The few axle ultraprecise large optical mirror grinding system of restructural
Technical field
The present invention relates to the grinding system in a kind of optical fabrication field, particularly relate to the few axle ultraprecise large optical mirror grinding system of a kind of restructural.
Background technology
In recent years, along with over the ground, sky is observed to the continuous increase to large telescope demand, the optical mirror plane of manufacturing large scale, high surface figure accuracy, low sub-surface damage becomes urgent requirement.Off-axis aspheric surface is the principal mode of current optical mirror plane.For the grinding of ultraprecise large optical mirror, the bore of general optical mirror plane will be more than 1m, and after processing, the surface figure accuracy of optical mirror plane is better than 10 microns.
At present, the form of ultraprecise off-axis aspheric surface grinding mainly contains five axles and determines contact point grinding and three axles and become contact point grinding.Three axles become contact point grinding also referred to as few axle grinding.Determine contact point grinding trajectory planning comparatively simple, but the machine tool structure complexity using, poor rigidity; At fixed contact point place, abrasion of grinding wheel is very serious; For hard brittle materials such as SiC, be difficult to processing.Few axle grinding can make lathe mechanism simple, reduces the faying face between machine tool component, the rigidity and the damping that greatly improve grinder structure.Lack axle grinding medium plain emery wheel even wearing, thereby can extend the service life of emery wheel.At present, few axle grinding is not also widely used.The most important characteristic that ultra-precision grinding machine possesses is high rigidity and large damping, and the characteristic of the high rigidity of grinding machine and large damping can effectively suppress vibration, and distortion etc. affects the unfavorable factor of machine tool accuracy.The restructural of grinding system refers to the different characteristic of state and the workpiece to be processed current according to system, structure to grinding machine, emery wheel geometric parameter, trajectory planning etc. reset, to meet the feasibility of curve surface of workpiece processing, improve the working (machining) efficiency of curve surface of workpiece.
Find by literature search, the Xavier Tonnellier of Cranfield university of Britain is at its thesis for the doctorate " superfine grinding of manufacturing fast for massive optics " (Precision Grinding for Rapid Manufacturing of Large Optics, Xavier Tonnellier, Cranfield University, may2009) a kind of typical three axle ultra-precision grinding machine-BOX have been described in a literary composition, BOX grinding machine has adopted the collocation form of two shifting axle one rotating shafts, and grinding machine spindle angle of inclination is fixed.The shortcoming of BOX grinding machine is very high to the requirement of rotating shaft circular runout, causes rotating shaft bearing element to be difficult to manufacture, and cannot meet the processing request of 2m bore space ultraprecise optical mirror plane.And its spindle tilt is fixed, run into different workpieces to be processed, can not change this angle to obtain best processing effect, do not there is reconfigurability.The people such as the Tsunemoto Kuriyagawa of Japan are at " a kind of new method for grinding of non-ball pottery minute surface " (Tsunemoto Kuriyagawa, Mohammad Saeed Sepasy Zahmaty, Katsuo Syoji, A new grinding method for aspheric ceramic mirrors, Journal of Materials Processing Technology62 (1996) 387-392) provide a kind of few axle grinding system in literary composition, but this system is only suitable for the processing of small-bore optical mirror plane, and its method for planning track can only be for specific lathe configuration, workpiece must have symmetrical centre, and algorithm complexity, do not there is versatility.
Summary of the invention
In view of this, the invention provides the few axle ultraprecise large optical mirror grinding system of a kind of restructural, comprise grinding machine supplemental characteristic library module, grinding process DBM, human-computer interaction module, constraints constructing module, emery wheel geometric parameter reconstructed module, imaginary axis generation module, few track shaft planning and the local checking module of interfering, abrasion of grinding wheel prediction and track correct module, few axle machining code generation module, processing step and technological parameter generation module, few axle ultraprecise numerically control grinder Executive Module, mirror-quality detection module, emery wheel dressing dressing module.System of the present invention can be for the arbitrary surface form optical mirror plane of (comprising off-axis aspheric surface), abrasion of grinding wheel is compensated, by generating virtual axle, make full use of the flexibility of five travelling wheelhead roll grinders, brought into play the advantage of the large damping of the high rigidity of few travelling wheelhead roll grinder simultaneously, can processing optical minute surface bore large, few axle, restructural, calculate simple, precision is high, good stability, highly versatile.
