CN115533675A - Optical element time-control grinding surface shape measuring system and surface shape measuring method - Google Patents

Optical element time-control grinding surface shape measuring system and surface shape measuring method Download PDF

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Publication number
CN115533675A
CN115533675A CN202211255656.9A CN202211255656A CN115533675A CN 115533675 A CN115533675 A CN 115533675A CN 202211255656 A CN202211255656 A CN 202211255656A CN 115533675 A CN115533675 A CN 115533675A
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China
Prior art keywords
time
axis
workpiece
controlled grinding
optical element
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CN202211255656.9A
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Chinese (zh)
Inventor
戴一帆
胡皓
孙梓洲
彭小强
关朝亮
赖涛
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National University of Defense Technology
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National University of Defense Technology
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Priority to CN202211255656.9A priority Critical patent/CN115533675A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B13/00—Machines or devices designed for grinding or polishing optical surfaces on lenses or surfaces of similar shape on other work; Accessories therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B13/00—Machines or devices designed for grinding or polishing optical surfaces on lenses or surfaces of similar shape on other work; Accessories therefor
    • B24B13/005—Blocking means, chucks or the like; Alignment devices
    • B24B13/0055—Positioning of lenses; Marking of lenses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B41/00—Component parts such as frames, beds, carriages, headstocks
    • B24B41/007—Weight compensation; Temperature compensation; Vibration damping
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
    • B24B49/02—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation according to the instantaneous size and required size of the workpiece acted upon, the measuring or gauging being continuous or intermittent
    • B24B49/03—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation according to the instantaneous size and required size of the workpiece acted upon, the measuring or gauging being continuous or intermittent according to the final size of the previously ground workpiece
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B49/00—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation
    • B24B49/12—Measuring or gauging equipment for controlling the feed movement of the grinding tool or work; Arrangements of indicating or measuring equipment, e.g. for indicating the start of the grinding operation involving optical means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
    • G01B11/2441—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures using interferometry

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Constituent Portions Of Griding Lathes, Driving, Sensing And Control (AREA)

Abstract

The invention discloses a time-controlled grinding surface shape measuring system for an optical element, which comprises a lathe bed, wherein the lathe bed is provided with a workpiece mounting seat which does linear motion along an X axis and a time-controlled grinding processing platform which moves along a Y axis and a Z axis, the time-controlled grinding processing platform is provided with a time-controlled grinding processing device and a time-controlled grinding processing platform used for measuring the displacement variation delta L of the time-controlled grinding processing platform in the Z axis direction 2 (x, y) first measuring device and method for measuring the distance L to the workpiece surface 3 (x, y) second measuring deviceAnd (4) placing. Also discloses a method for measuring the shape of the grinding surface of the optical element during time control, which comprises the following steps: calibrating; extracting errors; determining a measurement starting point and establishing a measurement coordinate system; and acquiring actual data of the surface shape of the workpiece. The time-controlled grinding surface shape measuring system and the time-controlled grinding surface shape measuring method for the optical element can realize in-situ measurement of optical element machining, reduce the influence on the machining precision and efficiency of workpieces caused by carrying and repeated clamping, improve the measuring efficiency and realize the integration of machining and detection.

Description

Optical element time-control grinding surface shape measuring system and surface shape measuring method
Technical Field
The invention relates to the technical field of measuring instruments, in particular to a time-controlled grinding surface shape measuring system and a time-controlled grinding surface shape measuring method for an optical element.
Background
With the development of the fields of material science, ultra-precision processing technology, finite element analysis and the like, materials such as fused quartz, K9 glass, monocrystalline silicon and the like used by optical elements realize the aim of lighter weight under structural topology optimization and a new processing method; the advance of ultra-precision processing equipment and process leads the aperture of the single-sided reflector to be larger and larger, the aperture of the single-sided reflector is improved from 2-3 meters in the last century to 8-10 meters nowadays, and the increase of the aperture greatly improves the imaging quality of an optical system; meanwhile, with the development of the fields of large-caliber sub-mirror splicing telescopes, laser fusion and the like, higher requirements are put forward on the processing efficiency and the processing precision of large-caliber optical elements.
