CN118089562A - Non-contact thickness gauge and thickness measuring method thereof - Google Patents

Non-contact thickness gauge and thickness measuring method thereof Download PDF

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Publication number
CN118089562A
CN118089562A CN202410207360.2A CN202410207360A CN118089562A CN 118089562 A CN118089562 A CN 118089562A CN 202410207360 A CN202410207360 A CN 202410207360A CN 118089562 A CN118089562 A CN 118089562A
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CN
China
Prior art keywords
fixedly connected
slide carriage
guide rail
unit
confocal sensor
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CN202410207360.2A
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Chinese (zh)
Inventor
刘龙
赵天明
林波
李宗亮
史想诚
高思煜
朱敏
卢礼华
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Institute of Materials of CAEP
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Institute of Materials of CAEP
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Priority to CN202410207360.2A priority Critical patent/CN118089562A/en
Publication of CN118089562A publication Critical patent/CN118089562A/en
Pending legal-status Critical Current

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    • 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
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
    • F16F15/02—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems
    • F16F15/023—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems using fluid means
    • F16F15/0232—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems using fluid means with at least one gas spring
    • 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
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G01B11/03—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness by measuring coordinates of points
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B5/00—Measuring arrangements characterised by the use of mechanical techniques
    • G01B5/0002—Arrangements for supporting, fixing or guiding the measuring instrument or the object to be measured
    • G01B5/0004—Supports

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

The invention discloses a non-contact thickness gauge and a thickness measuring method thereof, wherein the non-contact thickness gauge comprises a damping base and a control unit, the upper end of the damping base is provided with a gantry type support frame, a two-dimensional horizontal movement table is fixedly connected to the damping base and used for adjusting the horizontal position of a workpiece to be measured, a vertical movement shaft is fixedly connected to the gantry type support frame, the output end of the vertical movement shaft is fixedly connected with a spectrum confocal sensor unit and a visual detection guide unit, and the control unit is electrically connected with the two-dimensional horizontal movement table, the vertical movement shaft, the spectrum confocal sensor unit, the visual detection guide unit and a data processing terminal. In the invention, the positioning precision of the two-dimensional horizontal movement table and the vertical movement axis is submicron, so that the moving precision of the workpiece to be detected, the visual detection guiding unit and the spectral confocal sensor unit is improved, thereby being beneficial to improving the thickness measuring precision; the spectral confocal sensor unit performs non-contact measurement, and is beneficial to avoiding scratching the surface of a workpiece.