The present invention is achieved by the following technical solutions: human-computer interaction module is accepted user's input, constraints constructing module obtains the information of grinding machine parameter database and technological parameter database by database interface, in conjunction with the input of human-computer interaction module, tectonic system constraints; The system restriction condition that processing step and technological parameter generation module provide according to described constraints constructing module is determined processing step and the technological parameter of grinding; The geometric parameter of the calculation of parameter emery wheel that emery wheel geometric parameter reconstructed module provides according to constraints constructing module, processing step and technological parameter generation module; Two virtual pivots of the parametric configuration system that imaginary axis generation module provides according to constraints constructing module and processing step and technological parameter generation module; Few track shaft planning interferes the parameter that checking module provides according to imaginary axis generation module, processing step and technological parameter generation module to generate the wheel grinding motion path of interfering without local with local; Abrasion of grinding wheel prediction and track correct module are according to emery wheel geometric parameter reconstructed module, few track shaft planning and the local correction of interfering the variation of geometric parameter and profile in the parameter prediction wheel grinding process that checking module provides and obtaining grinding wheel movement track; Few axle machining code generation module plans that according to abrasion of grinding wheel prediction and track correct module, processing step and technological parameter generation module, few track shaft the parameter providing with local interference checking module generates the machining code of numerical control system of grinding machine; Few axle ultraprecise numerically control grinder Executive Module obtains machining code by numerical control system communication interface from few axle machining code generation module, completes the processing of optical mirror plane; Emery wheel dressing dressing module is carried out shaping, dressing according to the emery wheel geometric parameter of emery wheel geometric parameter reconstructed module input to emery wheel, for few axle ultraprecise numerically control grinder Executive Module provides the emery wheel that meets size and technological requirement; Mirror-quality detection module detects the mirror-quality of few axle ultraprecise numerically control grinder Executive Module processing, determine whether and reach processing request, and this grinding process parameters is input to grinding process DBM, mirror-quality index is input to abrasion of grinding wheel prediction and improves the accuracy of abrasion of grinding wheel prediction next time with track correct module; The characteristic parameter of the few axle ultraprecise numerically control grinder Executive Module of grinding machine parameter database record.
Below the inventive method is described further, particular content is as follows:
Human-computer interaction module, its effect is the intermediate object program of accepting user's input display system operation.User's input comprise optical mirror plane blank material, size, optical mirror plane geometry mathematic(al) representation and machine surface figure accuracy and the surface roughness that rear minute surface will reach.The movement locus of the position, emery wheel that the intermediate object program of system operation comprises geometric parameter, the imaginary axis of emery wheel in space, emery wheel profile are because of machining code, grinding process step and the technological parameter of the time dependent process of wearing and tearing, digital control system and the mathematic(al) representation of grinding process median curved surface geometry.
Grinding machine supplemental characteristic library module, its effect is the feature of the few axle ultraprecise numerically control grinder of record, comprises the physical dimension parameter of grinding machine, the extreme position of each axle motion, the highest and minimum operation speed and acceleration, the single order model frequency of grinding machine and the static rigidity of grinding machine of each axle.
Grinding process DBM, its effect is to record the technological parameter of grinding condition, use and the mirror-quality reaching.Grinding condition refers to attribute and the cooling fluid type of optical mirror plane blank material, emery wheel.The attribute of emery wheel refers to abrasive type, bonding agent type, abrasive particle size and the concentration of emery wheel.Technological parameter refers to the grinding depth of the speed of mainshaft, grinding speed, emery wheel feed speed and emery wheel.Mirror-quality refers to surface figure accuracy and the surface roughness of minute surface.
