Measuring body for checking geometric deviations of three-axis machine tool, three-axis machine tool and method for compensating for geometric deviations of three-axis machine tool

Abstract

The invention relates to a measuring body for checking geometric deviations of a three-axis machine tool (1), comprising: a base plate (8); a first wall (10) disposed on the substrate (8) and vertically protruding from the substrate (8); a second wall (20) disposed on the substrate (8) and protruding vertically from the substrate (8) and disposed perpendicular to the first wall (10), in which: a first hole row (101) and a second hole row (102) are formed in the substrate (8); the first wall (10) is of a stepped triangular structure and comprises a stepped region (12) with a plurality of steps (13) in an upper exposed region (11); the second wall (20) is quadrilateral and comprises a first row of wall holes (22) in an upper exposed area (21) extending parallel to the base plate (8); the first hole row (101) is arranged parallel to the stepped hole row (14) and the second hole row (102) is arranged parallel to the first wall hole row (22).

Description

Technical Field

[0001] The invention relates to a measuring body for checking geometric deviations of a three-axis machine tool and to a three-axis machine tool with increased geometric accuracy as well as to a method for checking and compensating geometric deviations of a three-axis machine tool. Background Art

[0002] In the case of machine tools, one known problem area is the geometric accuracy of the machine tool. The geometric accuracy of a machine tool is determined by the relative deviation of the actual position and orientation of the tool relative to the workpiece from the target position and orientation. This error is therefore the cause of the deviation from the ideal workpiece geometry and thus affects the operating accuracy of the machine tool. In order to improve the geometric accuracy, the deviations of the individual axes and the position and orientation of the individual axes relative to each other are usually taken into account.

[0003] Assuming a rigid body model, in this case, the three-axis machine tool has three linear deviations (one axial and two perpendicular to the axial direction) and three rotational deviations (yaw, pitch and roll). Therefore, 6 deviations are generated for each linear axis, so that 18 deviations are generated for 3 linear axes. In addition, the perpendicularity deviations of the three linear axes relative to each other must be taken into account. Therefore, there are a total of 21 possible geometric errors on the three-axis machine tool. In this case, the individual deviations can be superimposed on each other, which then actually leads to a significant overall error, which affects the geometric accuracy of the machine tool in an undesirable way.

[0004] The object of the present invention is to provide a measuring body for checking geometric deviations of a three-axis machine tool, a three-axis machine tool and a method for checking and compensating geometric deviations of a three-axis machine tool, wherein the measuring body and the three-axis machine tool are designed as simply and cost-effectively as possible and the method can be implemented as cost-effectively and quickly as possible. Summary of the invention

[0005] This object is achieved by a measuring body having the features of claim 1, a three-axis machine tool having the features of claim 10 and a method having the features of claim 12. The dependent claims each indicate preferred developments of the invention.

[0006] In contrast, the measuring body for checking geometric deviations of a three-axis machine tool according to the invention having the features of claim 1 has the advantage that with the help of the measuring body, geometric deviations of the three-axis machine tool can be compensated so that the three-axis machine tool does not have any linear deviations, any rotational deviations or any perpendicularity deviations. As a result, the workpiece can then be machined to the highest possible accuracy by the three-axis machine tool. In this case, the correction data determined based on the measuring body can be used directly for error compensation of the three-axis machine tool. The measuring body is particularly suitable for machine tools used for ultra-precision machining. In addition, the measuring body is also particularly suitable for the inspection, correction and long-term evaluation of machine tools and can therefore be used for ultra-precision machining throughout its entire service life.

[0007] According to the present invention, the measuring body includes a substrate, a first wall and a second wall. The first wall is arranged on a substrate, in particular a quadrilateral, and protrudes vertically from the substrate. The first wall is a stepped triangle and includes a stepped area having a plurality of steps in an exposed area at the top. In addition, the second wall is a quadrilateral and is also arranged to protrude vertically on the substrate and is arranged perpendicular to the first wall. In addition, a first row of holes and a second row of holes are formed in the substrate. Therefore, the first wall is configured to be stepped with a plurality of steps on the side facing away from the substrate. The second wall is a quadrilateral wall, in particular a rectangular wall, and includes an exposed area parallel to the top of the substrate, in which a first wall row of holes is formed.

[0008] Thus, the stepped area of ​​the first wall is located at the exposed area of ​​the upper part of the first wall. Thus, the exposed area of ​​the upper part of the first wall forms a step at which different positions in the Z direction can be detected, wherein the substrate intersects the base plane in the X and Y directions. Due to the exposed stepped area of ​​the upper part of the first wall, the first wall is essentially triangular in shape.

