In recent years, make technical progress quickly as laser, the means that laser coaxial sends pink to chase layer frit apply makes technology of metallic substance spare parts already became heat of domestic and international research directly. It uses the CAD model that the computer builds, decide a mould and need not produce the space model that gives complex appearance or substance inside short time especially. Apply this kind of technology to still can undertake high accuracy rehabilitate works besides, make its rehabilitate original precision and property quickly, saved cost and time. Laser coaxial sends pink is a complex high power laser and metallic pink - hold hooliganism put oneself in another's position the physical process that 2 photographs shed interaction. Existing the reflex of metallic powder particle to high power laser, scattering, diffractive, absorb and pass through wait for a phenomenon, involve the scattering between photon and small particle, beer-Lambert transmission, metallic particle sends radiation to absorb to the pliable but strong of laser, metallic particle interior conducts heat, convection, pass wait for fundamental theory problem character. Want to make stimulate beam of light and powdery the later and decadent stage of a school of thought to form good space coupling, involve appearance of laser facula, geometry, mode to distributing, design of powdery mouth geometry, gas - the dimensional chroma that pink sheds distributings, gas - the academic description such as the dimensional speed field that pink sheds and detect problem. Of parameter of craft of apply of frit of synchronous laser sending pink optimize, involve the energy that laser is absorbed in powdery the later and decadent stage of a school of thought and passes through to balance, the academic draw remark that draws field of postheat powder temperature detects wait for a problem. Laser coaxial sends the gas in pink - the chroma field of powdery two-phase, speed field, temperature field detects is the task with a great difficulty. Make clear they have fundamental academic value not only, more be helpful for guidance application. The realises laser coaxial sends pink basic research adequately already value on international, already somebody begins preliminary research, but research content and result are an abecedarian, lack advanced method and method. As the development of science and technology, the technology of PIV(Particle Image Velocimetry) that often is used at shedding a test shows its advantage gradually. And another kind of IR is infra-red the occurrence that measures lukewarm technology also undertakes for us powder shedding field offerred a possibility. The process of going from place to place of field of powdery the later and decadent stage of a school of thought and among them all sorts of in-house physics phenomena are complex. But the analysis that passes us, can put main research in mainly the following 3 respects: (1) the research that the research powder of field of speed of powdery the later and decadent stage of a school of thought sheds speed field or a blank, special send pink to carrier gas type. From powdery mouth the speed of ejective and pulverous particle distributings the figure that affecting bath. To pulverous utilization rate, and further theoretical analysis is having main effect. In hydromechanical domain, because the need on the project often undertakes a few fluids,check. PIV particle image measures fast technology technology from 20 centuries since seventies, already obtained great with encouraging progress. At present PIV technology already applied at all sorts of flow in shedding an observation to consider, but the three-dimensional gas firm that the powder feeder in using PIV technology at laser to be made quickly exports 2 photographs shed a research, this has not appeared in the newspaper in domestic and international document data. Flow through measuring mouth sending pink to export pulverous particle transverse distributing with fore-and-aft speed field, get a test sectional the 2 dimension inside or field of three-dimensional speed vector distributing, etc field of speed field, quantity waiting for eddy and 2 dimension are sectional streamline distributings. Beam of light is stimulated in carbon dioxide in, because laser of only station pulse cannot be offerred high-energy and laser of pulse interval cutty, because this uses laser of double pulse YAG,the 532nm of output stimulates beam of light to close bundle hind the course guides smooth arm and piece powder sheds an illuminant illume metal that group of illuminant cylinder lens forms, to film provide lighting light source. Such classics can form very good synchronism to cooperate with digital camera after synchronized adjustment. 