A machining platform of micro wire electrical discharge machining (MWEDM) was developed. The key technology of MWEDM mainly includes granite basement, micro energy pulse generator, detection and servo control system, ...A machining platform of micro wire electrical discharge machining (MWEDM) was developed. The key technology of MWEDM mainly includes granite basement, micro energy pulse generator, detection and servo control system, constant tension winding system and V-block guide wire mechanism. Utilizing micro wire electrode with 30μm in diameter, the MWEDM can machine the micro slot with the minimum size of 38μm wide, and the surface roughness is smaller than 0.1μm, the machining precision is less than 0.5μm, the white layer is no more than 2μm with main cut. All kinds of complex micro parts, such as micro gear, micro bearing bracket and micro shaped holes, can also be machined by using this platform.展开更多
The present work discusses the experimental study on wire-cut electric discharge machining of hot-pressed boron carbide.The effects of machining parameters,such as pulse on time(TON),peak current(IP),flushing pressure...The present work discusses the experimental study on wire-cut electric discharge machining of hot-pressed boron carbide.The effects of machining parameters,such as pulse on time(TON),peak current(IP),flushing pressure(FP) and spark voltage on material removal rate(MRR)and surface roughness(R_a) of the material,have been evaluated.These parameters are found to have an effect on the surface integrity of boron carbide machined samples.Wear rate of brass wire increases with rise in input energy in machining of hot-pressed boron carbide.The surfaces of machined samples were examined using scanning electron microscopy(SEM).The influence of machining parameters on mechanism of MRR and R_a was described.It was demonstrated that higher TON and peak current deteriorate the surface finish of boron carbide samples and result in the formation of large craters,debris and micro cracks.The generation of spherical particles was noticed and it was attributed to surface tension of molten material.Macro-ridges were also observed on the surface due to protrusion of molten material at higher discharge energy levels.展开更多
The analysis of cutting regularity is provided through using and comparing two typical cooling liquids. It is proved that cutting regularity is greatly affected by cooling liquid＇s washing ability. Discharge characte...The analysis of cutting regularity is provided through using and comparing two typical cooling liquids. It is proved that cutting regularity is greatly affected by cooling liquid＇s washing ability. Discharge characteristics and theoretic analysis between two electrodes are also discussed based on discharge waveform. By using composite cooling liquid which has strong washing ability, the efficiency in the first stable cutting phase has reached more than 200 mm^2/min, and the roughness of the surface has reached Ra〈0.8 μm after the fourth cutting with more than 50 mm^2/min average cutting efficiency. It is pointed out that cutting situation of the wire cut electrical discharge machine with high wire traveling speed （HSWEDM） is better than the wire cut electrical discharge machine with low wire traveling speed （LSWEDM） in the condition of improving the cooling liquid washing ability. The machining indices of HSWEDM will be increased remarkably by using the composite cooling liquid.展开更多
Wire electric discharge machining(WEDM)process is used for precision manufacturing.The accuracy of machining is function of various parameters like current,voltage,wire speed,gap between wire and work piece,wire oscil...Wire electric discharge machining(WEDM)process is used for precision manufacturing.The accuracy of machining is function of various parameters like current,voltage,wire speed,gap between wire and work piece,wire oscillation,work material,wire material,etc.Once the process parameters are selected,it is important that the wire vibrations are less to obtain a good surface finish.Due to the importance of wire vibration in obtaining the surface finish,it is necessary to study the wire vibration.This paper discusses different models of wire vibration presented in the literature and simulates a closed form solution of wire vibration using MATLAB.The transverse vibration of wire is analysed as forced vibration of moving wire with excitation due to the sparks during machining.The resulting partial differential equation is solved by using finite difference method and vibration is also simulated in the finite element package‘ANSYS’.The wire behaviour is investigated under different operating conditions and results of the two methods are展开更多
The wire electrical discharge machining（EDM） of 6061 aluminium alloy in terms of material removal rate,kerf/slit width,surface finish and wear of electrode wire for different pulse on time and wire tension was studi...The wire electrical discharge machining（EDM） of 6061 aluminium alloy in terms of material removal rate,kerf/slit width,surface finish and wear of electrode wire for different pulse on time and wire tension was studied.Eight experiments were carried out in a wire EDM machine by varying pulse on time and wire tension.It is found that the material removal rate increases with the increase of pulse on time though the wire tension does not affect the material removal rate.It seems that the higher wire tension facilitates steady machining process,which generates low wear in wire electrode and better surface finish.The surface roughness does not change notably with the variation of pulse on time.The appearance of the machined surfaces is very similar under all the machining conditions.The machined surface contains solidified molten material,splash of materials and blisters.The increase of the pulse on time increases the wear of wire electrode due to the increase of heat input.The wear of wire electrode generates tapered slot which has higher kerf width at top side than that at bottom side.The higher electrode wear introduces higher taper.展开更多