Description

Non-contact thickness gauge and thickness measuring method thereof
Technical Field
The invention belongs to the technical field of thickness precision measurement, and particularly relates to a non-contact thickness gauge and a thickness measuring method thereof.
Background
The thickness of the workpiece is an important parameter for production and processing, and the accuracy of thickness measurement directly influences the assembly characteristics of the workpiece and the processing parameters of the ultra-precise matching piece. Conventional thickness measurement methods are classified into contact measurement and non-contact measurement.
The contact measurement usually adopts a three-coordinate measuring machine, a probe type altimeter or a digital display dial gauge on a special gauge stand. When the thickness is measured, the probe or the probe of the three-coordinate measuring machine and the probe type altimeter touch the surface of the workpiece and finish measurement after a certain measuring force is reached, so that the three-coordinate measuring machine and the probe type altimeter can generate indentation on the surface of the workpiece when measuring soft materials or products with plating layers, the apparent quality of the workpiece is influenced, and measurement damage is generated; the three-coordinate measuring machine and other equipment are not special thickness measuring instruments, the functions are complex, the design redundancy is high, certain thickness measurement can be considered, but the accuracy is difficult to reach submicron level; in addition, when the digital display dial indicator is matched with the special meter frame to measure the thickness, the digital display dial indicator is greatly influenced by the artificial factors and the accuracy of the dial indicator because the digital display dial indicator belongs to manual measurement, and the overall accuracy can only reach the micron level.
The non-contact measurement usually adopts a non-contact three-coordinate measuring machine or an imager and other devices. Wherein, the non-contact three-coordinate measuring machine is influenced by the structure of the three-coordinate measuring machine, and the precision of the non-contact three-coordinate measuring machine can only reach the micron level; in addition, the imaging instruments mainly measure in two-dimensional directions, and displacement sensors are additionally arranged in the Z direction of some imaging instruments, but the imaging instruments are limited by the Z-axis precision, and the precision of the imaging instruments can only reach the micron level.
Disclosure of Invention
The invention provides a non-contact thickness gauge and a thickness measuring method thereof, which can improve thickness measuring precision.
The aim of the invention is achieved by the following technical scheme:
In a first aspect, there is provided a non-contact thickness gauge comprising:
the upper end of the damping base is provided with a gantry type supporting frame;
The lower end of the two-dimensional horizontal movement table is fixedly connected to the damping base, the two-dimensional horizontal movement table is used for adjusting the horizontal position of a workpiece to be measured, the positioning accuracy of the two-dimensional horizontal movement table is +/-0.5 um, and the repeatability of a movement plane of the two-dimensional horizontal movement table is 0.3um;
The vertical movement shaft is fixedly connected to the gantry type supporting frame, and the positioning accuracy of the vertical movement shaft is +/-0.2 um;
The spectral confocal sensor unit is fixedly connected to the output end of the vertical movement axis;
the visual detection guide unit is fixedly connected to the output end of the vertical movement shaft;
the control unit is electrically connected with the two-dimensional horizontal movement table, the vertical movement axis, the spectral confocal sensor unit, the visual detection guiding unit and the data processing terminal.
In one embodiment, the damping base comprises a base, a damping air cushion is arranged at the lower end of the base, and the lower end of the damping air cushion is fixedly connected with an anchor bolt;
The damping base comprises an air supply pipeline for supplying air to the damping air cushion, and the air supply pipeline is provided with a pressure regulating valve.
The beneficial effects of adopting above-mentioned technical scheme are: the base can be placed on the ground through the damping air cushion, and the foundation bolts can fix the damping air cushion and the ground.
In one embodiment, the two-dimensional horizontal motion platform comprises a longitudinal air-floating guide rail, a first linear motor, a transverse air-floating guide rail and a second linear motor which are electrically connected with the control unit, wherein the longitudinal air-floating guide rail comprises a first guide rail and a first slide carriage, and the transverse air-floating guide rail comprises a second guide rail and a second slide carriage; the first guide rail is fixedly connected to the damping base, and the stator and the rotor of the first linear motor are respectively and fixedly connected to the first guide rail and the first slide carriage; the second guide rail is fixedly connected to the first slide carriage, the stator and the rotor of the second linear motor are respectively and fixedly connected to the second guide rail and the second slide carriage, and the second slide carriage is fixedly connected with a carrying plate for placing a workpiece to be measured.
The beneficial effects of adopting above-mentioned technical scheme are: the first linear motor can drive the first slide carriage to longitudinally slide on the first guide rail, the second linear motor can drive the second slide carriage to transversely slide on the second guide rail, and the second guide rail is fixedly connected to the first slide carriage, and the object carrying plate for placing the workpiece to be measured is fixedly connected to the second slide carriage, so that the control unit can adjust the horizontal position of the workpiece to be measured through the first linear motor and the second linear motor; in addition, the longitudinal air floating guide rail and the transverse air floating guide rail are both air floating guide rails, so that the adjustment precision of the horizontal position of the workpiece to be measured can be improved, and a foundation is laid for improving the thickness measurement precision.