[0009] Particularly preferably, the stepped first wall comprises a stepped row of holes, wherein a hole is formed in each step.This makes it possible to detect the position in the X and Y directions at different heights in addition to determining the position in the Z direction.

[0010] More preferably, the measuring body further comprises a third wall, which is arranged on the substrate and is positioned perpendicular to the second wall. Like the second wall, the third wall is a quadrilateral wall having an exposed area at the top, which extends parallel to the substrate and comprises the second wall hole row. Therefore, the third wall is arranged on the substrate parallel to the first wall. In addition, the first wall hole row and the second wall hole row are therefore arranged perpendicular to each other. In this case, the first wall, the second wall and the third wall form a U-shaped configuration.

[0011] More preferably, the measuring body comprises a third row of holes on the base plate, the third row of holes being parallel to the second row of holes of the third wall.

[0012] Preferably, the first row of holes, the second row of holes and the third row of holes extend along the edge of the substrate on the upper side of the substrate, and the substrate is particularly preferably configured as a quadrilateral. Therefore, preferably, the first row of holes is parallel to the first edge of the substrate, the second row of holes is parallel to the second edge of the substrate, and the third row of holes is parallel to the third edge of the substrate.

[0013] Particularly preferably, the first row of holes is parallel to the first wall and / or the second row of holes is parallel to the second wall and / or the third row of holes is parallel to the third wall. This makes it possible to detect yaw errors and pitch errors as well as roll errors in particular by means of the measuring body.

[0014] The first row of holes, the second row of holes and the third row of holes particularly preferably have the same number of holes, the same hole spacings and the same hole diameters.

[0015] According to a further preferred embodiment of the present invention, the first wall, the second wall and the third wall are at predetermined intervals from the first edge, the second edge and the third edge respectively.

[0016] Further preferably, the step surfaces of the steps of the stepped triangle parallel to the substrate are ground or finely processed in another way so as to provide a significant flatness. Preferably, the exposed area of ​​the upper part of the second and / or third wall is also ground or finely processed so as to exhibit a significant flatness. As a result, the measurement accuracy by means of the measuring body can be significantly improved.

[0017] Further preferably, the region in the substrate where the first row of holes, the second row of holes, and / or the third row of holes are formed and / or the region beside the row of holes is set as the grinding region.

[0018] It is further preferred that the measuring body comprises a reinforcing element on the underside of the base plate in order to increase the stability of the measuring body. The reinforcing element is preferably a lath cross comprising two laths, one of which connects two opposite corners of the base plate on the underside of the base plate, respectively. The reinforcing element is preferably also used to clamp the measuring body in the machine tool.

[0019] Further preferably, the first hole row, the second hole row and the third hole row are arranged in the substrate in such a manner that, in the case of a quadrilateral substrate, a hole for measurement processing is formed in each corner region of the substrate.

[0020] The substrate is preferably configured as a quadrilateral, in particular a square. Further preferably, each hole row and step hole row in the substrate and the first wall hole row and the second wall hole row each comprise at least one reference hole. The area around each reference hole is preferably ground so that the ground surface is used as a reference element for determining the Z coordinate. The center of each reference hole can be used as a reference element for the X and Y coordinates.

[0021] Further preferably, the holes in the first hole row, the second hole row and the third hole row are arranged on a straight line.

[0022] The measuring body is preferably made of Invar. Invar has a very low coefficient of thermal expansion and is therefore particularly well suited for producing the measuring body. Further preferably, the thickness of the first wall, the second wall and the third wall is the same as the thickness of the base plate.

[0023] Furthermore, the invention relates to a three-axis machine tool, comprising a machine spindle, a measuring device, in particular a 3D measuring sensor, which can be clamped in the machine spindle, and a control unit for controlling the three-axis machine tool. Furthermore, the three-axis machine tool comprises a measuring body according to the invention, wherein the control unit is configured to perform a correction of the geometric data of the three-axis machine tool based on a target / actual comparison of a previously determined geometric target size of the measuring body with a geometric actual size of the measuring body determined by the measuring device in the three-axis machine tool. Therefore, the control unit comprises a memory in which the geometric target size of the measuring body determined in a previous step of the measuring machine is stored. In order to determine the geometric actual size of the measuring body in the three-axis machine tool, the control unit preferably starts an NC program for measuring the measuring body in order to determine the actual value of the measuring body. Therefore, by comparing the target value and the actual value, the geometric data of the three-axis machine tool can be corrected, as a result of which the accuracy during the machining of a workpiece using the three-axis machine tool is significantly improved. Therefore, compensation of geometric errors of the three-axis machine tool can be achieved in a simple manner. The target value is preferably stored in a memory.

