabVIEW software and accelerometer sensor are acquired for the vibration analysis integrated with virtual instrument were developed based on the vibration severity chart threshold in ISO 10816. Validation experiments of the predictive maintenance module were utilized on drilling and milling processes to test and verify the effectiveness of the module. Results obtained from current module can monitor and provide the machine conditions at different condition of good, satisfactory, unsatisfactory, and unacceptable for rotating machinery status according to the vibration severity chart as per ISO 10816.
Journal of Mechanical Engineering and Sciences, 2021
In modal analysis, measurement of input force and vibration response are crucial to accurately me... more In modal analysis, measurement of input force and vibration response are crucial to accurately measure the transfer function of the structure. However, under operating condition, the force induced by operating machinery is impossible to be measured due to the sensor placement issue. In this case, the ambient response induced by the operating force should be suppressed to minimize the error in the Frequency Response Function (FRF) calculation. This paper presents the utilization of a modified spectral subtraction filter for ambient suppression. The introduction of effective ambient magnitude in gain function calculation has increased the efficiency of spectral subtraction filter. This parameter is calculated based on the phase information of the reconstructed artificial ambient response. The measurement using EMA was carried out on a motor-driven structure to verify the proposed technique. Two sets of data under shutdown and running condition were recorded to observe the effect of am...
Milling is one of the most common manufacturing processes for automotive components, but its prod... more Milling is one of the most common manufacturing processes for automotive components, but its productivity is limited by the onset of regenerative chatter. This is a form of unstable self-excited vibration that occurs when the volume of material removed is too large for a particular spindle speed. This form of chatter is undesirable because it results in premature tool wear, poor surface finish on the machined component and the possibility of serious damage to the machine itself. The chatter stability of a milling process can be determined using well-established theory, provided that the frequency response of the flexible structure can be determined. In practice this usually involves the excitation of a stationery (non-rotating) milling tool with a modal hammer, and measurement of the response of the tool with a co-located accelerometer. However, this measurement is not necessarily accurate due to amplitude dependency factor consideration. There is anecdotal evidence that structural ...
Abstract Machining operation must be maintained for a long time in every period to achieve high p... more Abstract Machining operation must be maintained for a long time in every period to achieve high productivity and prevent sudden failure or breakdown. This study aims to monitor conditions of four CNC machines from different places simultaneously using Internet of things (IoT) for predictive maintenance. Vibration signals of four CNC machines are measured using an accelerometer to collect and send signals directly to the database in real time. Results showed that acceleration signal in both time and frequency domains can identify conditions of each machine in real time and simultaneously monitor the condition of four CNC machines at different places through IoT for predictive maintenance.
Journal of Mechanical Engineering and Sciences, 2020
Nanofluids possess many advantages over conventional working fluid especially in physical, therma... more Nanofluids possess many advantages over conventional working fluid especially in physical, thermal and rheology properties. Nowadays, nanofluids have been applied extensively in many engineering applications in enhancing the overall performance. Preparation and characterization of nanofluids are vital as the nanomaterials have significant effects on the dispersion and stability of nanofluids. On the other hand, there is a trend to employ more than a single nanoparticle for preparing nanofluid. The hybrid nanofluid receives wide attention due to its capability in improving the thermal-physical properties of single phase nanofluids. In this paper, the flow of formulating nanofluid from preparation method, characterization, wettability analysis and stability techniques are discussed comprehensively. Furthermore, the challenges for obtaining stable suspension and wettability behaviour of nanofluids are discussed as well. The main objective when preparing the nanofluids is to obtain a we...
IOP Conference Series: Materials Science and Engineering, 2019
A chip breaker plays an essential role for chip breaking as well as to enhance productivity and q... more A chip breaker plays an essential role for chip breaking as well as to enhance productivity and quality during the turning process. However, chip break as a tool is not able to break the chip and formulate continuous chip, that in turn, causes the tool to wear and the generate excessive heat. These affect the quality of the machined surface. Chip formation is influenced by cutting conditions and tool geometries such as spindle speed, feed rate, depth of cut and rake angle. In this study, experiments were carried out on carbon steel 1050 with chip breaker at a constant cutting speed of 275 m/mm with a depth of cut 0.9 mm. The effect of different feed rate and rake angle towards chip length formation were also investigated in the present investigation. The results obtained from the study indicates that segmented chips could be obtained at a feed rate of 0.4 mm/rev and a rake angle of -9°. Therefore, it could be concluded that the feed rate and rake angle can play a significant role in...