The appearance of the time-controlled grinding concept creates a good entrance condition for ultra-precise deterministic processing (such as magneto-rheological and ion beam polishing processes), greatly reduces the processing allowance caused by the processing error of the previous procedure, and is expected to improve the processing efficiency of the optical element by more than ten times. In order to ensure the precision and efficiency of the time-controlled grinding of the large-caliber optical element, the following requirements are provided for the workpiece measuring equipment and the workpiece measuring method:
(1) The times of repeated clamping and carrying of the workpiece are reduced as much as possible;
(2) The measurable range is more than 500mm;
(3) The measurement precision is better than 1 μm;
(4) The method has good measurement adaptability and universality.
In the existing high-precision measurement method, the measurement range of the swing arm type contourgraph and the three-coordinate instrument is large, but the measurement precision is slightly insufficient; the laser interferometry has extremely high precision, but the universality of a light path on workpieces with different surface shapes is poor, corresponding lenses and CGH compensating plates need to be prepared, and the requirements on the surface quality of the workpieces and the measurement space environment are high; the non-contact high-precision coordinate measuring machine has good measuring precision and measuring adaptability, but the measuring range is limited. Most importantly, the measuring equipment belongs to off-line measurement, and for a large-diameter workpiece ground in time control, the machining precision and the machining efficiency are influenced to a certain extent by repeated clamping and carrying. Therefore, a high-precision and high-efficiency measuring system capable of matching the characteristics of the grinding process during control is needed.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide an optical element time-control grinding surface shape measuring system and a surface shape measuring method, which can realize in-situ measurement of optical element processing, greatly reduce the influence on the processing precision and efficiency of workpieces caused by carrying and repeated clamping processes, improve the measuring efficiency, realize processing and detection integration and greatly shorten the manufacturing period of optical elements.
In order to solve the technical problems, the invention adopts the following technical scheme:
the time-controlled grinding surface shape measuring system for the optical element comprises a lathe bed, wherein a workpiece mounting seat which does linear motion along an X axis and a time-controlled grinding processing platform which does linear motion along a Y axis and a Z axis are arranged on the lathe bed, and the time-controlled grinding processing platform is provided with a time-controlled grinding processing device and a time-controlled grinding processing platform used for measuring the displacement variation delta L of the time-controlled grinding processing platform in the Z axis direction 2 (x, y) first measuring device and method for measuring the distance L to the workpiece surface 3 (x, y) second measuring means.
As a further improvement of the above technical solution:
the first measuring device comprises a laser interferometer and a reference flat crystal which are oppositely arranged, the laser interferometer is arranged on the time-controlled grinding platform, the reference flat crystal is fixed on the lathe bed, and the direction of a light path of the laser interferometer is parallel to the Z axis.
The lathe bed is provided with a mounting rack, and the reference flat crystal is fixed on the mounting rack.
The second measuring device is a spectrum confocal displacement sensor, and the light path direction of the spectrum confocal displacement sensor is parallel to the Z axis.
And the optical path of the laser interferometer is coaxial with the optical path of the spectrum confocal displacement sensor.
The time-controlled grinding machine is characterized in that a Y-axis track parallel to a Y axis is arranged on the machine body, a Y-axis moving seat is slidably arranged on the Y-axis track, a Z-axis track parallel to a Z axis is arranged on the Y-axis moving seat, and the time-controlled grinding platform is slidably arranged on the Z-axis track.
An X-axis rail parallel to the X axis is arranged on the lathe bed, and the workpiece mounting seat is arranged on the X-axis rail in a sliding mode.
The workpiece mounting seat comprises an X-axis moving table and a workpiece clamp platform rotating around a Z axis, the X-axis moving table is arranged on an X-axis track in a sliding mode, and the workpiece clamp platform is arranged on the X-axis moving table.
The optical element time-control grinding surface shape measuring system further comprises a numerical control module, and the first measuring device and the second measuring device are in signal connection with the numerical control module.
