Method for measuring cutting tools and coordinate measuring device for carrying out said method

Abstract

A method and a coordinate measuring device are proposed for measuring a cutting tool (1, 21). The cutting tool (1, 21) has a cutting tool body (2, 22) and a cutting insert (3, 4, 5, 23) with at least one cutting edge (10, 30) attached to the cutting tool body (2, 22). The coordinate measuring device includes a position fixing device (51) that accommodates and fixes the cutting tool (1, 21), a measuring head that scans the surface of the cutting tool (1, 21) arranged in the position fixing device (51) by contact or without contact, and the measuring head is movable relative to the position fixing device (51), and a movement device (53) that moves the cutting tool (1, 21) accommodated in the position fixing device (51) and the measuring head relative to each other. The measuring head is moved relative to the cutting tool along a movement trajectory to determine the coordinates of the cutting edge defining surface (11a, 12a, 31a, 32a) at set measurement points.

Description

[Technical Field]

[0001] The present invention begins with a method for measuring a cutting tool, the cutting tool having a cutting tool body and at least one cutting insert with at least one cutting edge attached to the cutting tool body, and an apparatus for carrying out the method. [Background technology]

[0002] Cutting tools include cutting tools for machining processes and cutting tools. These tools typically have a shank and a cutting portion. The shank serves to hold the cutting tool within a machine interface, for example, in a machining tool. The shank is equipped with a cutting portion. The cutting portion has at least one cutting edge by which the cutting tool interacts with the workpiece to be machined, thereby removing material from the workpiece. Such cutting tools include, for example, milling cutters, drills, reamers, chisels, scrapers, planes, and saws. Cutting tools can be solid tools made entirely of a single material. Alternatively, the cutting portion can have an insert with a cutting edge, which is made of a different material than the shank. Cutting tools are exposed to significant mechanical and thermal loads during use due to the forces acting on them and the temperatures generated. These loads include mechanical friction, oxidation, and abrasion, as well as diffusion and oxidation wear, especially at high machining speeds. This leads to wear of the cutting tool in the area of ​​the cutting edge.

[0003] To improve the wear resistance and extend the service life of cutting tools, cutting tools are provided with a material in the cutting edge region that is harder than the rest of the cutting tool body. For this purpose, in cutting tools with cutting inserts, the cutting inserts can be provided with a hard coating, or the entire cutting insert can consist of a hard material. Such hard or ultrahard materials include, for example, diamond, e.g., polycrystalline diamond (PCD), single crystal diamond, crystalline diamond, or diamond prepared by chemical vapor deposition (CVD), amorphous carbon (known as "Diamond-like Carbon DLC"), cubic boron nitride (CBN), titanium, or ceramics. If the cutting insert is provided with a hard coating, the coating can be applied to the cutting insert using, for example, chemical vapor deposition (CVD).

[0004] To attach cutting inserts to a tool body, they are usually soldered directly onto the tool body. While this connection is characterized by high strength, the soldering process is not precise enough to ensure accurate positioning of the cutting inserts on the cutting tool body. Furthermore, cutting inserts may have a certain degree of inaccuracy regarding their shape, length, width, depth, or, in some cases, curvature of their surfaces. These inaccuracies of the cutting inserts and their incorrect positioning on the cutting tool body may result in cutting tools to which these cutting inserts belong not meeting set tolerances and having poor quality. Cutting edge target data is set for the cutting edge. The cutting edge target data includes, for example, the position of the cutting edge relative to a coordinate system for the cutting tool, the geometric shape of the cutting edge, or the extension shape of the cutting edge relative to the coordinate system for the cutting edge. The actual cutting edge data must be detected to determine whether the cutting edge of the cutting insert meets these cutting edge target data after brazing the cutting insert onto the cutting tool body and, in some cases, how large the actual cutting edge's deviation from the cutting edge target data. The actual cutting edge data is compared with the target cutting edge data to determine how much material must be removed from the cutting insert at which locations so that the cutting edge meets the target cutting edge data within a set tolerance after material removal. The intentional material removal is performed using a machining device, which may include, for example, a grinding disk, a laser for generating a laser beam, or a device for electrical discharge machining (EDM).