In one embodiment, a first grating ruler is longitudinally arranged on the first guide rail, a first reading head for reading the first grating ruler is fixedly connected to the first slide carriage, a second grating ruler is transversely arranged on the second guide rail, a second reading head for reading the second grating ruler is fixedly connected to the second slide carriage, and the first grating ruler, the first reading head, the second grating ruler and the second reading head are all electrically connected with the control unit.
The beneficial effects of adopting above-mentioned technical scheme are: the first grating ruler, the first reading head, the second grating ruler and the second reading head are position feedback elements and are matched with the first linear motor and the second linear motor controlled by the control unit to realize closed-loop control, namely, when the movers of the first linear motor and the second linear motor move, the first reading head and the second reading head are respectively synchronously driven to move, the first reading head and the second reading head respectively read the first grating ruler and the second grating ruler and feed the first reading head and the second reading head back to the control unit, and the control unit respectively judges whether the first linear motor and the second linear motor are in place in real time according to real-time reading, and is favorable for respectively generating next operation parameters of the first linear motor and the second linear motor according to the next operation parameters, and circulation is performed so as to complete closed-loop control.
In one embodiment, both ends of the first guide rail are provided with a first limiting block and a first limiting switch for longitudinally limiting the first slide carriage, both ends of the second guide rail are provided with a second limiting block and a second limiting switch for transversely limiting the second slide carriage, and the first limiting switch and the second limiting switch are electrically connected with the control unit.
The beneficial effects of adopting above-mentioned technical scheme are: when the first limit switch and the second limit switch respectively detect the first slide carriage and the second slide carriage, signals can be fed back to the control unit so as to respectively stop the first linear motor and the second linear motor, and therefore the overrun of the movement of the first slide carriage and the second slide carriage is avoided; simultaneously, first stopper and second stopper can force spacing to first carriage and second carriage respectively.
In one embodiment, the vertical motion shaft comprises a vertical air floatation guide rail and a third linear motor which are electrically connected with the control unit, the vertical air floatation guide rail comprises a third guide rail and a third slide carriage, the third guide rail is fixedly connected to the gantry type supporting frame, a stator and a rotor of the third linear motor are respectively and fixedly connected to the third guide rail and the third slide carriage, and the third slide carriage is fixedly connected with the spectrum confocal sensor unit and the vision detection guiding unit.
The beneficial effects of adopting above-mentioned technical scheme are: the third linear motor can drive the third slide carriage to vertically slide on the third guide rail, and the control unit can adjust the vertical positions of the spectral confocal sensor unit and the visual detection guide unit through the third motor because the spectral confocal sensor unit and the visual detection guide unit are fixedly connected to the third slide carriage; in addition, the vertical air-float guide rail is an air-float guide rail, so that the adjustment precision of the vertical positions of the spectrum confocal sensor unit and the visual detection guide unit can be improved, and the thickness measurement precision can be improved.
In one embodiment, a third grating ruler is vertically arranged on the third guide rail, a third reading head for reading the third grating ruler is fixedly connected to the third slide carriage, a third limiting block and a third limiting switch for vertically limiting the third slide carriage are arranged on the third guide rail, and the third reading head and the third limiting switch are electrically connected with the control unit.
The beneficial effects of adopting above-mentioned technical scheme are: the third grating ruler and the third reading head are position feedback elements, and closed-loop control is realized by matching with the third linear motor controlled by the control unit, namely, when the mover of the third linear motor moves, the third reading head is synchronously driven to move, the third reading head reads the third grating ruler and feeds the third grating ruler back to the control unit, and the control unit judges whether the third linear motor is in place or not in real time according to the real-time reading, is favorable for generating the next operation parameter of the third linear motor according to the next operation parameter, and circulates in such a way, so that closed-loop control is completed.
In one embodiment, the vertical movement shaft comprises a balancing cylinder, the balancing cylinder is communicated with a cylinder adjusting valve electrically connected with the control unit, the output end of the balancing cylinder is fixedly connected with the third slide carriage, and the balancing cylinder is used for balancing the gravity born by the third slide carriage.