Constraints constructing module, its effect is to carry out tectonic system constraints according to human-computer interaction module, grinding process DBM and grinding machine supplemental characteristic library module.Constraints constructing module, for emery wheel geometric parameter reconstructed module provides system restriction condition, comprising: geometric expression formula, surface figure accuracy and the surface roughness of the model frequency of grinding machine, grinding linear velocity, optical mirror plane; Technological parameter under same or similar mirror base material, the identical or close minute surface aimed quality condition providing with technological parameter generation module for processing step; And the extreme position of the physical dimension parameter of the grinding machine providing for imaginary axis generation module and the motion of each axle.
Emery wheel geometric parameter reconstructed module, its effect is the parameter providing according to constraints constructing module and processing step and technological parameter generation module, the geometric parameter of reconstruct emery wheel.Medium plain emery wheel of the present invention is from large Shape Classification, for anchor ring emery wheel, emery wheel geometric parameter comprises grinding wheel diameter, emery wheel radius of clean-up, emery wheel rim angle and grinding wheel spindle inclination angle, grinding wheel spindle inclination angle is identical with machine tool chief axis inclination angle, and above-mentioned four geometric parameters can be determined the geometry of emery wheel completely.
The selection of grinding wheel diameter, according to the requirement of grinding process, emery wheel is known in the linear velocity at grinding points place, the mode of lathe is also fixed, the speed of machine tool chief axis is less than lathe single order model frequency, can obtain so good dynamic effect, the diameter of emery wheel just can be calculated by speed, linear velocity so.
The selection of emery wheel radius of clean-up, according to the hands-off requirement in part, the radius of clean-up of emery wheel is less than workpiece maximum curvature radius to be ground, by the upper limit of this requirement restriction emery wheel radius of clean-up.The lower limit of emery wheel radius of clean-up is limited by removing material clearance.In grinding, removing material clearance, as an index, must be greater than certain value.Removing material clearance increases along with the increase of radius of clean-up.The radius of clean-up of the emery wheel of finally selecting is as long as just can in lower limit thereon.
The selection at grinding wheel spindle inclination angle, the inclination angle of grinding wheel spindle is the inclination angle of grinding machine spindle namely.The excursion at grinding wheel spindle inclination angle is 0 ° to 90 ° in theory, and for definite workpiece to be processed, grinding wheel spindle inclination angle and the grinding points distribution angle on emery wheel circumferencial direction has definite functional relation.The distribution angle of grinding points on emery wheel circumferencial direction is wider, and local possibility of interfering is larger, but wearing and tearing are more even.Comprehensively interfere and both factor of wearing and tearing, the distribution angle of a selected grinding points on emery wheel circumferencial direction, can obtain the value at grinding wheel spindle inclination angle on the function relation figure of the distribution angle on emery wheel circumferencial direction at grinding wheel spindle inclination angle and grinding points.
The selection of emery wheel rim angle is done Gauss Map by emery wheel curved surface and workpiece to be processed curved surface simultaneously, and the image field of the Gauss Map of guarantee workpiece to be processed curved surface, in the image field of the Gauss Map of emery wheel curved surface, according to this condition, calculates emery wheel rim angle.
Imaginary axis generation module, outside three shifting axles of few axle ultra-precision grinding machine, the extreme position of the physical dimension parameter of the grinding machine that the emery wheel geometric parameter providing according to emery wheel geometric parameter reconstructed module and constraints constructing module provide and the motion of each axle, fictionalize two rotating shafts that geometric position is definite, obtain virtual five travelling wheelhead roll grinders, from virtual five travelling wheelhead roll grinders described in kinematic angle and actual five travelling wheelhead roll grinder equivalences.
