TWI630056B - Device for thermal drift precision measurement correction and compensation - Google Patents

Abstract

A thermal drift precision measurement correction and compensation device comprises: a three-axis translation stage comprising an X-axis translation stage, a Y-axis translation stage and a Z-axis translation stage, the X-axis translation stage and the Y-axis translation stage And the Z-axis translation stage is disposed perpendicular to each other; a positioning base unit is provided for providing a positioning coordinate, comprising an X-axis positioning base, a YZ-axis positioning base, the X-axis positioning base, and the YZ-axis positioning base Arranging mutually perpendicularly; an object unit disposed on the X-axis translation stage for fixing an object, comprising two spot image reading heads; a processing unit disposed on the Z-axis translation stage for use A processed object that includes two spot image reading heads. Thereby, the above device has the function of thermal drift precision measurement correction and compensation, and can avoid the processing precision of the high precision processing device due to the thermal expansion effect.

Description

Device for thermal drift precision measurement correction and compensation

The present invention relates to a precision machining apparatus, and more particularly to an apparatus having a thermal drift precision measurement correction and compensation mechanism.

In today's industry, under the goal of maximizing production capacity, the equipment in the factory must be operated for a long time, and the heat energy generated by the equipment machine itself or the change of the ambient temperature will cause the equipment machine to generate traces due to the thermal effect. The thermal deformation will cause the relative position of the tool and the workpiece of the high-precision machining tool to change, which will cause the deviation of the machining size or shape, and finally the machining accuracy will be reduced, and the high precision requirement cannot be achieved. The error of machining precision machining is about 40% to 70% caused by thermal deformation. Therefore, the degree of thermal behavior of high-precision machine tools can be regarded as one of the important indicators for measuring accuracy and stability. The thermal behavior is reproducible and stable, indicating that the machine tool can maintain good processing quality for a long time. Conversely, if the thermal behavior pattern of the machine tool is too large, the processing quality is difficult to ensure.

In view of this, many national and international manufacturers have regarded the technology of solving thermal error as a technical symbol of achieving high processing precision and high stability, and representing the country's high-precision processing technology, like the international company Okuma. The thermal affinity technology and the heat source cooling suppression technology of Makino are the technologies that are not currently available in China. At present, the methods used by foreign large factories to reduce the thermal deformation of the machine include: 1. Designing thermal symmetry and heat balance. The structure of the machine body makes the thermal deformation error of the machine tool have symmetrical characteristics and masterability. 2. The heat affinity body is used to effectively reduce the thermal deformation of the machine tool body. 3. The multi-channel zero heat source cooling technology is adopted to effectively reduce the heat source. The amount of change in temperature, 4. hot spot measurement and thermal deformation compensation, but each of the above technologies must have strong basic industrial capabilities, and must be fully implemented to achieve full thermal effect error control, complexity, difficulty The degree of production and production costs are very high, which is a technology that cannot be achieved by domestic players.

At present, the domestic machine tool related manufacturers solve the hot deformation method of the tool machine, mainly by developing the thermal deformation control technology of the CNC numerical control system, including: 1. Using the temperature sensor to be placed in a relatively significant position of the temperature change of the body (infrared thermal image can be utilized) The instrument performs measurement, to capture the temperature change of the machine, 2. Set up a three-dimensional measuring instrument to measure and record the temperature rise and deformation of the machine, 3. Use the temperature and thermal deformation data to establish the thermal deformation of the machine. Model, 4. Establish the thermal deformation model of the machine and the temperature rise correction verification equipment ; but use the thermal deformation control technology of the CNC numerical control system, measure the temperature variation of the machine, and then pass through the built-in software of the thermal deformation module of the machine. Calculate the instantaneous thermal deformation of the machine as the thermal offset correction displacement of the machining spindle. However, due to the development of the thermal deformation module software, the sampling range of the heat source and ambient temperature of the machine cannot fully simulate the actual situation, and the sampling is limited. And when the machine is working, the heating characteristics in the machine will gradually change and the temperature of the working environment will change too much, which will cause the originally set correction soft. The body calculation error causes the failure of the thermal effect error compensation mechanism.

