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

Abstract

The present invention relates to a measuring body for checking geometric deviations in a three-axis machine tool (1), comprising: a base plate (20); a first wall (21) arranged on the base plate (20) and protruding vertically from the base plate (20); and a second wall (22) arranged on the base plate (20) and protruding vertically from the base plate (20), wherein a first hole row (23) and a second hole row (24) are formed in the base plate (20), wherein the first wall (21) has a stepped area (25) at an upper exposed area, the stepped area (25) having a plurality of steps (25a), and wherein the second wall (22) has a stepped area (25) at an upper exposed area, the stepped area (25) having a plurality of steps (25a). The present invention also relates to a three-axis machine tool having such a measuring body and a method for checking and compensating geometric deviations of a three-axis machine tool.

Description

Technical Field

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

[0002] The geometric accuracy of machine tools is a well-known issue. It is determined by the deviation of the tool's actual position and orientation relative to the workpiece from the nominal position and orientation. This error leads to deviations from the ideal workpiece geometry and, consequently, affects the machine's operating accuracy. To improve geometric accuracy, individual axis deviations, as well as their relative position and orientation, are often considered.

[0003] Assuming a rigid body model, a three-axis machine tool has three linear deviations (one in the axial direction and two perpendicular to the axis) and three rotational deviations (yaw, pitch, and roll). Therefore, each linear axis has six deviations, resulting in 18 deviations across the three linear axes. In addition, the three perpendicularity deviations of the linear axes relative to one another must be considered. Therefore, a total of 21 possible geometric errors exist for a three-axis machine tool. Individual deviations can overlap and, in practice, result in a large total error, which adversely affects the machine tool's geometric accuracy. Summary of the Invention

[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 to be as simple and inexpensive as possible and the method can be carried out as inexpensively and quickly as possible.

[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 9, and a method having the features of claim 11. Preferred further embodiments of the invention are indicated in the corresponding dependent claims.

[0006] On the other hand, the measuring body for checking geometric deviations of a three-axis machine tool according to the present invention, having the features of claim 1, has the advantage that it can be used to compensate for the geometric deviations of the three-axis machine tool, resulting in a three-axis machine tool with zero linearity and zero perpendicularity deviation. This means that the three-axis machine tool can then be used to machine workpieces with maximum precision. The correction data determined based on the measuring body can be directly used to compensate for errors in the three-axis machine tool. According to the present invention, this is achieved by a measuring body comprising a base, a first wall, and a second wall. The first wall is disposed on and protrudes vertically from the base, and the second wall is also configured to protrude vertically from the base. A first row of holes and a second row of holes are formed in the base. Furthermore, the first wall is formed into a stepped shape with multiple steps on the side facing away from the base. Similarly, the second wall is also formed into a stepped shape with multiple steps on the side facing away from the base. Therefore, the stepped areas of the first wall and the second wall are located at the exposed upper areas of the first wall and the second wall, respectively. Therefore, the exposed upper regions of the first and second walls form a stepped portion, and when the substrate spans the base surface in the X and Y directions, different positions in the Z direction can be detected at this stepped portion. Due to the exposed upper stepped regions of the first and second walls, the first and second walls have a generally triangular shape.

[0007] Preferably, the first wall is arranged along a first edge of the substrate, and the second wall is arranged along a second edge of the substrate. Furthermore, the first row of holes is arranged along a third edge of the substrate, and the second row of holes is arranged along a fourth edge of the substrate. Thus, a rectangular (preferably square) substrate has first and second walls along two edges, and first and second rows of holes along the other two edges.

[0008] Most preferably, the first wall and the second wall are arranged so that they abut each other at a corner of the substrate or form a corner region. In this case, the first wall and the second wall can be arranged on the substrate, or alternatively, the first wall and the second wall are arranged on a lateral region of the substrate, with the corner of the substrate being located on a corner line of the contacting first wall and second wall.