A method for measuring the time-controlled grinding surface shape of an optical element is carried out by adopting the time-controlled grinding surface shape measuring system of the optical element, and comprises the following steps:
step S1, calibration: calibrating and calibrating the first measuring device and the second measuring device;
step S2, extracting errors: extracting the jumping error L of the workpiece mounting seat in the Z-axis direction 1 (x,y)；
S3, determining a measurement starting point and establishing a measurement coordinate system;
s4, acquiring actual data of the surface shape of the workpiece: inputting workpiece surface shape theoretical data into a numerical control module to obtain a preset running track of a time control grinding platform, the feed quantity of a workpiece mounting seat and a compensation coefficient k, wherein the time control grinding platform and the workpiece mounting seat run in a matched mode to measure a measurement value sigma L (x, y) of each position of a workpiece surface,
ΣL(x,y)＝L 1 (x,y)+δL 2 (x,y)+k*L 3 and (x, y) is the actual data of the surface shape of the workpiece.
Compared with the prior art, the invention has the advantages that:
according to the time-controlled grinding surface shape measuring system for the optical element, the workpiece surface A is directly measured on the workpiece mounting seat after being processed, the workpiece surface A does not need to be detached from the workpiece mounting seat for measurement, in-situ measurement of large-diameter optical element processing can be realized, and the influence on the processing precision and efficiency of the workpiece caused by carrying and repeated clamping processes is greatly reduced. Aiming at the characteristics of the shape, the size, the target precision, the surface quality and the like of the optical element, the invention greatly improves the measurement efficiency, reduces the requirements of the measurement process on environment, equipment and manpower, integrates the processing and the detection and greatly shortens the manufacturing period of the optical element.
According to the time-controlled grinding surface shape measuring system for the optical element, disclosed by the invention, the first measuring device and the second measuring device can compensate the motion error of the time-controlled grinding platform in the Z axis in real time, so that the measuring precision is further improved.
According to the time-controlled grinding surface shape measuring system for the optical element, the optical path of the laser interferometer is coaxial with the optical path of the spectral confocal displacement sensor, the length of the measured Abbe arm is reduced as much as possible, and the measuring certainty is improved.
According to the time-controlled grinding surface shape measuring method for the optical element, the workpiece surface A is directly measured on the workpiece mounting seat after being processed, the workpiece surface A does not need to be detached from the workpiece mounting seat for measurement, in-situ measurement of large-diameter optical element processing can be achieved, and the influence on the processing precision and efficiency of the workpiece caused by carrying and repeated clamping processes is greatly reduced. Aiming at the characteristics of the shape, the size, the target precision, the surface quality and the like of the optical element, the invention greatly improves the measurement efficiency, reduces the requirements of the measurement process on environment, equipment and manpower, integrates the processing and the detection and greatly shortens the manufacturing period of the optical element.
Drawings
FIG. 1 is a schematic perspective view of a time-controlled grinding surface shape measuring system of an optical element according to the present invention.
FIG. 2 is a schematic view of a first measuring device of the time-controlled grinding surface shape measuring system of the optical element of the present invention.
FIG. 3 is a measurement schematic diagram of a second measurement device of the time-controlled grinding surface shape measurement system of the optical element of the present invention.
FIG. 4 is a front view of a workpiece measuring track of the time-controlled grinding surface shape measuring system of the optical element of the present invention.
FIG. 5 is a top view of a workpiece measurement trace of the time-controlled grinding profile measurement system of the optical element of the present invention.
FIG. 6 is a flow chart of the method for measuring the timing of the grinding profile of the optical element of the present invention.
The reference numerals in the figures denote:
1. a workpiece mounting seat; 11. an X-axis moving stage; 12. a workpiece holder platform; 2. grinding the machining platform in a time-controlled manner; 3. a time-controlled grinding device; 4. a first measuring device; 41. a laser interferometer; 42. a reference flat crystal; 5. a second measuring device; 6. a bed body; 61. a mounting frame; 62. a Y-axis track; 63. a Y-axis moving base; 64. a Z-axis track; 65. an X-axis orbit; A. and (5) workpiece surface.
Detailed Description
The invention will be described in further detail below with reference to the drawings and specific examples.