[0024] Furthermore, the invention relates to a method for checking and compensating geometric deviations in a three-axis machine tool, wherein the method comprises the steps of:

[0025] - clamping a measuring device, in particular a 3D measuring sensor, in the spindle of the three-axis machine tool,

[0026] - arranging the measuring body according to the invention in the working space of the three-axis machine tool, in particular by clamping to a reinforcement element,

[0027] - approaching a plurality of different positions of the measuring volume by means of the measuring device in order to acquire geometric actual data of the measuring volume,

[0028] - performing a target / actual comparison between the acquired actual data and previously determined target data of the measuring body in order to determine geometric deviations, in particular linear deviations and rotational deviations and perpendicularity deviations, and

[0029] - Compensating for geometrical deviations of the three-axis machine tool in a control unit of the three-axis machine tool in order to improve the working accuracy of the three-axis machine tool.

[0030] In this case, the method according to the invention can be carried out relatively quickly and reliably. In particular, the method according to the invention can also be carried out at the customer's location within a short time after delivery of the three-axis machine tool, so that the conditions prevailing there, in particular the temperature conditions at the customer's location, no longer have any negative impact on the geometric accuracy of the three-axis machine tool during operation.

[0031] Of course, the method can also be carried out at the manufacturer of the three-axis machine tool, so that the production process can be optimized at the manufacturer of the three-axis machine tool.

[0032] Preferably, target values ​​of the measuring body are determined in advance in a coordinate measuring machine and the measuring body is then arranged in the working space of the three-axis machine tool in such a way that its coordinate system corresponds to the coordinate system of the three-axis machine tool.

[0033] Further preferably, when measuring the measuring body in the three-axis machine tool, the temperature of the working space is detected, and the correction of the actual data is performed based on the detected working space temperature. This further improves the accuracy of compensating for geometric deviations.

[0034] The method according to the invention is preferably used for the inspection, calibration and long-term evaluation of three-axis machine tools. In this case, the method according to the invention preferably determines 21 possible geometric errors:

[0035] - individual position deviations (translation movement for each axis (3 possible errors because of 3 axes)),

[0036] - two straightness deviations for each axis (translational movement transverse to the axial direction), i.e. a total of 6 possible geometric errors,

[0037] - three rotational deviations on each of the 3 axes: yaw, pitch, roll (i.e. 9 geometric deviations),

[0038] - 3 perpendicularity deviations of the linear axes X, Y, Z relative to each other (XY perpendicularity deviation, XZ perpendicularity deviation, YZ perpendicularity deviation).

[0039] It should be noted that, depending on the design and kinematics of the three-axis machine tool, individual errors can be ignored. Preferably, the pitch error of the Y axis is corrected by the Y positioning error, the straightness error of the Y axis in the X direction, and the perpendicularity error between the Y axis and the X axis. In this case, the X spacing of the spindle from the worktable of the machine tool is constant. Further preferably, since the tool rotates on this axis, the roll error of the Z axis is ignored. If it is further preferred that the tool length is constant, the pitch error of the Z axis and the yaw error of the Z axis can be ignored. Both errors can be corrected by the straightness error and the perpendicularity error of the Z axis. Therefore, the measurement complexity can be reduced by this measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0041] Figure 1 is a schematic perspective view of a measuring body in a three-axis machine tool according to a preferred embodiment of the present invention,

[0042] Figure 2 yes Figure 1 Schematic stereograms of different viewing angles of the measuring volume,

[0043] Figure 3 yes Figure 2 Schematic plan view of the measuring body,

[0044] Figure 4 is a schematic side view of a measuring body, which shows by way of example the determination of the pitch error of the X-axis,

[0045] Figure 5 is a partial side view of a measuring body, which shows by way of example the determination of the roll error of the X-axis, and

[0046] Figure 6 is a schematic diagram for determining the yaw error of the X-axis. DETAILED DESCRIPTION

[0047] Refer to the following Figures 1 to 6 A three-axis machine tool and a measuring body 2 for checking geometrical deviations of the three-axis machine tool are described in detail.

[0048] In addition, refer to Figures 1 to 6 A method for checking and compensating geometric deviations of a three-axis machine tool is described.

[0049] As from Figures 1 to 5 It can be seen that the three-axis machine tool 1 comprises a working space 3 , a spindle 4 and a control unit 9 .

[0050] As from Figure 1 It can be seen that the measuring body 2 is arranged on the machine table 6 of the three-axis machine tool 1 .

