Overview from 20 centuries 80 time begin, laser beam welding receives a technology to begin to apply create a field at car automobile body, basically be to apply at laser beam welding to receive automobile body. Laser technology is used polarizing the beam of light that the light beam that lens reflex laser produces makes its are centered in focusing device to produce tremendous energy, make workpiece fuses in the instant, come true thereby solder process. Laser beam welding receives the laser that equipment uses to basically have two kinds big: One kind is solid laser, call Nd ∶ YAG laser again, the beam of light that main good point is generation can be passed fiber-optic and deferent. Power of commonly used output is auto industry the laser of Nd ∶ YAG of 3 ～ 4kW; Another kind is CO2 laser, molecular gas makes working medium, can work continuously and output very high power, standard laser power is between 2 ～ 5kW. Current, automobile body solders to basically have the kind such as resistor spot welding, MIG and MAG solder. In car production process, laser technology basically is used at automobile body to differ thick board spell solder and automobile body to solder. Laser beam welding receives what basically be used at structure of automobile body frame to solder, for example of coping and side wall solder, in one steam masses, traditional resistor spot welding has been soldered by laser gradually be replaced. Laser beam welding is received apply at the car, can reduce automobile body weight and achieve the goal that saves oil; The assembly that raises automobile body precision, make the stiffness of automobile body promotes the 30% security that enhanced automobile body thereby; The punch in reducing car automobile body to make a process and assemble cost, the number that reduces automobile body hardware raises rate of automobile body unifinication. In development laser beam welding receives new technology respect, the development in automobile body production process experienced laser technology to differ laser beam welding of technology of joining together of large board laser, automobile body receives technology and laser compound solder development course of the technology. Compare with look of single technology of laser fusion welding, laser is compound solder the technology has distinct advantage: The frit with the taller stability, bigger electric arc when high speed solders is deep, the solder of larger crack is better even the tenacity of ability, welding line, pass welding wire to be able to affect welding line to organize a structure, and wait without phenomenon of prolapse of welding line the reverse side. At present company of one steam people comes in Audi C6, Golf A6, treasure, fast vacate, stride vacate, the model of the almost all brand such as Model X makes a process in, all differ level land uses Laser Cutting, laser to fuse solder and stimulate recover to close solder wait for advanced production technology (see next tables) . 2.
Laser beam welding of principle of laser beam welding uses laser to regard as solder heat source, the robot regards motion as the system. The advantage of laser heat source depends on, it has move pole to increase heat energy power high, can concentrate much energy on very small solder contact, have energy density so tall, heat concentration, solder speed is mixed quickly solder be out of shape small wait for a characteristic, can realize laminose fast join. The power density that goes up when laser facula is enough big when (> 106W/cm2) , the metal heats quickly below the illuminate of laser, its surface temperature is elevatory inside cutty time to boiling point, the metal produces aerification. Metallic vapour leaves the outside of metallic bath with fixed rate, produce the metal that counteractive Yu Rong melts an additional stress, make its cave downward, hole of a small protruding arises below laser spot. As heat of the process undertake, laser can shoot hole base directly, form a slightness " alveolus " . After the exterior pulling force that controls force and liquid state metal when metallic steam recoil and gravitational balance, alveolus continues no longer thorough. When facula power density is very big, the alveolus that produces will continue no longer thorough. When facula density is very big, the alveolus that produces will be perforative at whole board thick, form dark penetrable welding line. Alveolus is opposite as photograph of beam of light at workpiece advance along direction of welding. The metal fuses in alveolus ahead, bypass alveolus is flowed to rear, new and caky form welding line (see a picture 1) . (1) laser basically has CO2 gas laser and YAG solid laser with the laser that receives at laser beam welding two kinds. The function with the mainest laser is output power and quality of beam of light. From consideration of this two direction, CO2 laser has larger dominant position than YAG laser, it is the laser that at present deep frit solders to basically be used. The most illuminant power that one steam masses uses in car production process is controlled in 4000W. (2) light guides and focusing system light guides focusing system by round polarization lens, enlarge bundle lens, illuminator or fiber-optic reach the composition such as focusing lens, condition, direction, transmission beam of light mixes polarization of implementation change beam of light the function of focusing. The state of these optical spare partses receives quality to have all in all effect to laser beam welding. Below high-power laser action, optical component, especially lenticular function is met deterioration, make transmitance drops, generation heats up lenticular effect, at the same time exterior pollution also can increase transmission loss. (3) solder the robot because laser fusion welding, laser - MIG is compound solder of technics different and solder of contact form different, be opposite so solder the assembly of contact precision demand is diverse also. Solder can use the laser drill steel that takes the laser fusion welding that receives welding line and fillet weld to solder commonly robot. The solder of laser drill rod that seams to butt welding and laser beam welding must use distinction to solder at the type twisting an arm of groovy robot robot, normally design welding line dogs automatically correctional system. (4) the spirit of board of link of the place when fixture can make sure laser beam welding is received or assembly is certain, assure welding line clearance, prevent to solder be out of shape, raise laser beam welding to receive the quality of contact thereby. (5) laser beam welding receives control system to control a system to basically include to solder the welding line of the video monitoring system of the process, robot dogs automatically system of system and correctional system, control sending silk. Receive kind to different laser beam welding, the composition that controls a system also somewhat identical. Laser fusion welding need not send filar system, welding line to dog automatically system and moving contrail is correctional system. To Laser Cutting technology, toward contact need and laser online testing system is used in coordination. Graph 2 for laser - MIG is compound solder equipment composition of the system, it needs to match system sending silk. 4.
