The technology of cut of electric spark line that is based on complex job fluid studies (on)

Summary: Extremely the angle of discharge mechanism was analysed at present block up high speed takes a cut of electric spark line (the catharsis sex problem that WEDM-HS) technology index and the prime cause that produce stripe of exterior black and white across are working medium, after the experiment proves WEDM-HS is using the complex job liquid with catharsis good sex as a result of extremely improve and achieve cut craft target of cooling condition rise substantially, current cut rate has exceeded 200mm2/min, bear from the discharge energy of silk of discharge clearance, electrode the respect such as ability and carry silk speed undertook WEDM-HS more efficient the feasibility research of cut, analysed be based on electric spark of complex job fluid the direction of 4 kinds of development of line cut technology. Keyword: WEDM-HS discharge mechanism is compound efficient cut develops working fluid index of line cut technology basically includes directional electric spark the project such as cut efficiency, precision and exterior integrality, at present in cut efficiency respect low speed takes a cut of electric spark line (WEDM-LS) highest efficiency can have amounted to cut 500m M²/min, intermediate cut with practical WEDM-LS is the most efficient control for 150m M²/min [1] , and our country's particular high speed takes a cut of electric spark line (WEDMHS) go up oneself practical cut is the most efficient since 80 time of century still wander in 60 ～ 80 Mm²/min, other technology index also the discrepancy with WEDM-LS is very far, difference is very apparent. The problem that how the technology of cut of electric spark line of our country develops already made the central point that pays close attention to inside course of study. One, the main problem that at present WEDM-HS exists and the main problem that analyse WEDM-HS technology existence are cut efficiency on the low side above all, bring such as for many times from this cut technology is practical the sense is not great, bring about cut precision and exterior quality to cannot be improved substantially wait for a series of problems; Next cut surface is put in stripe of black and white across also is surface of influence WEDM-HS cut a of macroscopical quality serious problem. The premise that stability of cut of electric spark line machines must assure ceaseless in cut process silk above all. The machine rate of fracture of wire is main increase as what put electric energy and cut ply and increase, closely related the ionic bombard that gets inside discharge passageway with electrode silk namely, cooling condition and retention period. The efficiency of cut and exterior surface roughness also with extremely refrigeration and disappear ionization regain insulation position about. Use generally at present contain the emulsion that 5 ％ control mechanical oil to regard the job as medium, two phenomena appear after cut ends: Above all the test specimen that cut ends is conglutinate on matrix, general need exerts oneself to do sth. even knock just can make its and matrix are broken away from; Next the test specimen surface that cut ends is being enclothed gooey is farinose corrode removes product even, need to use kerosene ability scrub clean. This basically is the high temperature that accompanying above of C of the 10000 ° inside discharge passageway, emulsion will be decomposed generate compound of many the high polymer that contain carbon to divide child reaction to generate colloid shape or be caused by of grain form substance with metallic corrode. If the graph is shown 1 times, these corporeal conglutinate are being cut seam inside, basically cutting seam export position to pile up, affect electric corrode result badly eliminate, held back new job medium to enter cut seam. As a result of polar a working medium that unwarrantable existence updates ceaselessly, the continuance that discharges immediate impact normally is to be in even mix undertake discharging inside the space that has many colloid material and produce electric arc discharge, make workpiece and electrode silk face cannot get seasonable refrigeration thereby, insulation condition is abnormal, cause normal discharge scale to reduce, cut speed is reduced, workpiece surface burn, inverting stripe makes badly machine quality aggravation, injure the durability of electrode silk at the same time, serious when cause burn silk. Because this chooses emulsion to regard the job as medium to extremely ionization of the improvement of cooling condition inside the passageway, disappear restores insulation condition to all have bigger effect, production of ropy even state can rise to electrode silk instead " heat preservation " action, and workpiece heals tall, carry silk speed heals slow, electrode silk is machining area retention period to will grow more, the machine rate of fracture of wire can increase naturally. And emulsion is in extremely colloid or grain shape matter will be being resolved when discharge is a kind of inevitable phenomenon, so use emulsion meets what restrict cut technology index greatly rise necessarily. Extremely cooling condition is exasperate the treatment condition that its most immediate result will cause WEDM-HS to must exchange ceaseless silk with very conservative discharge energy. When at present use emulsion is working medium, electric current of general and average cut is in 3A less than, it is impossible to achieve taller cut efficiency