Laser Cutting technology
- Time:
- Click:132
1--0.
5mm) , precision is tall (general aperture center is apart from an error 0.
1--0.
4mm, outline on size error 0.
1--0.
5mm) , cut surface surface roughness is good (general Ra is 12.
5--25 μ M) , cut seam do not need rework to be able to solder commonly. (2) cut rate is rapid. Use 2KW laser power for example, the speed of carbolic steel cut with thick 8mm is 1.
6m/min; The speed of stainless steel cut with thick 2mm is 3.
5m/min, hot influence area is small, be out of shape dinky. (3) clean, safe, free from contamination. Improved the working environment that operates personnel greatly. Mix with respect to precision of course cut surface surface roughness, CO2Laser Cutting exceeds electric treatment impossibly; With respect to the level that blaze and Plasma Cutting reach hard cut ply. But with respect to above remarkable advantage enough proves: CO2Laser Cutting has been mixed the cut technique that replacing one part convention, especially the cut of all sorts of metalloid material. It is development rapid, use method of a increasingly extensive kind of advanced treatment. Since 90 time, as a result of the development of our country socialist market economy, the competition between the enterprise is intense, every industry must choose certain and advanced production technology correctly to character is measured and manufacture efficiency in order to raise high yield according to oneself condition. Because technology of this CO2Laser Cutting obtained rapidder development in our country. The machine of the first CO2Laser Cutting of industrial application world of CO2Laser Cutting is 20 centuries of the birth seventies. Come more than 30 years, expand of the domain ceaselessly as a result of application, CO2Laser Cutting machine is improved ceaselessly, at present international home already had much home company to be engaged in producing all sorts of CO2Laser Cutting engine in order to satisfy the requirement of the market, machine of cut of machine of machine of cut of 2 dimension flat, cut of curve of three dimensional space, pipe waits. Foreign well-known company has company of HG Laser Lab of company of Amada of German Trumpf company, Italian Prima company, Swiss Bystronic company, Japan, MAZAK company, NTC company, Australia to wait. The company that at present home can offer flat cut opportunity has Shanghai to unite nimble of company of Pu Ruima company, Shenyang Pu Ruima, Jinan strides company, Wuhan Chu Tian company. Use authoritative magazine according to American laser industry " Industrial Laser Solution " statistic of 2000 year report: The Laser Cutting system that the whole world sold in all 1999 (basically be CO2Laser Cutting system) it is 3325, in all 11.
7.4 billion dollar. Produce CO2Laser Cutting engine every year at present according to our country of not complete count nearly 100, in all 1.
500 million yuan of RMBs. Although the development trend of Laser Cutting is sharper, but applied level and developed country photograph are older than difference. Already amounted to 500 or so to the accumulative total of CO2Laser Cutting system that our country already used in industrial production 2003, 1 what occupy a whole world to running systematic gross about.
5% . Of CO2Laser Cutting system purchasing basically is two kinds of units: One kind is large and medium-sized production enterprise, these enterprises have a large number of board in manufacturing product the makings below need, cut makings, and have stronger economy and technical actual strength; Another kind of unit is treatment station (abroad weighs Job Shop) , machining a station is special carry on external of business of laser beam machining, oneself does not have dominant product. Its existence can satisfy the need that a few medium and small businesses machine on one hand; Use the function that sets an example to conduct propaganda since Laser Cutting technology to promotion in initial stage on one hand. Mutual laser beam machining of American whole nation stood 1999 2700, among them 51% pursue Laser Cutting job. Station of laser beam machining of 80 time our country basically pursues job of laser heat treatment, after 90 time, laser Cutting reachs the step up that attack a station. Go up in this foundation as our country large and medium-sized of the development that company system reforms and economic actual strength increase, more and more enterprises will use CO2Laser Cutting technology. From at present domestic application circumstance is analysed, CO2Laser Cutting applies extensively at the mild steel with thick 12mm board the stainless steel with thick;6mm board reach; The metalloid material with thick 20mm. To the cut of curve of three dimensional space, also began to win application in industry of car, aviation. The product substantially that suits to use CO2Laser Cutting at present but reduce 3 kinds: The first kind: Should not be from technical economy angle the metallic Ban gold of production mould, especially outline form is complex, batch is not big, the mild steel of general ply;12mm, ; The stainless steel with thick 6mm, make the cost of the mould and cycle in order to save. The typical product that already introduced has: Automatic elevator structural member, litre fall silicon steel of structural member of machine of spare parts of machinery of all sorts of elevator face plate, machine tool and food machinery outer garment, electric ark, switch ark, spin, project, big electric machinery piece etc. The 2nd kind: The stainless steel that adornment, advertisement, service industry uses (general ply 3mm) or metalloid material (general ply 20mm) design, mark, font. If art reflects the pattern of album, the mark of company, unit, guesthouse, bazaar, station, dock, public Chinese and English font. The 3rd kind: The requirement cuts seamed special part equably. The typical part that uses the most extensively is to pack presswork the model that the industry uses is cut edition, its requirement is cut on the wooden pattern plate with thick 20mm seam wide for 0.