Few track shaft planning and interference checking module, on the basis of virtual five travelling wheelhead roll grinders that provide at imaginary axis generation module, the geometric properties of the grinding process median curved surface providing according to processing step and technological parameter generation module, determine the form of surface of the work upper slitter contact track, if curve surface of workpiece does not have axially symmetric structure, select zigzag cutter-contact point track.So-called zigzag cutter-contact point track, refer to a series of vertical parallel planes crossing with workpiece to be processed, the track of a series of intersections formation of acquisition.If curve surface of workpiece has axially symmetric structure, select spiral cutter-contact point track.
The calculating of adjacent track line space on surface of the work, for two corresponding points on adjacent track, the ultimate range between them be between these 2 effectively cutting width and.Spirality cutter-contact point track adjacent track line space is exactly the above ultimate range, and zigzag cutter-contact point track adjacent track line space is the minimum of a value of ultimate range between all corresponding points on adjacent track.
The calculating of the coordinate of putting on grinding wheel movement track, on the basis of described virtual five travelling wheelhead roll grinders, according to the coordinate of cutter-contact point on curve surface of workpiece and normal vector, calculates the value of the each axle of described virtual five travelling wheelhead roll grinder.The value of three shifting axles is on grinding wheel movement track the position of point under workpiece coordinate system, the value representation of two virtual pivots the position of cutter-contact point on wheel face.
Local interference checking, carries out local interference checking according to the deviation value of grinding points place emery wheel curved surface and workpiece to be processed curved surface.If the deviation along all directions in the common tangent plane of grinding points place emery wheel curved surface and curve surface of workpiece is all not less than zero, local the interference do not exist, otherwise local the interference exists.
Abrasion of grinding wheel prediction and track correct module; its effect is on the basis of the emery wheel geometric parameter that provides in emery wheel geometric parameter reconstructed module; predict the profile of emery wheel over time, and the position correction amount producing because of abrasion of grinding wheel according to the grinding wheel movement track acquisition that few track shaft is planned and local interference checking module provides.The mirror shape precision that the order of accuarcy of process medium plain emery wheel wearing and tearing prediction can provide by mirror-quality detection module judges.If prediction deviation is excessive, according to the parameter in the process of surface figure accuracy value correction abrasion of grinding wheel prediction, further improve the accuracy of abrasion of grinding wheel prediction.
Few axle machining code generation module, interferes grinding wheel movement track and the abrasion of grinding wheel prediction that checking module provides to combine with the position correction amount that track correct module provides with local few track shaft planning, obtains revised grinding wheel movement track.Grinding wheel movement track adopts the expression-form of discrete point, and digital control system cannot directly be utilized, so discrete point track is converted to the G code of numerically control grinder processing use.Emery wheel feed speed in G code and the speed of mainshaft are provided by processing step and technological parameter generation module.According to the type of digital control system and ability, both can be converted into the G code of linear interpolation type, also can be converted into the G code of spline interpolation type.
Processing step and technological parameter generation module, effect is the constraints providing according to constraints constructing module, determines the processing step of this grinding and the technological parameter that each step adopts according to the existing technological parameter under same or similar mirror base material, identical or close minute surface aimed quality condition.Processing step refers to roughing, semifinishing and accurately machined grinding sequentially and the number sequence expression formula of the median curved surface geometry producing.Under roughing, semifinishing and fine finishining, technological parameter will be determined respectively.
Few axle ultraprecise numerically control grinder Executive Module, adopts three shifting axle configurations, can avoid the run-out error that adopts rotating shaft to bring.Wherein Y-axis adopts arch twin beams form, can improve greatly the integral rigidity of system.Main shaft is between twin beams, and spindle tilt is adjustable, spindle tilt according to different curve surface of workpiece by system reconfiguration of the present invention.System of the present invention can be processed the ultraprecise optical mirror plane of maximum 2m bore.
Emery wheel dressing dressing module, its effect is the emery wheel geometric parameter providing according to emery wheel geometric parameter reconstructed module, emery wheel is carried out to the shaping of profile, to reach the physical dimension of regulation, emery wheel is carried out to dressing, makes emery wheel sharper, improves the effect of cutting.If abrasion of grinding wheel is too serious, depart from when excessive with original profile, use emery wheel dressing dressing module to emery wheel again shaping dressing.