The first embodiment is as follows:
fig. 1 to 5 show an embodiment of a time-controlled grinding surface shape measuring system of an optical element according to the present invention, which includes a bed 6, a workpiece mounting base 1 linearly moving along an X-axis and a time-controlled grinding platform 2 moving along a Y-axis and a Z-axis are provided on the bed 6, a time-controlled grinding device 3, a first measuring device 4 for measuring a displacement variation δ L2 (X, Y) of the time-controlled grinding platform 2 in a Z-axis direction, and a distance L from a workpiece surface a are provided on the time-controlled grinding platform 2 3 (x, y) second measuring means 5. The workpiece mount 1 is used for mounting a workpiece (optical element); the X axis, the Y axis and the Z axis are mutually vertical and are three axes of a coordinate system, generally, the X axis and the Y axis are a transverse axis and a longitudinal axis on a horizontal plane, and the Z axis is a vertical axisAnd (4) towards the shaft.
The use process comprises the following steps: firstly, a workpiece (an optical element) is arranged on a workpiece mounting seat 1, and the workpiece is machined through the matched operation of a time-controlled grinding platform 2 and the workpiece mounting seat 1 to form a workpiece surface A; secondly, calibrating and calibrating the first measuring device 4 and the second measuring device 5; next, a run-out error L of the workpiece mount 1 in the Z-axis direction is extracted 1 (X, y), for example, a spectral interferometer of an external laser measuring instrument for measuring motion errors is vertically fixed on the workpiece mounting seat 1, a reflector of the external laser measuring instrument is fixed on the lathe bed 6, the light path of the external laser measuring instrument reaches a measuring state through repeated fine adjustment, the machining platform 2 is ground during fixed control, only the motion of the workpiece mounting seat 1 along the X axis is kept, the data of the laser measuring instrument is recorded in the motion stroke of the workpiece mounting seat 1, and the jumping error L in the Z axis direction during the motion of the workpiece mounting seat 1 is obtained 1 (x, y) is vertical straightness error data when the workpiece mounting base 1 moves, L 1 (x, y) is a function related to the absolute position of the workpiece mount 1, i.e., L 1 (X, y) = f (X), where X is the absolute position of the workpiece mount 1 on the X-axis; then, a predetermined running track of the time-controlled grinding platform 2, the feed amount of the workpiece mounting seat 1 and the compensation coefficient k are obtained from the theoretical data of the workpiece surface shape, the time-controlled grinding platform 2 and the workpiece mounting seat 1 run in cooperation, and the measured numerical value Σ L (x, y), Σ L (x, y) = L at each position of the workpiece surface a is measured 1 (x,y)+δL 2 (x,y)+k*L 3 And (x, y) is the actual data of the surface shape of the workpiece. If the actual data of the surface shape of the workpiece meet the machining precision requirement, finishing the grinding machining; if the actual data of the surface shape of the workpiece does not meet the machining precision requirement, the optical element time-controlled grinding surface shape measurement system is used for carrying out grinding machining and surface shape measurement on the workpiece again until the actual data of the surface shape of the workpiece meets the machining precision requirement.
According to the time-controlled grinding surface shape measuring system for the optical element, the workpiece surface A is directly measured on the workpiece mounting seat 1 after being processed, the workpiece surface A does not need to be detached from the workpiece mounting seat 1 for measurement, in-situ measurement of large-caliber optical element processing can be realized, and the influence on the processing precision and efficiency of the workpiece caused by carrying and repeated clamping processes is greatly reduced. Aiming at the characteristics of the shape, the size, the target precision, the surface quality and the like of the optical element, the invention greatly improves the measurement efficiency, reduces the requirements of the measurement process on environment, equipment and manpower, integrates processing and detection and greatly shortens the manufacturing period of the optical element.
In this embodiment, as shown in fig. 1 and 2, the first measurement device 4 includes a laser interferometer 41 and a reference flat crystal 42 that are arranged oppositely, the laser interferometer 41 is disposed on the controlled grinding platform 2, the reference flat crystal 42 is fixed on the bed 6, and the optical path direction of the laser interferometer 41 is parallel to the Z axis.