[0005] Before the cutting inserts brazed onto the cutting tool body can be post-machined by a machining device, the exact position of each cutting insert must be determined in three dimensions relative to a known reference point on the cutting tool. Furthermore, it must be determined whether the surface is flat or curved. If the cutting tool is configured as a rotary tool that is rotated about a geometrical axis of rotation during use, this geometrical axis of rotation can be the reference point, for example. Another reference point can be the top surface of the cutting tool or the bottom surface of the cutting tool.

[0006] In order to achieve the material removal in the cutting insert required for post-processing, a trajectory along which the material removal device must be moved relative to the cutting tool is determined based on the detected position, orientation and shape of the cutting insert and based on a comparison of the actual cutting edge data with the target cutting edge data.

[0007] It is known to detect the position of a cutting insert soldered to a cutting tool using a mechanical, electrical, or optical measuring feeler or measuring head. Detection can be performed tactilely, i.e., by touching the surface of the cutting insert with the measuring head, or non-contact. For this purpose, the measuring head is arranged on a processing device or a coordinate measuring machine. The measuring head is moved relative to the cutting tool to determine the coordinates of measurement points on the surface of the cutting insert. Depending on the type and shape of the cutting tool and the type and number of cutting inserts in the cutting tool, the measuring head must be moved relative to the cutting tool to detect the surface position at at least three measurement points on each cutting insert relative to a reference value, such as the geometric axis of rotation of the cutting tool. For this purpose, a coordinate system is defined. The coordinates of the measurement points are determined by the measuring head. The relative movement of the measuring head with respect to the cutting tool is usually controlled using a computer, e.g., a CNC. The responsible operator must create and configure software based on the type, number, and approximate positions of the cutting inserts. While the operator can certainly rely on the technical settings and drawings of the cutting tool, these settings do not include the inaccuracies that arise due to the soldering of the cutting insert. Therefore, the details must be entered by the operator into the control system, which then brings the measuring feeler close to the measuring point of the cutting insert. This is associated with considerable effort, especially for cutting tools with a large number of cutting inserts. Furthermore, there is a risk of errors occurring when entering the details into the control system. Summary of the Invention [Problem to be solved by the invention]

[0008] The problem underlying the present invention is to provide a method and a coordinate measuring device that facilitates the measurement of cutting inserts after soldering onto a cutting tool, wherein the measurement is performed automatically and collisions between the coordinate measuring device and the cutting tool are avoided. [Means for solving the problem]

[0009] This problem is solved by a method having the features of claim 1 and by a coordinate measuring device having the features of claim 15. a position fixing device for receiving and fixing the cutting tool; a measuring head for scanning the surface of a cutting tool arranged in a position fixing device by contact or without contact, the measuring head being movable relative to the position fixing device; a movement device for moving the cutting tool and the measuring head housed in the position fixing device relative to each other; It is equipped with: The method is characterized in that it comprises the following method steps: a) setting geometrical measuring head data including the shape and size of the measuring head; b) fixing the cutting tool in the fixing device. c) determining a three-dimensional coordinate system having a zero point and coordinate axes; d) defining a three-dimensional surface of the cutting tool, at least in the section of the cutting tool containing the cutting insert, arranged in the position fixing device, the surface being defined as a three-dimensional cutting tool surface, the surface being capable of being defined in a three-dimensional coordinate system. e) identifying sub-regions of the three-dimensional cutting tool surface that form one surface of the cutting insert and are located adjacent to the cutting edge of the cutting insert, and defining these sub-regions as cutting edge-defining surfaces. f) Identifying measurement points on the cutting edge defining surface. g) determining a motion trajectory of a motion device for relative motion between the measuring head and the cutting tool, wherein the coordinates of the cutting tool are detected at the measurement points by a coordinate measuring device during the relative motion of the measuring head and the cutting tool along the motion trajectory, and the motion trajectory is determined based on the geometric measuring head data, the cutting edge defining surface and the measurement points so that collisions between the cutting tool and the measuring head during the relative motion are eliminated. h) moving the measuring head relative to the cutting tool along a movement trajectory. i) determining the coordinates of the measurement points on the cutting edge defining surface with a coordinate measuring device relative to a coordinate system; j) Finally, fitting the cutting edge defining surface to the detected coordinates of the measurement points, such that the detected coordinates lie on the fitted cutting edge defining surface.

