Low speed of rigid numerical control walks along a processing technique of cut of electric spark line

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Development of industry of mould of overview our country is rapid, the mould production value 2005 predicts to amount to 570~600 100 million, to 2010 " 915 " end, mould production value predicts to amount to 100 billion. The development of mould industry basically relies on technical progress, pattern of the large, nicety with technical at present high content, complex, macrobian order grows ceaselessly, the development of these hi-tech moulds, the technology that promoted a mould to machine equipment progresses, low speed of efficient, nicety, numerical control takes a cut of electric spark line machine tool (LSWEDM) , machine tool of figuration of electric spark of rigid numerical control (NCSEDM) , high speed mill (HSM) wait for moulds of a lot of new and high technology to machine equipment emerge as the times require, and the respect is machined in punch model, develop a school of one's own of LSWEDM it may be said. LSWEDM is in quite long period of time, because its machine the exterior quality problem after, affected the life of the mould, reason did not serve as the method that machines finally all the time. In last few years, because LSWEDM solved problem of treatment surface quality, and as a result of it a series of the technology progresses, make LSWEDM had qualitative flight, its machine function exceedingly goodly, still cannot find which kind of processing technique to be able to compete to it at present. The development of model of punch of nicety, efficient, macrobian life promoted LSWEDM technology the treatment that ascensive LSWEDM basically uses at model of punch of nicety, efficient, macrobian life is made. Mark punch model is advanced horizontal is multitask class receives a standard, this kind of mould has a structure complex, production difficulty big, precision efficiency of long, production reachs tall, life high material of bad news specific power consumption is low a series of characteristics, have in these moulds have representatively: The electric machinery core of Electromechanical unifinication is automatic a powerful person piece hard alloy multitask class receives a standard, its precision amounts to 2 μ M, step pitch precision amounts to 3 μ M, section precision 1 μ M, double circumgyrate precision 1 ' , ra0 of exterior surface roughness.

10~0.

40 μ M. Have automatic punch, a powerful person piece, twist groove, in group, the function such as circumgyrate, mould life is amounted to 1.

0 above; The air conditioning of nicety, efficient, macrobian life implement wing piece multitask class receives a standard, its precision amounts to 2 μ M, working face of concave and convex model is close 1000 place, strong reduce gap for 0.

Of 01mm have 300 much place, with the type but crossing-over, mould life amounts to above 200 million times; The colour of figuration is in charge of tall difficulty electron gun spare parts, the 25 labour end G5 hard alloy class receives a standard, its precision amounts to 2 μ M, strong make 0.

245mm does not have magnetism stainless steel thickly, 5 μ of goods precision ± M, mould life 30 million above; Integrated circuit frame of Gao Shuiping 32 labour class receives a standard, its precision amounts to 2 μ M, the pattern is strong fast amount to 350~500 second / cent, life 30 million above; The mobile phone connector of own innovation 50 labour class receives a standard, its precision amounts to 2 μ M, step pitch precision 3 μ M, strong fast 400 / cent above, mould life 200 million; Still be like digital camera to play reed 18 labour class enters multitask of model, car spare parts class receives a standard, receive plug-in unit 46 labour class takes 12 work of housing of model, electrical micro-machine the punch that class takes a model to belong to current level commanding elevation etc, the treatment of these moulds is made, LSWEDM is indispensable crucial equipment, especially the hard alloy of crucial position in pattern of these nicety, efficient, macrobian order Kong Jia is versed in is LSWEDM more " the ground of use force " . The need that machines to get used to moulds of these new and high technology at the same time drove the ceaseless progress of LSWEDM technology again. The new progress of LSWEDM efficient processing technique one, the efficiency of the biggest treatment of LSWEDM of abroad of efficiency of the biggest treatment stays in 300mm2/min to already had old, but there was new breakthrough again recently, our country just begins to achieve 300mm2/min. Efficiency of the biggest treatment is relied on narrow the development of power source of pulse of electric current of value of wide height of arteries and veins, abroad is in narrow below the case with broad arteries and veins, its are the biggest 1200A of ≧ of peak value electric current, electric current of high peak value and other condition cooperate (silk of condition of all sorts of control means, feed flow, compound electrode) , can make efficiency of the biggest treatment achieves 400~500mm2/min. For example, the AGIECUTPROGESS machine tool of Swiss A rare company uses the IPG intelligence power source of digitlization, with Φ 0.

The electrode silk of 33mm, its are the biggest treatment efficiency can amount to 500mm2/min above; The FA-V machine tool of companies of 3 water chestnut electric machinery, use Φ 0.

The electrode silk of 36mm, treatment efficiency also can achieve 500mm2/min; The LQ33W new power supply that company of Japanese sanded Dick develops, on AQ325L machine tool, with Φ 0.