The laser interferometer 41 is mounted on the controlled time grinding platform 2 and can servo-move along the Z-axis and Y-axis directions along with the controlled time grinding platform 2. The measurement schematic diagram of the first measurement device 4 is shown in fig. 2, the optical path direction of the laser interferometer 41 is parallel to the Z-axis direction, the emergent light is emitted along the Z-axis direction, reflected by the high reference flat crystal 42, the reflected light returns to the laser interferometer 41 along the Z-axis negative direction, the displacement variation of the grinding platform 2 in the Z-axis direction can be accurately measured by the interference fringes generated by emitting and reflecting the laser, and the displacement resolution can reach pm level.
Run-out error L in Z-axis direction when workpiece mounting base 1 moves 1 The (x, y) can also be extracted by means of the first measuring device 4, but the measurement accuracy is higher with an external laser measuring device.
In this embodiment, the bed 6 is provided with a mounting frame 61, and the reference flat crystal 42 is fixed to the mounting frame 61. The mounting frame 61 is mounted on the bed 6 and does not contact with moving parts such as the time-controlled grinding platform 2 and the workpiece mounting base 1. The mounting frame 61 is preferably made of invar (invar) with an extremely low linear expansion coefficient, and is isolated from the moving parts so that the mounting frame 61 is not affected by coupling factors such as vibration, temperature rise, movement errors and the like caused by the operation of other moving parts on the bed 6 during measurement, and extremely high measurement stability is maintained. The mounting frame 61 of the optical element time-control grinding surface shape measuring system is separated from other moving parts, so that the optical element time-control grinding surface shape measuring system is not influenced by coupling of factors such as motion errors, thermal deformation and vibration of other moving parts in the measuring process, and the measuring stability is greatly improved.
In this embodiment, the reference flat crystal 42 is manufactured by a wave surface interferometry method and a deterministic processing method such as magnetorheological, ion beam, etc., the flatness of the reference surface can reach λ/30- λ/10 (λ =632.8 nm), and the reference flat crystal 42 can be used as a measurement reference in comparison with the sub- μm-level measurement accuracy requirement required by the time-controlled grinding method.
The first measuring device 4 and the second measuring device 5 can compensate the motion error of the time-controlled grinding platform 2 in the Z axis in real time, and the measuring precision is further improved.
In this embodiment, the second measuring device 5 is a spectral confocal displacement sensor, and the optical path direction of the spectral confocal displacement sensor is parallel to the Z axis.
The second measuring device 5 is installed on the time-controlled grinding platform 2, and the time-controlled grinding platform 2 moves along the Z-axis direction and the Y-axis direction in a servo mode. As shown in fig. 3, the light path direction of the spectral confocal displacement sensor is parallel to the Z-axis direction, the emergent light of the spectral confocal displacement sensor is emitted along the Z-axis negative direction, reflected by the workpiece surface a, and the reflected light returns to the spectral confocal displacement sensor along the Z-axis positive direction, and the distance between the second measuring device 5 and the workpiece surface can be calculated according to the difference of the positions of the focusing points of the light rays with different wavelengths, and the resolution can reach 80nm. The adaptability of the spectrum confocal displacement sensor to the measuring surface is better than that of the laser interferometer 41, and the measurement of a rough surface and a surface with higher gradient can be realized.
Due to the working characteristics of the second measuring device 5 (high-precision surface shape measuring sensor), corresponding compensation is required when workpieces with different gradients are measured, so that the gradient at each measuring position can be obtained according to theoretical data of the surface shape of the workpiece, and the real-time compensation coefficient k of the second measuring device 5 is correspondingly obtained.
In this embodiment, the optical path of the laser interferometer 41 is coaxial with the optical path of the spectral confocal displacement sensor. The optical path of the laser interferometer 41 is coaxial with the optical path of the spectrum confocal displacement sensor, so that the length of an Abbe arm to be measured is reduced as much as possible, and the measurement certainty is improved.