ASEAN Journal on Science and Technology for Development, 2017
The paper presents an approach to investigate and monitor the air pollution caused by the palm oi... more The paper presents an approach to investigate and monitor the air pollution caused by the palm oil mill. A concept of dealing with the problem from its causes is used where the sources of pollution from the stack gases were examined. The main causes were from the combustion of shell fibre and of the palm oil. However, in the boiler itself, several parameters like steam load and pressure, fuel capacity and temperature also contribute to the pollution. The study uses Neural Network (NN) to simulate the process of combustion and stack gases. This neural network was trained by using the data on emission and combustion bed taken from local palm oil plant in Perak, Malaysia. The trained data by NN agrees well with the measured data, i.e. almost within 8% error for pollutants like CO, SO2, NO and particulate matters.
Chatter produces a poor surface finish and high tool wear and can even damage machine tools as a ... more Chatter produces a poor surface finish and high tool wear and can even damage machine tools as a result of the regenerative effect, the loss of the contact effect and the mode coupling effect. The early and latest researches are to suppress chatter by either passive or active methods by applying absorber, damping, varied speed and alternatives. In this paper, it can be observed that the optimization focuses on spindle design, tool path, cutting process and variable pitch for chatter suppression. There are various algorithms which can be applied in optimization of machining problems; however, Differential Evolution (DE) is the appropriate candidate that can solve time consuming, local optimal and more robust as compared to Genetic Algorithm (GA), although it has widely applications, and Sequential Quadratic Programming (SQP) as a famous conventional algorithm can be employed for chatter suppression.
... present study, a semi discretisation method (SDM) has been combined with Differential Evoluti... more ... present study, a semi discretisation method (SDM) has been combined with Differential Evolution (DE) to optimise variable helix end milling tools. The target is to reduce chatter, and Sequential Quadratic Programming (SQP) is used to benchmark the optimisation performance. ...
High productivity, low cost and high profits are important issues in aerospace, automotive and to... more High productivity, low cost and high profits are important issues in aerospace, automotive and tool/die metal manufacturing industries. Machining processes are widely used in manufacturing operations for metal manufacturing rather than casting and forming. However, the dynamic deflection of tool and workpiece systems generates unstable cutting forces when machining with high material removal rate. Here, sudden large vibration amplitudes occur when energy input exceeds the energy dissipated from the system, leading to self-excited vibration or chatter. This thesis focuses on the avoidance of milling chatter by using variable helix milling tools. Since milling chatter is strongly influenced by the frequency response function of the dynamic system, a preliminary study is first presented to assess the feasibility of non-contacting electromagnetic modal analysis for milling tools. It is shown that this approach shows some promise for use in real machining problems where traditional modal...
The elastic relaxation behavior of dual phase steel DP800 is studied in this investigation, based... more The elastic relaxation behavior of dual phase steel DP800 is studied in this investigation, based on experimental and numerical methods the true stress-true strain curve obtained from a standard uniaxial tensile test differs according to angular rolling direction The relationship between true stress and true strain are presented in the form of power law equation. This form of material constitutive model shows that the strength coefficient and strain hardening exponent vary significantly in describing the nonlinear true stress-true strain relationship of the material. Finite Element (FE) calculations with Belytschko-Lin-Tsay shell element formulation are performed using the non-linear FE code Ls-Dyna to predict the plastic deformation of the material. Power Law Isotropic Plasticity criterion is adopted for these numerical analyses. The local strains in plastic deformations zone and true stress-strains characteristics obtained by experiment are compared. Using the same parameter the s...
Efficient and effective lubricants have great application prospects in the manufacturing industri... more Efficient and effective lubricants have great application prospects in the manufacturing industries. Minimum quantity lubrication (MQL) machining with low flow rate of nanolubricants is investigated for cooling and lubrication during the process. This paper investigates the characterization of graphene-mixed aluminium oxide (G-Al2O3) hybrid nanomixture spent lubricants for MQL machining purposes. The main advantage of this method is to reduce the disposal lubricants to develop high-performance cooling-lubrication by using nanolubricants of G-Al2O3 nanoparticles in different volume composition ratios at a constant 1.0% volume concentration in a base liquid mixture of 40% spent lubricants. Before conducting the measurements of the nanolubricants’ thermal conductivity and dynamic viscosity, the nanolubricants were homogenous and stable. The tribological performance of all ratios was evaluated by using a four-ball wear tribotester machine. The thermal conductivity peak value for the G-A...