[0009] Preferably, the first and second walls are formed in the same manner to facilitate production of the measuring body. Furthermore, preferably, each step surface of the stepped region of each wall has a reference hole. Preferably, the reference hole is formed at the center of the step surface. Furthermore, preferably, each step surface is ground or milled. Preferably, the reference hole is a perforated hole. This allows the hole and the ground surface to serve as separate reference elements, with the ground surface of the step used to determine the Z coordinate and the center point of the hole serving as the X and Y coordinates.

[0010] Furthermore, preferably, a first reference surface is formed on the substrate adjacent to the first hole row, and a second reference surface is formed on the substrate adjacent to the second hole row. Therefore, both reference surfaces are also reference elements and are respectively configured for determining the Z coordinate.

[0011] In order to make the measurement process as simple as possible, the holes of the first hole row are arranged along a first straight line, and the holes of the second hole row are arranged along a second straight line. The first straight line is preferably perpendicular to the second straight line.

[0012] Furthermore, the first and second reference surfaces are preferably arranged in a strip-like pattern adjacent to and parallel to the rows of holes. Most preferably, the first and second reference surfaces are ground or milled surfaces. Furthermore, the first and second reference surfaces preferably extend parallel to the edge of the substrate.

[0013] Most preferably, the first hole row and the second hole row comprise the same number of holes, the same hole spacing and the same hole diameter.

[0014] The measuring body is preferably made of Invar alloy. Invar alloy has a very low coefficient of thermal expansion and is therefore particularly suitable for producing the measuring body. Furthermore, the thickness of the first wall and the second wall is preferably the same as the thickness of the base plate.

[0015] The present invention also relates to a three-axis machine tool comprising a tool spindle; a measuring device, in particular a 3D measuring probe, which can be clamped into the tool spindle; and a control unit for controlling the three-axis machine tool. Furthermore, the three-axis machine tool includes a measuring body according to the present invention, wherein the control unit is configured to correct the geometric data of the three-axis machine tool based on a nominal / actual comparison of previously determined nominal geometric dimensions of the measuring body with the actual geometric dimensions of the measuring body determined by the measuring device in the three-axis machine tool. The control unit thus includes a memory in which the nominal geometric dimensions of the measuring body, determined in a previous step in the measuring machine, are recorded. To determine the actual geometric dimensions of the measuring body in the three-axis machine tool, the control unit preferably starts an NC program for measuring the measuring body to determine the actual values of the measuring body. Thus, by comparing the nominal values with the actual values, the geometric data of the three-axis machine tool can be corrected, significantly improving the accuracy of workpiece machining by the three-axis machine tool. Consequently, geometric errors of the three-axis machine tool can be compensated in a simple manner. The nominal values are preferably recorded in the memory. Furthermore, it is preferred that the measuring body comprises a three-point support for placing or clamping the measuring body on the processing table. This means that the measuring body stands on three feet, which are arranged as far as possible below the base plate.

[0016] Furthermore, the present invention relates to a method for detecting and compensating geometric deviations of a three-axis machine tool, the method comprising the following steps:

[0017] - clamping the measuring device, in particular a 3D measuring probe, in the spindle of a three-axis machine tool,

[0018] - Place the measuring body in the working area of the three-axis machine tool,

[0019] - moving to different locations of the measurement volume to collect actual geometric data of the measurement volume,

[0020] - performing a nominal / actual comparison between actual data acquired of the measurement volume and predetermined nominal data of the measurement volume in order to determine geometric deviations, and

[0021] -Compensate for the geometric deviation of the three-axis machine tool in the control unit of the three-axis machine tool to improve the working accuracy of the three-axis machine tool.

[0022] The process according to the invention can be carried out relatively quickly and safely. In particular, the method according to the invention can also be carried out shortly after the three-axis machine tool has been delivered to the customer, so that the prevailing conditions at the customer's location, in particular the temperature conditions at the customer's site, are no longer detrimental to the geometric accuracy of the three-axis machine tool during operation.

[0023] Of course, if necessary, the method can also be performed at the manufacturer of the three-axis machine tool to optimize the manufacturing process at the manufacturer's site.

[0024] Preferably, the nominal values of the measuring body are predetermined in the coordinate measuring machine and the measuring body is then arranged in the working area of the three-axis machine tool in such a way that the coordinate system of the measuring body coincides with the coordinate system of the three-axis machine tool.

