Raise mould EDM to machine speed

The development of EDM craft and the mould treatment industry that its reach the progress of respect of miniature mould processing technique to be home in precision, automation made enormous contribution. Graph 1: Latent capacity depends on rinsing. Sheet relies on to raise what speed has been not to solve method to raise drive rate is a kind of solution that improves mould EDM to machine speed. Use this kind of method, the nonproductive time that promotes sport decreased; Nevertheless, the advantage on speed is mixed however by small electrode deep model the limitation of antrum. Additional, it is considerable that when speed of prep above some electrode wears away, and the great loss that very high axial rate can cause machine, this makes a machine tool more valuable and shorten its service life. Accordingly, those who believe to pass frequent promotion campaign to achieve treatment rate only is comprehensive raise be a mistake. Axial moves quickly the contribution to machining a process is merely to including generator, course width of clearance of control, discharge adjusts and the link such as machine is collective a complement of action. Mould EDM treatment asks to erode intelligence is changed. Graph 2: Purify rate and exterior quality depend on what need time. It is OK that latent capacity depends on rinsing you the balance has between the material that craft of EDM of have visions of wants the is processed by EDM data in discharge clearance and eduction. If this kind of balance is nonexistent, you are in result or to rinse treatment area needlessly (include to waste the instability with time and additional craft) , or you undertake EDM several times to identical grain, make its cannot effectively from the purify in clearance (see a picture one) . In material from inside discharge clearance before eduction, you must depart it from workpiece. How can you just achieve higher purify rate? In all circumstances that optimize a problem, the greatest potential depends on the place of efficiency lowest. What workpiece serves as cathode is extremely odd the efficiency of discharge is theoretic it is about 25% . Additional, some elements can make efficiency lower (for example: The process controls a problem, unfavorable erodes operating mode, discharge clearance width is too small) , actually so you must be met considering efficiency under 10% . Graph 3: Searched the rate of correct hour purify that increases electric current and exterior quality to decide what to need time to be in EDM application, the purify that the target always wants to optimize treatment on one hand leads index, and should obtain on the other hand by the exterior quality of treatment workpiece. When treatment, workpiece shows affirmatory final surface surface roughness and affirmatory form easily precision. Additional, requirement two conditions: (1) the heat of workpiece surface affects area as far as possible small, (2) electrode wears away as far as possible small. These attrib border conditions decided the handling time that workpiece produces and cost. In applying actually, because begin to end to finish machining from rough machining, use successive craft parameter so, pulse energy drop off till the craft result that achieves place to need. The order of nature that applies again: You can get medium quality quickly, but only slower ability acquires high quality (see a picture 2) . Physical processing is a kind of solution adjacent and good position means characteristic curve to move to arrowhead direction. That means EDM faster, and surface roughness of discharge clearance width, surface and wear extent keep changeless. Up-to-date, if the discharge capabilities of EDM pulse adds, the rate that you also change to differ and bring about rough machining for exterior surface roughness rises however because finish machining time is longer and lose an advantage to feel regretful. If you return to the main point of EDM theory, you will find a solution -- the formation that physical processing brings about scintilla and metallic purify. In discharge process, you can make out 3 successive main physics phase: (1) establish level (2) discharge phase (3) decline level. Discharge passageway is built in the first phase. After electric current crosses working medium almost overall effect the exterior area at discharge passageway, and positive pole gets electronic bombard and the part evaporates. Electrode wears away to basically happen here. No matter whether make very large contribution to material purify, every pulse is caused microcosmic wear away. In discharge phase, supply electric energy basically causes workpiece to the material that go up fuses or evaporate. Supply when power source after shutting, begin to enter decline phase. Plasma passageway ebbs and the part evaporates, partial liquid material by ejective. Nextpage pursues 4: Do not use new EDM technology, the chip electrode that contains chamfer of end of a swallow (15 X 1 Mm) treatment deepness needs EDM handling time 70 minutes for 20 Mm. Use new EDM technology to need 50 minutes, mean wear away in width of clearance of exterior surface roughness, discharge and electrode (wear extent 0.