IOP Conference Series: Materials Science and Engineering, 2019
Machining coolant is used in manufacturing industry for lubrication, rusting control and cooling ... more Machining coolant is used in manufacturing industry for lubrication, rusting control and cooling which are crucial in operations such as grinding and cutting process. However, the machining coolant lose efficiency in months due to the thermal degradation and contamination. To recycle the used of machining coolant while enhancing the performance, the mixture of nanofluids (N) based Al2O3 with better thermal properties to synthesize with the recycled machining coolant (RMC). This study suspended Al2O3 nanofluids in four base ratios of recycled machining coolant (i.e. 0:100, 20:80, 40:60 and 60:40) by ultrasonic homogenies. The three main parameters in cooling rate performance and rusting control are thermal conductivity, dynamic viscosity and pH indication, respectively. The thermal conductivity and dynamic viscosity are then measured at temperature range of 30 to 60°C. The highest enhancement of thermal conductivity was evaluated to be 37.9% higher than machining coolant base fluid a...
Journal of Mechanical Engineering and Sciences, 2021
This paper presents a complete and well tested virtual instrument (VI) for computer numerical con... more This paper presents a complete and well tested virtual instrument (VI) for computer numerical control (CNC) machine predictive maintenance. The national instrument (NI) hardware, LabVIEW software and accelerometer sensor are acquired for the vibration analysis integrated with virtual instrument were developed based on the vibration severity chart threshold in ISO 10816. Validation experiments of the predictive maintenance module were utilized on drilling and milling processes to test and verify the effectiveness of the module. Results obtained from current module can monitor and provide the machine conditions at different condition of good, satisfactory, unsatisfactory, and unacceptable for rotating machinery status according to the vibration severity chart as per ISO 10816.
Journal of Mechanical Engineering and Sciences, 2021
In modal analysis, measurement of input force and vibration response are crucial to accurately me... more In modal analysis, measurement of input force and vibration response are crucial to accurately measure the transfer function of the structure. However, under operating condition, the force induced by operating machinery is impossible to be measured due to the sensor placement issue. In this case, the ambient response induced by the operating force should be suppressed to minimize the error in the Frequency Response Function (FRF) calculation. This paper presents the utilization of a modified spectral subtraction filter for ambient suppression. The introduction of effective ambient magnitude in gain function calculation has increased the efficiency of spectral subtraction filter. This parameter is calculated based on the phase information of the reconstructed artificial ambient response. The measurement using EMA was carried out on a motor-driven structure to verify the proposed technique. Two sets of data under shutdown and running condition were recorded to observe the effect of am...
Milling is one of the most common manufacturing processes for automotive components, but its prod... more Milling is one of the most common manufacturing processes for automotive components, but its productivity is limited by the onset of regenerative chatter. This is a form of unstable self-excited vibration that occurs when the volume of material removed is too large for a particular spindle speed. This form of chatter is undesirable because it results in premature tool wear, poor surface finish on the machined component and the possibility of serious damage to the machine itself. The chatter stability of a milling process can be determined using well-established theory, provided that the frequency response of the flexible structure can be determined. In practice this usually involves the excitation of a stationery (non-rotating) milling tool with a modal hammer, and measurement of the response of the tool with a co-located accelerometer. However, this measurement is not necessarily accurate due to amplitude dependency factor consideration. There is anecdotal evidence that structural ...
Abstract Machining operation must be maintained for a long time in every period to achieve high p... more Abstract Machining operation must be maintained for a long time in every period to achieve high productivity and prevent sudden failure or breakdown. This study aims to monitor conditions of four CNC machines from different places simultaneously using Internet of things (IoT) for predictive maintenance. Vibration signals of four CNC machines are measured using an accelerometer to collect and send signals directly to the database in real time. Results showed that acceleration signal in both time and frequency domains can identify conditions of each machine in real time and simultaneously monitor the condition of four CNC machines at different places through IoT for predictive maintenance.
Journal of Mechanical Engineering and Sciences, 2020
Nanofluids possess many advantages over conventional working fluid especially in physical, therma... more Nanofluids possess many advantages over conventional working fluid especially in physical, thermal and rheology properties. Nowadays, nanofluids have been applied extensively in many engineering applications in enhancing the overall performance. Preparation and characterization of nanofluids are vital as the nanomaterials have significant effects on the dispersion and stability of nanofluids. On the other hand, there is a trend to employ more than a single nanoparticle for preparing nanofluid. The hybrid nanofluid receives wide attention due to its capability in improving the thermal-physical properties of single phase nanofluids. In this paper, the flow of formulating nanofluid from preparation method, characterization, wettability analysis and stability techniques are discussed comprehensively. Furthermore, the challenges for obtaining stable suspension and wettability behaviour of nanofluids are discussed as well. The main objective when preparing the nanofluids is to obtain a we...