Stride the characteristic that vacates laser beam welding to receive a technology to stride the laser welding line that vacate to be as long as 42m, assured intensity of the accuracy of its whole dimension, automobile body and tigidity. Fast the join that the laser beam welding that vacate is received basically is the coping in automobile body and side wall, motherboard differs thick board inside joining together, door board differ thick board the joint such as window of wind of joining together, motherboard and side wall, back panel, around and doorcase. On the exterior, use the roof that stimulates solder of smooth compound drill rod to have a meticulous and flowing welding line only, serve as outside face directly and increased the streamline vision result of automobile body. And the roof that uses technology of traditional spot welding has two balata sealing strip. (1) stride the characteristic that vacates technology of automobile body Laser Cutting to will differ with laser a few thin plate of qualitative, different or same function spell ply, different capable person solder rises, again strike out form. Not only raised plank utilization rate (by 40% ～ 60% raise 70% ～ 80% ) , and reduced automobile body weight, improved the integrated and mechanical performance of automobile body structure. Laser spells solder is in automobile body the design is made in, according to automobile body different design and function ask, choose the stencil steel of different specifications, install what the technology finishs place of automobile body some to make through laser cuts out and going all out, step frame of the windshield before vacating, door for example inside board, the place such as the motherboard before automobile body all uses technology of laser joining together (see a picture 3) . Laser spells solder to have reduce spare parts and mould amount, reduce spot welding number, optimize material dosage, reduce spare parts weight, reduce cost and raise dimension precision to wait for an advantage. Graph 3 stride the application that soars technology of joining together of automobile body laser (2) fast vacate fusion welding of automobile body laser to solder methodological characteristic with respect to spot welding itself character, the intensity that solder nods is OK very tall, but the share that orders without solder is intermittent still and detached, the laser beam welding that should become an organic whole than soldering in respect of intensity of automobile body whole receives contact intensity to want low. The characteristic of the discontinuous sex of spot welding and its oneself: If solder dot allows changeful entity, soldering especially when the join of join of three-layer board join, plating zine plate and excel in steel, solder be out of shape bigger, the flatness that brings about solder point point is reduced reach generation gap, and spot welding can cause the mother capable person all round solder contact to heat up influence area intensity to drop, when car is bumped badly by rupture place often is in the place. Current, only masses car fastened our country to use laser beam welding generally to receive this kind to solder advancedly workmanship. Stride 4 when vacate automobile body two lids, hind a lot of place such as gutter channel, back panel and around wind window all used technology of laser fusion welding. Because solder rate is rapidder, solder so the hot influence area of contact is otherer solder the method is small, did not solder almost be out of shape. The composition that can improve automobile body greatly so and those who match lid of dimension, door and side wall is smooth degree with window of glass of sealed effect, windscreen and wind match with sealed, and implementation is multilayer board high grade join. Additional, because stride,vacate automobile body to use galvanization board entirely, if use conventional spot welding technology, because three-layer board is mixed the cause of galvanization, must use bigger solder electric current and solder pressure, its bring about solder to nod quality to drop to be out of shape with solder dot necessarily as a result serious, bring about thereby assemble quality to drop. In striding those who vacate side wall assembly to make a process, because steel of high grade excel in is in side wall B - before column, side wall inside board inside assembly, side wall hind board assembly, doorsill is strengthened board strengthen with side wall coping board general application, solder to what side wall chases class assembly it is difficult to brought huge. Of excel in steel succumb the 3 ～ that intensity is common armor plate about 4 times, the spot welding that uses a convention cannot have realized high grade join, only is feasible is to use technology of join of intermediate frequency spot welding and technology of join of laser fusion welding. Stride vacate side wall to join almost all choice uses technology of laser fusion welding (see a picture 4, graph 5) and a few intermediate frequency solders technology. Laser beam welding receives a technology to have taller hot input not only, and solder rate is rapidder, without solder be out of shape, can obtain other solder the excellent welding line that the method cannot obtain. Because increased match accuracy of automobile body dimension and contact strength, make strode the intensity that