[0010] The measurement points are set, for example, by determining one or two coordinates of the measurement points and the motion device positions the measuring head relative to the cutting edge defining surface in relation to the set one coordinate or the set coordinates, and the measuring head then detects the missing coordinate or coordinates of the cutting edge defining surface.

[0011] The coordinates are related to a set coordinate system. Advantageously, the coordinates are a coordinate system related to the cutting tool. The coordinate system related to the cutting tool includes coordinate axes extending through the cutting tool and a zero point within or tangent to the cutting tool. When the cutting tool moves, the coordinate system related to the cutting tool moves accordingly. Therefore, when the cutting tool moves, the coordinates of the cutting edge position and the coordinates of the cutting edge extension shape do not change in this coordinate system related to the cutting tool.

[0012] Basically, a cutting insert does not only have a surface that is part of the surface of the cutting tool and is located adjacent to the cutting edge of the cutting insert. For example, a cutting insert also includes a surface where the cutting insert is brazed to the cutting tool body. Given that the surface of the cutting insert that is part of the surface of the cutting tool and adjacent to the cutting edge of the cutting insert is particularly important for the quality of the cutting tool, checking and post-processing in this area are particularly important. Of course, if necessary, measurements can also be made on surfaces of the cutting insert that are not adjacent to the cutting edge. Typically, measurements are not made on the section of the cutting insert where the cutting insert is brazed to the cutting tool body. This is because this section is not exposed and therefore does not, at least directly, affect the characteristics of the cutting edge, and processing in this section could lead to the cutting insert being detached from the cutting tool body. In addition to these mounting sections and the surface defining the cutting edge, the cutting insert may have other surfaces on which measurements can be made.

[0013] The three-dimensional cutting tool surface is generated without the need for manual data entry into the coordinate measuring machine. The three-dimensional cutting tool surface can be generated and generated, for example, using known CAD data of the cutting tool. This CAD data can include the cutting tool surface in two or three dimensions. For example, the surface of the cutting tool body can be generated in three dimensions, and the surface of the cutting insert can be generated in two dimensions. The three-dimensional surface of the cutting tool is then determined based on these data. In this case, the three-dimensional cutting tool surface corresponds to or is a part of the theoretical geometric surface of the cutting tool generated based on the CAD design of the cutting tool. Alternatively, the three-dimensional surface can be generated using a surface scanner based on the cutting tool clamped in a positioning fixture and entered into the machine. In this case, the three-dimensional cutting tool surface corresponds to the actual surface of the cutting tool after the cutting insert is soldered. In either case, manual input of surface data into the system is not required. This method is therefore significantly less time-consuming and less error-prone for the user.

[0014] By evaluating the three-dimensional cutting tool surface, subregions forming the surface of the cutting insert and located adjacent to the cutting edge are identified. These subregions are characterized by having a specific orientation relative to a predetermined reference value of the cutting tool, such as the geometric cutting tool rotation axis, the bottom or top surface of the cutting tool. This characteristic of the cutting insert surface is utilized when identifying the cutting insert surface. The method according to the present invention identifies the cutting edge-defining surface regardless of how and in what form the three-dimensional cutting tool surface is defined. This does not require the user to input any data or information.