7~0.
The chamfer of 8mm, set bit in groove next. Use fashionable dress is cut in the model on machine, cut all sorts of already pressworked the packing box of good figure. A when home applies in recent years new field is oil sieve seams a canal. Enter oil well pump to hold off silt, in the wall thick cut on the alloy steel tube that is 6~9mm 0.
3mm is wide cut equably seam, perforation is cut to be in alveolus diameter since cannot 0.
3mm, cut technology difficulty is great, already many units throw production. Abroad divides afore-mentioned application outside, still expanding its use a field ceaselessly. (1) use system of three-dimensional Laser Cutting or configure industrial robot, cut space curve, develop all sorts of three-dimensional cut software, arrive in order to accelerate from draw the process of cut part. (2) manufacture efficiency to rise, research develops all sorts of special cut systems, material carries a system, system of drive of linear electric machinery, at present the cut speed of cut system already exceeded 100m/min. (3) the application that waits for industry of patulous project machine, shipbuilding, ply of cut mild steel already exceeded 30mm, special attention considers to use the engineering technology of nitrogen cut mild steel, in order to increase cut thick board cut quality. Because this is in our country to enlarge the industry of CO2Laser Cutting to use a field, difficult problem of a few technologies in solving new application remains the main task of project technology personnel. The function of the parameter that the integrated technology that a few crucial technologies of CO2Laser Cutting are unifinication of light, machine, report stimulates beam of light, machine and numerical control system and precision affect the efficiency of Laser Cutting and quality directly. Especially the part with taller to cut precision or larger ply, must master and solve the following crucial technologies: 1, focal position controls a technology: The energy density that one of advantages of Laser Cutting are beam of light is high, general 10W/cm2. Because energy density and 4/ π D2 become direct ratio, so focal facula diameter as far as possible small, so that arise to be cut narrowly,seam; At the same time focal facula diameter is returned and lenticular Jiao Shen becomes direct ratio. Focusing lens Jiao Shen is smaller, focal facula diameter is smaller. But cut has splatter, lens leaves workpiece too close to damage lens easily, use 5 〃 ~7 because application of industry of this general high-power CO2Laser Cutting is medium extensively.
5 〃 〞 (the focal length of 127~190mm) . Diameter of facula of real central issue is in 0.
1~0.