Therefore, there is a need in the industry to develop a device for thermal drift precision measurement correction and compensation, which has a low-cost, simple-state method for correcting thermal distortion correction, so that it can simultaneously combine process cost and efficiency, and utilize heat. Drift precision measurement correction and compensation mechanism to effectively improve the machining accuracy of multi-axis machining machines.

In view of the above disadvantages of the prior art, the main object of the present invention is to provide a device for thermal drift precision measurement correction and compensation, integrating a three-axis translation stage, a positioning base unit, an object unit, a processing unit, etc. Effectively control the error caused by thermal drift and obtain high-quality precision machining equipment.

In order to achieve the above object, according to one aspect of the present invention, a device for thermal drift precision measurement correction and compensation is provided, comprising: a three-axis translation stage including an X-axis translation stage, a Y-axis translation stage, and a a Z-axis translation stage, the X-axis translation stage, the Y-axis translation stage and the Z-axis translation stage are arranged perpendicular to each other; a positioning base unit is provided for providing a positioning coordinate, comprising an X-axis positioning base and a YZ-axis positioning a base, the X-axis positioning base and the YZ-axis positioning base are disposed perpendicular to each other; an object unit is disposed on the X-axis translation stage for fixing the object, and comprises two spot image reading heads; The processing unit is disposed on the Z-axis translation stage for processing the object, and comprises two spot image reading heads.

The above-mentioned middle X-axis positioning pedestal table can be designed to be parallel to the X-axis translation stage (but not limited thereto), and the YZ-axis positioning pedestal stage can be designed to be parallel to the Y-axis translation stage (but not limited thereto). Wherein, the object unit on the X-axis translation stage can use a fixed arm as a connection with the two spot image reading heads (but not limited thereto), so that the object unit and the spot image reading head are integrated and fixed. The distance between the object unit and the spot image reading head, and the main function of the object unit is to fix the item to be processed to carry the item to be processed; and the processing unit on the YZ axis translation stage can be fixed by two The arm is used as a connection with the two spot image reading heads (but not limited thereto), so that the processing unit and the spot image reading head are integrated to fix the distance between the processing unit and the spot image reading head, and the processing is performed. The main function of the unit is to provide a tool for processing, such as a tool, for processing the item to be processed.

The spot image reading head on the object unit is used to read the non-deformed spot image of the X-axis positioning base table, and the two spot image reading heads are respectively used to read different faces of the X-axis positioning base table. The non-deformed spot image, for example, one spot image read head reads the undeformed spot image of the Z=Z ₁ XY plane on the X-axis positioning pedestal table, and the other spot image read head reads the X-axis Positioning the non-deformed spot image of the XZ plane of Y=0 on the pedestal table, so that the object unit can define the spot image positioning coordinate on the X-axis positioning pedestal table; the spot image reading on the processing unit The head is used to read the non-deformed spot image of the YZ axis positioning base table surface, and the two spot image reading heads are respectively used to read the non-deformed spot image of the different faces of the YZ axis positioning base table, for example, One of the spot image reading heads reads the undeformed spot image of the Z=Z ₂ XY plane on the YZ axis positioning base table, and the other spot image reading head reads the X= on the YZ axis positioning base table. a non-deformed spot image of the YZ plane of 0, so that processing can be performed The unit defines the spot image positioning coordinates on the YZ axis positioning pedestal table.

The X-axis positioning base and the YZ-axis positioning base in the present invention can be designed as a low thermal expansion coefficient material, and the low thermal expansion coefficient material can be selected from one of zero-expansion glass, invariable steel invar, and granite (but Not limited to this).

The above summary and the following detailed description and drawings are intended to further illustrate the manner, means and effects of the present invention in achieving its intended purpose. Other purposes and advantages of this creation will be explained in the following description and drawings.