Due to the second measuring device 5 (spectral confocal displacement sensor)Device) has a limited range, so the time-controlled grinding platform 2 provided with the second measuring device 5 and the laser interferometer 41 needs to move according to a preset track calculated by theoretical data of the surface shape of the workpiece to ensure that the distance between the second measuring device 5 and the surface of the workpiece is always within the range of the second measuring device 5, and when the time-controlled grinding platform 2 moves, the laser interferometer 41 continuously measures the accurate displacement deltaL of the time-controlled grinding platform 2 on the Z axis 2 (x,y)。
In this embodiment, the bed 6 is provided with a Y-axis rail 62 parallel to the Y-axis, the Y-axis rail 62 is slidably provided with a Y-axis moving base 63, the Y-axis moving base 63 is provided with a Z-axis rail 64 parallel to the Z-axis, and the time-controlled grinding platform 2 is slidably provided on the Z-axis rail 64. The Y-axis moving base 63 is connected to a Y-axis servo mechanism (not shown) for driving the Y-axis moving base 63 to translate along the Y-axis rail 62, and the time-controlled grinding platform 2 is connected to a Z-axis servo mechanism (not shown) for driving the time-controlled grinding platform 2 to translate along the Z-axis rail 64.
In this embodiment, the bed 6 is provided with an X-axis rail 65 parallel to the X-axis, and the workpiece mounting base 1 is slidably disposed on the X-axis rail 65. The workpiece mount 1 is connected to an X-axis servo (not shown) for driving the workpiece mount 1 to translate along the X-axis rails 65.
In this embodiment, the workpiece mounting base 1 includes an X-axis moving stage 11 and a workpiece holder platform 12 rotating around the Z-axis, the X-axis moving stage 11 is slidably disposed on the X-axis rail 65, and the workpiece holder platform 12 is disposed on the X-axis moving stage 11. The work holder table 12 is connected to a rotation servo (not shown) for driving the X-axis moving stage 11 to rotate about the Z-axis.
In this embodiment, the optical element time-control grinding surface shape measuring system further includes a numerical control module, and the first measuring device 4 and the second measuring device 5 are both in signal connection with the numerical control module. And the numerical control module receives an external command and/or signal data of the first measuring device 4 and the second measuring device 5 to carry out numerical control on each moving part.
Example two:
fig. 6 shows an embodiment of the time-controlled grinding surface shape measuring method of an optical element according to the present invention, which is performed by using the time-controlled grinding surface shape measuring system of the first embodiment, and includes the following steps:
step S1, calibration: calibrating and calibrating the first measuring device 4 and the second measuring device 5;
step S2, extracting errors: extracting the jumping error L of the workpiece mounting seat 1 in the Z-axis direction 1 (x,y)；
S3, determining a measurement starting point and establishing a measurement coordinate system;
s4, acquiring actual data of the surface shape of the workpiece: inputting theoretical data of the surface shape of the workpiece into the numerical control module to obtain a preset running track of the time-controlled grinding platform 2, the feed amount of the workpiece mounting seat 1 and a compensation coefficient k, wherein the time-controlled grinding platform 2 and the workpiece mounting seat 1 run in a matched mode to measure a measurement value sigma L (x, y) of each position of the workpiece surface A,
ΣL(x,y)＝L 1 (x,y)+δL 2 (x,y)+k*L 3 and (x, y) is the actual data of the surface shape of the workpiece.
A workpiece (optical element) is arranged on the workpiece mounting seat 1, and after a workpiece surface A is formed by grinding through the matched operation of the time-controlled grinding platform 2 and the workpiece mounting seat 1, the surface shape of the workpiece surface A is measured.
Step S2 includes the following substeps:
step S2.1: vertically fixing a spectral interference mirror of an external laser measuring instrument for measuring motion errors on a workpiece mounting seat 1, fixing a reflecting mirror of the external laser measuring instrument on a lathe bed 6, and repeatedly finely adjusting to enable the light path of the external laser measuring instrument to reach a measuring state;
step S2.2: the time-controlled grinding platform 2 is fixed, only the movement of the workpiece mounting seat 1 along the X axis is reserved, the data of the laser measuring instrument is recorded in the movement stroke of the workpiece mounting seat 1, and the jumping error L of the workpiece mounting seat 1 in the Z axis direction during movement is obtained 1 (x, y) is vertical straightness error data, L, of the workpiece holder 1 during movement 1 (x, y) is a function related to the absolute position of the workpiece mount 1, i.e., L 1 (X, y) = f (X), where X is the absolute position of the workpiece mount 1 on the X-axis.