The beneficial effects of adopting above-mentioned technical scheme are: the third slide carriage can receive invariable downward gravity, and the control unit adjusts the pressure in the balance cylinder through the cylinder governing valve to adjust the holding power that the balance cylinder provided the third slide carriage, so that this holding power is the same with the gravity that the third slide carriage receives, and then realize the balance of gravity on the third slide carriage, with the influence of gravity on the third slide carriage to third linear electric motor drive, thereby improve the visual detection and guide unit and spectral confocal sensor unit's mobile accuracy, and then be favorable to improving thickness measurement accuracy.
In one embodiment, the visual detection guiding unit comprises an industrial camera, a fixed focus lens and a coaxial light source which are sequentially connected along the vertical downward direction, and the industrial camera, the fixed focus lens and the coaxial light source are electrically connected with the control unit; the spectral confocal sensor unit comprises a white light confocal sensor probe which is electrically connected with the control unit, and the white light confocal sensor probe is arranged vertically downwards.
The beneficial effects of adopting above-mentioned technical scheme are: the fixed focus lens and the coaxial light source can respectively adjust the distance and the brightness, so that the industrial camera is facilitated to collect images of the workpiece to be measured; in addition, the white light confocal sensor can generate signals when the workpiece to be measured reaches a measuring position, so that the collection, analysis and calculation of the signals can be completed through the data processing terminal, and the thickness measurement can be realized.
In a second aspect, a thickness measuring method of a non-contact thickness gauge is provided, which includes the following steps:
Placing the primary standard plane flat crystal on a two-dimensional horizontal movement table, taking the primary standard plane flat crystal as a measurement reference, and then placing a workpiece to be measured on the primary standard plane flat crystal;
The two-dimensional horizontal motion platform is used for placing a workpiece to be detected in the visual field of the visual detection guiding unit, the visual detection guiding unit is used for acquiring images, focusing module parameters are set in the data processing terminal, and the data processing terminal is used for automatically calculating and moving the visual detection guiding unit and the spectral confocal sensor unit through the vertical motion axis so as to realize coarse focusing of the visual detection guiding unit on the workpiece to be detected and establish a coordinate system;
selecting a measurement area from the image acquired by the visual detection guiding unit according to the coordinate system, establishing a measurement reference plane and obtaining a plurality of measurement points;
According to the surface to be measured where the measuring point is located, the spectral confocal sensor unit is moved along the vertical movement axis until the spectral confocal sensor unit reads, and coordinate data of the measuring point are acquired;
and calculating the thickness of the workpiece to be measured according to the coordinate data of the measuring reference plane and the measuring points.
The invention has the beneficial effects that:
The positioning accuracy of the two-dimensional horizontal movement table and the vertical movement axis is submicron, so that the moving accuracy of the workpiece to be measured, the visual detection guide unit and the spectral confocal sensor unit is improved, and the thickness measurement accuracy is improved; the spectral confocal sensor unit is based on a white light confocal optical probe to perform non-contact measurement, so that scratch on the surface of a workpiece is avoided; in addition, the thickness of the workpiece to be measured is calculated by the coordinate data of a plurality of measuring points during thickness measurement, which is beneficial to further improving the thickness measurement precision.
Drawings
The invention will be described in more detail hereinafter on the basis of embodiments and with reference to the accompanying drawings. Wherein:
FIG. 1 shows a schematic structural diagram of the present invention;
FIG. 2 is a schematic view showing the structure of a two-dimensional horizontal movement table according to the present invention;
FIG. 3 shows a schematic view of the structure of the vertical movement axis in the present invention;
FIG. 4 shows a schematic installation of a spectral confocal sensor unit and a visual inspection guide unit of the invention;
in the drawings, like parts are designated with like reference numerals. The figures are not to scale.
Reference numerals:
The device comprises a 1-two-dimensional horizontal movement table, 101-a first guide rail, 102-a first linear motor, 103-a first limiting block, 104-a first reader, 105-a first grating ruler, 106-a first slide carriage, 107-a first limiting switch, 108-a second guide rail, 109-a second linear motor, 110-a second slide carriage, 111-a carrier plate, 112-a second limiting block, a 2-spectral confocal sensor unit, 201-a white light confocal sensor probe, 3-a vertical movement shaft, 301-a third reader, 302-a third grating ruler, 303-a third slide carriage, 304-a third guide rail, 305-a third limiting block, 306-a third linear motor, 307-an adapter plate, 308-a balance cylinder, 309-a third limiting switch, 310-a cylinder adjusting valve, 4-visual detection guiding unit, 401-an industrial camera, 402-a fixed focus lens, 403-a coaxial light source, 5-gantry type supporting frame and 6-damping base.
Detailed Description
The invention will be further described with reference to the accompanying drawings.
The invention provides a non-contact thickness gauge, as shown in fig. 1, comprising:
The upper end of the damping base 6 is provided with a gantry type supporting frame 5;