[0051] from Figure 1 , Figure 2 and Figure 3 The measuring body 2 can be seen in detail. The measuring body 2 is designed for checking geometrical deviations of three-axis machine tools, wherein when the measuring body is clamped, all linear errors, rotational errors and squareness errors, a total of 21 errors, can be determined. In particular, the coordinates of the tool for positioning the three-axis machine tool 1 can be determined very accurately with the aid of the measuring body 2.

[0052] The measuring body 2 includes a flat base plate 8 that penetrates a base plane in the X direction and the Y direction. The measuring body 2 also includes a first wall 10, a second wall 20, and a third wall 30. The first wall 10, the second wall 20, and the third wall 30 are arranged on the base plate 8 and protrude vertically from the base plate 8 and form a U shape.

[0053] like Figure 2 As shown, the Z direction is perpendicular to the X direction and perpendicular to the Y direction.

[0054] As from Figure 2 It can be seen that in this case, the first wall 10 , the second wall 20 and the third wall 30 are arranged on the base surface of the base plate 8 .

[0055] The base plate 8 is configured in a quadrilateral shape, and includes a first edge 81 , a second edge 82 , a third edge 83 , and a fourth edge 84 .

[0056] In particular, Figure 1 and Figure 2 It can be seen that the three walls 10 , 20 , 30 are constructed differently in geometry. In this case, the first wall 10 is a stepped triangle including an upper exposed area 11 , on which a stepped area 12 is formed. The stepped area 12 includes a plurality of steps 13 .

[0057] A hole 15 is formed in each step 13. The holes 15 form a stepped hole row 14. In this embodiment, the stepped triangle configured as the first wall 10 comprises 7 steps in this case.

[0058] The second wall 20 is a rectangular wall and also has an upper exposed area 21. A first wall hole row 22 having a plurality of holes 23 is formed in the upper exposed area 21.

[0059] The third wall 30 is also a rectangular wall and also has an upper exposed area 31. A second wall hole row 32 having a plurality of holes 33 is formed in the upper exposed area 31.

[0060] In particular, Figure 2 It can be seen that the size of the second wall 20 is smaller than the size of the third wall 30 .

[0061] The holes 23 of the second wall 20 are located on a straight line. The holes 33 of the third wall 30 are also located on a straight line. In this case, the holes of the second wall and the third wall are arranged so that the straight lines formed by the holes 23 and 33 intersect at right angles.

[0062] In particular, Figure 2 As can be seen, the first wall 10 is arranged at a right angle relative to the second wall 20. The second wall 20 is also arranged at a right angle relative to the third wall 30. As a result, the first wall 10 and the second wall 30 are parallel to each other.

[0063] Furthermore, the first wall 10, the second wall 20 and the third wall 30 are arranged spaced apart from the corresponding edges 81, 82, 83 of the base plate 8 along their long sides. Only one end region of the third plate 30 extends to the fourth edge 84 (see Figure 2 ).

[0064] For the purpose of reducing weight, the base plate 8 has a relatively large central opening and a plurality of longitudinal openings (without reference numerals).

[0065] Arranged on the underside of the base plate 8 is a reinforcing element 7 which has a first strip 71 and a second strip 72. The two strips 71, 72 are arranged in a cross shape and reinforce the base plate 8 and thus the measuring body 2. The reinforcing element 7 also makes it possible to clamp the measuring body 2 on the machine table 6 in a simple manner. This prevents in particular the introduction of undesired stresses into the base plate or the three walls 10, 20, 30 due to the clamping process, which stresses could lead to a falsification of the measurement results.

[0066] Furthermore, the measuring body 2 includes a first hole row 101, a second hole row 102, and a third hole row 103 located on the upper side in the substrate. The first hole row 101 includes a plurality of holes 101a arranged on a first straight line 111. The first straight line 111 extends parallel to the first edge 81. The second hole row 102 includes a plurality of holes 102a arranged on a second straight line 112. In this case, the second hole row 102 is parallel to the second edge 82. The third hole row 103 includes a plurality of holes 103a arranged on a third straight line 113. The third hole row 103 is parallel to the third edge 83 (see Figure 3 ). To make it clearer, Figure 3 In the drawings, not all holes of the first hole row, the second hole row and the third hole row are provided with reference numerals.

[0067] In addition, if Figure 3 It can be seen that the first hole row 101 is parallel to the step hole row 14. The second hole row 102 is parallel to the first wall hole row 22 of the second wall 20. The third hole row 103 is parallel to the second wall hole row 32.

[0068] The number of holes of the first row of holes, the second row of holes and the third row of holes is preferably identical, as are the geometric dimensions, in particular the hole spacings.

[0069] It should be noted that, for example, a strip-shaped grinding reference surface ( Figure 3 not shown).