2 Mm, only movable type is cleaned) constant the rate below the condition rises 40% . When to interrupt pulse to be in discharge process, indentation is formed on workpiece. The basic research of concerned discharge has made clear: Begin from sometime, the growth of the indentation on workpiece backwater. This is the balance was formed between the energy because of supply energy and dissipation, the energy that the energy of dissipation runs plasma with Yu Wei namely and send out the quantity of heat to workpiece and dielectric. This kind of asymptote that indentation grows can pass scintilla voltage and electric current to get real time is recorded. But, why is the asymptote that indentation grows so important? Because this is,interrupt the correct hour of pulse. If the target radius of indentation and need exterior surface roughness had been obtained, let pulse last longer it is needless. You can begin next pulse immediately. The time that pulse arrives at this state institute to need also is not invariable, because discharge achieves the rate of diameter of some scintilla foundation,depend on the local appearance in the microcosmic situation in discharge clearance and scintilla discharge area. Had this kind of first-hand data that measures alone, your aux will be able to optimizes the discharge frequency of unit time to raise purify rate. When to if you observe the decline level of charge now,increase electric current, you will see electric corrode production is caused by plasma passageway decline. Drop suddenly by the pressure that shuts power source to spark brought about material exceeding heat evaporate and ejective. Plasma passageway has very high temperature and pressure. The gradient that its ebb affects the purify of material. Energy disappears more suddenly, indentation material will be so ejective that indentation material had jumped over. To improve this kind of result, use a kind of special key: Before pulse is interrupted, increase electric current momently. The think of a way that increases pulse electric current actually is not new, the time that the place of innovation depends on wanting seasonable definition to add gist to happen when this kind of electric current is nodded. Increase pulse electric current to be opposite exterior surface roughness, wear away or discharge clearance width is nonexistent causal, but raise purify to lead really (see a picture 3) . Additional, increase as the purify rate of every pulse, need fewer pulse to machining you, and wear away to also decrease accordingly. Graph 5: To the globose electrode of 20 Mm of a diameter, the deepness 20 Mm that EDM machines and Ra = 1 of final surface surface roughness.

M of 6 μ . Because use new EDM technology, machine speed rise to be about 25% . The purify rate on the spare parts is double this kind of new treatment strategy (asymptote detects, electric current is increased and pulse is interrupted) the theme that is the patent application that processes a system one kind with mould of Yu Jixin EDM. Result and theoretical value photograph are consistent, should rinse goodly especially have when assuring (for example, the workpiece of prior operation) . Machine the task to these, purify rate is already double. In the graph 4, 5 with the applied circumstance of 6, purify leads rise from 25% rise to 40% . Graph 6: Chip electrode, machine deepness 40mm. The challenge depends on wanting to obtain optimal and consistent surface surface roughness. Chip to this kind electrode (20 X 1 X 40 Mm, taper 1 ° , the deviation below dimension 0.

5 Mm, EDM3 black lead, only movable type is cleaned) , machine surface roughness of deepness 40mm, surface, if do not use new EDM technology to need 230 minutes to just can be finished; But, the handling time after using this kind of new EDM technology is 170 minutes, rate rises 36% , electrode wear extent 0.

3 Mm. Exterior quality is wonderful. The increases improvement generator opposite yield significantly contribution that generator brings function is about 30% ; But, pass high speed treatment to be finished in coordination to be like what increase increasingly today beforehand mill mould can be as high as 100% . Here thinks all rough machining and finish machining use cupreous electrode and black lead electrode. Have rinse goodly condition and beforehand the dominant position when the workpiece of mill is particularly large. These convincing results explained the rate that should raise mould EDM to machine and productivity are feasible, and the latent capacity that improves this kind of technology is remained considerable. More information contacts El of company of Swiss Agie Ltd please.

Ing.

Dipl.

Sectional Marco Boccadoro, phone + 41 91 806 9584 or E-mail: Marco.

Boccadoro@agie.

Ch. The picture expresses gratitude Agie Ltd.

An Increase In Productivity Of Approximately 30 Percent, and Up To 100 Percent With Pre-milled Molds, is Possible With New EDM Technology.

Developments In The EDM Process And Its Technology Along With Improvements In Accuracy, automation And Micro-moldmaking Technology Can Pay Enormous Pidends To The Domestic Moldmaking Industry.

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