The two-dimensional horizontal movement table 1, the lower end of the two-dimensional horizontal movement table 1 is fixedly connected to the shock absorption base 6, the two-dimensional horizontal movement table 1 is used for adjusting the horizontal position of a workpiece to be measured, the positioning accuracy of the two-dimensional horizontal movement table 1 is +/-0.5 um, and the repeatability of the movement plane of the two-dimensional horizontal movement table 1 is 0.3um;
the vertical movement shaft 3 is fixedly connected to the gantry type supporting frame 5, and the positioning accuracy of the vertical movement shaft 3 is +/-0.2 um;
The spectral confocal sensor unit 2 is fixedly connected to the output end of the vertical movement shaft 3;
the visual detection guide unit 4 is fixedly connected to the output end of the vertical movement shaft 3;
The control unit is electrically connected with a two-dimensional horizontal movement table 1, a vertical movement shaft 3, a spectrum confocal sensor unit 2, a visual detection guiding unit 4 and a data processing terminal.
It can be understood that the positioning accuracy of the two-dimensional horizontal movement table 1 and the vertical movement axis 3 is in submicron order, so that the moving accuracy of the workpiece to be measured, the visual detection guiding unit 4 and the spectral confocal sensor unit 2 is improved, thereby being beneficial to improving the thickness measurement accuracy; and the spectral confocal sensor unit 2 is an optical probe based on white light confocal to perform non-contact measurement, which is beneficial to avoiding scratching the surface of the workpiece.
It should be noted that the control unit may include a plurality of controllers, through which the two-dimensional horizontal movement stage 1, the vertical movement axis 3, the spectral confocal sensor unit 2, the visual detection guide unit 4, and the like are controlled, respectively; software with functions of system parameter setting, measurement path planning, data analysis and calculation, accuracy verification and debugging, data display and the like is installed in the data processing terminal; in addition, the visual inspection guide unit 4 and the spectral confocal sensor unit 2 may be coupled together with the vertical movement axis 3 by means of an adapter plate 307 for guiding, driving and data acquisition of thickness measurements.
In one embodiment, the damping base 6 comprises a base, wherein the lower end of the base is provided with a damping air cushion, and the lower end of the damping air cushion is fixedly connected with an anchor bolt;
the damping base 6 comprises an air supply pipeline for supplying air to the damping air cushion, and the air supply pipeline is provided with a pressure regulating valve.
It will be appreciated that the base may be placed on the ground by the cushion, while the anchor bolts may fix the cushion to the ground.
In one embodiment, as shown in fig. 2, the two-dimensional horizontal movement table 1 comprises a longitudinal air-floating guide rail, a first linear motor 102, a transverse air-floating guide rail and a second linear motor 109 which are electrically connected with the control unit, wherein the longitudinal air-floating guide rail comprises a first guide rail 101 and a first slide carriage 106, and the transverse air-floating guide rail comprises a second guide rail 108 and a second slide carriage 110; the first guide rail 101 is fixedly connected to the shock absorption base 6, and a stator and a rotor of the first linear motor 102 are respectively and fixedly connected to the first guide rail 101 and the first slide carriage 106; the second guide rail 108 is fixedly connected to the first slide carriage 106, the stator and the rotor of the second linear motor 109 are respectively and fixedly connected to the second guide rail 108 and the second slide carriage 110, and the second slide carriage 110 is fixedly connected with a carrying plate 111 for placing a workpiece to be measured.
It can be understood that the first linear motor 102 can drive the first slide carriage 106 to slide on the first guide rail 101 along the longitudinal direction, the second linear motor 109 can drive the second slide carriage 110 to slide on the second guide rail 108 along the transverse direction, and the second guide rail 108 is fixedly connected to the first slide carriage 106, and the carrier plate 111 for placing the workpiece to be measured is fixedly connected to the second slide carriage 110, so that the control unit can adjust the horizontal position of the workpiece to be measured through the first linear motor 102 and the second linear motor 109; in addition, the longitudinal air floating guide rail and the transverse air floating guide rail are both air floating guide rails, so that the adjustment precision of the horizontal position of the workpiece to be measured can be improved, and a foundation is laid for improving the thickness measurement precision.
In one embodiment, a first grating ruler 105 is longitudinally arranged on the first guide rail 101, a first reading head 104 for reading the first grating ruler 105 is fixedly connected to the first slide carriage 106, a second grating ruler is transversely arranged on the second guide rail 108, a second reading head for reading the second grating ruler is fixedly connected to the second slide carriage 110, and the first grating ruler 105, the first reading head 104, the second grating ruler and the second reading head are all electrically connected with the control unit.
It can be understood that the first grating ruler 105, the first readhead 104, the second grating ruler and the second readhead are all position feedback elements, and cooperate with the first linear motor 102 and the second linear motor 109 controlled by the control unit to realize closed-loop control, that is, when the movers of the first linear motor 102 and the second linear motor 109 move, the first readhead 104 and the second readhead are respectively and synchronously driven to move, the first readhead 104 and the second readhead respectively read the first grating ruler 105 and the second grating ruler and feed the first readhead and the second readhead back to the control unit, and the control unit respectively judges whether the first linear motor 102 and the second linear motor 109 are in place in real time according to the real-time reading, and is favorable for respectively generating the next operation parameters of the first linear motor 102 and the second linear motor 109 according to the real-time reading, so circulation is realized, so that closed-loop control is completed.
