Add hot cutting technology and its development and application

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As the progress of science and technology and the rapid progress that industry produces, taller and taller to the requirement of structural material function, introduced a lot of high strenth, tall hardness and high temperature resistant new material. These material add man-hour cutting muscularity, temperature rise is fast, cutting tool wears away serious, treatment surface quality is poor, treatment precision also rises hard. The most outstanding issue is treatment difficulty, some material cannot be machined almost. Adding hot cutting is one of the most effective methods in overcoming the non-traditional machining technique that processes difficult question, it is embarrassed the cutting that processes data machines open up a new approach, already used Yu Hangyu, enginery, mechanical, car, chemical industry, microelectronics and medical treatment industry. Current, add hot cutting technology to reach its development is creating technical field very get attention. 1 add hot cutting technology and current situation to add what cut a technology eagerly to appear reach development to pursue 1 heat the fuel factor that cutting sketch map adds hot cutting to machined a method to use high-energy heat source ably, to be being made heat by cutting material, make bate of be heated of material cutting position, hardness, intensity drops, easy generation plasticity is out of shape (graph 1) . Because heat,the shear strength of material of the workpiece after temperature rise drops, make cutting force and power are used up reduce, vibration is reduced, can raise metallic excision rate consequently, improvement machines exterior surface roughness. The concern with exist particular because of cutting tool durability and workpiece temperature again (normally, be in when workpiece temperature the durability of the cutting tool when 810 ℃ are controlled is the biggest) , still can prolong cutting tool life so. Be in what appeared to undertake electrify to material 1890 early to add hot cutting, win the United States and German patent. 20 centuries 40 time, add hot cutting to begin to enter industrial application to carry out in beautiful, heart, proof high temperature can make " impossible " the metal of treatment improves treatment performance, obtain economic benefits. But the initial level that this period increases hot cutting to still be in development, treatment quality assures hard, basically arrive without application production is actual in. After 60 time, use cutting tool and workpiece to form loop to connect with low-pressure big electric current, realized electric conduction to add hot cutting, make cutting can go on wheels. At the beginning of 70 time, appeared a kind of effective plasma arc adds hot cutting, develop a success by England at first. After 80 time, developed laser to add hot cutting, because stimulate beam of light can fast local heating, better land satisfied the requirement that imposes hot cutting, rose to increase the economic value of hot cutting technology consequently. Common heat source adds hot cutting place to use heat source, if electrify heats, solder quadrature heats, whole heats, blaze and inductive local heating and electric conduction heat, appellative for common heat source. These heat source can are opposite be heated by treatment material, appeared to have main effect with development to adding those who heat up cutting technology, but they are put in thermal treatment zone too big, thermal efficiency is low, lukewarm accuse quality of difficult, treatment to assure to wait for a problem hard, make cutting not ideal, fail to use production even hard actual in go. Arc adds plasma arc and plasma of laser heat source to be cut eagerly, with plasma arc spray gun medium tungsten makes negative electrode, workpiece material makes positive pole, electrify hind forms the plasma arc of high temperature, its characteristic is to heat temperature is high, energy concentration, can undertake efficient cutting to difficult treatment material. Consider to make clear, heating cutting is cold hard cast-iron when waiting for difficult treatment material with tall manganese steel, cutting speed is as high as 100 ~ 150m/min, cutting tool durability can raise 1 ~ 4 times. The problem that this kind of method exists is to add heat to must have certain space with the knife, heat effect difficult control; Treatment condition is abominable, need guard. Laser adds hot cutting to be heat source in order to stimulate beam of light, undertake local heating to workpiece, its advantage is concentration of quantity of heat, warm up rapid; Quantity of heat is reached by the watch in permeate gradually, the quantity of heat of cutting tool and face of workpiece have a common boundary is inferior; Any treatment place that stimulate smooth Shu Kezhao to shoot workpiece form focusing to nod, facilitating implementation can accuse local heating. Study the result makes clear, laser adds hot cutting to be able to make cutting force drops 25% the left and right sides, return the exterior surface roughness that can improve work effectively. The main problem of existence is high-power laser price costly, energy changeover efficiency is low, metallic stuff draws ability difference to laser, absorptivity has 15% ~ only commonly 20% the left and right sides, after classics phosphoric acid is handled, absorb ability to be able to raise 80% ~ 90% , but economic feasibility is poor, this is this kind heats one of reasons that the method popularizes application hard. Above the occurrence of two kinds of heat source, promoted the development that adds hot cutting skill greatly, already undertook a large number of fruitful research work domestic and internationally. But should use smoothly at production, achieve expectant cutting result, still a few problems need to solve, especially cutting mechanism still requires further exploration and research, if existence is returned to affect treatment quality as a result of certain thermal diffusion in treatment process, power is used up much, temperature controls difficulty, heat source fit is not good, the price is high wait for a problem, economic progress is so unhappy on production. The key that adds hot cutting skill depends on heating, current, common cause is the temperature that bate is in before heating to fuse to difficult treatment material, but this one temperature is proper, how be achieved and control this temperature, still require further exploration, analysis and research. The 2 research that increase hot cutting and target of crucial technology research and meaning research task change with organization of difficult treatment material principle of cutting of theory, metal and heat are conducted for the foundation, with difficult treatment material the mechanism of difficult cutting is jumping-off place, emphasize analysis and the change that seek temperature, material to organize form and with the relation between cutting force, fumble cutting rule, improve data certainly but the countermeasure of cutting sex, then from go up at all the cutting problem that solves difficult treatment material. One of premise conditions that study the work are, already had laser and plasma arc at present the heat source with this kind of hot very steep gradient, heat temperature can reach need value inside a few millisecond, easy control, adjust the discretion of temperature. Of premise condition is, quite the feature exceeding model when material organization