[0015] Based on evaluation of the three-dimensional cutting tool surface and identification of the cutting edge-defining surface, the position, orientation, and possibly the surface curvature as well as the length, width, or depth of the cutting insert are determined.

[0016] The cutting edge-defining surface determined from the three-dimensional cutting tool surface is adapted to the coordinates acquired by the measuring head during scanning. If the measurement point with the detected coordinates is already on the cutting edge-defining surface, the cutting edge-defining surface does not need to be modified. If the measurement point with the detected coordinates is not on the cutting edge-defining surface, the cutting edge-defining surface needs to be modified so that the measurement point is on the modified cutting edge-defining surface. To intentionally remove material from the cutting insert, for example, based on the cutting edge-defining surface possibly adapted by the scanning-based data, it can be determined how the material removal device must be moved relative to the cutting tool, thereby post-machining the brazed cutting insert, and the cutting tool then meets the settings for the position, orientation, and extension shape of the cutting edge and the surface defined by this cutting edge within certain tolerances.

[0017] When determining the movement trajectory for the relative movement of the measuring head and the cutting tool, the geometry and dimensions of the measuring head and the cutting tool are taken into account, so that this relative movement takes place without collisions.

[0018] Cutting tools can be assigned the following surfaces: 1. The theoretical, geometric, three-dimensional surface of the cutting tool resulting from its design: insofar as the cutting tool is designed using CAD, the theoretical, geometric, three-dimensional surface of the cutting tool can be derived from the CAD data, which may not include inaccuracies resulting from the manufacturing and brazing of the cutting insert. 2. The actual three-dimensional surface of the cutting tool after brazing the cutting insert; this surface includes inaccuracies arising from the manufacturing and brazing of the cutting insert; this surface can be acquired, for example, using a surface scanner that detects the entire surface of the cutting tool. The surface acquired by the surface scanner is checked at the set measurement points by scanning with a measuring head. Alternatively, this surface can be checked using the data obtained according to item 1 and subsequent scanning of the cutting insert surface at the set measurement points with the measuring head. In both cases, the set surface of the cutting insert is corrected so that the coordinates of the measurement points acquired by scanning are on the surface of the cutting insert. The number of measurement points depends on the accuracy of the set three-dimensional surface. The higher the accuracy of the set surface, the fewer measurement points are required. The three-dimensional cutting tool surface of claim 1 can be derived from the theoretical three-dimensional surface described in item 1 or from the actual three-dimensional surface described in item 2. 3. Cutting edge defining surface determined from the three-dimensional surface of the cutting tool: The cutting edge defining surface can be determined based on the theoretical, geometrical three-dimensional surface of the cutting tool as described in item 1 above, or from the actual three-dimensional surface of the cutting tool after brazing of the cutting insert as described in item 2 above. 4. Identifying measurement points on the cutting edge defining surface. The surface of the cutting tool, which is arranged in a position fixing device, is detected by the measuring head at these measurement points. This serves to adapt the theoretical cutting edge defining surface to reality. The cutting edge defining surface is adapted so that the coordinates of the measurement points, detected by the measuring head, lie on the cutting edge defining surface. These cutting edge defining surfaces contain actual cutting edge data.

[0019] In the method according to the present invention, the three-dimensional cutting tool surface according to item 1 or 2 is defined, and the cutting edge defining surface according to item 3 is determined based on this. It is assumed that the adapted cutting edge defining surface according to item 4 corresponds to the actual surface of the cutting tool to be processed, which is clamped in a fixing device, and has actual cutting edge data. Starting from this cutting edge defining surface, material removal can be performed as needed to adapt the cutting edge to the defined cutting edge target data.

[0020] The data required to measure the cutting insert on the cutting tool is automatically determined based on the cutting tool surface, without the need for manual input by the operator and without the operator having to specify the measurement data. This significantly simplifies the measurement. Since input errors cannot occur, the measurement is also more accurate.