Mirror-quality detection module, its effect is the surface quality detecting after optical fabrication, comprises surface figure accuracy and surface roughness.The result that mirror-quality detects is recorded to grinding process DBM together with the grinding condition of this grinding, grinding process parameters, is definite foundation that provides of later grinding process parameters.
The present invention compared with prior art, provide a set of complete restructural ultraprecise large optical mirror grinding system, on few axle ultraprecise numerically control grinder of the present invention, for free form surface, the optical mirror plane of the maximum 2m of bore, can be reconstructed emery wheel geometric parameter and machine tool chief axis angle of inclination; For the character of curve surface of workpiece, can be reconstructed the movement locus of emery wheel; For dissimilar digital control system, can be reconstructed the G code of processing use.For the wearing and tearing in wheel grinding process, can compensate grinding wheel movement track.System of the present invention can, for any optical mirror plane, by generating virtual axle, make full use of the flexibility of five travelling wheelhead roll grinders, has brought into play the advantage of the large damping of the high rigidity of few travelling wheelhead roll grinder simultaneously, and has possessed abrasion of grinding wheel forecast value revision ability, has significantly improved machining accuracy.System of the present invention has can processing optical minute surface bore large, few axle, restructural, efficiency is high, precision is high, good stability, adaptable feature.
Brief description of the drawings
Fig. 1 is the schematic block diagram of system of the present invention
Fig. 2 be the few axle ultraprecise numerically control grinder Executive Module in the present invention few axle ultraprecise numerically control grinder structure and be arranged on shaping dressing module and the mirror-quality detection module on this few axle ultraprecise numerically control grinder.
Fig. 3 is the imaginary axis in each geometric parameter and the imaginary axis generation module of toroidal wheel cross section, emery wheel of the emery wheel geometric parameter reconstructed module in the present invention.
Detailed description of the invention
As shown in the figure, describe specific embodiment of the invention scheme in detail below in conjunction with accompanying drawing.
Fig. 1 is the schematic block diagram of system of the present invention.In figure, 101 is computer A, and 102 is computer B, and 200 is workstation computer.
First user, by Man Machine Interface, specifies optical mirror plane blank material to be processed, size, and the mathematic(al) representation of optical mirror plane geometry, machines surface figure accuracy and surface roughness that rear minute surface will reach.In system running, pass through Man Machine Interface, check the intermediate object program of system operation, comprise the geometric parameter of emery wheel, the position of imaginary axis, the movement locus of emery wheel in space, emery wheel profile is because of the time dependent process of wearing and tearing, the machining code of digital control system, grinding process step and technological parameter, the mathematic(al) representation of grinding process median curved surface geometry.
Grinding machine parameter database module records the feature of few axle ultraprecise numerically control grinder, comprise the physical dimension parameter of grinding machine, the extreme position of each axle motion, the highest, the minimum operation speed of each axle, acceleration, the single order model frequency of grinding machine, the static rigidity of grinding machine.
Grinding process DBM has recorded grinding condition, the technological parameter of use, the mirror-quality reaching.Described grinding condition refers to the attribute of optical mirror plane blank material, emery wheel, the type of cooling fluid.The attribute of described emery wheel refers to abrasive type, bonding agent type, abrasive particle size, the concentration of emery wheel.Described technological parameter refers to the grinding depth of the speed of mainshaft, grinding speed, emery wheel feed speed, emery wheel.Described mirror-quality refers to surface figure accuracy and the surface roughness of minute surface.
Then in constraints constructing module according to human-computer interaction module, grinding process DBM, grinding machine parameter database module structure system restriction condition.Described system restriction condition refers to that the constraints providing for emery wheel geometric parameter reconstructed module comprises model frequency, the grinding linear velocity of grinding machine, geometric expression formula, surface figure accuracy and the surface roughness of optical mirror plane, technological parameter under same or similar mirror base material, the identical or close minute surface aimed quality condition providing with technological parameter generation module for processing step, the physical dimension parameter of the grinding machine providing for imaginary axis generation module, the extreme position of each axle motion.