Ti Ni shape memory alloys（SMAs） have been normally used as the competent elements in large part of the industries due to outstanding properties, such as super elasticity and shape memory effects. However, traditiona...Ti Ni shape memory alloys（SMAs） have been normally used as the competent elements in large part of the industries due to outstanding properties, such as super elasticity and shape memory effects. However, traditional machining of SMAs is quite complex due to these properties. Hence, the wire electric discharge machining（WEDM） characteristics of Ti Ni SMA was studied. The experiments were planned as per L27 orthogonal array to minimize the experiments, each experiment was performed under different conditions of pulse duration, pulse off time, servo voltage, flushing pressure and wire speed. A multi-response optimization method using Taguchi design with utility concept has been proposed for simultaneous optimization. The analysis of means（ANOM） and analysis of variance（ANOVA） on signal to noise（S/N） ratio were performed for determining the optimal parameter levels. Taguchi analysis reveals that a combination of 1 μs pulse duration, 3.8 μs pulse off time, 40 V servo voltage, 1.8×105 Pa flushing pressure and 8 m/min wire speed is beneficial for simultaneously maximizing the material removal rate（MRR） and minimizing the surface roughness. The optimization results of WEDM of Ti Ni SMA also indicate that pulse duration significantly affects the material removal rate and surface roughness. The discharged craters, micro cracks and recast layer were observed on the machined surface at large pulse duration.展开更多
For the design of gears manufactured with wire electrical discharge machining （WEDM） technology, determination of the primary gear parameters is discussed considering the characteristics of the machining method. Som...For the design of gears manufactured with wire electrical discharge machining （WEDM） technology, determination of the primary gear parameters is discussed considering the characteristics of the machining method. Some constraint conditions on gear parameters are abnegated, which makes micro gear design more flexible. Based on gear mesh theory, the algorithm of generating gear tooth profiles is studied, which includes involute and non-involute curve segments. The phenomena of tooth profile interferences during gear mesh are analyzed, and a gear mesh simulation algorithm is designed. Based on ACIS, the WEDM oriented software for the design and mesh simulation of micro gears is developed, by which the modeling, mesh simulation and interference check can be implemented. An experiment is carried out to design and manufacture a pair of micro involute gears, and the proposed method is proved feasible.展开更多
In the verification of wire electrical discharge machining （EDM）, the motion and the performance of the wire-EDM system are analyzed. The maximum inclining angle of the wire is calculated. The relevant judgment meth...In the verification of wire electrical discharge machining （EDM）, the motion and the performance of the wire-EDM system are analyzed. The maximum inclining angle of the wire is calculated. The relevant judgment methods are used for the collision between the wire, the fixture, and the machining table. In the wire-EDM simulation, the generated solid model can he used to investigate programming results and to check the machining accuracy. The generation algorithm for the solid model in the simulation is solved based on Boolean operations. The wire swept volume for each cutting step is united to form the entire wire swept volume. Through Boolean subtraction between the stock model and the entire wire swept volume, the solid model in the wire-EDM simulation is generated. The method is also suitable for the wire path intersection occurred in cutting cone-shaped models. Finally, experiments are given to prove the method.展开更多
Shape memory alloys （SMAs） are the developing advanced materials due to their versatile specific properties such as pseudoelasticity, shape memory effect （SME）, biocompatibility, high specific strength, high corro...Shape memory alloys （SMAs） are the developing advanced materials due to their versatile specific properties such as pseudoelasticity, shape memory effect （SME）, biocompatibility, high specific strength, high corrosion resistance, high wear resistance and high anti-fatigue property. Therefore, the SMAs are used in many applications such as aerospace, medical and automobile. However, the conventional machining of SMAs causes serious tool wear, time consuming and less dimensional deformity due to severe strain hardening and pseudoelasticity. These materials can be machined using non-conventional methods such as laser machining, water jet machining （WJM） and electrochemical machining （ECM）, but these processes are limited to complexity and mechanical properties of the component. Electrical discharge machining （EDM） and wire EDM （WEDM） show high capability to machine SMAs of complex shapes with precise dimensions. The aim of this work is to present the consolidated references on the machining of SMAs using EDM and WEDM and subsequently identify the research gaps. In support to these research gaps, this work has also evolved the future research directions.展开更多
The goal of this research is to identify the best set of process machining parameters for wire-EDM(Electrical Discharge Machining)cutting of hardened SKD11 steel when machining a curve profile.The multi-objective func...The goal of this research is to identify the best set of process machining parameters for wire-EDM(Electrical Discharge Machining)cutting of hardened SKD11 steel when machining a curve profile.The multi-objective function includes reducing surface roughness and increasing MRR(Material Removal Rate).The optimization process is prepared by using Taguchi method coupled Grey Relational Analysis.The obtained results revealed that Toff has the greatest influence on the average grey value(48.30%),followed by the influence of WF(Wire Feed,15.99%),VM(Cutting Voltage,9.33%),SV(Server Voltage,5.05%),Ton(Pulse on Time,1.81%),while SPD(Cutting Speed)has a negligible effect(0.89%).Moreover,using the optimal set of machining parameters generates in surface roughness of 1.25399mm and MRR of 26.5562 mm^(2)/min.The verification experiment and Anderson-Darling method demonstrate the validity of the proposed model,which can be utilized for estimating surface roughness and MRR.展开更多
文摘A machining platform of micro wire electrical discharge machining (MWEDM) was developed. The key technology of MWEDM mainly includes granite basement, micro energy pulse generator, detection and servo control system, constant tension winding system and V-block guide wire mechanism. Utilizing micro wire electrode with 30μm in diameter, the MWEDM can machine the micro slot with the minimum size of 38μm wide, and the surface roughness is smaller than 0.1μm, the machining precision is less than 0.5μm, the white layer is no more than 2μm with main cut. All kinds of complex micro parts, such as micro gear, micro bearing bracket and micro shaped holes, can also be machined by using this platform.