[0070] Furthermore, the first hole row 101 , the second hole row 102 , and the third hole row 103 are arranged so that a hole is provided in each corner of the substrate 8 .

[0071] Further preferably, the thickness of the base plate 8 is also the same as the thickness of the walls 10 , 20 , 30 .

[0072] The measuring body 2 is arranged on the machine table 6 of the three-axis machine tool 1. Furthermore, a 3D measuring sensor is arranged in the spindle 4, with the aid of which the actual coordinates of the three-axis machine tool are determined via the measuring body 2.

[0073] The three-axis machine tool 1 further comprises a control unit 9 which is designed to control the three-axis machine tool 1. The control unit 9 is also designed to perform a correction of geometric data of the three-axis machine tool 1 based on a target / actual comparison of the geometrical dimensions of the measuring body 2.

[0074] As has been explained above, the three-axis machine tool includes three linear axes, specifically, a first axis in the X direction, a second axis in the Y direction, and a third axis in the Z direction.

[0075] In total, the three linear axes produce 21 deviations, three of which are perpendicularity deviations of the linear axes relative to each other. Therefore, a total of 21 error parameters are caused for a three-axis machine tool.

[0076] Thus, with the aid of the method according to the invention, a check and correction of all straightness deviations, rotational deviations and squareness deviations of a three-axis machine tool can be performed.

[0077] For this purpose, the measuring body 2 must first be measured by means of a coordinate measuring machine (not shown) in order to generate target values. The target values ​​are then provided to the control unit 9 of the three-axis machine tool 1 and stored in a memory. In this case, in order to measure the measuring body 2, a coordinate system is established in such a way that the XY plane is parallel to the substrate 8. Therefore, based on the repeatedly determined Z position, X position and Y position of different reference elements of the measuring body 2, the geometry of the measuring body 2, which is preferably made of Invar alloy, is determined. At the same time, the zero point of the coordinate system of the measuring body 2 is also specified. For example, a ground step surface or a ground reference surface is used as a reference element for the Z position. The holes of the hole rows 101, 102, 103, the hole 15 in the step 13 and the holes 23, 33 in the exposed areas 11, 21 are used as reference elements for the X position and the Y position.

[0078] In order to detect geometric deviations of a three-axis machine tool, a measuring body 2 is introduced on a machine table 6 into the working space 3 of the three-axis machine tool. In this case, the measuring body 2 can be clamped or fastened to the machine table in another way. In this case, the XYZ coordinate system of the measuring body should in principle be oriented parallel to the XYZ coordinate system of the three-axis machine tool. The measurement of the measuring body 2 in the three-axis machine tool 1 is then performed with the aid of a 3D measuring device 5, for example a 3D measuring sensor. Typically, modern three-axis machine tools include a 3D measuring sensor of this type, for example for detecting component positions and component geometries.

[0079] Therefore, before the measurement, the coordinate system of the three-axis machine tool is oriented to be identical to the coordinate system of the coordinate measuring machine that previously measured the measuring body 2 .

[0080] After the measuring body 2 has been fixed in the working space 3 of the three-axis machine tool, the control unit 9 can preferably allow a fully automatically executed NC program to be executed in order to measure the measuring body 2 by means of the 3D measuring sensor 5 and thereby determine actual values ​​of the three-axis machine tool 1 .

[0081] Preferably, during the measurement of the measuring body 2 in the working space of the three-axis machine tool 1, the temperature of the working space 3 of the three-axis machine tool 1 is also detected and stored. If this temperature of the working space differs from a reference temperature of, for example, 20° C., the thermal expansion coefficient of the workpiece to be machined on the three-axis machine tool must be taken into account during the machining of the workpiece. A corresponding correction of the actual values ​​of the three-axis machine tool must then be performed here.

[0082] After the measurement of the measuring body 2 in the three-axis machine tool 1 and the optional thermal adjustment of the actual values, the actual values ​​of the three-axis machine tool are determined and can be compared with the target values ​​of the measuring body. Thus, by comparing the target values ​​and the actual values, geometric deviations in the form of position deviations, straightness deviations and squareness deviations of the three-axis machine tool can be calculated and thus checked and corrected. In this case, Figure 3 The straightness deviation G, the perpendicularity deviation R (angle α) and the position deviation P are shown by way of example in a plan view of the measuring body 2 .

[0083] For example, first, the position deviation of the X-axis can be determined, i.e., the difference between the actual position of the measured reference element in the X-direction along the X-axis direction and the target position on the evaluation substrate 8. Since the zero point of the measuring body 2 and the position of the reference element relative to the zero point are known, the determined difference can be associated with the X-axis position of the three-axis machine tool. Thus, a table of the X-axis positions of the three-axis machine tool and the position deviations in the X-direction at these X-axis positions is generated. In this case, these position deviations can be stored in the control unit 9 and used directly in the control unit 9 as correction data or error compensation for the three-axis machine tool.

