Be not spherical and optical spare parts to apply Yu Hang extensively empty airborne equipment (radar range finder) , satellite (what the pickup system that advanced optics looks at far system, high resolution, Gao Lingmin spends is infra-red pass feeling system) , laser control and guide, infra-red explore, the application on civil photoelectricity product is more wide at the same time. The technology of 1 ductility means grinding that is not spherical and optical spare parts 1. Technology of grinding of 1 ductility means is the closest, short wavelengh is optical, especially the research activity in domain of X ray optics makes clear, the optical component of X ray domain is used more blame is spherical, ask the appearance precision of the spare parts reachs accept rice level, exterior surface roughness reachs dust level, and more and more use hard brittleness material. The conventional treatment method of these spare partses is grinding after treatment, through working procedure of abrade, polish, finish machining wants a part into place, the manufacturing efficiency of this kind of method is low, treatment cycle is long, cannot get used to the need of modern production. Regard optics as the treatment of the spare parts, on one hand claimed accuracy is tall, treatment surface exceeds smooth, ask to machine the surface to did not machine degenerative layer again on the other hand. Below this kind of demand, produced the ductility means grinding of hard fragile data, become a heat of superprecision. In proper control the condition falls, can use only place or tool of many bits of diamond (grinding) glass of treatment such as and pottery and porcelain a kind brittleness material, because material is of purify of plasticity flow means, get doing not have the treatment surface of crackle, because this calls this one process,be " ductility (plasticity) " or " cut " means grinding. The material volume that grinds an excision when every emery wheel is minor when flow to enough plasticity and producing brittleness to rupture to produce crackle namely, realized ductility way " nondestructive is hurt " grinding. Actually, this is meant should assure to not was out of shape cutting ply is less than brittleness one by one ductility changes critical value, because material differs and this critical value changes, but it is O about. 1 μ M. Because this realizes the main factor of ductility means grinding,be the dynamic stiffness between precision of machine tool system and tool and workpiece, specific requirement is: The tall nicety that 1) grinds an emery wheel imperceptibly " nap " and " Xiu Rui " the main shaft that 2) is designed and makes a tall trends stiffness in order to make sure emery wheel is enough and sharp, the athletic error of main shaft (radial and axial) must be less than 0. M of 1 μ ; 3) is designed and make the slideway that gives tall dynamic stiffness, its motion error (linear and circumgyrate) must be less than 0. 1 μ M; 4) the smooth, campaign that spends servo drive control to form cutting without noise, Gao Gang. According to experience, one is not less than static state of M(of 300N ／ μ ) stiffness of machine tool closed circuit (between tool and workpiece) it is indispensible, to satisfy afore-mentioned requirements, except above introductory main shaft and slideway satisfy afore-mentioned requirements outside, still must develop the grinding spindle that gives high accuracy, tall stiffness, still must want development to give unit of efficient emery wheel nap at the same time. Additional of hot, Zhen Yuan decrease reach its segregation and active control, accept rice class is measured and control a system, the make choice of with workpiece qualitative material, workpiece maintains those who wait for the problem of periphery technology to solve, also be the serious problem of processing technique of grinding of means of sex of bearing the court of a feudal ruler. The accurate project institute of British Cranfield university (CUPE) personal development exceeds nicety successfully grinder of 3 axes CNC, can mix to pottery and porcelain of a few advanced projects material of glass of one little scope undertakes ductility means grinding. Coarse person adopts Japanese scholar a note of the ancient Chinese five-tone scale the grinding of vertical plane grinder that contains minim feed is crystal, the exterior surface roughness of workpiece achieved P, V2nm, the person such as Japanese scholar difficult wave passes the grinding of accurate and planar grinder that has 0 expanding vitreous