vacates automobile body to reach higher level. Graph 4 graphs 5 stride the application that soars automobile body laser beam welding to receive a technology (3) fast vacate automobile body to stimulate recover to add up to soldering characteristic to pursue 6 depicted laser - MIG is compound the fundamental of solder. Outside inputting energy to weld zone besides electric arc, laser also inputs quantity of heat to welding line metal. Stimulating technology of smooth compound solder is not two kinds solder the method is ordinal action, however two kinds solder method at the same time action at weld zone. Laser and electric arc are affected in different level and formally compound soldering function. In laser - MIG is compound when soldering, volatilize to happen in the surface of workpiece not only, also happen on fill welding wire at the same time, make more metals volatilize, it is more easy to make the energy of laser is transmitted thereby. Laser is compound solder the interaction that the technology is laser and other heat source, make solder thereby rate rises, solder cycle shortens, and achieve solder likewise the laser power that purpose place needs is reduced greatly, these can make solder cost is reduced greatly. Accordingly, laser is compound solder the technology no matter from craft angle, still have capacious development and applied perspective from the point of economic angle. Laser is compound solder the technology has distinct advantage. Solder to stimulating recover to close, the advantage basically reflects in: Without the phenomenon that burns prolapse of the reverse side of the welding line when wearing, suitable scope is wider; Solder to laser ＋ MIG, the advantage basically reflects in: Taller solder deepness of speed, fusion welding of big, generation solder the intensity that heats up little, welding line width of tall, welding line is small reach welding line is bulgy small, make the manufacturing process stability of whole system good thereby, good, welding line prepares equipment usability workload and workload of processing of the welding line after soldering are small, and solder deliver a child produces man-hour weak point, cost efficiency of low, production is tall. The join of coping of automobile body of one steam masses and side wall uses laser - MIG compound solder, form of commonly used connect and stride if the graph is shown 7 times,vacate form of connect of solder of coping laser drill rod. As a result of laser - MIG compound solder has better electric arc stability and fill property, frit of the welding line after solder is wide smoother than according with surface of design requirement, welding line, have relatively high strenth and plasticity, general surface need not PVC coating, can use as bare surface directly. Because welding line is successive seal weld, consequently the respect such as rigid to truckload automobile body, sealing and the generation that prevent in-house noise all has positive effect. Graph 6 laser - MIG is compound solder the principle pursues coping of automobile body of masses of 7 one steam and the complexity that because laser beam welding accepts a system,side wall laser solders, opposite to the requirement of maintenance taller, normally to a model, all laser beam welding receive equipment to need to form a local area network, accomplish the communication between data interior. Each solder illuminant all needs an Internet interface, analyse a system to be linked together with the computer breakdown of supplier of laser illuminant equipment directly. When laser beam welding receives equipment to malfunction, if spot maintenance is insoluble, can undertake by equipment supplier long-range breakdown is diagnosed with maintenance, avoided needless long stop production. It is the information communication between facilitating personnel, laser illuminant deposits word of dispatches from foreign news agency of ground stock country (see a picture 8) . Additional, because laser beam welding receives equipment to have higher price, must make full use of so resource of existing laser illuminant, so that reduce spare parts reserve. One steam masses strides those who vacate automobile body laser beam welding to receive place to use to solder illuminant exports smooth way by several times evener illuminant commonly. Of the amount more or less to depend on on one hand solder the design form of craft and fixture; Depend on on the other hand laser is urgent maintenance beforehand case. Graph 8 fast vacate position of communication of data of laser beam welding 5.
One steam masses regards epilogue as home famous car creates a company, precede with the technology all the time the development way that leads domestic car to make a technology, laser beam welding is received reach its are compound solder technical development and use, it is the important sign of the flight that automobile body of one steam masses makes horizontal happening pledge. Laser fusion welding and its are compound solder the technology serves as at present most advanced solder one of methods, came true to solder higher speed and good solder the perfect union of quality. Have broad applied range and efficient character, shortened at the same time manufacturing time, improved productivity, make product of one steam popular has stronger degree of belief and market competition ability more. CNC Milling