8 bit CCD is used to cross frame camera camera lens in detecting the image of going from place to place of field of convection of add 532nm filter undertakes real time is recorded. The double exposure mode of camera can be in instantaneous exposure two, the control that passes synchronized and pulse lighting light source are synchronous, extremely short time (particle whereabouts resembles element a few times) inside take two picture. The speed field information that the method that repass number image handles gets needing. To perpendicular at axes of powder feeder exit sectional speed field is measured, as a result of camera cannot convection field undertakes integrity films, get shed an image to arise to be out of shape, this handles medium image drawing to be out of shape with respect to image of need union number match a technology to undertake corrective, have the consideration of speed field again next. Distributing through gotten speed field, can measure computational formula to get corresponding eddy quantity field through annulus further, and get corresponding 2 dimension streamline distributing through integral computation. Three-dimensional speed field is to pass same two PIV system films at the same time, result of field of speed of two 2 dimension, according to binocular the speed field with three-dimensional computation of synthesis of visual stereo principle. (2) in the measures research to make place use quickly pink mouth that field of chroma of powdery the later and decadent stage of a school of thought distributings and grain diameter distributings, we hope powder of its annular chew missive is even most, have axial symmetry to distributing. This not only interest shapes at rising an exterior quality, and facilitate optimize laser energy to distributing. In be not carrier gas to send pink, because powder relies on self-prossessed whereabouts, be affected by the outside smaller, missive powder uniformity is better, but also can not know its are specific circumstance. And carrier gas type sends pink the means in, as a result of the influence of air current, condition of pulverous going from place to place is complex and changeful, the verdict that the method that uses theory gets is like person meaning very much. The digital image in use PIV technology handles a technology, union stimulates the lighting engineering of mating plate light, the gray scale of image of field of metallic pink the later and decadent stage of a school of thought through filming distributings, can analyse get powder feeder exit sheds the chroma field of field to distributing. What hold in image according to particle at the same time like element number still can get individual particle diameter and bulk, in order to facilitate to be being measured diameter of metallic particle bead undertakes statistic is analysed. Stimulate mating plate illuminant to use long focal distance piece light gathers together camera lens, illume sheds a light that produces adjacent and parallel light beam, at the same time to offset the attenuation effect after a smooth course metal is pulverous, it is on the smooth road of a semmetry of smooth incident direction increase an illuminator to reflex incident light metallic powder to flow along Yuan Guanglu again, increase shed field illuminative uniformity, also assured the accuracy that chroma field measures. (3) the key that the research that powder sheds bundle of temperature field that leaving with action of high power laser to study powder sheds bundle of temperature field below laser action is researcher research all the time. But the characteristic that heats in view of laser high temperature, the research progress in temperature field respect is not great. Some scholars get through theoretical calculation the temperature of individual particle will judge powdery field situation, also put forward the trial test conception of this respect by the scholar of Taiwan, but actual not feasible. Still some of scholar puts forward to use fiber-optic sensor or colorimetric to measure Wen Yi, but unworkable. Although also commercialized heat resembles appearance, but the hot pink that falls as a result of laser action sheds the characteristic of field, majority cannot be satisfied detect requirement, and the price is too high. For this we solder through thorough research of temperature field survey lukewarm system, according to us actual, designed one apply mechanically at field of pulverous thermal current detect method. According to law of dimension favour displacement, after course of metallic iron pink stimulates beam of light, the biggest spectral radiate spends wavelengh to answer limits (1970nm-5060nm) , we want the influence of purify visible light, also want the influence of escape environment element at the same time, accordingly we choose double colorimetric to measure lukewarm filter parameter to be respectively 804. 5nm and 894.
