How to raise modular antrum to machine speed

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  • source:TRIANA CNC Machining
The improvement of production technology of the precision of newest development along with of EDM craft and technology, automation and miniature mould together, can bring unexpected results to domestic mould manufacturing industry. Speed is not a solution increasing drive rate is an idea that raises EDM to drive modular rate, use this method to be able to reduce the time of nonproductive promotion movement, but increase rate can small electrode of bureau be confined to and very deep model antrum. Additional, if exceed fixed rate, of electrode wearing away is quite considerable, and axis fast huge stress will be caused too high in mechanical system, make the machine tool pays higher price, shorten working life. Accordingly, if think to raise treatment speed generally to be able to promote a movement to come true through accelerating only, that is wrong. Accelerate an axis to have a kind of auxiliary effect only to machining, improve width of controller of pulse generator, process, clearance to adjust from a flank with the complex relation between mechanical system. Treatment of EDM flying a model needs intelligence to rinse. It is OK that latent capacity depends on rinsing you the certain clearance that becomes imagination of EDM treatment process between the data that processes through discharge and the material that are removed by corrode achieves a balance. Once this kind of balance is nonexistent, you rinse treatment area can infructuously (to treatment the process brings time loss and additional instability) , the particle that perhaps distributes land to eliminate to go out from inside this clearance to cannot be being filled undertakes a certain number of second " discharge " (see a picture 1) . Before material can be smoked to leave this gap, must divide it from the corrode on workpiece come down. How can you just achieve bigger corrode divide so lead? Like optimizing a problem with everything, the latent capacity of the biggest gain depends on the place of the least efficiency. Discharge is machining efficiency theoreticly is about 25% . In addition still a few elements make this one efficiency is reduced further (cross what programmed control makes ideal of problem, blame to rinse state, clearance for example too small) , because this is in,must consider 10% the following efficiency actually. Corrode decides except rate and exterior quality time needs to be below EDM circumstance, our target always optimizes the corrode that discharge machines to divide property on one hand, it is the exterior quality requirement that obtains work on the other hand. The final surface roughness with after workpiece passes treatment, often show certain and form precision. Still need two requirements additionally: (The heat of 1) workpiece surface affects an area as far as possible small; (2) electrode wears away as far as possible small. These limit requirements produce the conclusive effect since cost to handling time and workpiece. It is to use actually a series of craft parameter, because arrive from rough machining final precision work, pulse energy is reduced gradually, until achieve necessary craft result. "Slow work yields fine products " truth again applicable (see a picture 2) . Physical process explains a solution tends the way of good position is meant by curve of feature of arrowhead direction shift, its intention is the clearance width that accelerate EDM rate and keeps identical, surface roughness and electrode wear away. Regretful is, so far, if increase the discharge energy of EDM pulse, can increase surface roughness and clearance breadth only, the speed gain that scores in rough machining process so was offsetted by longer finish machining again. Should return EDM foundation theory afresh only -- bring about scintilla to fashion the physical process that eliminates with metallic corrode, can discover a way that leads to a solution. In discharge process, you can identify 3 main physics level that produce one after another: (1) is built; (2) discharge; (3) disappears level. The first phase forms discharge channel gradually. After electric current passes working medium, center to the outside face of discharge passageway entirely almost, and positive pole issues local vaporization in electronic bombard, electrode wears away to basically happen in this phase. Every pulse, no matter whether facilitate thoroughly,metallic corrode is divided, can cause microcosmic wear away. In discharge phase, provides electric energy basically causes workpiece to the material that go up is fused or evaporate. Disappear level begins from dump, plasma passageway breaks down, and local the material that evaporate and melts by eduction. When to interrupt pulse to be in discharge process, the hollow of crater shape is formed on workpiece. About the basic research proof of discharge, the hollow on workpiece stops to increase from a certain hour, because the balance was achieved between supply energy and loss energy,this is, and the balance also was achieved between the quantity of heat that goes up to workpiece and dielectric in the energy that maintains plasma and loss. As to cave growth asymptote, can undertake according to scintilla voltage and electric current real time is recorded. But, cave it why growth asymptote is like here is important why growth asymptote is like here? Because it expresses to interrupt the right moment of pulse, the target diameter that should cave only and must surface roughness was achieved, not was necessary to let pulse continue to continue, you can begin another pulse instantly. The time that pulse achieves this one status also is not constant, because discharge scintilla achieves the rate of certain root diameter,depend on the local geometry feature of the microcosmic state of clearance and scintilla discharge area. Chan Ping the first measure, the discharge number that can optimize unit time increases corrode to eliminate rate. When if observe discharge charge now,increase electric current disappear level, be broken down by plasma passageway and can seeing from workpiece corrode divides a metal is caused. The metallic stuff vaporization of the voltage light overheat that dump causes is ejective. Plasma passageway has very high temperature and pressure, its break down the corrode of gradient change data eliminates rate. Energy disappears more suddenly, "Crater " ejective metal is more. To enhance this one effect, use a special tricks of the trade: Before interrupting pulse, the instant increases electric current. The thought that increases pulse electric current is not achieve newly, the place of innovation depends on dominating the time that increases electric current. Pulse electric current increases with surface roughness, wear away or clearance width is done not have any causal, but increase purify to lead really (see a picture 3) . In addition, as the accretion that unit pulse purify leads, the pulse amount that processes a need decreases, reduce thereby wear away. Workpiece metal corrode is divided lead strategy of double new treatment (asymptote is explored, electric current increases and pulse is interrupted) the theme that is a patent application and apply to system of new EDM flying a model. Its agree with academic reflex action as a result, be in especially assure reasonable below the circumstance that rinses a condition (if workpiece passes prior operation) , to such treatment task, corrode broke up one time except rate. In the graph 4, graph 5 with the graph in the application of 6, metallic purify rate increases 25~40% . Pulse generator makes in the generator that there was breathtaking improvement to innovate on function productivity increases nearly 30% , nevertheless, to current more and more course HSM beforehand for the mould of milling, productivity can increase 100% . This includes all rough machining that use copper and black lead electrode and precision work. Use rinse a condition reasonably and undertake to workpiece beforehand milling, its advantage is particularly remarkable. The effect of these be convinced making a person explains, raising EDM to drive modular speed and efficiency is likely, and the latent capacity that the technology improves still is quite considerable. CNC Milling