In one embodiment, both ends of the first guide rail 101 are provided with a first limiting block 103 and a first limiting switch 107 for longitudinally limiting the first slide carriage 106, both ends of the second guide rail 108 are provided with a second limiting block 112 and a second limiting switch for transversely limiting the second slide carriage 110, and both the first limiting switch 107 and the second limiting switch are electrically connected with the control unit.
It can be appreciated that when the first limit switch 107 and the second limit switch detect the first carriage 106 and the second carriage 110 respectively, signals can be fed back to the control unit to stop the operation of the first linear motor 102 and the second linear motor 109 respectively, so as to avoid overrun of the movement of the first carriage 106 and the second carriage 110; meanwhile, the first limiting block 103 and the second limiting block 112 can respectively force limiting of the first slide carriage 106 and the second slide carriage 110.
In one embodiment, as shown in fig. 3, the vertical movement shaft 3 includes a vertical air-floating guide rail and a third linear motor 306, which are electrically connected with the control unit, the vertical air-floating guide rail includes a third guide rail 304 and a third slide carriage 303, the third guide rail 304 is fixedly connected to the gantry supporting frame 5, a stator and a mover of the third linear motor 306 are respectively fixedly connected to the third guide rail 304 and the third slide carriage 303, and the third slide carriage 303 is fixedly connected to the spectral confocal sensor unit 2 and the visual detection guiding unit 4.
It can be understood that the third linear motor 306 can drive the third slide carriage 303 to slide vertically on the third guide rail 304, and since the spectral confocal sensor unit 2 and the visual detection guide unit 4 are fixedly connected to the third slide carriage 303, the control unit can adjust the vertical positions of the spectral confocal sensor unit 2 and the visual detection guide unit 4 through the third motor; in addition, the vertical air-float guide rail is an air-float guide rail, so that the adjustment precision of the vertical positions of the spectrum confocal sensor unit 2 and the visual detection guide unit 4 can be improved, and the thickness measurement precision can be improved.
In one embodiment, a third grating ruler 302 is vertically arranged on the third guide rail 304, a third reading head 301 for reading the third grating ruler 302 is fixedly connected to the third slide carriage 303, a third limiting block 305 and a third limiting switch 309 for vertically limiting the third slide carriage 303 are arranged on the third guide rail 304, and the third reading head 301 and the third limiting switch 309 are electrically connected with the control unit.
It can be understood that the third grating ruler 302 and the third reading head 301 are both position feedback elements, and cooperate with the third linear motor 306 controlled by the control unit to realize closed-loop control, that is, when the mover of the third linear motor 306 moves, the third reading head 301 is synchronously driven to move, the third reading head 301 reads the third grating ruler 302 and feeds back the third grating ruler 302 to the control unit, and the control unit determines whether the third linear motor 306 is in place in real time according to the real-time reading, and is favorable for generating the next operation parameter of the third linear motor 306 accordingly, and the loop is circulated to complete closed-loop control.
In one embodiment, the vertical movement shaft 3 comprises a balancing cylinder 308, the balancing cylinder 308 is communicated with a cylinder adjusting valve 310 electrically connected with the control unit, an output end of the balancing cylinder 308 is fixedly connected with the third slide carriage 303, and the balancing cylinder 308 is used for balancing the gravity borne by the third slide carriage 303.
It will be appreciated that the third slide 303 will receive a constant downward gravity, and the control unit adjusts the pressure in the balancing cylinder 308 through the cylinder adjusting valve 310, so as to adjust the supporting force provided by the balancing cylinder 308 to the third slide 303, so that the supporting force is the same as the gravity received by the third slide 303, and further balance the gravity on the third slide 303 is achieved, so as to reduce the influence of the gravity on the third slide 303 on the driving of the third linear motor 306, thereby improving the movement precision of the visual detection guiding unit 4 and the spectral confocal sensor unit 2, and further being beneficial to improving the thickness measurement precision.
In one embodiment, as shown in fig. 4, the visual inspection guide unit 4 includes an industrial camera 401, a fixed focus lens 402, and a coaxial light source 403 connected in sequence in a vertically downward direction, and the industrial camera 401, the fixed focus lens 402, and the coaxial light source 403 are all electrically connected to the control unit; the spectral confocal sensor unit 2 comprises a white light confocal sensor probe 201 electrically connected with the control unit, and the white light confocal sensor probe 201 is arranged vertically downwards.
It can be appreciated that the fixed focus lens 402 and the on-axis light source 403 can respectively adjust the distance and brightness to facilitate the industrial camera 401 to collect images of the workpiece to be measured; in addition, the white light confocal sensor can generate signals when the workpiece to be measured reaches a measuring position, so that the collection, analysis and calculation of the signals can be completed through software in the data processing terminal, and thickness measurement can be realized.