[0084] Alternatively, the deviations can also be preprocessed mathematically. For example, the deviations can also be approximated using different mathematical functions. Specifically, in the case of a small measuring body 2 with few reference elements, it is conceivable, for example, to approximate the differences using a straight line (best fit line). In this case, only scaling errors are corrected.

[0085] Since the measuring body 2 covers only a part of the working space 3 of the three-axis machine tool, the detected actual values ​​are preferably extrapolated with the aid of corresponding mathematical functions. As a result, the deviation of the entire working space 3 of the three-axis machine tool 1 is obtained.

[0086] The straightness deviation G of the X-axis is determined in the same way. In this case, the position deviation P in the Y-direction or in the Z-direction is associated with the X-axis position. In this case, the difference between the actual position and the target position in the Y-direction is produced by the determined centers of the holes of the three hole rows 101, 102, 103 and the reference holes on the first wall 10, the second wall 20 and the third wall 30. The difference between the actual position and the target position in the Z-direction is produced, for example, by the reference surface on the substrate 8 and the ground surface of the step 13. In this case, mathematical preprocessing or approximation is also possible.

[0087] When the correction data for the position deviation and the straightness deviation of the X-axis have been calculated, for further evaluation, all the measured data for the actual position of the reference element are adjusted based on the correction data for the position deviation of the X-axis, the straightness deviation of the X-axis in the Y direction and the straightness deviation of the X-axis in the Z direction. It is preferably assumed here that the adjusted actual position no longer has any error in the X-direction. As a result, the error in the X-direction can be ignored in the further evaluation.

[0088] In the next step, the perpendicularity error R between the X-axis and the Y-axis can be calculated. For this purpose, two best fit lines are calculated. The first best fit line is generated by the X-axis position of the reference element on the substrate 8 along the X direction and its position deviation in the Y direction. The second best fit line is generated by the Y-axis position of the reference element on the substrate 8 along the Y direction and its position deviation in the X direction. Subsequently, the angle α between the two best fit lines is calculated (see Figure 3 ). In this case, the determined deviation can be used directly as a correction value for error compensation in the control unit 9 .

[0089] Subsequently, based on the squareness error, the actual positions of all reference elements in the measurement data are adjusted according to the Y positions of all reference elements, so that the measurement data no longer contains any XY squareness error.

[0090] Subsequently, the position deviation and straightness deviation of the Y-axis are calculated in the same manner as in the case of the X-axis. For this purpose, the difference between the actual position and the target position of the reference position on the substrate 8 along the Y-axis is evaluated (see Figure 3 ). Together with the zero point, a table is generated with the Y-axis positions of the three-axis machine and the position deviations in the X, Y and Z directions at these Y-axis positions. As in the case of the X-axis, the data can be further processed in the control unit 9 or used directly as correction data for error compensation of the three-axis machine. Here too, the correction data should be extrapolated using corresponding mathematical functions in order to define the entire working space 3.

[0091] Subsequently, for further evaluation, all actual positions of the reference element are adjusted based on the position deviation of the Y axis and the two straightness deviations. At this point, it is preferably assumed that the adjusted actual positions no longer have any errors in the Y direction. As a result, the errors in the Y direction can be ignored in further evaluation. Figure 4 , Figure 5 and Figure 6 The determination of the pitch error on the X-axis is shown by way of example ( Figure 4 ) and the determination of the rolling error of the X axis ( Figure 5 ) and determination of the X-axis yaw error ( Figure 6 ).

[0092] In order to determine the yaw error of the X-axis ( Figure 6 ), there must be a geometric feature in the X direction whose X position can be detected using a measuring sensor. In order to be able to determine the error independently of other errors, the Y and Z positions of the feature must be identical. In order to be able to measure the influence of the X yaw error, the measurement must also be performed at a Y position that is different from the first X feature series. Furthermore, the Y distance d from the first X feature series must be known (see Figure 6 ).

[0093] In the next step, the pitch error of the X-axis is calculated. To determine the pitch error of the X-axis ( Figure 4 ) There must be a geometric feature in the X direction whose X position can be detected using a measuring sensor. In order to be able to determine the error independently of other errors, the Y position and Z position of the feature must be identical. In order to be able to measure the influence of the X pitch error, the measurement must also be performed at a different Z position than in the case of the first X feature series. Furthermore, the Z distance d from the first X feature series must be known.