110‧‧‧Three-axis translation stage

111‧‧‧X-axis translation stage

112‧‧‧Y-axis translation stage

113‧‧‧Z-axis translation stage

120‧‧‧ Positioning base unit

121‧‧‧X-axis positioning base

122‧‧‧Y-Z axis positioning base

130‧‧‧object unit

131, 141‧‧‧ spot image reading head

132, 142‧‧‧ fixed arm

140‧‧‧Processing unit (tool unit)

The first figure is a schematic diagram of a device for correcting and compensating the thermal drift precision measurement according to the present invention; the second figure is a schematic diagram of reading the coordinates of the object unit of the present invention; and the third figure is a schematic diagram of reading the coordinates of the processing unit of the present invention.

The embodiments of the present invention are described by way of specific examples, and those skilled in the art can readily understand the advantages and effects of the present invention from the disclosure of the present disclosure.

Different from the previous method of measuring the temperature change of the machine by the thermal deformation compensation technology and then calculating the thermal deformation of the machine, we have revealed a new solution, which is to install a thermal expansion three-dimensional correction positioning base on the multi-axis processing machine. The low thermal variability of the three-dimensional positioning pedestal with the low thermal expansion amount is combined with the image forming and positioning technology of the non-deformed spot image, and the three-dimensional thermal expansion sensing displacement amount of the processing (tool) unit and the object unit is provided, thereby obtaining the machining (tool) accurately. The three-dimensional relative thermal drift of the unit and the object unit is used to correct the positioning accuracy of the compensation machine to meet the precision machining positioning requirements of the multi-axis machining machine.

Please refer to the first figure, which is a schematic diagram of a device for thermal drift precision measurement correction and compensation according to the present invention. As shown in FIG. 1 , the present invention provides a thermal drift precision measurement correction and compensation device, comprising: a three-axis translation stage 110 comprising an X-axis translation stage 111, a Y-axis translation stage 112 and a Z-axis. a translation stage 113, the X-axis translation stage 111, the Y-axis translation stage 112, and the Z-axis translation stage 113 are disposed perpendicular to each other; a positioning base unit 120 is provided for providing a positioning coordinate, which includes an X-axis positioning base 121, a YZ-axis positioning base 122, the X-axis positioning base 121 and the YZ-axis positioning base 122 are disposed perpendicular to each other; an object unit 130 is disposed on the X-axis translation stage 111 for fixing an object, which comprises Two spot image reading heads 131; a processing unit 140 disposed on the Z-axis translation stage 113 for processing objects, comprising two spot images The read head 141 is a machine base 150 for providing a stable substrate, and all of the above components are disposed on the machine base 150.

In the non-deformed spot image capturing and positioning technology of the spot image reading heads 131 and 141 of the present invention, the (non-deformed) spot image reading heads 131 and 141 are designed to confirm that a radiant interference spot enters the two-dimensional image capturing device. When the window moves out of the image capturing window, the relative optical path difference of the interference spot is less than one-fifth of the wavelength, so the spotlight spot that enters the spot image capturing range is bright spot, and the spot that removes the spot image capturing range is mostly Still maintaining constructive interference, it seems to be a bright spot. The spot image is aligned by image processing software (SAD, SSD, NCC, SURF, SIFT, etc.), and the correct amount of displacement can be obtained. The two non-deformed spot images are used to generate and compare the feature points of the spot image. Using the statistical elimination method to remove the feature pairing points that are 1.5 times larger than the standard deviation of the displacement, the standard of the image plane displacement of two adjacent spot images can be accurately compared. The difference is less than 0.008 pixels, which is approximately equal to the standard deviation of one hundredth of a pixel. Therefore, using the (non-deformed) spot image reading head to pick up the surface of the thermally expandable object Zhang spot images, then by like SIFT or SURF positioning image comparison method, can be obtained accurately relative displacement amount of thermal expansion of the surface before and after the thermal expansion thereof, to provide data required for precise measurement of the amount of displacement of the present invention.