IOP Conference Series: Materials Science and Engineering, 2019
A chip breaker plays an essential role for chip breaking as well as to enhance productivity and q... more A chip breaker plays an essential role for chip breaking as well as to enhance productivity and quality during the turning process. However, chip break as a tool is not able to break the chip and formulate continuous chip, that in turn, causes the tool to wear and the generate excessive heat. These affect the quality of the machined surface. Chip formation is influenced by cutting conditions and tool geometries such as spindle speed, feed rate, depth of cut and rake angle. In this study, experiments were carried out on carbon steel 1050 with chip breaker at a constant cutting speed of 275 m/mm with a depth of cut 0.9 mm. The effect of different feed rate and rake angle towards chip length formation were also investigated in the present investigation. The results obtained from the study indicates that segmented chips could be obtained at a feed rate of 0.4 mm/rev and a rake angle of -9°. Therefore, it could be concluded that the feed rate and rake angle can play a significant role in...
ASEAN Journal on Science and Technology for Development, 2017
The paper presents an approach to investigate and monitor the air pollution caused by the palm oi... more The paper presents an approach to investigate and monitor the air pollution caused by the palm oil mill. A concept of dealing with the problem from its causes is used where the sources of pollution from the stack gases were examined. The main causes were from the combustion of shell fibre and of the palm oil. However, in the boiler itself, several parameters like steam load and pressure, fuel capacity and temperature also contribute to the pollution. The study uses Neural Network (NN) to simulate the process of combustion and stack gases. This neural network was trained by using the data on emission and combustion bed taken from local palm oil plant in Perak, Malaysia. The trained data by NN agrees well with the measured data, i.e. almost within 8% error for pollutants like CO, SO2, NO and particulate matters.
Chatter produces a poor surface finish and high tool wear and can even damage machine tools as a ... more Chatter produces a poor surface finish and high tool wear and can even damage machine tools as a result of the regenerative effect, the loss of the contact effect and the mode coupling effect. The early and latest researches are to suppress chatter by either passive or active methods by applying absorber, damping, varied speed and alternatives. In this paper, it can be observed that the optimization focuses on spindle design, tool path, cutting process and variable pitch for chatter suppression. There are various algorithms which can be applied in optimization of machining problems; however, Differential Evolution (DE) is the appropriate candidate that can solve time consuming, local optimal and more robust as compared to Genetic Algorithm (GA), although it has widely applications, and Sequential Quadratic Programming (SQP) as a famous conventional algorithm can be employed for chatter suppression.
... present study, a semi discretisation method (SDM) has been combined with Differential Evoluti... more ... present study, a semi discretisation method (SDM) has been combined with Differential Evolution (DE) to optimise variable helix end milling tools. The target is to reduce chatter, and Sequential Quadratic Programming (SQP) is used to benchmark the optimisation performance. ...
High productivity, low cost and high profits are important issues in aerospace, automotive and to... more High productivity, low cost and high profits are important issues in aerospace, automotive and tool/die metal manufacturing industries. Machining processes are widely used in manufacturing operations for metal manufacturing rather than casting and forming. However, the dynamic deflection of tool and workpiece systems generates unstable cutting forces when machining with high material removal rate. Here, sudden large vibration amplitudes occur when energy input exceeds the energy dissipated from the system, leading to self-excited vibration or chatter. This thesis focuses on the avoidance of milling chatter by using variable helix milling tools. Since milling chatter is strongly influenced by the frequency response function of the dynamic system, a preliminary study is first presented to assess the feasibility of non-contacting electromagnetic modal analysis for milling tools. It is shown that this approach shows some promise for use in real machining problems where traditional modal...
The elastic relaxation behavior of dual phase steel DP800 is studied in this investigation, based... more The elastic relaxation behavior of dual phase steel DP800 is studied in this investigation, based on experimental and numerical methods the true stress-true strain curve obtained from a standard uniaxial tensile test differs according to angular rolling direction The relationship between true stress and true strain are presented in the form of power law equation. This form of material constitutive model shows that the strength coefficient and strain hardening exponent vary significantly in describing the nonlinear true stress-true strain relationship of the material. Finite Element (FE) calculations with Belytschko-Lin-Tsay shell element formulation are performed using the non-linear FE code Ls-Dyna to predict the plastic deformation of the material. Power Law Isotropic Plasticity criterion is adopted for these numerical analyses. The local strains in plastic deformations zone and true stress-strains characteristics obtained by experiment are compared. Using the same parameter the s...
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