[0094] To determine the roll error of the X-axis ( Figure 5 ), there must be a geometric feature in the X direction whose Y position can be detected using a measuring sensor. In order to be able to determine the error independently of other errors, the Y and Z positions of the feature must be identical. In order to be able to measure the influence of the X roll error, it is also necessary to measure at a different Z position than the first X feature series. Furthermore, the Z distance d from the first X feature series must be known (see Figure 5 ).

[0095] according to Figure 4 and Figure 5 The measurements described in , determine the roll error and yaw error in the Y axis.

[0096] In the next step, the perpendicularity between the X-axis and the Z-axis is calculated. For this purpose, two best fit lines are calculated. The first best fit line results from the X-axis position of the reference element on the substrate 8 along the X direction and its position deviation in the Z direction. The second best fit line results from the Z-axis position of the reference element on the first wall 10 (triangle with steps) in the X direction and its position deviation in the X direction. Subsequently, the angle α between the two best fit lines is calculated. The determined deviation can be used directly as a correction value for the error compensation in the control unit 9.

[0097] The perpendicularity between the Y-axis and the Z-axis is calculated in the same way. In this case, the first best fit line is generated by the Y-axis position of the reference element on the substrate 8 along the Y direction and its position deviation in the Z direction. The second best fit line is generated by the Z-axis position of the reference element on the second wall 20 in the Y direction and its position deviation in the Y direction. The perpendicularity deviation between these two straight lines can also be directly used as a correction value for error compensation.

[0098] Then, based on the squareness error, the actual positions of all reference elements are adjusted in the measurement data according to the Z position of the reference element, so that the measurement data no longer contains any XZ squareness error or any YZ squareness error.

[0099] In a further step, the geometric deviation of the Z axis is calculated. For this purpose, the reference elements (reference holes and ground step surfaces) of the three walls 10, 20, 30 are used. Since the X-axis errors and the Y-axis errors as well as the three perpendicularity errors have been eliminated from the measurement data in the previous evaluation, it is assumed in this step that the displacements in the X or Y direction necessary for the measurement step do not affect the geometric deviation of the Z axis.

[0100] Thus, the position deviation of the Z axis is determined, i.e. the difference between the actual position in the Z direction and the target position of the reference position on the first wall 10 is evaluated. Since the zero point of the measuring body 2 and the position of the reference element relative to the zero point are known, the determined difference can be associated with the Z axis position of the three-axis machine tool. Thus, a table of Z axis positions is generated, which can thus be used directly as correction data or error compensation for the three-axis machine tool. As in the case of the X-axis and Y-axis, the data can be further processed or used directly as correction data. Here, the correction data can also be inferred using corresponding mathematical functions.

[0101] As in the case of the other axes, the straightness deviation of the Z axis is determined in the same way. In this case, the position deviation in the Y direction or in the X direction is associated with the Z axis position. In this case, the difference between the actual position and the target position results from the determined hole center. The further processing of the straightness deviation can be the same as the position deviation of the Z axis.

[0102] In this way, all relevant geometric errors including yaw, pitch and roll can be checked and corrected with the aid of the measuring body 2. The method is particularly suitable for the correction of the geometry of a three-axis machine tool after changing thermal conditions, since in this case linear errors that are easy to deduce generally occur. Furthermore, the method can also be used to adjust the geometry of a three-axis machine tool for materials with different thermal expansion coefficients when temperatures different from the reference temperature are present in the working space.

[0103] In addition to the above written description of the invention, for additional disclosure of the invention, reference is hereby made expressly to Figures 1 to 6 An illustration of the present invention in FIG.

[0104] Reference numerals list

[0105] 1 Three-axis machine tool

[0106] 2 Measurement body

[0107] 3. Workspace

[0108] 4 spindles

[0109] 5. Measuring device (3D measuring sensor)