6nm. These two wavelengh all are in close red outskirt and limits is answered in CCD camera inside. Because want to pass the difference of gray scale class of image to come,judge the discretion of temperature again, be opposite so the films the requirement chooses tall bit to count CCD camera of temperature image. If the Megaplus-ES/10 of Kodak has class of 1024 gray scale, can satisfy a requirement. Because particle itself is below laser action, so need not lighting light source. If the graph is shown 5 times,colorimetric surveys lukewarm bearing plant decorate, smooth route system chooses only station camera, the only channel of different colour filter image records switch means. Filter and its control make sure image of camera of alternant park number records two filter in smooth road, shift answers time to be less than 10ms, by computer pilot high accuracy the pace comes true to decide definitely into electric machinery. Software includes two shares: One part controls filter to turn to record smooth road machinery to control a share, another part undertakes real time synchronous image is collected, processing. We can use as same as the content that be measured data, heat its to appoint temperature, the digital image that uses image to collect a system to be collected undertakes noise, image filters going processing, make its gray scale value serves as calibration value. The gray scale that uses the hot powder that software technology already received his to shed an image is worth conversion to become temperature value, showing through different thermometric scale the real time on equipment shows temperature value distributings. Can undertake cloud atlas of curve of 2 dimension isotherm at the same time, and of the Gao Tu such as three-dimensional temperature field show. The speed of powdery shedding field, chroma distributings and high-energy the temperature field research that stimulates the hot pink below action of beam of light to flow is a new field, in studying so, a little crucial question still needs to solve: 1.
The chroma field that analyses cross section and speed field need tilt camera proper point of view films the blame integrity photography that brings image is out of shape problem, need undertakes demarcate is mixed corrective, demarcate nods choose and the computational result that corrective algorithm affects later period directly. 2.
Use carrier gas type to send pink, the rate that pulverous particle sheds is rapidder, the double exposure function that because this uses double pulse laser to cooperate,crosses frame number camera, must want will all sorts of electric need strict synchro control with optical signal. Accordingly, synchro control implement the technical issue that development also is a key. For CCD number camera outside spark the control signal synchronism such as the switch of xenon lamp Q of double exposure function and double pulse laser works, need has source of a base mark signal to spark they. This needs can periodic (15Hz) generation much passageway touchs signalled signal synchronized to control whole picture to collect a system, and measure in the colorimetric of temperature field also want to collect filter machinery control and CCD image synchro control in lukewarm control. 3.
Dynamic inaccuracy changes colorimetric measures lukewarm temperature field surely, need colorimetric measures lukewarm trends to answer enough fast, this needs the digital watch for an opportunity of high-speed delicacy. And the gray scale of temperature differs smaller, this needs the watch for an opportunity that tall bit counts, facilitate accurate state temperature is worth. Filter wave piece switch rate is rapid, the step that also needs high accuracy enters electric machinery. 4.
The affects place to catch directly through wavelengh video quality of filter. Ask to answer limits effectively of camera in CCD already in, cannot suffer visible light to reach again all round the influence of the element. It is very important also that on the other hand the can pass light wavelengh of two filters needs a value, it is affecting the colorimeter from the back to calculate, the influence measures precision. Because this just is elected as choose,two filter are one of main factors that want an attention in surveying lukewarm plan. 5.
Smooth road design needs to consider the carbon dioxide with original powder feeder to stimulate beam of light to affect, the illume of 532nm piece light wants thin, fixed position wants to allow, and chroma field is measured in enlarge Shu Guang sheds an energy to want through metallic pink even, this is the element that needs a consideration in the choice of lens and design. 6.
The action of stereo displacement orgnaization is cross two frame number camera according to proper point of view, be similar to biology vision principle to film shed an image. This includes the mobile orgnaization of stationary phase machine not only among them, return those who have digital camera camera lens to move orgnaization of axial camera lens, with the requirement that films foursquare at contented blame. In three-dimensional speed field in detecting, this is very important. 7.
Corresponding digital image handles a technology. Field of powdery the later and decadent stage of a school of thought falls ceaselessly as a result of particle, whole is ceaseless change, a picture that we get represents the state of some instant only. For analytic shedding the metabolic rule of field reachs judgement its stability, we must use real time to collect, solid chronometer calculates shown skill. The algorithm that handles because of this number image is attached most importance to especially wanted. We should be developed can be in the algorithm that the result gets inside short time as far as possible, facilitating real time detects. Summary: Of field of powdery the later and decadent stage of a school of thought detecting is a newer research field. Thorough in this domain research builds accurate theoretical model to us, the design goes out best flexible powdery chew has important sense. Use its at the project to also have immediate direct sense actually. CNC Milling
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