文摘The present work discusses the experimental study on wire-cut electric discharge machining of hot-pressed boron carbide.The effects of machining parameters,such as pulse on time(TON),peak current(IP),flushing pressure(FP) and spark voltage on material removal rate(MRR)and surface roughness(R_a) of the material,have been evaluated.These parameters are found to have an effect on the surface integrity of boron carbide machined samples.Wear rate of brass wire increases with rise in input energy in machining of hot-pressed boron carbide.The surfaces of machined samples were examined using scanning electron microscopy(SEM).The influence of machining parameters on mechanism of MRR and R_a was described.It was demonstrated that higher TON and peak current deteriorate the surface finish of boron carbide samples and result in the formation of large craters,debris and micro cracks.The generation of spherical particles was noticed and it was attributed to surface tension of molten material.Macro-ridges were also observed on the surface due to protrusion of molten material at higher discharge energy levels.
基金Provincial Key Laboratory of Precision and Micro-Manufacturing Technology of Jiangsu,China(No.Z0601-052-02).
文摘The analysis of cutting regularity is provided through using and comparing two typical cooling liquids. It is proved that cutting regularity is greatly affected by cooling liquid＇s washing ability. Discharge characteristics and theoretic analysis between two electrodes are also discussed based on discharge waveform. By using composite cooling liquid which has strong washing ability, the efficiency in the first stable cutting phase has reached more than 200 mm^2/min, and the roughness of the surface has reached Ra〈0.8 μm after the fourth cutting with more than 50 mm^2/min average cutting efficiency. It is pointed out that cutting situation of the wire cut electrical discharge machine with high wire traveling speed （HSWEDM） is better than the wire cut electrical discharge machine with low wire traveling speed （LSWEDM） in the condition of improving the cooling liquid washing ability. The machining indices of HSWEDM will be increased remarkably by using the composite cooling liquid.
文摘Wire electric discharge machining(WEDM)process is used for precision manufacturing.The accuracy of machining is function of various parameters like current,voltage,wire speed,gap between wire and work piece,wire oscillation,work material,wire material,etc.Once the process parameters are selected,it is important that the wire vibrations are less to obtain a good surface finish.Due to the importance of wire vibration in obtaining the surface finish,it is necessary to study the wire vibration.This paper discusses different models of wire vibration presented in the literature and simulates a closed form solution of wire vibration using MATLAB.The transverse vibration of wire is analysed as forced vibration of moving wire with excitation due to the sparks during machining.The resulting partial differential equation is solved by using finite difference method and vibration is also simulated in the finite element package‘ANSYS’.The wire behaviour is investigated under different operating conditions and results of the two methods are
文摘The wire electrical discharge machining（EDM） of 6061 aluminium alloy in terms of material removal rate,kerf/slit width,surface finish and wear of electrode wire for different pulse on time and wire tension was studied.Eight experiments were carried out in a wire EDM machine by varying pulse on time and wire tension.It is found that the material removal rate increases with the increase of pulse on time though the wire tension does not affect the material removal rate.It seems that the higher wire tension facilitates steady machining process,which generates low wear in wire electrode and better surface finish.The surface roughness does not change notably with the variation of pulse on time.The appearance of the machined surfaces is very similar under all the machining conditions.The machined surface contains solidified molten material,splash of materials and blisters.The increase of the pulse on time increases the wear of wire electrode due to the increase of heat input.The wear of wire electrode generates tapered slot which has higher kerf width at top side than that at bottom side.The higher electrode wear introduces higher taper.