[0110] 6 machines

[0111] 7. Reinforcement elements

[0112] 8 substrates

[0113] 9Control Unit

[0114] 10 First Wall

[0115] 11 The exposed area on the upper part

[0116] 12 Stepped area

[0117] 13 steps

[0118] 14-step hole row

[0119] 15 holes

[0120] 20 Second Wall

[0121] 21 The exposed area on the upper part

[0122] 22 First wall hole row

[0123] 23 holes

[0124] 30 The Third Wall

[0125] 31 The exposed area on the upper part

[0126] 32 Second wall hole row

[0127] 33 holes

[0128] 71 First board

[0129] 72 Second board

[0130] 81 First Edge

[0131] 82 Second Edge

[0132] 83 The Third Edge

[0133] 84 The Fourth Edge

[0134] 101 first hole row

[0135] 101a hole

[0136] 102 Second hole row

[0137] 102a hole

[0138] 103 Third hole row

[0139] 103a hole

[0140] 111 First Straight Line

[0141] 112 Second Straight Line

[0142] 113 The third straight line

[0143] d-spacing

[0144] G Straightness deviation

[0145] R verticality error

[0146] P Position Deviation

[0147] XX axis

[0148] YY Axis

[0149] ZZ axis

[0150] α Verticality Deviation

Claims

1. A measuring body for checking geometrical deviations in a three-axis machine tool (1), comprising: - base plate (8), - a first wall (10) arranged on the base plate (8) and protruding vertically from the base plate (8), a second wall (20) arranged on the base plate (8) and protruding vertically from the base plate (8) and arranged perpendicularly to the first wall (10), - wherein a first row of holes (101) and a second row of holes (102) are formed in the substrate (8), - wherein the first wall (10) is a stepped triangle and comprises a stepped area (12) with a plurality of steps (13) on the upper exposed area (11), - wherein the second wall (20) is a quadrilateral wall and comprises a first row of wall holes (22) on an upper exposed area (21) extending parallel to the base plate (8), and - wherein the first hole row (101) is arranged parallel to the step hole row (14), and the second hole row (102) is arranged parallel to the first wall hole row (22).

2. The measuring body according to claim 1, wherein: The stepped region (12) comprises a first stepped hole row (14), wherein, in particular, a hole (15) and a ground reference surface are formed in each step (13).

3. The measuring body according to any one of the preceding claims, further comprising a third wall (30) which is arranged on the base plate (8) and protrudes vertically from the base plate (8), wherein: The third wall (30) is arranged perpendicular to the second wall (20), and the second wall (30) comprises a second wall hole row (32) having holes (33) on an upper exposed area (31).

4. The measuring body according to claim 3, wherein: The first wall (10), the second wall (20) and the third wall (30) are configured in a U shape on the substrate.

5. The measuring body according to claim 3 or 4, further comprising a third row of holes (103) in the base plate (8), the third row of holes extending parallel to the second row of wall holes (32).

6. The measuring body according to claim 4 or 5, wherein: The first row of holes (101), the second row of holes (102) and the third row of holes (103) all extend along the edge of the substrate (8) in such a way that one hole in a row of holes is arranged at each corner of the substrate (8).

7. The measuring body according to any one of claims 4 to 6, wherein: The first wall (10), the second wall (20) and the third wall (30) are arranged on the substrate (8) in a manner that they are spaced apart from a first edge (81), a second edge (82) and a third edge (83), wherein the space is greater than or equal to twice the diameter of the holes in the first hole row, the second hole row and the third hole row.

8. The measuring body according to claim 1, wherein: In addition to the holes in the step (13), there is also a grinding surface, and / or in addition to the holes of the first hole row (101) and / or the second hole row (102) and / or the third hole row (103), a grinding surface is also formed.

9. The measuring body according to any of the preceding claims, further comprising a reinforcing element (7) which is arranged below the base plate (8) for mechanically reinforcing the base plate (8) and / or as a clamping aid to the machine tool.

10. Three-axis machine tools, including: -Machine tool spindle (4), - a measuring body (2) according to any one of the preceding claims, a measuring device (5) which can be clamped in the machine spindle (4) and is designed to detect actual values ​​of a measuring body (2) fixed in the three-axis machine tool (1), and - a control unit (9) which is designed to control the three-axis machine tool (1), The control unit (9) is further configured to perform a target / actual comparison based on a geometric target value of a size of the measuring body (2) and an actual value of the measuring body (2) fixed in the three-axis machine tool (1) determined for the three-axis machine tool (1) by means of the measuring device (5), and, if a deviation occurs between the target value and the actual value, a correction of the geometric data of the three-axis machine tool (1) is performed in a control program of the control unit (9).

11. The three-axis machine tool according to claim 10, wherein: The control unit (9) comprises a memory in which a target value for the measuring volume (2) is stored.

12. A method for checking and compensating for geometric deviations in a three-axis machine tool, comprising the steps of: - clamping the measuring device (5) in the machine spindle (4) of the three-axis machine tool, - arranging a measuring body (2) according to any one of claims 1 to 9 in a working space (3) of the three-axis machine tool, - approaching a plurality of positions of the measuring body (2) in order to acquire geometric actual data of the three-axis machine tool with the aid of the measuring body (2), - performing a target / actual comparison of the geometric actual data with stored target data of the measuring volume (2) in order to determine geometric deviations, and - Compensation for geometrical deviations in the control unit (9) of the three-axis machine tool.

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