Then the constraints providing according to constraints constructing module in processing step and technological parameter generation module, determines the processing step of this grinding and the technological parameter that each step adopts according to the existing technological parameter under same or similar mirror base material, identical or close minute surface aimed quality condition.Described processing step refers to roughing, semifinishing and accurately machined grinding sequentially and the mathematic(al) representation of the median curved surface geometry producing.Under roughing, semifinishing and fine finishining, technological parameter is determined respectively.
Then in emery wheel geometric parameter reconstructed module, according to system restriction condition, realize functions of modules according to the following step, the first step, what limit emery wheel is shaped as anchor ring; Second step, in the linear velocity of grinding points, calculates grinding wheel diameter according to the single order model frequency of grinding machine and emery wheel; The 3rd step, according to the maximum of radius of curvature on the material removing rate requirement of grinding points and workpiece, calculates emery wheel radius of clean-up; The 4th step, follows according to emery wheel and does not interfere and the requirement of uniform wear, makes the distribution angle of grinding points on emery wheel circumferencial direction, calculates grinding wheel spindle inclination angle; The 5th step, in the image field of the Gauss Map of emery wheel curved surface, calculates emery wheel rim angle according to the image field of the Gauss Map of machining curve surface of workpiece.
Then in imaginary axis generation module, except three shifting axles of few axle ultra-precision grinding machine, the extreme position of the physical dimension parameter of the grinding machine that the emery wheel geometric parameter providing according to described emery wheel geometric parameter reconstructed module and constraints constructing module provide, the motion of each axle, fictionalize two rotating shafts that geometric position is definite, obtain virtual five travelling wheelhead roll grinders, from virtual five travelling wheelhead roll grinders described in kinematic angle and actual five travelling wheelhead roll grinder equivalences.
Then in few track shaft planning and interference checking module, on the basis of virtual five travelling wheelhead roll grinders that provide at described imaginary axis generation module, under described constraints, realize functions of modules according to the following step:
The first step, the geometric properties of the grinding process median curved surface providing according to described processing step and technological parameter generation module, determines the form of surface of the work upper slitter contact track, if curve surface of workpiece does not have axially symmetric structure, selects zigzag cutter-contact point track.So-called zigzag cutter-contact point track, refer to a series of vertical parallel planes crossing with workpiece to be processed, the track of a series of intersections formation of acquisition.If curve surface of workpiece has axially symmetric structure, select spiral cutter-contact point track.
Second step calculates adjacent track line space on surface of the work.For two corresponding points on adjacent track, the ultimate range between them be between these 2 effectively cutting width and.Spirality cutter-contact point track adjacent track line space is exactly the above ultimate range, and zigzag cutter-contact point track adjacent track line space is the minimum of a value of ultimate range between all corresponding points on adjacent track.
The 3rd step, on the basis of described virtual five travelling wheelhead roll grinders, according to the coordinate of cutter-contact point on curve surface of workpiece and normal vector, calculates the value of the each axle of described virtual five travelling wheelhead roll grinder.The value of three shifting axles is on grinding wheel movement track the position of point under workpiece coordinate system, the value representation of two virtual pivots the position of cutter-contact point on wheel face.
The 4th step, carries out local interference checking according to the deviation value of grinding points place emery wheel curved surface and workpiece to be processed curved surface.Concrete grammar is if the deviation along all directions is all not less than zero in the public tangent plane of grinding points place emery wheel curved surface and curve surface of workpiece, and local the interference do not exist, otherwise local the interference exists.
Then in abrasion of grinding wheel prediction and track correct module; on the basis of the emery wheel geometric parameter providing in described emery wheel geometric parameter reconstructed module; predict the profile of emery wheel over time, and obtain according to described few track shaft planning and the grinding wheel movement track that local interference checking module provides the position correction amount producing because of abrasion of grinding wheel.The mirror shape precision that the order of accuarcy of process medium plain emery wheel wearing and tearing prediction can provide by mirror-quality detection module judges.If prediction deviation is excessive, according to the parameter in the process of surface figure accuracy value correction abrasion of grinding wheel prediction, further improve the accuracy of abrasion of grinding wheel prediction.
