40 research outputs found
Fabrication of deep micro-holes in reaction-bonded SiC by ultrasonic cavitation assisted micro-EDM
Ultrasonic vibration was applied to dielectric fluid by a probe-type vibrator to assist micro electrical
discharge machining of deep micro-holes in ceramic materials. Changes of machined hole depth, hole geometry, surface topography, machining stability and tool material deposition under various machining conditions were investigated. Results show that ultrasonic vibration not only induces stirring effect, but also causes cloud cavitation effect which is helpful for removing debris and preventing tool material deposition on machined surface. The machining characteristics are strongly affected by the vibration amplitude, and the best machining performance is obtained when carbon nanofibers are added into the
vibrated dielectric fluid. As test pieces, micro-holes having 10 μm level diameters and high aspect ratios
(420) were successfully fabricated on reaction-bonded silicon carbide in a few minutes. The hybrid EDM
process combining ultrasonic cavitation and carbon nanofiber addition is demonstrated to be useful for
fabricating microstructures on hard brittle ceramic materials
Carbon nanofiber assisted micro electro discharge machining of reaction-bonded silicon carbide
Carbon nanofiber assisted micro electro discharge machining was proposed and experiments were performed on reaction-bonded silicon carbide. The changes in electro discharging behavior, material removal rate, electrode wear ratio, electrode geometry, spark gap, surface finish, surface topography and surface damage with carbon nanofiber concentration were examined. It has been found that the addition of carbon nanofiber not only improves the electro discharge frequency, material removal rate, discharge
gap, but also reduces the electrode wear and electrode tip concavity. Bidirectional material migrations between the electrode and the workpiece surface were detected, and the migration behavior was strongly suppressed by carbon nanofiber addition. Adhesion of carbon nanofibers to the workpiece surface occurs, which contributes to the improvement of electro discharge machinability. These findings provide possibility for high-efficiency precision manufacturing of microstructures on ultra-hard ceramic materials
Effect of Different Dielectric Fluids on Micro EDM of Low Conductivity Ceramic Material RB-SiC
The machining characteristics of reaction bonded silicon carbide (RB-SiC) in micro electrical discharge machining process were studied by using EDM oil, deionized water, and graphite fiber mixed EDM oil as the dielectric fluids. The process performances were measured in terms of material removal rate, surface roughness and surface topography. The effect of deionized water on SUS 304 also was tried and compared with that on RB-SiC. It was found that when graphite fiber mixed EDM oil was used, higher material removal rate, better surface finish and smoother surface
topography were obtained compared to that pure EDM oil and deionized water on RB-SiC. Deionized water could produce better form accuracy, however, electrolytic corrosion occurred and small pits were formed around the machining area of RB-SiC. In contrast, electrolytic corrosion was
insignificant for SUS 304
The mold cost estimation calculator for plastic injection mold manufacturing
This paper presents a research about the
software system to calculate cost estimation in plastic
injection mould manufacturing which is named as
mold cost estimation calculator (MCEC). The
objectives for MCEC is to optimize the cost
estimation problems in plastic injection mould,
assists industrial practitioner in estimating budget
for manufacturing and assists for teaching purposes.
There are three target users for this project that is
industrial practitioner, lecturers and students. MCEC
is developed using JavaScript programming
language which each embedding of JavaScript within
a particular environment provides the means to
interact with that environment. All users may use this
software easily even those who are not expert in
injection molding because this software are user
friendly
Surface Modification Of Tungsten Carbide Cobalt By Electrical Discharge Coating With Quarry Dust Powder: An Optimisation Study
In this paper, quarry dust was reused as a coating material on tungsten carbide cobalt (WC-Co) via electrical discharge coating (EDC). Before the EDC process, the quarry dust was mixed well with low smell kerosene oil and surfactant Span 85 to produce a new formulation of dielectric fluid. Response surface methodology was used to investigate the effect of EDC parameters, namely peak current (Ip, 3-5 A) and pulse on time (Ton, 100-300 μs) on the characteristics of the coating surface, including its Vickers micro-hardness, surface roughness and coating layer thickness. Results showed that an increment in Ip and Ton increased the Vickers micro-hardness and coating layer thickness yet decreased the surface finish. The optimum parameters for achieving a hard surface, thick coating layer and low surface roughness are Ip = 4 A and Ton = 341 μs. The established RSM model was in reasonable agreement with the experimental outcomes, and these findings could be useful in the cutting tools, moulds and dies industries for surface modification purposes
Experimental investigation on material migration phenomena in micro-EDM of reaction-bonded silicon carbide
Material migration between tool electrode and workpiece material in micro electrical discharge machining of reaction-bonded silicon carbide was experimentally investigated. The microstructural changes of workpiece and tungsten tool electrode were examined using scanning electron microscopy, cross sectional transmission electron microscopy and energy dispersive X-ray under various voltage, capacitance and carbon nanofibre concentration in the dielectric fluid. Results show that tungsten is deposited intensively inside the discharge-induced craters on the RB-SiC surface as amorphous structure forming micro
particles, and on flat surface region as a thin interdiffusion layer of poly-crystalline structure. Deposition of carbon element on tool electrode was detected, indicating possible material migration to the tool electrode from workpiece material, carbon nanofibres and dielectric oil. Material deposition rate was found to
be strongly affected by workpiece surface roughness, voltage and capacitance of the electrical discharge
circuit. Carbon nanofibre addition in the dielectric at a suitable concentration significantly reduced the
material deposition rate
Fabrication of Microstructures on RB-SiC by Ultrasonic Cavitation Assisted Micro-Electrical Discharge Machining
Ultrasonic cavitation assisted micro-electrical discharge
machining was used to fabricate microstructures
on reaction-bonded silicon carbide. To aid the
removal of debris from the machining gap and to obtain
a good surface finish, carbon nanofibers were
added into the dielectric fluid. The suspension of carbon
nanofibers in the dielectric fluid and the cavitation
bubble effect induced by the vibration of the dielectric
fluid proved to be effective in reducing the deposition
of tool material on the workpiece surface. The tool material
deposition rate was found to be significantly affected
by the vibration amplitude and the distance between
the oscillator and the workpiece. With a hemispherical
electrode and inclined workpiece, high accuracy
micro-dimples could be obtained within a short
time. A nanometer-level surface finish was successfully
obtained on a hard-brittle RB-SiCmoldmaterial