It should be noted that, after the industrial camera 401 collects the image of the workpiece to be measured, the data processing terminal may select the workpiece to be measured through software therein, so as to complete positioning of the workpiece after unifying the coordinate system, and guide the subsequent measurement.
The invention also provides a thickness measuring method of the non-contact thickness meter, which comprises the following steps:
Step S1: placing the primary standard plane flat crystal on a two-dimensional horizontal movement table 1, taking the primary standard plane flat crystal as a measurement reference, and then placing a workpiece to be measured on the primary standard plane flat crystal; the workpiece to be tested can be clamped and fixed according to the quality and the size of the workpiece to be tested;
Step S2: the two-dimensional horizontal movement table 1 places a workpiece to be detected in the visual field of the visual detection guiding unit 4, the visual detection guiding unit 4 acquires images, focusing module parameters are set in the data processing terminal, the data processing terminal automatically calculates and moves the visual detection guiding unit 4 and the spectral confocal sensor unit 2 through the vertical movement axis 3 so as to realize coarse focusing of the visual detection guiding unit 4 on the workpiece to be detected and establish a coordinate system;
Step S3: selecting a measurement area from the image acquired by the visual detection guiding unit 4 according to the coordinate system, establishing a measurement reference plane and obtaining a plurality of measurement points;
Step S4: according to the surface to be measured where the measuring point is located, the vertical movement axis 3 moves the spectral confocal sensor unit 2 until the spectral confocal sensor unit 2 reads, coarse focusing of the white light confocal sensor is achieved, and coordinate data of the measuring point are collected;
step S5: and calculating the thickness of the workpiece to be measured according to the coordinate data of the measuring reference plane and the measuring points.
It should be noted that in step S2, the working principle of the focusing module is to adjust the vertical position of the industrial camera 401 and fix the vertical position under the condition that the focal length of the fixed focus lens 402 is known, so that when the vertical position moves to the lower limit, the focal point of the fixed focus lens 402 is located on the object carrying plate 111; during measurement, the set focusing module parameter is the thickness value of the workpiece to be measured, namely the distance value of vertical upward movement from the lower limit; the thickness of the workpiece to be measured can be measured by a vernier caliper with the precision of 0.01 mm;
In addition, because of the fixed focus lens 402, the size of the focused image in the two-dimensional direction after image calibration is known; according to the measurement requirements, points, lines, drawings and other elements can be selected to establish a measurement coordinate system, so that the workpiece is positioned in X, Y, Z and R Z directions; meanwhile, the verticality of the Z axis and the two horizontal motion tables is required to be controlled within 6arcsec during design, so the positioning in the directions of R X and R Y is also known.
In the step S3, a measurement reference plane is established, and a plurality of measurement points are obtained to respectively plan a measurement path in a first step and a second step; when a measurement reference plane is established, taking a plane to be measured as projection in the vertical direction, extending outwards for a proper distance, acquiring multiple points, and obtaining the measurement reference plane through least square fitting; the measurement points are obtained by means of direct selection in the image or by means of importing external data according to an established coordinate system.
In step S5, when calculating the thickness of the workpiece to be measured, the coordinate data (x i,yi,zi) of the measurement points are taken into the measurement reference plane equation ax+by+cz+d=0, the distance d i between each measurement point and the measurement reference plane is calculated, and then the average value d= (Σd i)/n is calculated, so as to obtain the thickness of the workpiece to be measured.
To verify the function of the present invention, a verification test was performed after the instrument was integrated. And a group of three-equal gauge blocks are ground on the primary standard plane crystal, the primary standard plane crystal is measured, and the indication error and the indication repeatability of the measuring instrument are verified. The specific test contents are shown in the following table.
As shown in the table, the maximum deviation of the invention is 0.31um when the thickness is measured, and the indicating value error E is less than or equal to 0.31um.
The flatness measurement results are shown in the following table.
As can be seen from the above table, the repeatability of the present invention was 0.06um when measuring flatness.
In summary, the invention can achieve submicron measurement accuracy during thickness measurement and flatness measurement.
In the description of the present invention, it should be understood that the terms "upper," "lower," "bottom," "top," "front," "rear," "inner," "outer," "left," "right," and the like indicate or are based on the orientation or positional relationship shown in the drawings, merely to facilitate description of the present invention and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be configured and operated in a particular orientation, and thus should not be construed as limiting the present invention.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the different dependent claims and the features described herein may be combined in ways other than as described in the original claims. It is also to be understood that features described in connection with separate embodiments may be used in other described embodiments.