Step S4 includes the following substeps:
step S4.1: intercepting a workpiece surface A by a plurality of planes parallel to a YOZ plane to obtain a plurality of curves, wherein the distance between every two planes is delta X, and the delta X is 1mm in general measurement;
step S4.2: the profile curve of a certain section on a workpiece surface A is shown in fig. 4, the optical element time-controlled grinding surface shape measuring system finishes the movement of a preset track through the linkage of the time-controlled grinding processing platform 2 in the Z-axis and Y-axis directions, and a first measuring device 4 and a second measuring device 5 continuously acquire data in the movement process to finish the measurement of the profile of the curve on one section of the workpiece surface A;
because the second measuring device 5 (spectrum confocal displacement sensor) has a limited measuring range, the time-controlled grinding platform 2 provided with the second measuring device 5 and the first measuring device 4 needs to move according to a preset track calculated by the theoretical data of the surface shape of the workpiece so as to ensure that the distance between the second measuring device 5 and the surface of the workpiece is always within the measuring range of the second measuring device 5, and when the time-controlled grinding platform 2 moves, the first measuring device 4 continuously measures the accurate displacement delta L of the time-controlled grinding platform 2 on the Z axis 2 (x, y). And obtaining the preset running track of the time-controlled grinding platform 2, the feeding amount of the workpiece mounting seat 1 and the compensation coefficient k through the theoretical data of the surface shape of the workpiece.
Step S4.3: the workpiece mounting seat 1 feeds delta X, the time control grinding platform 2 moves to the starting point of the next section of the workpiece under the linkage of the Z-axis direction and the Y-axis direction, and the step S4.2 is repeated: completing the profile measurement on the subsequent section of the workpiece, wherein the track of the measurement process in the XOY plane is shown in FIG. 5;
step S4.4: the actual measurement for each location includes four parts: vertical straightness error L of workpiece mount 1 1 (x, y), the first measuring device 4 feeds back the displacement variation delta L of the controlled grinding platform 2 in the Z-axis direction 2 (x, y), the second measuring device 5 measures the distance L between the second measuring device 5 and the workpiece surface A 3 (x, y) and compensation coefficients k corresponding to different steepnesses of the workpiece surface a, and finally the measured value Σ L (x, y) at each position of the workpiece surface a is:
ΣL(x,y)＝L 1 (x,y)+δL 2 (x,y)+k*L 3 and (x, y) is the actual data of the surface shape of the workpiece.
Step S4.5: and converting the measured data into an xyz three-dimensional point cloud image through a numerical control module, and evaluating each subsequent index.
According to the time-controlled grinding surface shape measuring method for the optical element, the workpiece surface A is directly measured on the workpiece mounting seat 1 after the workpiece surface A is machined, the workpiece surface A does not need to be detached from the workpiece mounting seat 1 for measurement, on-site measurement of machining of the large-diameter optical element can be achieved, and the influence on the machining precision and efficiency of the workpiece caused by carrying and repeated clamping processes is greatly reduced. Aiming at the characteristics of the shape, the size, the target precision, the surface quality and the like of the optical element, the invention greatly improves the measurement efficiency, reduces the requirements of the measurement process on environment, equipment and manpower, integrates the processing and the detection and greatly shortens the manufacturing period of the optical element.
Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make numerous possible variations and modifications to the present invention, or modify equivalent embodiments to equivalent variations, without departing from the scope of the invention, using the teachings disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention should fall within the protection scope of the technical scheme of the present invention, unless the technical spirit of the present invention departs from the content of the technical scheme of the present invention.

Claims (10)

1. The utility model provides an optical element grinding surface shape measurement system of accuse time which characterized in that: the automatic grinding machine comprises a machine body (6), wherein a workpiece mounting seat (1) which moves linearly along an X axis and a time-controlled grinding machining platform (2) which moves along a Y axis and a Z axis are arranged on the machine body (6), and a time-controlled grinding machining device (3) and a first measuring device (4) which is used for measuring the displacement variation delta L2 (X, Y) of the time-controlled grinding machining platform (2) in the Z axis direction and is used for measuring the distance L between the time-controlled grinding machining platform and a workpiece surface (A) are arranged on the time-controlled grinding machining platform (2) 3 (x, y) second measuring means (5).