[0025] Furthermore, when measuring a measuring volume in a three-axis machine tool, the temperature of the working space is preferably detected, and the actual data is corrected based on the detected working space temperature. This further improves the accuracy of compensating geometric deviations.

[0026] According to the method of the present invention, the position deviations of the respective axes in the X, Y and Z directions are preferably determined respectively, and two straightness deviations of the respective axes are also determined. Thus, a total of nine different geometric error sources can be detected.

[0027] Furthermore, preferably, perpendicularity errors between three axes (ie, X-axis, Y-axis, and Z-axis), respectively, are calculated, thereby further improving the accuracy for compensating for geometric deviations and enabling detection of a total of twelve geometric deviations. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Preferred exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which:

[0029] Figure 1 is a schematic perspective view of a measuring body in a three-axis machine tool according to a preferred exemplary embodiment of the present invention,

[0030] Figure 2 To observe from another angle Figure 1 Schematic stereogram of the measuring body,

[0031] Figure 3 for Figure 2 A schematic top view of the measuring body, and

[0032] Figure 4 for Figure 1 Schematic overall stereogram of a three-axis machine tool. DETAILED DESCRIPTION

[0033] In the following, in reference Figures 1 to 4 In the present case, a three-axis machine tool 1 with a measuring body 2 for checking geometrical deviations of a three-axis machine tool is described in detail.

[0034] In addition, in the reference Figures 1 to 4 In this case, a method for detecting and compensating geometric deviations of a three-axis machine tool will also be described.

[0035] As from Figure 1 and Figure 4 It can be seen that the three-axis machine tool 1 includes a work area 3 , a spindle 4 and a control unit 10 .

[0036] As from Figure 1 and Figure 4 It can be seen that the measuring body 2 is arranged on a machining table 6 of the three-axis machine tool 1 .

[0037] Measuring body 2 Figure 2 and Figure 3 The measuring body 2 is designed to check geometric deviations of a three-axis machine tool. In particular, the measuring body 2 can be used to very accurately determine the coordinates of a tool for positioning the three-axis machine tool 1.

[0038] The measuring body 2 includes a planar substrate 20 having a base surface extending in the X and Y directions. Furthermore, the measuring body 2 includes a first wall 21 and a second wall 22. The first wall 21 and the second wall 22 are arranged on the substrate 20 and protrude perpendicularly therefrom.

[0039] As from Figure 2 It can be seen that the first wall 21 and the second wall 22 are arranged on the base surface of the substrate 20 .

[0040] The first wall 21 and the second wall 22 are arranged along the edge of the substrate 20. More specifically, the first wall 21 is arranged along the first edge 20a of the substrate 20, and the second wall 22 is arranged along the second edge 20b of the substrate 20.

[0041] The first wall 21 and the second wall 22 are thus arranged on the substrate 20 so that the first wall and the second wall come into contact with each other at the corner of the substrate. This creates a corner line 27 (see Figure 1 ), the corner line 27 is perpendicular to the base surface of the substrate 20.

[0042] As from Figure 1 and Figure 2 It can be seen that the first wall 21 and the second wall 22 are triangular in shape, and a step is formed at the upper free end of each of the first wall and the second wall. Therefore, when the step area 25 is exposed on each wall, a triangle composed of steps is formed. Figure 2 As shown, each step 25a has a reference hole 26 and a ground or milled step surface 26a. The thickness of the first wall and the second wall is preferably selected to be the same. In addition, the thickness of the base plate 20 is also preferably the same as the wall thickness of the walls 21, 22.

[0043] Furthermore, measuring body 2 includes a first hole row 23 and a second hole row 24 in base plate 20. First hole row 23 includes a plurality of holes 23a arranged along a first straight line 31. Second hole row 24 includes a plurality of second holes 24a arranged along a second straight line 32. The centers of holes 23a, 24a are arranged along straight lines 31, 32. First straight line 31 and second straight line 32 intersect at a right angle.

[0044] As from Figure 2 It can be seen that the first strip-shaped reference surface 28 is arranged beside the first hole row 23. The second strip-shaped reference surface 29 is arranged beside the second hole row 24. The reference surfaces are respectively located between the third edge 20c and the fourth edge 20d and the hole row (see Figure 2 ).