has the part to change, below this kind of condition, material organizes adhesion lowest of the element, and the temperature of the bate before the temperature of this condition fuses under material greatly again, cast off cutting of difficult treatment material to machine current and located predicament likely so. Because, if implementation of difficult treatment material adds hot cutting to must reach material bate temperature, practice already proved to obtain expectant cutting result very hard. The meaning of research depends on the is based on a change to organize form cutting means that offer, be material scientific solid state photograph becomes academic and patulous to be used at cutting to machine a domain. This kind of thorough mechanism is discussed and study, it is the innovation of metallic cutting principle, also be the new thinking on direction of production technology development. Additional, if can make of difficult treatment material add hot cutting technology to compare current cutting temperature forward the way with rapidder rate of taller, treatment develops precision of lower, treatment, can advance the economic progress that adds hot cutting undoubtedly. The photograph of crucial technology material changes force of function exceeding model and metabolic rule. Metallic stuff exceeds the characteristic of plasticity condition, be show below certain condition agglutinant or half agglutinant, do not have or have appearance of very small sclerosis of meet an emergency only, fluidity and fill sex are very good, exceed model to be out of shape for macroscopical homogeneous deformation, the surface after be out of shape is slick, did not wrinkle, cave, small crack reach slippage trace to wait. Metallic stuff undertakes in condition exceeding model whether cutting also presents afore-mentioned appearances, whether still perhaps having other and special appearance need to make clear Hunan. Material issues the ability of sex exceeding model when cutting and its change rule in condition exceeding model is one of crucial technologies that need research, the cutting effect of material of this difficult to rising treatment is having important sense. Graph 2 iron - carbon exceeds position of model temperature area in the graph evenly material of general iron and steel has sketch map to change exceed plasticity (graph 2) , it arises when changing to happen and undertake, depend on sb or sth for existence at heating) cooling rate. Black metal exceeds plasticity to be out of shape have particular temperature area, this temperature area is narrower, can have 1, also can have 2 above. It is better to if 30CrMnSiA is in only,be in 770 ℃ to just appear exceed plasticity, the volume ratio of A and B two-phase is right now adjacent at 1, the greatest stress falls 30MPa, temperature area is narrow; Inside a range that influences in 700 ℃ , exceed critical temperature to did not exceed plasticity. Inside area exceeding model, temperature value should be stable, should not rise and fall fluctuant, constant temperature duration also should not grow too, exceed model phenomenon to be able to disappear otherwise. Steel undertakes quenching with be more than critical cooling rate from austenite area, attainable martensite. As a result of treatment meet an emergency is caused and undertake martensite photograph changes, generation changes exceed plasticity. Martensite is changed concern with temperature, have certain limit. Exceeding plasticity is the condition that in some proper temperature limits just appears, if want to be used effectively,exceed plasticity, must be in 0.

5T frit above arrives to change temperature undertakes machining inside the following temperature limits. Heat the influencing factor of temperature and control method. The photograph of metallic stuff changes exceed plasticity to have slashing demand to temperature, stress of speed of the meet an emergency in temperature loop, meet an emergency, action and heat the metropolis such as speed produces an effect to temperature, this is the crucial technology of research. When laser radiate material, its light energy is absorbed by material, change for heat energy. The heat that laser heats is conducted is a very complex process, laser penetrates with very high rate the surface enters data in, its are initiative speed can amount to 5 ~ 20cm/s. Quantity of heat is conducted in material diffuse, create certain temperature field. With mathematical method analytic computation heat is conducted, to holding laser to heat the effect has important sense. What can use laser radiate to form is linear of heat source change the property of length and heated source, method of analyse of the credit that use number will consider, search the temperature field of heat source. Conduct heat according to what afore-mentioned theory build mathematical model and laser add hot cutting process to undertake emulation, main to each parameter is made forecast accurately, the research that increases hot cutting is very important, also be those who obtain favorable result is strong assure. Plasma arc adds hot cutting to quench the experiment of steel makes clear, if plasma torch finds a place for proper before cutting cutting tool place, its tilt the angle, space that leaves treatment area and the arc length that are apart from cutting point of a knife all adjustable, and with proper voltage, electric current, compress aeriform pressure and discharge to close suitably, such coming that control heat temperature, implementation exceeds model to organize the cutting below condition, can acquire good treatment quality. Use two kinds of afore-mentioned heat source to heat, make metal (especially Fe-C alloy is) in inferior eutectoid steel comes true easily exceed plasticity, the material such as mild steel is in more easily change condition exceeding model, can achieve heat short, heat source adjusts effect time the purpose with material action small area, its area, appearance, size is adjustable, exceed model to organized configuration application to create a condition at cutting treatment for the metal. Applied foreground makes the metal is in what organize form certainly to add hot cutting to having wide applied perspective: (1) realizes the cutting treatment of difficult treatment material, improve cutting quality, this is main applied field; (2) belongs to the cutting that waits for material to mild steel, bullion, can improve treatment surface surface roughness; (3) to stuff of commonly used metal, be like the cutting of 45 steel, because cutting force is reduced, can save the sources of energy to use up; (4) can be solved effectively machine the difficult cutting problem of layer of tall hardness v in building industry; (5) considers to there is distinct effect in the job in the production technology of the advanced science such as boat world industry. The metal with 3 certain last words organizes what configuration falls to add hot cutting, can improve treatment effect and treatment quality, advance practical change; This is the innovation of metallic cutting principle, the new development of non-traditional machining technology. Be based on what specific data organizes form to although already proved to be on the technology,add hot cutting is feasible, but still need to try to perfect and rise. Our country already developed generator of successful and of all kinds laser, measure power of lukewarm instrument, cutting measurement unit and control system, the promotion application that processes production technique for this kind created good condition. CNC Milling