Example

The invention designs a three-dimensional positioning base unit 120 using a low thermal expansion coefficient material, including an X-axis granite positioning base (X-axis positioning base 121) and a spot wall (Y, Z-axis) granite positioning base (YZ axis positioning base) 122), wherein, X-axis positioning granite base wall and spot (Y, Z-axis) granite base is positioned perpendicular to each other, and the object unit (object holding means comprises a rotary table and a C-axis), compared with the carrier, solid The mechanical unit for loading the workpiece can be moved on the X-axis translation stage 111 and rotated on the C-axis rotary table (not shown). In addition, the cutter unit (machining unit 140) is a mechanical unit for carrying and fixing the machining tool, which can be in Y. The Z-axis translation stage moves and rotates on the A-axis rotary table. The present invention uses the fixed arm 142 to fix the spot image reading head 141 and the cutter unit 140 integrally, and uses the two non-deformed spot images on the fixed arm 142 to read. The head 141 is taken to read the spot image of the tool unit 140 at the YZ surface positioning point of the spot wall (Y, Z axis) granite positioning base (YZ axis positioning base 122) X=0.

Please refer to the second figure, which is a schematic diagram of reading the coordinates of the object unit of the present invention. As shown in FIG. 2, the coordinates of the two-spot image positioning points of the object unit on the X-axis positioning base 121 are the coordinates of the positioning point of the three-dimensional calibration of the X-axis positioning base, respectively, and the spot coordinates of the spot image of the Y=0 and the XZ plane ( X _object) , 0, Z _object ) and Z = Z1, XY plane spot image positioning point coordinates ( X _object , Y _object , Z ₁ ), comprehensive two positioning points can be obtained by positioning the object unit on the positioning pedestal of the three-dimensional calibration of granite The image positioning coordinates are ( X _object , Y _object , Z _object ), wherein the coordinates of the positioning base for the three-dimensional correction are respectively read by the two spot image reading heads on the object unit to read the X-axis positioning base Deformation spot images of different faces of the table are used to define object object positioning point coordinates ( X _object , Y _object , Z _object ).

Please refer to the third figure, which is a schematic diagram of reading a coordinate of a processing unit according to the present invention. As shown in Figure 3, the fixing method of the tool unit (machining unit) is more complicated. First, the Z-axis translation stage is fixed on the Y-axis translation stage, so moving the Y-direction displacement is to move the entire Z-axis translation stage, and then the tool unit. It is fixed on the Z-axis translation stage, so the tool unit can be moved in the Y and Z directions. In this embodiment, a fixed arm of the spot image reading head is attached to the top of the Z-axis translation stage for measuring the YZ axis positioning base. Z = Z ₂ XY plane spot image positioning point coordinates ( X _cutter , Y _cutter , Z ₂ ), and another fixed arm, used to measure YZ axis positioning base X = 0 YZ surface spot image positioning Point coordinates (0, Y _cutter , Z _cutter ), the integrated two positioning points can be obtained by positioning the tool unit on the positioning base of the three-dimensional calibration of the granite ( X _cutter , Y _cutter , Z _cutter ), wherein The coordinate of the positioning base for the three-dimensional correction of the tool unit is to use the two spot image reading heads on the tool unit to respectively read the non-deformed spot images on different faces of the YZ axis positioning base to define the machining (tool). Unit positioning point coordinates ( X _cutter , Y _cutter , Z _cutter ) .

The object object unit is positioned on the positioning target ( X _object , Y _object , Z _object ) of the positioning base (X-axis positioning base) for the three-dimensional calibration of the granite and the positioning unit of the tool unit is positioned for the three-dimensional correction of the granite ( YZ axis positioning base) X-ray image positioning coordinates ( X _cutter , Y _cutter , Z _cutter ), with the fixed size and orientation of each spot image reading head fixed arm, the geometrical center of the object unit and the tool unit can be obtained from the granite three-dimensional The absolute coordinate address of the positioning base for calibration; the accuracy of the positioning base (positioning base unit) for 3D calibration will affect the accuracy of future thermal expansion compensation correction, so the X-axis positioning base must be as vertical as possible. YZ axis spot wall (YZ axis positioning base), also need additional making X, Y, Z three-axis positioning of the reticle starting, making Z = Z1, XY plane of X = X _0, X-axis positioning start The marked line and Y=0, the XZ plane X= X ₀ , the X axis starting positioning line, the X axis reading values of the two X axis starting positioning lines are the same, and the Z=Z2 and XY planes are similarly made. from the starting Y = Y Y-axis and positioning the reticle X = 0, YZ plane, Z = Z _0, Z ₀ axis of Positioning reticle, this reticle three-axis positioning accuracy of the operation start of the next machine also affects the thermal expansion compensation correction accuracy.