ceramics main shaft optical glass NBFl, the exterior surface roughness of workpiece achieved Rmax5nm, can lean only previously abrade the spare parts that comes out with polishing ability treatment, with ductility means grinding also can be machined now; 1. The 2 blame that used technology of ductility means grinding are spherical and optical the company of Rank Pneumo of superprecision machine tool of the spare parts gives Nanoform250 superprecision system at been develop 1996, this system has two axes to exceed accurate CNC machine tool, can undertake exceeding accurate turning already on this machine tool, can undertake exceeding accurate grinding again, still can undertake exceeding accurate polish additionally, the characteristic with this the most outstanding machine tool is the optical part that can direct grinding gives the hard fragile data that satisfies knead dough of optical surface quality precision. This machine tool introduced the advanced design idea of a lot of Nanoform600, 0ptoform50, the machine tool is the biggest 250mm of φ of treatment workpiece diameter, through elevatory device can make the diameter of workpiece of the biggest treatment of the machine tool achieves φ 450mm, pass the liquid that controls perpendicular direction additionally static press slideway (Y axis) , still can the spare parts of grinding blame axial symmetry. The resolution of system of machine tool numerical control is 0. 001 μ M: Positional feedback component is resolution 8. The grating of 6nm or resolution 1. The laser interferometer of 25nm, excel of the face that processes work precision 0. Ra0 of excel of surface roughness of surface of ／ of 2 μ M. 01 μ M. The accurate project institute of British Cranfield university (the Nanocentre250 of treatment machine tool that the Nanocentre that COPE) develops is not spherical and optical spare parts, Nanocentre600, it is a kind of 3 axes exceed accurate CNC to be not spherical treatment device, it is by Cranfield Precision Engineering Ltd. To satisfy only place and ductility grinding the use of two respects asks and the design makes, adopt the machine tool structure of rationalize, use Gao Gang spends servo drive and liquid static press bearing to make the machine tool has taller closed circuit stiffness, the resolution of X and Z axis is 1. 25nm, this machine tool is considered as to accord with modern technology standard. Treatment workpiece diameter is φ 250mm and φ 600mm, excel of its face precision 0. 1 μ M, ra0 of excel of exterior surface roughness. 01 μ M, CUPE still is research of American Kodak company, design and production the biggest on current world exceed grinding machine of spare parts of optics of accurate and large CNC " 0AGM2500 " , this machine tool basically is used at the treatment of the hard fragile data such as optical glass, can be machined and measure 2. 5m × 2. 5m × 0. The workpiece of 61m, the face of lens of optics of blame axial symmetry that it can machine square giving 2m, the appearance error of lens face is 1 μ M only. The AHN60 that machine of work of Japanese abundant field develops, 3D is high accuracy of a CNC grinding of three-dimensional cut form and turning machine tool, the optical part that it can play figure of grinding and turning axial semmetry in X, Z and B3 axle control, in X, Z and Y axis 2 half axle control falls can the optical spare parts of grinding and turning blame axial symmetry, the cut form precision that processes work is 0. 35 μ M, ra0 of exterior surface roughness. 016 μ M. Home began the research of superprecision technology from 80 time, lagged behind 20 years full than abroad, the research that already a few units began those who be not spherical spare parts to exceed accurate turning technology now works. The one 325CNC of MSG that recommended Rank Pneumo company before growing place of spring scenery machine among them a few years exceeds accurate lathe, basically use turning spare parts of optics of a few metals, at the same time this still began the blame of the material such as germanium of CNC Machining optical glass, crystal research of spherical processing technique, gained certain headway. Additionally home still has a few units to exceed nicety through accurate grinding abrade the blame that also can machine a high accuracy with manual polish is spherical and optical spare parts. At present accordingly home still does not have development of a proper motion to be able to achieve the CNC that exceeds exact level to be not spherical grinding to machine a machine tool, be not