that in this kind discharge energy condition falls. Graph 1 use emulsion cuts the premise that seams condition sketch map to regard the job as medium in use emulsion accordingly to fall before to power source of high frequency pulse improve and of carry silk system perfect include to increase the measure such as carry silk speed to all be opposite of cut efficiency raise effects very small, this is at present WEDM-HS cut efficiency wanders for a long time in very low-level prime cause. Will bring about corrode as a result of the use of emulsion in addition cutting except child seam export position to pile up, in existence a large number of corrode remove product and the discharge that refrigeration produces below inadequate condition will bring about carbon black to material is stuck in workpiece surface instead and may cause workpiece surface burn, produce stripe of black and white across (graph 2) , accordingly the stripe of black and white across of cut surface appears in the exit of silk of electrode silk carry commonly, color is by workpiece interior becomes deep gradually outwards, and the action as a result of gravity, when fluctuation gush fluid is basic and symmetrical, the eduction capacity that electrode silk leaves to carry product is removed as a result of corrode when silk up oneself compares electrode silk from above to below loses when carry silk, the streak of workpiece upside will be deeper than lower stripe color and long (like the graph 3 show) , the workpiece surface quality that is in in stripe wants under be in without stripe. The stripe of the emulsion cut surface with catharsis poorer ability can be jumped over apparent. Because stripe of black and white across arises when this WEDMHS cut,its primary reason remains the catharsis sex problem of working medium. At present people can pass the concentration that increases emulsion only, add sex of a few catharsis material and increase improvement will cut between arteries and veins seam the refrigeration inside and catharsis condition, the color of abate stripe. Graph after 2 use emulsion stripe cut surface pursues 3 cut face produces sketch map of reason of stripe of black and white across to must choose the blame oil that does not make compound of ropy shape high polymer as far as possible in discharge process or fluid of little oily job accordingly, assure to cut thereby seam inside of working medium achieve the goal that improves discharge position with ability of going from place to place equably. The experiment proves, should choose catharsis sex good and oily scale is strict pilot is compound after working fluid (the JR1A of series of the embellish that be like beautiful, JR3A) , cut ending workpiece falls automatically, cut surface has substance of a filmy form only, the surface does not have inverting stripe, proof its extremely present the even refrigeration that the graph shows 4 times state. Here cooling condition falls, can use bigger discharge energy (average cut electric current 6 - 7A) undertakes stabilizing cut for a long time, cut efficiency already exceeded 200m M ²/min. Graph complex job fluid cuts profit of 4 use beautiful seam condition sketch map to pursue 5, 6 to use emulsion and JR1A respectively complex job fluid is in the figure of appearance of treatment surface form that same treatment wins below the condition. Graph appearance of form of surface of cut of 5 use emulsion pursues the burr with the many existence of emulsion cut surface that appearance of form of surface of cut of complex job fluid can see catharsis ability is poorer from inside the graph mixes embellish of 6 use beautiful burn trace, existence is more at the same time was not taken away in time and remain the metallic droplet in cut surface; And the surface of cut of complex job fluid with catharsis stronger capability compares smooth, level, the metallic droplet of exterior remaining is less also. Observe from collection typical discharge weaveform, poorer to catharsis ability emulsion, as a result of extremely the colloid that is full of electric conduction or grain material, the discharge weaveform that collects does not have puncture delay time basically, more proportional pulse is in initiative when present short circuit position namely, and in discharge process voltage beats bigger (graph 7) , condition of the clearance in showing discharge process is not stable; And using condition of complex job fluid to fall (graph 8) , the typical feature that puts electric wave form to present a clearance to discharge - phenomenon of discharge puncture delay time, and catharsis condition has healed (be like the) when cut ply is inferior, the scale of discharge puncture delay time heals tall, the wave motion of spark voltage is lesser also, the area between demonstrative pole is put in evener working medium to reflect the feature that gives clearance discharge thereby. Graph weaveform of discharge of model of 7 use emulsion pursues embellish of 8 use beautiful is compound after weaveform of discharge of working fluid model is using complex job liquid, because cut,seam inside can get even refrigeration, cut seam inside working medium is in of electrode silk drive next OK and perforative flow, because this inverting stripe can be accomplished very weak do not have completely even, graph 9 to use compound model working fluid JR1A is in with the graph 2 same cut parameter conditions fall obtain without stripe cut surface. Graph the 9 embellish that use beautiful are compound of working fluid cut without stripe surface CNC Milling