[0021] The measuring range and the machine coordinate system are determined by the travel axis and guide of the motion device, the drive, and the incremental measuring system. The machine coordinate system does not coincide with the coordinate system of the cutting tool. However, it is possible to convert coordinates from the machine coordinate system to the coordinate system of the cutting tool. Motion devices with x-, y-, and z-axes typically result in a Cartesian coordinate system for the machine. However, motion devices in which the guides form cylindrical or spherical coordinate systems are also common. These motion devices operate using a combination of incremental distance sensors and angle sensors.

[0022] The measuring head may include a switching sensor and a measuring sensor. The switching sensor sends a trigger signal only when recording a measurement point, which triggers the reading of the length measuring system. In contrast, the measuring sensor has an internal measurement range of several millimeters. The internally measured sensor value is superimposed on the position of the sensor determined by the length measuring system.

[0023] To avoid undesired collisions between the material removal device and the cutting tool, geometrical measuring head data, including the shape and size of the measuring head, are taken into account when determining the movement trajectory. This can be done using known calculation methods for collision avoidance. Set data for the cutting tool and the measuring head are taken into account. Known calculation methods for collision avoidance can be taken into account. For example, Minkowski addition is useful for this purpose. Other calculation methods are also possible.

[0024] According to an advantageous configuration of the invention, the coordinate system is a coordinate system relative to a cutting tool.

[0025] According to another advantageous embodiment of the invention, the cutting tool is a rotary cutting tool that is rotated during use about a geometric cutting tool rotation axis. The geometric cutting tool rotation axis corresponds to an axis about which the cutting tool will be rotated at the point of subsequent use. Advantageously, the cutting tool configured as a rotary tool is accommodated in a fixing device so that it can be rotated about the geometric cutting tool rotation axis by a motion device. One of the coordinate axes of the coordinate system coincides with the cutting tool rotation axis.

[0026] According to another advantageous embodiment of the invention, the orientation of the cutting edge-defining surface relative to the geometrical cutting tool rotation axis is determined by utilizing the fact that the cutting set usually has a specific orientation relative to the geometrical cutting tool rotation axis, which is a prerequisite for the cutting insert to cause the desired cutting-type material removal at the subsequent use point of the cutting tool.

[0027] According to another advantageous embodiment of the invention, the position of the cutting edge-defining surface relative to the geometrical cutting tool rotation axis is determined, making use of the fact that the cutting set normally has a specific position in relation to the geometrical cutting tool rotation axis.

[0028] According to another advantageous configuration of the invention, the position of the cutting edge-defining surface relative to an end face of the cutting tool is determined. If the cutting tool is configured as a rotary tool that is rotated about a cutting tool rotation axis at the point of use and extends from a first end to a second end along the cutting tool rotation axis, the end face is preferably a surface of the cutting tool at the first end or the second end that is perpendicular to the cutting tool rotation axis.

[0029] According to another advantageous configuration of the invention, the coordinates detected at the measurement points are used to check whether the cutting edge defining surface is curved or flat. For example, if it is found that one of the cutting edge defining surfaces has a curvature that leads to an undesired distortion of the cutting edge, the corresponding cutting edge defining surface can be smoothed and turned into a flat surface by post-processing, so that the cutting edge has the set linear extension shape. If the cutting edge defining surface has a curve according to the setting, preferably more than three measurement points must be set.

[0030] According to another advantageous embodiment of the invention, the cutting insert is made of an ultrahard material such as polycrystalline diamond (PCD), cubic boron nitride (CBN), diamond by chemical vapor deposition (CVD), single crystal diamond or ceramics. In the case of a coating, the coating may be applied by CVD. Alternatively, diamond-like amorphous carbon (DLC) can also be used.