2. The time-controlled grinding surface shape measuring system of the optical element according to claim 1, wherein: the first measuring device (4) comprises a laser interferometer (41) and a reference flat crystal (42) which are oppositely arranged, the laser interferometer (41) is arranged on the time-controlled grinding machining platform (2), the reference flat crystal (42) is fixed on the machine body (6), and the optical path direction of the laser interferometer (41) is parallel to the Z axis.
3. The optical element time-controlled grinding surface shape measuring system according to claim 2, wherein: and a mounting frame (61) is arranged on the lathe bed (6), and the reference flat crystal (42) is fixed on the mounting frame (61).
4. The optical element time-controlled grinding surface shape measuring system according to claim 3, wherein: the second measuring device (5) is a spectrum confocal displacement sensor, and the light path direction of the spectrum confocal displacement sensor is parallel to the Z axis.
5. The optical element time-controlled grinding surface shape measuring system according to claim 4, wherein: the optical path of the laser interferometer (41) is coaxial with the optical path of the spectrum confocal displacement sensor.
6. An optical element time-controlled grinding profile measurement system according to any one of claims 1 to 5, wherein: the grinding machine is characterized in that a Y-axis track (62) parallel to a Y axis is arranged on the machine body (6), a Y-axis moving seat (63) is arranged on the Y-axis track (62) in a sliding mode, a Z-axis track (64) parallel to the Z axis is arranged on the Y-axis moving seat (63), and the time-controlled grinding platform (2) is arranged on the Z-axis track (64) in a sliding mode.
7. An optical element time-controlled grinding profile measurement system according to any one of claims 1 to 5, wherein: an X-axis track (65) parallel to the X axis is arranged on the lathe bed (6), and the workpiece mounting seat (1) is arranged on the X-axis track (65) in a sliding mode.
8. The optical element time-controlled grinding profile measurement system of claim 7, wherein: the workpiece mounting seat (1) comprises an X-axis moving platform (11) and a workpiece clamp platform (12) rotating around a Z axis, the X-axis moving platform (11) is arranged on an X-axis track (65) in a sliding mode, and the workpiece clamp platform (12) is arranged on the X-axis moving platform (11).
9. An optical element time-controlled grinding profile measurement system according to any one of claims 1 to 5, wherein: the optical element time-control grinding surface shape measuring system further comprises a numerical control module, and the first measuring device (4) and the second measuring device (5) are in signal connection with the numerical control module.
10. A method for measuring the time-controlled grinding surface shape of an optical element is characterized in that: the optical element time-controlled grinding profile measurement system of claim 9, comprising the steps of:
step S1, calibration: calibrating and calibrating the first measuring device (4) and the second measuring device (5);
step S2, extracting errors: extracting the jumping error L of the workpiece mounting seat (1) in the Z-axis direction 1 (x,y)；
S3, determining a measurement starting point and establishing a measurement coordinate system;
s4, acquiring actual data of the surface shape of the workpiece: inputting theoretical data of the surface shape of the workpiece into the numerical control module to obtain a preset running track of the time-controlled grinding platform (2), the feed amount of the workpiece mounting seat (1) and a compensation coefficient k, wherein the time-controlled grinding platform (2) and the workpiece mounting seat (1) run in a matched mode to measure a measurement value sigma L (x, y) of each position of the surface (A) of the workpiece,
ΣL(x,y)＝L 1 (x,y)+δL 2 (x,y)+k*L 3 and (x, y) is the actual data of the surface shape of the workpiece.
CN202211255656.9A 2022-10-13 2022-10-13 Optical element time-control grinding surface shape measuring system and surface shape measuring method Pending CN115533675A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114018174A (en) * 2021-11-05 2022-02-08 上海科技大学 Complex curved surface profile measuring system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114018174A (en) * 2021-11-05 2022-02-08 上海科技大学 Complex curved surface profile measuring system

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