Claims (10)

1. A non-contact thickness gauge, comprising:
The device comprises a damping base (6), wherein a gantry type supporting frame (5) is arranged at the upper end of the damping base (6);
The two-dimensional horizontal movement table (1), the lower end of the two-dimensional horizontal movement table (1) is fixedly connected to the shock absorption base (6), the two-dimensional horizontal movement table (1) is used for adjusting the horizontal position of a workpiece to be measured, the positioning precision of the two-dimensional horizontal movement table (1) is +/-0.5 um, and the repeatability of the movement plane of the two-dimensional horizontal movement table (1) is 0.3um;
The vertical movement shaft (3), the vertical movement shaft (3) is fixedly connected to the gantry type supporting frame (5), and the positioning precision of the vertical movement shaft (3) is +/-0.2 um;
the spectral confocal sensor unit (2), the spectral confocal sensor unit (2) is fixedly connected to the output end of the vertical movement shaft (3);
The visual detection guide unit (4), the visual detection guide unit (4) is fixedly connected to the output end of the vertical movement shaft (3);
the control unit is electrically connected with the two-dimensional horizontal movement table (1), the vertical movement shaft (3), the spectral confocal sensor unit (2), the visual detection guiding unit (4) and the data processing terminal.
2. The non-contact thickness gauge according to claim 1, wherein the shock-absorbing base (6) comprises a base, a shock-absorbing air cushion is arranged at the lower end of the base, and an anchor bolt is fixedly connected to the lower end of the shock-absorbing air cushion;
the damping base (6) comprises an air supply pipeline for supplying air to the damping air cushion, and the air supply pipeline is provided with a pressure regulating valve.
3. The non-contact thickness gauge according to claim 1, characterized in that the two-dimensional horizontal movement table (1) comprises a longitudinal air-bearing rail, a first linear motor (102), a transverse air-bearing rail and a second linear motor (109), which are electrically connected with the control unit, the longitudinal air-bearing rail comprising a first rail (101) and a first slide carriage (106), the transverse air-bearing rail comprising a second rail (108) and a second slide carriage (110); the first guide rail (101) is fixedly connected to the shock absorption base (6), and a stator and a rotor of the first linear motor (102) are respectively and fixedly connected to the first guide rail (101) and the first slide carriage (106); the second guide rail (108) is fixedly connected to the first slide carriage (106), the stator and the rotor of the second linear motor (109) are respectively and fixedly connected to the second guide rail (108) and the second slide carriage (110), and the second slide carriage (110) is fixedly connected with a carrying plate (111) for placing a workpiece to be measured.
4. A non-contact thickness gauge according to claim 3, wherein a first grating scale (105) is longitudinally arranged on the first guide rail (101), a first reading head (104) for reading the first grating scale (105) is fixedly connected to the first slide carriage (106), a second grating scale is transversely arranged on the second guide rail (108), a second reading head for reading the second grating scale is fixedly connected to the second slide carriage (110), and the first grating scale (105), the first reading head (104), the second grating scale and the second reading head are all electrically connected with the control unit.
5. A non-contact thickness gauge according to claim 3, wherein both ends of the first guide rail (101) are provided with a first limit block (103) and a first limit switch (107) for longitudinally limiting the first slide carriage (106), both ends of the second guide rail (108) are provided with a second limit block (112) and a second limit switch for transversely limiting the second slide carriage (110), and both the first limit switch (107) and the second limit switch are electrically connected with the control unit.
6. The non-contact thickness gauge according to claim 1, wherein the vertical movement shaft (3) comprises a vertical air-floating guide rail and a third linear motor (306), which are electrically connected with the control unit, the vertical air-floating guide rail comprises a third guide rail (304) and a third slide carriage (303), the third guide rail (304) is fixedly connected to the gantry support frame (5), a stator and a rotor of the third linear motor (306) are respectively fixedly connected to the third guide rail (304) and the third slide carriage (303), and the third slide carriage (303) is fixedly connected to the spectral confocal sensor unit (2) and the visual detection guide unit (4).
7. The non-contact thickness gauge according to claim 6, wherein a third grating ruler (302) is vertically arranged on the third guide rail (304), a third reading head (301) for reading the third grating ruler (302) is fixedly connected to the third slide carriage (303), a third limiting block (305) and a third limiting switch (309) for vertically limiting the third slide carriage (303) are arranged on the third guide rail (304), and the third reading head (301) and the third limiting switch (309) are electrically connected with the control unit.
8. The non-contact thickness gauge according to claim 6, wherein the vertical movement shaft (3) comprises a balancing cylinder (308), the balancing cylinder (308) is communicated with a cylinder adjusting valve (310) electrically connected with the control unit, an output end of the balancing cylinder (308) is fixedly connected with the third slide carriage (303), and the balancing cylinder (308) is used for balancing the gravity borne by the third slide carriage (303).
9. The non-contact thickness gauge according to claim 1, wherein the visual inspection guiding unit (4) comprises an industrial camera (401), a fixed focus lens (402) and a coaxial light source (403) connected in sequence in a vertically downward direction, the industrial camera (401), the fixed focus lens (402) and the coaxial light source (403) being electrically connected to the control unit; the spectral confocal sensor unit (2) comprises a white light confocal sensor probe (201) electrically connected with the control unit, and the white light confocal sensor probe (201) is arranged vertically downwards.
10. A thickness measuring method according to any one of claims 1 to 9, comprising the steps of:
Placing the primary standard plane flat crystal on a two-dimensional horizontal movement table (1) to take the primary standard plane flat crystal as a measurement reference, and then placing a workpiece to be measured on the primary standard plane flat crystal;
the two-dimensional horizontal movement table (1) is used for placing a workpiece to be detected in the visual field of the visual detection guiding unit (4), the visual detection guiding unit (4) is used for acquiring images, focusing module parameters are set in the data processing terminal, and the data processing terminal automatically calculates and moves the visual detection guiding unit (4) and the spectral confocal sensor unit (2) through the vertical movement axis (3) so as to realize coarse focusing of the visual detection guiding unit (4) on the workpiece to be detected and establish a coordinate system;
Selecting a measurement area from the image acquired by the visual detection guiding unit (4) according to the coordinate system, establishing a measurement reference plane and obtaining a plurality of measurement points;
According to the surface to be measured where the measuring point is located, the vertical movement axis (3) moves the spectral confocal sensor unit (2) until the spectral confocal sensor unit (2) reads, and coordinate data of the measuring point are acquired;
and calculating the thickness of the workpiece to be measured according to the coordinate data of the measuring reference plane and the measuring points.
CN202410207360.2A 2024-02-26 2024-02-26 Non-contact thickness gauge and thickness measuring method thereof Pending CN118089562A (en)

Priority Applications (1)

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CN202410207360.2A CN118089562A (en) 2024-02-26 2024-02-26 Non-contact thickness gauge and thickness measuring method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202410207360.2A CN118089562A (en) 2024-02-26 2024-02-26 Non-contact thickness gauge and thickness measuring method thereof

Publications (1)

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CN118089562A true CN118089562A (en) 2024-05-28

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Family Applications (1)

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