spherical spare parts so exceeding accurate grinding technology still basically is a blank, cannot satisfy the need of national defence industry. The 2 ELID that are not spherical and optical spare parts exceed accurate grinding technology from the analysis above knowable, want to realize ductility means grinding, need the machine of high accuracy, tall stiffness, the tall accurate prune that still needs the imperceptible emery wheel that wear bead at the same time and Xiu Rui. Coarse person put forward the palace of the person that study respect Japanology that grinding an emery wheel imperceptibly to use the emery wheel of imperceptible nap, in the imperceptible grinding that undertakes under quantity of plasticity domain grinding. In the person that be in this respect Japan to learn plain, big dark technology of ELID of whole application waiting for a person, realized divisions of pair of good fragile material successfully exceed accurate grinding. Japanese learned man is old dark those who make the bond of high strenth metal that waits for a person from 1987 to emery wheel of diamond of cast-iron fiber bond exceed hard abrasive emery wheel, developed the filing that uses Electro1ytic Ln ProcessDr9ssin8(ELID) , those who realized hard fragile data exceed accurate grinding, personal success applies at the spherical, superprecision that is not spherical lens, mould now. 2. 1 ELOD exceeds the system of principle ElID grinding of accurate grinding to include: Metallic bond exceeds imperceptible granuality to exceed hard abrasive emery wheel, electroanalysis whole electrode of disintegrate of nap power source, report, electrolyte (hold grinding fluid concurrently) , the brush that receive report and machine tool equipment. ELID grinding principle sees this publication 1994 No. 9 " online electroanalysis nap grinding is advanced pottery and porcelain " one article. The mechanical intensity of emery wheel of metallic radical bond is high, measure through set electroanalysises suitably, can make emery wheel wears away decrease, in exceed accurate grinding while, can get taller appearance precision again, apply this one principle, can come true to arrive from plane blame is spherical, of the optical component of all sorts of appearance exceed accurate grinding. 2. The ASG that 2 ELlD exceeds system of accurate grinding test to be in Rank Pneumo company, on 2500T machine tool, mount is big dark whole ELID system, this system reachs the composition such as grinding fluid by emery wheel, power source, electrode. When rough machining of semifinished product figuration, use 400 emery wheel, semifinishing machining uses 1000 emery wheel or 2000 emery wheel, and when exceeding accurate grinding, use 4000 (average bead diameter is 4 μ M) or 8000 (the emery wheel of cast-iron bond diamond that average bead diameter is 2 μ M) about. Emery wheel dimension, appearance makes the same score form emery wheel for φ 75W3. Electroanalysis the power source that build fighting spirit () of ELID power source, used the special power source that happens to shed voltage of high frequency pulse continuously, the voltage of power source is 60V, electric current is 10A. Grinding fluid is AFH of water-solubility grinding fluid, M and CEM dilute become 50 times, rely on tap water or pure water dilute. 2. 3 ELID exceeds the experimental result of accurate grinding to be when treatment blame is spherical, the bowl form tool that goes up in workpiece axis through installation (30 × W2mm) undertakes φ of emery wheel of diamond of 325 cast-iron bond the R figuration nap of smooth emery wheel, make an appointment with 10min electroanalysis after earlier Xiu Rui, through the kibble of 400 emery wheel, the semifinishing machining of 1000 emery wheel, rely on 4000 emery wheel to undertake ELID exceeds accurate grinding. In exceed nicety to be not spherical treatment machine tool to go up, technology of grinding of ELID of have the aid of, machine optical glass BK the one blame of 7 is spherical lens, achieve O of face precision excel successfully. 2 μ M, rmax20nm of exterior surface roughness, and to a bit soft the blame of the material such as qualitative LASFN30 and Ge is spherical, also got face precision excel 0.
2 μ M-0.
3 μ M, rmax30nm of exterior surface roughness, step of Rmax30nm of exterior surface roughness is good lens face. ELID grinding technology, as the practical production technology that is not spherical and optical spare parts, can make the final polish quantity of the spare parts is reduced minimal. CNC Milling
CNC Machining