[0031] According to another advantageous embodiment of the present invention, the three-dimensional cutting tool surface is determined from established CAD data of the cutting tool. Due to computer-aided design and manufacturing of a cutting tool with at least one cutting insert, a geometric model of the cutting tool exists as a digital data set. The CAD data includes this digital data set. A theoretical, geometric, three-dimensional cutting tool surface can be determined from the CAD data by calculation. Because the CAD data is derived from the geometric model, it does not include inaccuracies resulting from the manufacturing of the cutting insert and its soldering onto the cutting tool body. Therefore, the CAD data does not reflect reality in the same way. For this reason, it may be advantageous to determine measurement points on the surface of the cutting insert, detect the actual, real cutting edge-defining surface by scanning the measurement points with a measuring head, and fit the cutting edge-defining surface to the scan data.

[0032] According to another advantageous embodiment of the present invention, a three-dimensional cutting tool surface is generated using a surface scanner. The surface scanner includes one or more sensors. These sensors systematically or regularly scan or measure the cutting tool. A complete image of the cutting tool is generated by a large number of individual measurements. The measurements detected by the sensors are converted into digital data and processed by a computer. Based on this data, the three-dimensional cutting tool surface can be determined by calculation. The three-dimensional cutting tool surface detected by the surface scanner can reproduce the actual surface of the cutting tool very well. In this case, to check the quality of the surface detected by the scanner, measurement points are determined on the surface of the cutting insert, and this surface is measured at these measurement points using a measuring head. The scanning serves for inspection purposes. For example, if, during such an inspection of the surface of the cutting insert, it is found that the coordinates detected by the measuring head are part of the three-dimensional cutting tool surface detected by the surface scanner, further inspection of the remaining surface of the cutting insert may not be necessary. However, if differences are found, the inspection can continue.

[0033] According to another advantageous embodiment of the invention, a grid of partial surfaces is laid across the three-dimensional cutting tool surface, and for each partial surface, a reference value, e.g., an orientation relative to the geometric cutting tool rotation axis, is determined, and a cutting edge defining surface is determined based on this.

[0034] According to another advantageous embodiment of the invention, the partial surfaces are triangular, whereas alternatively the partial surfaces may be quadrilateral or other polygonal.

[0035] According to another advantageous embodiment of the invention, the orientations of two adjacent partial surfaces are compared with each other, and the cutting edge defining surface is determined based on this, taking advantage of the fact that adjacent partial surfaces with identical or similar orientations belong to the same cutting edge defining surface.

[0036] According to another advantageous embodiment of the invention, the coordinates of the measurement points on the cutting edge surface are detected by contact with a tactile sensor of the measuring head, also called a mechanical sensor.

[0037] According to another advantageous embodiment of the invention, the coordinates of the measurement points on the cutting edge-defining surface are detected in a contactless manner by optical or electrical sensors in the measuring head.

[0038] According to another advantageous embodiment of the invention, the collision-free motion trajectory is determined using Minkowski summation.Furthermore, other methods of calculating the collision-free motion trajectory are possible.

[0039] The coordinate measuring device according to the invention is characterized in that it comprises a control device which controls the position fixing device, the measuring head and the movement device so as to carry out the method according to the invention.

[0040] Further advantages and advantageous configurations of the invention can be seen from the following description, drawings and claims.

[0041] The drawings show an embodiment of the subject matter of the invention. [Brief explanation of the drawings]