[0045] The base plate 20 is square in shape, so the number of holes is the same in the first hole row 23 and the second hole row 24. The common holes 30 of the two hole rows are provided in the corner opposite to the corner where the two wall portions contact each other.

[0046] like Figure 2 As shown, the Z direction is perpendicular to the X direction and the Z direction is perpendicular to the Y direction.

[0047] The measuring body 2 is fixed to the machining table 6 of the three-axis machine tool 1. Furthermore, a 3D measuring probe is arranged in the spindle 4 for determining the actual coordinates of the three-axis machine tool using the measuring body 2.

[0048] The three-axis machine tool 1 further comprises a control unit 10 configured to control the three-axis machine tool and to perform a correction of the geometrical data of the three-axis machine tool 1 based on a nominal / actual comparison of the geometrical dimensions of the measuring body 2 .

[0049] As explained above, the three-axis machine tool includes three linear axes, namely, a first axis in the X direction, a second axis in the Y direction, and a third axis in the Z direction.

[0050] In total, the three linear axes cause twenty-one deviations, three of which are perpendicularity deviations with respect to each other. Therefore, a three-axis machine tool generates a total of twenty-one error parameters.

[0051] Therefore, using the method according to the present invention, it is possible to Figure 4 The position deviation, straightness deviation, and squareness deviation of the three-axis machine tool (gantry type machine) shown are inspected and corrected.

[0052] To this end, the measuring body 2 is first measured using a coordinate measuring machine (not shown) to generate nominal values. These nominal values are then provided to the control unit 10 of the three-axis machine tool 1 and recorded in a memory. To measure the measuring body 2, a coordinate system is established with the XY plane parallel to the base plate 20. Thus, the geometry of the measuring body 2 (preferably made of Invar) is determined based on repeated determination of the Z position, X position, and Y position of different reference elements of the measuring body 2. Simultaneously, the zero point of the coordinate system of the measuring body 2 is also determined. For example, the first and second reference surfaces 28, 29, and the ground step surface 26a are used as reference elements for the Z position. The holes in the hole rows 23 and 24 and the hole 26 in the step serve as reference elements for the X and Y positions.

[0053] Now, the measuring body 2 is placed on the machining table 6 in the work area 3 of the three-axis machine tool to measure its geometric deviations. During this process, the measuring body 2 can be clamped or otherwise fixed to the machining table. In this case, the XYZ coordinate system of the measuring body should be aligned approximately parallel to the XYZ coordinate system of the three-axis machine tool. The measuring body 2 in the three-axis machine tool 1 is then measured using a 3D measuring device 5 (e.g., a 3D measuring probe). Modern three-axis machine tools typically have a 3D measuring probe for detecting component position and geometry, for example.

[0054] Therefore, before measuring, the coordinate system of the three-axis machine tool is aligned identically with the coordinate system of the coordinate measuring machine that previously measured the measuring body 2 .

[0055] After the measuring body 2 has been fixed in the working area 3 of the three-axis machine tool, the control unit 10 can preferably run a fully automatic NC program to measure the measuring body 2 using the 3D measuring probe 5 in order to determine actual values of the three-axis machine tool 1 .

[0056] Preferably, when measuring the measuring body 2 in the working area of the three-axis machine tool 1, the temperature of the working area 3 of the three-axis machine tool 1 is also measured and recorded. If this working area temperature differs from a reference temperature (e.g., 20°C), the coefficient of thermal expansion of the workpiece to be machined on the three-axis machine tool must be taken into account during machining. The actual values of the three-axis machine tool must therefore be corrected accordingly.

[0057] After measuring the measuring body 2 in the three-axis machine tool 1 and, if necessary, thermodynamically adjusting the actual values, the actual values of the three-axis machine tool are determined and can be compared with the nominal values of the measuring body. By comparing the nominal / actual values, geometric deviations of the three-axis machine tool in the form of position deviations, straightness deviations, and squareness deviations can be calculated and thus checked and corrected. Figure 3 Examples of straightness deviation G, perpendicularity deviation R, and position deviation P in a plan view of measuring body 2 are shown.