Between 4mm. To the cut of high quality, effective Jiao Shen still reachs the material that be cut to concern with lenticular diameter. The lens that uses 5 〃 for example cuts carbolic steel, jiao Shen is focal length + inside 2% limits, namely 5mm left and right sides. Because this controls focal appearance to be being cut the position of material surface is very significant. Apprehension arrives the element such as speed of cut quality, cut, the metallic stuff of in principle 6mm, the focus is in apparently; The carbolic steel of 6mm, the focus is over the surface; The stainless steel of 6mm, the focus is under the surface. Specific measure is decided by the experiment. The simple method of position of certain in industrial production central point has 3 kinds: (1) the law that print: Make cut head from go up to move downward, in plastic board aspirant travel stimulates beam of light to print, the smallest part is the diameter that print focus. (2) inclined board law: Use and vertical axis becomes one angle inclined those who put is plastic board make its water flat tension is moved, search those who stimulate beam of light the smallest part is a focus. (3) blue scintilla law: Take out nozzle, blow air, make pulse laser in stainless steel board on, make cut head from go up to move downward, till blue scintilla is the biggest,be in for the focus. To the cut machine of flight smooth path, as a result of horn of diverge of beam of light, cut close end and strong and weak points of the light path when far end are diverse, the dimension of beam of light before focusing has certain difference. The diameter of incident beam of light is bigger, the diameter of focal facula is smaller. The change of the focal facula measure that brings to because dimension of the beam of light before focusing changes,decrease, the manufacturer of system of domestic and international Laser Cutting offerred device of a few appropriative to choose for the user: (1) collimator. This is a kind of commonly used method, add one collimator to have spread in the output end of CO2 laser namely bundle processing, enlarge bundle the diameter of beam of light after greatens, decrescent of horn of disperse the internal heat with sudorifics, make close inside cut work limits end and measure of the beam of light before Yuan Duanju is anxious adjacent and consistent. (2) the lower shaft of the mobile lens that increases one independence on cut head, it and control nozzle are apart from to material surface (Stand Off) the part that Z axis is two mutual independence. When machine tool workbench moves or smooth axis moves, beam of light to far end from close end F axis also moves at the same time, make diameter of spot of gloriole of focusing of beam of light is inside whole treatment area keep consistent. (3) control focusing lens (reflex focusing system for the metal commonly) hydraulic. Decrescent of dimension of the beam of light before be like focusing and when making focal facula diameter greatens, automata is hydraulic change focusing curvature makes decrescent of focal facula diameter. (4) the compensation that way of X, Y adds on machine of cut of flight smooth path is smooth route system. Make compensate smooth road to shorten when Yuan Duanguang Cheng increases cut namely; Carry light path to decrease Xiaoshi nearly when cut conversely, make compensate smooth road to increase, agree in order to maintain light path length. 2.
Cut perforation technology: Technologies of any a kind of hot cut, it is OK to remove a few condition from board the brim begins outside, must be in commonly board on wear one alveolus. Punch of early preexistence laser is to use drift to develop one aperture first on compound machine, next reoccupy laser begins to have cut from alveolus place. Have the basic method of two kinds of perforation to doing not have the Laser Cutting machine of punch device: (1) blow up perforative: (Blast Drilling) , material classics forms one indentation in the center after the illuminate of successive laser, next by flow to form melt material purify very quickly one hole with the oxygen that stimulates coaxial of beam of light. The size of general aperture and board thick about, blow up perforative and average diameter is board large in part, because this is right thicker board blow up perforative aperture is bigger, and out of round, unfavorable asking to be used on taller spare parts (if oil sieve seams a canal) , can use on flotsam only. In addition when the aerobic pressure that uses as a result of perforative place and cut identical, splatter bigger. (2) pulse is perforative: (Pulse Drilling) the pulse laser that uses power of high peak value makes a few material fused or vaporization, commonly used air or nitrogen serve as auxiliary gas, in order to because radiative oxidation makes aperture patulous,decrease, aeriform pressure relatively the aerobic pressure when cut is little. Every pulse laser produces small atomic jet only, progressively development, because this is thick board perforative time needs a few seconds. Once perforation is finished, change auxiliary gas oxygen have cut instantly. So perforative diameter is lesser, its punch quality excel blows up perforative. The laser that uses for this not only should have higher output power; More important when the time of beam of light and dimensional character, because this is general,crosscurrent CO2 laser cannot get used to the requirement of Laser Cutting. In addition pulse perforation still must want to more reliable gas district controls a system, in order to realize the control of the switch of pressure of aeriform sort, gas and perforative time. Below the case that uses pulse perforation, to win the cut of high quality, wait to workpiece from the pulse perforation when workpiece is dormant fast the transition of successive cut technology should in order to take seriously. From theoretic tell quicken convertibly normally paragraph cut condition: Wait like pressure of position of focal length, nozzle, gas, but because time is too short the possibility of change above condition is not actually large. Basically use change laser in industrial production the measure of average power is realer, specific means has the following 3 kinds: (1) change pulse width; (2) change pulse frequency; (3) change pulse width and frequency at the same time. Actual result makes clear, (3) kind the effect is best. 3.