The invention uses a sufficiently strong granite as the positioning base for three-dimensional correction, so that the total deformation amount is smaller than the specification value, and the good thermal insulation mechanism is designed, so that the heat of the machine is not easily transmitted to the positioning base of the three-dimensional calibration of the granite (positioning base Unit), and the body temperature of the positioning base for granite three-dimensional correction can be easily controlled accurately, so the positioning base for granite three-dimensional correction can provide an excellent and extremely stable three-dimensional reference coordinate system; the present invention proposes multi-axis On the processing machine, a positioning base for three-dimensional correction with a low expansion coefficient is placed, and a three-dimensional coordinate positioning base that does not change with temperature is provided by using the low thermal variability and good rigidity of the positioning base itself for three-dimensional correction. Matching the object unit and the tool unit to the absolute positioning coordinates of the three-dimensional positioning base of the granite, and feeding back to the axis control unit for precision machining. This machining positioning method can eliminate the thermal deformation error of the machine from time to time and obtain excellent results. Precision.

The above-described embodiments are merely illustrative of the features and functions of the present invention and are not intended to limit the scope of the technical content of the present invention. Any person skilled in the art can modify and change the above embodiments without departing from the spirit and scope of the creation. Therefore, the scope of protection of this creation should be as listed in the scope of the patent application described later.

Claims (9)

A thermal drift precision measurement correction and compensation device comprises: a three-axis translation stage comprising an X-axis translation stage, a Y-axis translation stage and a Z-axis translation stage, the X-axis translation stage and the Y-axis translation stage And the Z-axis translation stage is disposed perpendicular to each other; a three-dimensional positioning base unit is provided for providing a three-dimensional positioning coordinate, comprising an X-axis positioning base, a YZ-axis positioning base, the X-axis positioning base, and the YZ axis positioning The bases are disposed perpendicular to each other; an object unit is disposed on the X-axis translation stage for fixing the object, and includes two spot image reading heads; and a processing unit disposed on the Z-axis translation stage The utility model is used for processing an object, which comprises two spot image reading heads, wherein the processing unit is coupled to the spot image reading head by a fixed arm. The apparatus for correcting and compensating for thermal drift precision measurement according to claim 1, wherein the X-axis positioning base is parallel to the X-axis translation stage. The apparatus for correcting and compensating for thermal drift precision measurement according to claim 1, wherein the Y-Z axis positioning base station is parallel to the Y-axis translation stage. The apparatus for correcting and compensating for thermal drift precision measurement according to claim 1, wherein the object unit is coupled to the spot image reading head by a fixed arm. The apparatus for correcting and compensating for thermal drift precision measurement according to claim 4, wherein the spot image reading head on the object unit is configured to read the non-deformed spot image of the X-axis positioning base station. . The device for correcting and compensating for thermal drift precision measurement according to claim 5, wherein the two spot image reading heads on the object unit are respectively used to read different faces of the X-axis positioning base table. The image of the undistorted spot. The device for correcting and compensating for thermal drift precision measurement according to claim 1, wherein the spot image reading head on the processing unit is configured to read the non-deformed spot image of the YZ axis positioning base table. . The device for correcting and compensating for thermal drift precision measurement according to claim 1, wherein the two spot image reading heads on the processing unit are respectively used to read different faces of the YZ axis positioning base table. The image of the undistorted spot. The apparatus for correcting and compensating for thermal drift precision measurement according to claim 1, wherein the X-axis positioning base and the YZ-axis positioning base are constructed by a low thermal expansion coefficient material, and the low thermal expansion coefficient is The material is selected from one of zero-expansion glass, invariable steel invar, and granite.