文摘Ti Ni shape memory alloys（SMAs） have been normally used as the competent elements in large part of the industries due to outstanding properties, such as super elasticity and shape memory effects. However, traditional machining of SMAs is quite complex due to these properties. Hence, the wire electric discharge machining（WEDM） characteristics of Ti Ni SMA was studied. The experiments were planned as per L27 orthogonal array to minimize the experiments, each experiment was performed under different conditions of pulse duration, pulse off time, servo voltage, flushing pressure and wire speed. A multi-response optimization method using Taguchi design with utility concept has been proposed for simultaneous optimization. The analysis of means（ANOM） and analysis of variance（ANOVA） on signal to noise（S/N） ratio were performed for determining the optimal parameter levels. Taguchi analysis reveals that a combination of 1 μs pulse duration, 3.8 μs pulse off time, 40 V servo voltage, 1.8×105 Pa flushing pressure and 8 m/min wire speed is beneficial for simultaneously maximizing the material removal rate（MRR） and minimizing the surface roughness. The optimization results of WEDM of Ti Ni SMA also indicate that pulse duration significantly affects the material removal rate and surface roughness. The discharged craters, micro cracks and recast layer were observed on the machined surface at large pulse duration.
基金The Teaching and Research Award Program for Out-standing Young Teachers in Higher Education Institutions of MOE,P.R.China.
文摘For the design of gears manufactured with wire electrical discharge machining （WEDM） technology, determination of the primary gear parameters is discussed considering the characteristics of the machining method. Some constraint conditions on gear parameters are abnegated, which makes micro gear design more flexible. Based on gear mesh theory, the algorithm of generating gear tooth profiles is studied, which includes involute and non-involute curve segments. The phenomena of tooth profile interferences during gear mesh are analyzed, and a gear mesh simulation algorithm is designed. Based on ACIS, the WEDM oriented software for the design and mesh simulation of micro gears is developed, by which the modeling, mesh simulation and interference check can be implemented. An experiment is carried out to design and manufacture a pair of micro involute gears, and the proposed method is proved feasible.
文摘In the verification of wire electrical discharge machining （EDM）, the motion and the performance of the wire-EDM system are analyzed. The maximum inclining angle of the wire is calculated. The relevant judgment methods are used for the collision between the wire, the fixture, and the machining table. In the wire-EDM simulation, the generated solid model can he used to investigate programming results and to check the machining accuracy. The generation algorithm for the solid model in the simulation is solved based on Boolean operations. The wire swept volume for each cutting step is united to form the entire wire swept volume. Through Boolean subtraction between the stock model and the entire wire swept volume, the solid model in the wire-EDM simulation is generated. The method is also suitable for the wire path intersection occurred in cutting cone-shaped models. Finally, experiments are given to prove the method.
文摘Shape memory alloys （SMAs） are the developing advanced materials due to their versatile specific properties such as pseudoelasticity, shape memory effect （SME）, biocompatibility, high specific strength, high corrosion resistance, high wear resistance and high anti-fatigue property. Therefore, the SMAs are used in many applications such as aerospace, medical and automobile. However, the conventional machining of SMAs causes serious tool wear, time consuming and less dimensional deformity due to severe strain hardening and pseudoelasticity. These materials can be machined using non-conventional methods such as laser machining, water jet machining （WJM） and electrochemical machining （ECM）, but these processes are limited to complexity and mechanical properties of the component. Electrical discharge machining （EDM） and wire EDM （WEDM） show high capability to machine SMAs of complex shapes with precise dimensions. The aim of this work is to present the consolidated references on the machining of SMAs using EDM and WEDM and subsequently identify the research gaps. In support to these research gaps, this work has also evolved the future research directions.
文摘The goal of this research is to identify the best set of process machining parameters for wire-EDM(Electrical Discharge Machining)cutting of hardened SKD11 steel when machining a curve profile.The multi-objective function includes reducing surface roughness and increasing MRR(Material Removal Rate).The optimization process is prepared by using Taguchi method coupled Grey Relational Analysis.The obtained results revealed that Toff has the greatest influence on the average grey value(48.30%),followed by the influence of WF(Wire Feed,15.99%),VM(Cutting Voltage,9.33%),SV(Server Voltage,5.05%),Ton(Pulse on Time,1.81%),while SPD(Cutting Speed)has a negligible effect(0.89%).Moreover,using the optimal set of machining parameters generates in surface roughness of 1.25399mm and MRR of 26.5562 mm^(2)/min.The verification experiment and Anderson-Darling method demonstrate the validity of the proposed model,which can be utilized for estimating surface roughness and MRR.