[0058] For example, the X-axis position deviation can be determined by first evaluating the difference between the actual position of the reference element measured along the X-axis on the base plate 20 and the nominal position in the X-direction. 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 assigned to the X-axis position of the three-axis machine tool. This results in 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. These position deviations can then be recorded and used directly as correction data for error compensation of the three-axis machine tool in the control unit 10.

[0059] Alternatively, the deviations can also be mathematically preprocessed. For example, various mathematical functions can be used to roughly estimate the deviations. Especially with small measuring bodies 2 with few reference elements, it is conceivable to use straight lines (compensation lines) to roughly estimate the differences. In this case, only the scale errors are corrected.

[0060] Since the measuring body 2 covers only a portion of the working area 3 of the three-axis machine tool, the actual values determined are preferably extrapolated by means of corresponding mathematical functions. In this way, deviations are determined for the entire working area 3 of the three-axis machine tool 1 .

[0061] The X-axis straightness deviation G is determined in the same manner. Here, the position deviations P in the Y and Z directions are assigned to the X-axis position, respectively. The difference between the actual position and the nominal position in the Y direction is derived from the centers defined by the reference hole 26 and the holes in the hole rows 23 and 24 on the step area 25. The difference between the actual position and the nominal position in the Z direction is derived from the reference surfaces 28 and 29 on the substrate 20 and the ground step surface 26a. Here, too, mathematical preprocessing or rough estimation is possible.

[0062] Once the correction data for the positional deviation and straightness deviation of the X-axis have been calculated, all measurement data for the actual position of the reference element are adjusted for further evaluation using the correction data for the positional 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. At this point, it is preferably assumed that the actual position after adjustment no longer has any errors in the X-direction. This allows errors in the Z-direction to be calculated in subsequent evaluations without being affected by errors in the X-direction. This is because, if the wall 21 is arranged in the X-direction, the X-axis must be moved to enable measurement of the reference hole 26 at different Z-axis positions.

[0063] In the next step, the perpendicularity error R between the X-axis and the Y-axis can be calculated. For this purpose, two compensation lines are calculated. The first compensation line is obtained from the X-axis position of the reference elements on the substrate 2 along the X direction and their position deviation in the Y direction. The second compensation line is obtained from the Y-axis position of the reference elements on the substrate 2 along the Y direction and their position deviation in the X direction. The angle α between the two compensation lines is then calculated (see Figure 3 The determined deviation can be used directly as a correction value for error compensation in the control unit 10 .

[0064] Then, based on the squareness error, the actual positions of all the fiducial elements in the measurement data are adjusted according to the Y position of the fiducial element so that the measurement data no longer contains the XY squareness error.

[0065] The position deviation and straightness deviation of the Y axis are then calculated in the same way as for the X axis. For this purpose, the difference between the actual position of the reference position on the substrate 2 along the Y axis and the nominal position is evaluated (see Figure 3 Together with the zero point, a table of the Y-axis positions of the three-axis machine tool and the position deviations in the X, Y, and Z directions at these Y-axis positions is obtained. As with the X-axis, the data can be further processed or directly transmitted to the control unit 10 as correction data for error compensation of the three-axis machine tool. Similarly, the compensation data should be extrapolated using appropriate mathematical functions to define the entire working area 3.

[0066] Subsequently, the correction data for the Y-axis position deviation and the two straightness deviations are used to adjust all actual positions of the reference element for further evaluation. At this point, it is preferably assumed that the adjusted actual positions no longer have any errors in the Y direction. This allows errors in the Z direction to be calculated in further evaluations without being affected by the errors in the Y direction. This is because, if the second wall 22 is configured in the Y direction, the Y axis must be moved to measure the hole 26 at different Z-axis positions.

[0067] In the next step, the perpendicularity between the X and Z axes is calculated. For this purpose, two compensation lines are calculated. The first compensation line is derived from the X-axis positions of the reference elements on substrate 2 along the X direction and their positional deviations in the Z direction. The second compensation line is derived from the Z-axis positions of the reference elements on first wall 21 (stepped triangle) along the X direction and their positional deviations in the X direction. The angle α between the two compensation lines is then calculated. The resulting deviation can be directly used as a correction value for error compensation in control unit 10.