Then in few axle machining code generation module, interfere grinding wheel movement track and the prediction of described abrasion of grinding wheel that checking module provides to combine with the position correction amount that track correct module provides with local described few track shaft planning, obtain revised grinding wheel movement track.Grinding wheel movement track adopts the expression-form of discrete point, and digital control system cannot directly be used, so discrete point track is converted to the G code of numerically control grinder processing use.Emery wheel feed speed in G code and the speed of mainshaft are provided by processing step and technological parameter generation module.According to the type of digital control system and ability, both can be converted into the G code of linear interpolation type, also can be converted into the G code of spline interpolation type.
Then in few axle ultraprecise numerically control grinder Executive Module, few axle ultraprecise numerically control grinder adopts three shifting axle configurations, can avoid the run-out error that adopts rotating shaft to bring.Wherein Y-axis adopts arch twin beams form, can improve greatly the integral rigidity of system.Main shaft is between twin beams, and spindle tilt is adjustable, spindle tilt according to different curve surface of workpiece by system reconfiguration of the present invention.System of the present invention can be processed the ultraprecise optical mirror plane of maximum 2m bore.
Then in emery wheel dressing dressing module, the emery wheel geometric parameter providing according to emery wheel geometric parameter reconstructed module, carries out the shaping of profile to emery wheel, to reach the physical dimension of regulation, emery wheel is carried out to dressing, makes emery wheel sharper, improves the effect of cutting.If abrasion of grinding wheel is too serious, depart from when excessive with original profile, use emery wheel dressing dressing module to emery wheel again shaping dressing.
Finally, in mirror-quality detection module, detect the surface quality after optical fabrication, comprise surface figure accuracy and surface roughness.The result that mirror-quality detects is recorded to grinding process DBM together with the grinding condition of this grinding, grinding process parameters, is definite foundation that provides of later grinding process parameters.
Fig. 2 be the few axle ultraprecise numerically control grinder Executive Module in the present invention few axle ultraprecise numerically control grinder structure and be arranged on shaping dressing module and the mirror-quality detection module on this few axle ultraprecise numerically control grinder.Grinding machine overall structure adopts the form of three shifting axles.1,3,6 X-axis, Y-axis, the Z axis that are respectively grinding machine in Fig. 2.Y-axis adopts arch twin-spar construction.In Fig. 2,5 is grinding machine spindle, and main shaft is between twin beams, and spindle tilt can be adjusted in the plane between twin beams.In Fig. 2,4 for being arranged on the emery wheel on main shaft, and 2 is emery wheel dressing dressing module, and 7 is mirror-quality detection module.
Fig. 3 shows cross section, each geometric parameter of emery wheel and the position of two imaginary axis of toroidal wheel.The angle β of figure medium plain emery wheel axis and vertical direction is grinding wheel spindle inclination angle, namely the inclination angle of grinding machine spindle.D
wrepresent the diameter of emery wheel, R
cthe radius of clean-up of emery wheel, in Fig. 3 cross section, O
cr
ca center of circle.O
t-X
ty
tz
trepresent workpiece coordinate system, in the present invention, trajectory planning obtains series of discrete point and just refers to workpiece coordinate system initial point O
tcoordinate.O
m-X
my
mz
mrefer to workpiece coordinate system, the rim angle that γ 1 and γ 2 are emery wheel.A
axiswith B
axisfor two virtual pivots, wherein A of few travelling wheelhead roll grinder
axisrotating shaft be emery wheel axis, B
axisrotating shaft pass through O
cpoint, and perpendicular to Fig. 3 cross section, B
axisbe fixed on A
axisupper, with A
axismotion.A
axisbe fixed on Z axis, move with Z axis.