The compound electrode silk of 30mm, treatment efficiency can amount to 400mm2/min to wait a moment. Anyhow, at present efficiency of the biggest treatment is in abroad 400~500mm2/min, had new progress again. But the AGIECUTPROGESS machine tool that at present efficiency of the most valuable the biggest treatment wants to count Swiss A rare company, the E-cut power source that this machine tool develops uses standard electrode silk to be below the circumstance that machines efficiency to achieve 350~500mm2/min, ra can be achieved 0.

8 μ M (see a picture 1) , this kind of efficient rough machining can achieve Ra0.

Level of 8 μ M, of accurate to coming true finally treatment for many times for cut, can save the handling time of about 50% , reduce the filter core of about 40% to use up, the colophony of 40% is used up, the filar material of 60% is used up, have obvious technical economic benefits. Graph 1PROGRESS machine tool is in Ra0.

The efficiency of the biggest treatment when 8 μ M 2, average treatment efficiency is the biggest in efficiency is being machined in accurate punch model, often be hard to apply, main reason is need of efficiency of the biggest treatment uses thick silk (Φ 0.

33~0.

36mm) , and thick silk is hard to realize accurate treatment, accurate treatment can use filament only, for example Φ 0.

10mm. Company of Er of rice of Swiss A strange summer is the efficiency of the biggest treatment of play machine tool, developed machine tool of double silk cut, can undertake electrode silk is exchanged automatically, implementation rough machining uses thick silk, finish machining uses filamentary end, can rise to machine efficiency on average substantially, still can realize accurate treatment. Double silk of the ROBOFIL2050TW of Er of Swiss summer rice, ROBOFIL6050TW machines a machine tool, resolved the contradiction of nicety and efficient treatment, make total handling time shortens greatly, can save the handling time of 30~50% commonly, can save the filament with high price at the same time, reduced finished cost. The system of double silk cut with Swiss strange A has same effect, still have: (1) exchange silk of different diameter electrode automatically to need not change guider; (2) automatic exchange does not have precision loss; (3) wear filar time automatically to have 15 seconds only commonly; (4) the dependability that wears silk 100% wait for a characteristic. 3, in becoming sectional to machine efficiency LSWEDM to machine a process actually in the mould, inevitably meeting encounters different treatment sectional. As the change with sectional treatment, through detecting automatically, machine energy according to sectional metabolic automata, make machine efficiency to maintain groove first and last, it is to raise the significant step that becomes sectional to machine efficiency. For example, the FA series machine tool of 3 water chestnut companies of Japanese used system of treatment report source control, this system is mixed by workpiece ply detector, treatment status detector pulse is energy out-put the partial composition such as controller, in order to get used to the change with sectional treatment, suit the spare parts treatment such as step form, hollow form, light body especially, can prevent fracture of wire effectively, improve treatment efficiency. The example that changes processing technique as this kind of intelligence is shown 2 times like the graph. The biggest energy controls expert system to want to input material of electrode silk diameter and type, workpiece to be able to have optimal treatment automatically only, according to machining the treatment ply that differs in the process automatic increase and decrease machines energy, in order to carry highest treatment efficiency, apply efficiency of system of this kind of expert to be able to rise commonly 30% the left and right sides. Graph the key that the treatment surface quality that 2 have the new breakthrough LSWEDM that controls expert system treatment to compare LSWEDM to machine exterior quality without the biggest energy is influence LSWEDM development, namely LSWEDM whether the crucial technology that enters accurate treatment field directly. Treatment surface quality eliminates exterior surface roughness and geometrical form appearance (dimension precision) outside, still should include 2 fields in LSWEDM: It is the chemistry of LSWEDM treatment surface layer, physics, mechanical function, what basically include organization of surface layer metallographic, surface layer is microscopical hardness, leftover stress and macroscopical wait with microcosmic crackle, namely alleged surface " degenerative layer " ; 2 because LSWEDM uses liquid of water quality job,be, the surface that the electrochemistry reaction that produces below the action of pulse power source forms in workpiece surface " bate layer " , also weigh the surface " degenerative layer " . Of these 2 respects " degenerative layer " life of immediate impact mould and function (wearability, corrosion resistance, fatigue intensity) wait. As the development of LSWEDM, the improvement of exterior quality had new breakthrough, its technology progress is main body is the following now 2 respects. One, when the electric spark of new-style power source that optimizes discharge energy is machined, metallic stuff corrode divides cent to change 2 kinds compatibly to fuse, wide arteries and veins is wide (discharge time is long) easy cause fused discharge treatment, make machine exterior form appearance to become poor, " degenerative layer " add thick, internal stress to increase, easy generation crackle; And when arteries and veins wide small when arriving to be worth certainly, easy become aerification discharge treatment, layer of metamorphism of aerification discharge treatment is very small, internal stress also is reduced, can avoid the generation of exterior crackle, improved exterior quality. Lead to maintain same treatment effect accordingly, in discharge energy same principle falls, adopt compress discharge time and the method that increase I of peak value electric current, this kind optimizes the method of pulse energy, make exterior quality gets very big improvement. If the graph is shown 3 times,optimize discharge energy sketch map. Graph 3 optimize discharge energy sketch map 2, prevent electroanalysis (AE) the exterior quality that pulse power source optimizes discharge energy to be able to improve an aspect only, if appearance of exterior surface roughness, form, internal stress, crackle is waited a moment. Nevertheless LSWEDM uses liquid of water quality job, although use, is " go ionic " water, but still exist a certain quantity of ionic, electrochemistry reaction produces below the action of pulse power source. When workpiece receives positive electrode, below the action of electric field, hydroxyl anion (OH- ) can ceaseless on workpiece deposit, make the material such as tungsten of iron, aluminous, copper, zinc, titanium, carbonization oxidizes, corrode, cause so called " bate layer " . When workpiece of use hard alloy, the bond cobalt in hard alloy becomes ionic condition to dissolve in water, form likewise " bate layer " . The AE pulse power source of development, a series of manufacturing practice proof is the method with the most effective response of electrochemistry of control workpiece surface. AE power source is its are handed in change pulse counterbalance voltage is the pulse power source of 0 (see a picture 4) , because hand in change pulse makes OH- ion is in oscillation condition in working fluid, not incline to reachs electrode silk at workpiece, can prevent the rustily combustion of workpiece surface so, the cobaltic bond of hard alloy also won't prediction of a person's luck in a given year, with optimize discharge energy to cooperate, can make the surface " degenerative layer " control is under 1 μ M, the life of hard alloy mould that such LSWEDM machine can reach the level of mechanical grinding, see a picture 4. Weaveform of graph 4AE power source and LSWEDM anode sex machine degenerative layer to distributing to be machined with model of IC down-lead frame as example, power source of traditional to using LSWEDM pulse is being machined, with LSWEDM tradition the oiled type of pulse power source is machined, the AE power source that uses LSWEDM is going in ionic water treatment and the mould life that machine with mechanical grinding undertake checking comparative, result proof, the life of hard alloy mould that AE power source machines already reached the level of mechanical grinding, be close to wear limit place to return excel machinery grinding. On LSWEDM treatment precision new chance to extricateoneself from an awkward position one, the treatment precision that structure of burgeoning and accurate machine tool raises LSWEDM is systematic project, wait besides engineering technology of all sorts of pulse power source, control systems, working fluid system, treatment beyond, structure of accurate machine tool is the foundation of accurate treatment. Structure of typical accurate machine tool should count the AGIECUTVERTEX machine tool of Swiss A rare company. This machine tool was used similar 3 coordinate are measured sucked of machine at 3 o'clock brace up the structure that prop up, the motion of each axis does not affect the precision of other axis; Each movement rod uses linear grating feet and coder double measure feedback servo, its position detects control precision is achieved 0.