[0068] Similarly, the perpendicularity between the Y-axis and the Z-axis is calculated. A first compensation line is derived from the Y-axis positions of the reference elements on substrate 20 and their positional deviation in the Z-direction. A second compensation line is derived from the Z-axis positions of the reference elements on second wall 22 and their positional deviation in the Y-direction. The perpendicularity deviation between these two lines can also be directly used as a correction value for error compensation.

[0069] Then, based on the perpendicularity error, the actual positions of all reference elements in the measurement data are adjusted according to the Z position of the reference element, so that the measurement data no longer contains the XZ perpendicularity error and the YZ perpendicularity error.

[0070] In the final step, the geometric deviation of the Z axis is calculated. For this purpose, the reference elements of the two triangular walls 21 and 22 (reference hole 26 and ground step surface 26a) are used. Since the errors of the X and Y axes and the three perpendicularity errors have already been calculated from the measurement data in the previous evaluation, it is assumed in this step that the process required to measure the step in the X or Y direction will not affect the geometric deviation of the Z axis.

[0071] Therefore, the Z-axis position deviation is determined by evaluating the difference between the actual and target positions of the reference positions on the two walls 21 and 22 in the Z direction. Since the zero point of measuring volume 2 and the position of the reference element relative to that zero point are known, the determined difference can be assigned to the Z-axis position of the three-axis machine tool. This results in a Z-axis position table that can be directly used as correction data for error compensation in the three-axis machine tool. As with the X- and Y-axes, this data can be further processed or used directly as correction data. Similarly, appropriate mathematical functions can be used to deduce the compensation data.

[0072] The straightness deviation of the Z axis is determined in a similar manner to the other axes. Here, the position deviation in the Y or X direction is assigned to the Z axis position. The difference between the actual position and the nominal position is derived from the determined hole center. Further processing of the straightness deviation can be performed in the same manner as for the Z axis position deviation.

[0073] In this way, all geometric errors except yaw, pitch, and roll can be checked and corrected using measuring body 2. This method is particularly suitable for correcting the geometry of three-axis machine tools after changes in thermal conditions, as linear errors often occur in these cases and can be easily deduced. Furthermore, this method can also be used to adapt the geometry of three-axis machine tools to materials with different thermal expansion coefficients, if the temperatures prevailing in the work area differ from a reference temperature.

[0074] In addition to the above written description of the invention, reference is made specifically to Figures 1 to 4 The illustrations of the present invention are used to supplement the disclosure thereof.

[0075] Reference Signs List

[0076] 1 three-axis machine tool

[0077] 2 measuring body

[0078] 3 Workspace

[0079] 4 spindles

[0080] 5. Measuring device (3D probe)

[0081] 6 processing tables

[0082] 10Control Unit

[0083] 20 substrates

[0084] 20a First Edge

[0085] 20b Second Edge

[0086] 20c Third Edge

[0087] 20d Fourth Edge

[0088] 21 First Wall

[0089] 22 Second Wall

[0090] 23 first hole row

[0091] 23a Holes in the first hole row

[0092] 24 second hole row

[0093] 24a Holes of the second hole row

[0094] 25-step area

[0095] 25a steps

[0096] 26 reference holes

[0097] 26a Grinding step area

[0098] 27 Corner Line

[0099] 28 first reference surface

[0100] 29 Second reference surface

[0101] 30 common holes

[0102] 31 First Line

[0103] 32 Second straight line

[0104] G Straightness deviation

[0105] R verticality

[0106] P position deviation

[0107] XX axis

[0108] YY axis

[0109] ZZ axis

Claims

1. A measuring body for checking geometric deviations in a three-axis machine tool (1), the measuring body comprising: -Substrate (20), - a first wall (21) arranged on the base plate (20) and protruding vertically from the base plate (20), and - a second wall (22), the second wall (22) being arranged on the base plate (20) and protruding vertically from the base plate (20), - wherein a first row of holes (23) and a second row of holes (24) are formed in the substrate (20), - wherein the first wall (21) has a stepped region (25) at an upper exposed region, the stepped region (25) having a plurality of steps (25a), and - wherein the second wall (22) has a stepped region (25) at an upper exposed region, the stepped region (25) having a plurality of steps (25a).