Nozzle design and air current control a technology: When Laser Cutting rolled steel, of oxygen and focusing stimulating beam of light is to pass nozzle to shoot the material that be cut to be in, form an air current thereby bundle. It is to enter the throughput of cut to want to the main demand of air current big, speed wants tall, so that enough oxidation makes cut material has exothermic reaction adequately; At the same time again enough momentum blows melt material jet. Outside because this divides the quality of beam of light to reach its to control,affecting cut quality directly, the control of the design of nozzle and air current (wait in the position in air current like nozzle pressure, workpiece) also be very main factor. The spray head that at present Laser Cutting uses uses simple structure, namely aperture of roundlet of ministry of end of belt of one cone-shaped aperture. Undertake designing with experiment and error method normally. Because nozzle is made with red copper commonly, volume is minor, it is fragile spare parts, need to often change, because this does not undertake hydromechanical computation and analysis. The gas that is Pg) into gauge pressure of constant pressure Pn(is connected from nozzle flank when use, call nozzle pressure, export from nozzle ejective, arrive at workpiece surface via certain distance, its pressure calls cut pressure Pc, final gas expands to press force Pa to atmosphere. Research work makes clear as Pn increase, air current velocity of flow increases, pc also increases ceaselessly. Usable and following formula calculates: V=8.
Pressure of nozzle of Mm Pg- of diameter of nozzle of L/min D- of velocity of flow of 2d2(Pg+1) V- gas (gauge pressure) Bar has different pressure threshold value to different gas, when nozzle pressure exceeds this value, air current is normal inclined shock wave, air velocity of flow transfers to supersonic speed from subsonic speed. The freedom of ratio of this threshold value and Pn, Pa and aeriform element spends (N) two elements concern: Be like N=5 of oxygen, airy, because of × of Pn=1bar of this its threshold value (1.
2)3.
5=1.
89bar. When nozzle pressure when taller Pn/Pa=(1+1/n)1+n/2 (Pn; 4bar) , normal inclined shock wave seals air current turn into shock wave, cut pressure Pc drops, air velocity of flow spends a bring down, form eddy current in workpiece surface, weakened the action of material of melt of air current purify, affected cut rate. Because this uses taper hole to carry the spray head of aperture of the roundlet that carry a department, the nozzle pressure of its oxygen often is under 3bar. To raise Laser Cutting rate further, but according to aerodynamics principle, do not arise below the premise that increases nozzle pressure shock wave, the design makes a kind shrink put model nozzle, pull cut down Er namely (Laval) nozzle. Make to go to the lavatory if pursue,can use the structure of 4. Center of laser of university of German Han Nuowei uses 500WCO2 laser, lenticular focal length 2.
5 〃 , used alveolus nozzle and nozzle of the Er that draw attack to make a test respectively, see a picture 4. Test result shows 5 times like the graph: State nozzle of NO2, NO4, NO5 is below different aerobic pressure respectively, cut surface surface roughness the function of Rz and cut speed Vc concerns. Can see from inside the graph NO2 alveolus nozzle is 400Kpa in Pn (or 4bar) when cut speed can be achieved only 2.
75m/min (carbolic stencil steel is thick for 2mm) . NO4, NO5 pulls nozzle of cut down Er 2 kinds to be 500Kpa to be able to be achieved to speed of the cut when 600Kpa in Pn 3.
5m/min and 5.
5m/min. What should point out is cut pressure Pc or workpiece and the function that nozzle is apart from. Because inclined shock wave is reflexed for many times in the border of air current, make cut pressure shows periodic change. Proximate nozzle exports area of pressure of the first tall cut, the distance that workpiece surface exports to nozzle is about 0.
5~1.
5mm, cut pressure Pc is big and stable, it is at present hand of the cut in industrial production pulls commonly used craft parameter. Area of pressure of the 2nd tall cut makes an appointment with the 3~3 that exports for nozzle.
5mm, cut pressure Pc is bigger also, can obtain good result likewise, be helpful for protecting lens, improve its service life. Because the area of pressure of other tall cut on the curve is apart from nozzle to export too far, match hard with focusing beam of light and cannot use. The place on put together is narrated, technology of CO2 laser cut is receiving more and more application in production of our country industry, abroad is considering to develop the cut technology of taller cut speed and larger board and device. To satisfy industry production confrontations to measure and produce the demand with higher and higher efficiency, must take seriously solve all sorts of crucial technologies and executive quality standard, in order to make this one new technology wins wider application in our country. CNC Milling