1 μ M. All pyrotoxin on the machine tool installed temperature sensor, have circular air cooling, water-cooling or hot segregation structure, removed the temperature rise effect to machine tool precision. Machine tool not only thermal capacity is large, and tigidity is good, because the change of this load is right influence of machine tool precision is dinky. The allow of precision of average fixed position of axis of the X of the machine tool, Y, U, V differs Pa for 0.

8 μ M, repeat allow of fixed position precision on average to differ Ps for 0.

4 μ M. This machine tool has double silk to exchange a system automatically, silk of the finest electrode is Φ 0.

02mm, can undertake accurate and automatic wear silk, the diameter of the aperture that wear silk needs to compare electrode silk only big 5 μ M can. To satisfy Φ 0.

The essence of 02mm electrode silk cuts treatment closely, detector of two electrode silk was installed on the machine tool in order to detect moving condition of silk, the tension with controlling silk accurately, absorb vibration and isolation outside interference to wait, the deflection that the machine tool still can issue guider on self-correcting measures loss of fluctuation of silk of the electrode in compensate treatment automatically to differ, and the verticality error that causes to fluid. This machine tool still rolled out taper cut new function, raise taper cut precision effectively to wait a moment. 2, for many times cut machines craft LSWEDM of thick, finish machining for many times cut treatment is not new technology, but it is the vital engineering technology that implements accurate treatment, can reflect overall overall level. For many times the technology index that cut machines finally, the design that reflected accurate machine tool makes technology, numerical control technology, intelligence change system of fluid of technology of technology, pulse power source, accurate drive and control technology, job to wait a moment. But fall in the condition that obtains same treatment quality of late, for many times the frequency of cut decreases greatly. For example, original cut frequency needs 7~9 second, achieve same treatment quality to need 3~4 only now second, saved a large number of time, this basically relies on pulse power source the technology of efficient rough machining progresses, the place before be like namely is narrated, first time is efficient cut (350~500mm2/min) , can achieve Ra0.