2. A measuring body according to claim 1, wherein the first wall (21) is configured along a first edge (20a) of the substrate (20), and wherein the second wall (22) is configured along a second edge (20b) of the substrate (20), wherein the first row of holes (23) is configured along a third edge (20c) of the substrate (20), and wherein the second row of holes (24) is configured along a fourth edge (20d) of the substrate (20).

3. The measuring body according to claim 1 or 2, wherein the first wall (21) and the second wall (22) are adjacent to each other at a corner of the base plate (20).

4. The measuring body according to claim 1 or 2, wherein the steps (25a) of the first wall (21) and the steps (25a) of the second wall (22) have equal step heights and / or equal step lengths and / or equal number of steps.

5. The measuring body according to claim 1 or 2, wherein each step (25a) has a ground or milled step surface (26a) and a reference hole (26).

6. A measuring body according to claim 1 or 2, wherein a first reference surface (28) is configured adjacent to the first row of holes (23) as a reference for the Z direction, and a second reference surface (29) is configured adjacent to the second row of holes (24) as a reference for the Z direction, wherein the Z direction is perpendicular to the substrate (20).

7. The measuring body according to claim 6, wherein the holes of the first hole row (23) are located on a first straight line (31) and / or wherein the holes of the second hole row (24) are located on a second straight line (32).

8. The measuring body according to claim 7, wherein the first reference surface (28) and the second reference surface (29) are configured in a strip-like manner and are parallel to the first hole row (23) and the second hole row (24).

9. A three-axis machine tool comprising - tool spindle (4), - a measuring body (2) according to any one of the preceding claims, a measuring device (5) which can be clamped into the tool spindle (4) and is designed to detect actual values of the measuring body (2) fixed in the three-axis machine tool (1), and - a control unit (10) configured to control the three-axis machine tool (1), The control unit (10) is further configured to perform a nominal-actual comparison based on the geometric nominal values of the dimensions of the measuring body (2) and the actual values of the measuring body (2) fixed in the three-axis machine tool (1) determined for the three-axis machine tool (1) using the measuring device (5); and to perform a correction of the geometric data of the three-axis machine tool (1) in the control program of the control unit (10) in the event of a deviation between the nominal value and the actual value.

10. The three-axis machine tool according to claim 9, wherein the control unit comprises a memory, in which the nominal value of the measuring body (2) is recorded.

11. A method for detecting and compensating for geometric deviations of a three-axis machine tool, the method comprising the following steps: - clamping the measuring device (5) in the tool spindle (4) of the three-axis machine tool, - arranging a measuring body (2) according to any one of claims 1 to 8 in the working area (3) of the three-axis machine tool, - moving to a plurality of positions of the measuring volume (2) in order to collect geometric actual values of the three-axis machine tool using the measuring volume (2), - performing a nominal / actual comparison of the geometric actual values of the measuring volume (2) with the recorded nominal values in order to determine the geometric deviations, and - Compensating for the geometrical deviations in a control unit (10) of the three-axis machine tool.

12. A method according to claim 11, wherein the nominal value of the measuring body (2) is predetermined in a coordinate measuring machine, and the measuring body (2) is configured in the working area (3) of the three-axis machine tool so that the coordinate system of the measuring body (2) is consistent with the coordinate system of the three-axis machine tool.

13. The method according to claim 11 or 12, wherein during the measurement of the measuring body (2) in the three-axis machine tool (1), the temperature of the working area (3) is detected, and a correction of the actual value is performed based on the detected temperature of the working area (3). 14 . The method according to claim 11 , wherein the position deviation of the corresponding axis and the two straightness deviations of the corresponding axis are determined in the X direction, the Y direction and the Z direction, respectively.

15. The method according to claim 11 or 12, wherein the squareness error between the X axis, the Y axis and the Z axis is calculated.

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