8 μ M, so good surface surface roughness, natural meeting reduces cut number for many times, and the level that can reach accurate treatment. The main index that machines on behalf of LSWEDM nicety is treatment precision and exterior surface roughness, to machining precision, domestic and international the expressive means of each manufacturer each are not identical. For example, the outline precision Tkm that Swiss A rare company uses work () will convey, and foreign other company looks from offerred data, be conveyed with the precision of the specific treatment workpiece of different figure and dimension, our country examines by the requirement of national level treatment precision. Although do not have uniform standard, but the level that machines to show current LSWEDM nicety, in order to have representative Swiss A rare company machine tool is exemple (see a table 1) . Express nicety of LSWEDM of rare company of 1 Switzerland A to machine horizontal above specification, LSWEDM with perfect exterior quality (without degenerative layer) , treatment precision of Gao Shuiping, can develop tool set completely to undertake final nicety is machined to of all kinds nicety, need not after waiting, manual polish working procedure, because this workpiece surface won't have any polishing loss. 3, cut of filament of filament cut processing technique belongs to accurate processing technique. The diameter of filament cut silk in the past is Φ 0.

05mm, already achieved Φ now 0.

02mm. In filament cut treatment it is very important to wear filar function automatically, already can be opposite at present Φ 0.

The filament of 02mm undertakes wearing silk automatically. Undertake on a machine tool thick, filament exchanges treatment automatically, it is the clear advantage of LSWEDM of double silk system. In be machined to tool set, filament is used at inside clear part treatment, with Φ 0.

The filament of 02mm, can machine a radius of an internal angle to be 15 μ M inside clear part. In IC industry, the filament cut of model of integrated circuit frame is machined, have its fundamental application value. At present foot of integrated circuit down-lead already amounted to 100 above, the architrave span of its down-lead is very small, mould material is hard alloy commonly, suit filament treatment so. Other receives motor of plug-in unit, miniature like miniature the mould treatment such as gear of core, miniature. Precision respect is machined in LSWEDM, besides afore-mentioned content, still be like taper to machine precision, corner to machine precision, flatness to wait. The domestic field of LSWEDM of state of affairs of development of LSWEDM home market appeared to develop a tendency newly in last few years, crop and sales volume show 30~40% speed growth. The LSWEDM crop of our country made an appointment with 150 only 2001 / year, to 2004 a few years short in, crop amounts to 1800 / year (the measure that includes the enterprise such as Japan, Switzerland and Taiwan to be produced in the mainland) , to mainland LSWEDM crop already amounted to 2400 about 2005 / year, grew about 35% than 2004. Predict " 915 " evening crop can amount to 6000~8000 stage / year, production value makes an appointment with 35~40 100 million RMBs / year. The main reason that LSWEDM field grows quickly has the following sides: (1) LSWEDM basically applies at the domain such as mould industry, aerospace, war industry. Mould production value grows every year with the speed of 20% , the mould made an enterprise already had many 20 thousand 2005. Wait for direction to develop to nicety, complex, macrobian life as the mould, each mould makes the treatment facilities of the enterprise change in succession, and LSWEDM is the high-grade equipment with mould essential industry. The development of career of our country aerospace is be obvious to all, add other the development of domain of a few application, promoted the rapid development of LSWEDM field. (2) surface of past LSWEDM treatment arises " degenerative layer " , affect the component life of mould and other place treatment. As technical progress, the exterior quality that LSWEDM machines and precision already can satisfy the requirement of pattern of nicety, complex, macrobian order, can regard exact pattern as the main measure that machines finally, "Grind in order to cut era " the trend is clearer and clearer, this also promoted the field development of LSWEDM. (3) the treatment performance with superior LSWEDM, at present other treatment method still cannot compete to it, and the treatment craft level of LSWEDM and the economy that run already treatment of excel machinery grinding. (4) the WEDM cent of our country reachs HSWEDM for LSWEDM (high speed takes a machine tool of cut of electric spark line) two kinds big, and HSWEDM is cheap product, but belong to same treatment craft with LSWEDM, use a field together. As industry of our country mould and other the technology of each domain progresses, HSWEDM cannot get used to the need that the technology admits gradually, and as LSWEDM performance/price ratio rise, at present HSWEDM makes an appointment with 40 thousand / year big field can be squashed certainly, regular meeting vacates field of one part gives LSWEDM, also can see LSWEDM from which the development space henceforth. Author: Suzhou report machines Chen Dezhong of machine tool institute CNC Milling CNC Machining