[0042] [Figure 1] 1 is a perspective view of a first embodiment of a cutting tool to be measured by the method according to the invention, the drawing being based on CAD data; [Figure 2] FIG. 2 is a perspective view of the cutting tool shown in FIG. 1 using triangles based on data acquired using a surface scanner. [Figure 3] The diagram shown in FIG. 2 using different grey scales. [Figure 4] FIG. 4 is a perspective view of the cutting tool shown in FIGS. 1, 2 and 3 after post-processing is completed. [Figure 5] 2 shows the cutting tool shown in FIG. 1 with the outer cutting tool geometry marked; FIG. [Figure 6] 2 is a diagram showing the cutting tool shown in FIG. 1 together with the movement trajectory of the measuring head; [Figure 7] 2 shows the cutting tool shown in FIG. 1 with measuring points marked at which the surface of the cutting insert is scanned by the measuring head; [Figure 8] 8 is a comparison diagram between CAD data relating to the cutting tool shown in FIGS. 1 to 7 and data acquired by a surface scanner. FIG. [Figure 9] 1 shows a perspective view of a second embodiment of a cutting tool to be measured by the method according to the invention, the drawing being based on CAD data; [Figure 10] FIG. 10 is a perspective view of the cutting tool shown in FIG. 9 based on data acquired using a surface scanner. [Figure 11] FIG. 10 is a partial view of FIG. 9. [Figure 12] FIG. 12 is a partial view of FIG. [Figure 13] 11 is a view showing a part of the cutting tool shown in FIGS. 9 and 10 after post-processing is completed. FIG. [Figure 14] 1 shows a coordinate measuring apparatus for implementing the method; DETAILED DESCRIPTION OF THE INVENTION

[0043] Description of the Examples FIGS. 1 to 8 illustrate a first cutting tool to be measured by the method according to the present invention. The coordinate measuring device for carrying out the measurement is illustrated in FIG. 14. FIGS. 1 and 2 show the cutting tool before measurement. FIG. 1 corresponds to a diagram of CAD data for the cutting tool, which is established from a CAD-based cutting tool design. FIG. 2 corresponds to a diagram of data acquired using a surface scanner. The cutting tool 1 includes a cutting tool body 2 in which a total of six cutting inserts 3, 4, and 5 are arranged. The cutting tool is a rotary tool that is rotated around a geometric cutting tool rotation axis 6 at its point of use. The cutting tool is not shown in its entirety in the drawings. The shank 7, which serves to accommodate the cutting tool 1 in a machine (not shown), is only partially illustrated for clarity. No cutting inserts are arranged in the non-illustrated parts of the cutting tool. Therefore, measurements are not performed in the non-illustrated parts of the cutting tool according to the present method. The section of the cutting tool 1 where the cutting inserts 3, 4, and 5 are arranged in the cutting tool body 2 is defined as the three-dimensional cutting tool surface. This three-dimensional cutting tool surface is visible in Figures 1 and 2, at least as far as it faces the viewer. The part of the three-dimensional cutting tool surface facing away from the viewer is obscured in Figures 1 and 2 by the cutting tool body 2.

[0044] The cutting inserts 3, 4, and 5 are arranged offset with respect to the cutting tool rotation axis. Two first cutting inserts 3 are located at one end 8 of the cutting tool. These cutting inserts 3 are arranged in the cutting tool body 2 offset from each other by 180° and inclined at a predetermined angle α with respect to the cutting tool rotation axis. Two second cutting inserts 4 are arranged axially with respect to the end 8 and spaced apart from both first cutting inserts 3 with respect to the cutting tool rotation axis 6. These second cutting inserts 4 are accommodated in the cutting tool body offset from the first cutting inserts 3 in the axial direction. The angular interval between the two second cutting inserts is also 180°. Two third cutting inserts 5 are located between the two first cutting inserts 3 and the two second cutting inserts 4 with respect to their axial positions and between the two first cutting inserts 3 and the two second cutting inserts 4 with respect to their angular positions. In the drawing, only one of the two third cutting inserts 5 is visible, since the other third cutting insert 5 is covered by the cutting tool body 2.

[0045] The first cutting insert 3, the second cutting insert 4 and the third cutting insert 5 are brazed onto the cutting tool body 2. After brazing, the cutting inserts 3, 4, 5 initially protrude radially outward beyond the cutting tool body 2. Figures 1 and 2 show the cutting tool after brazing of the cutting inserts 3, 4, 5. In particular, the portions of the first cutting insert 3 and the second cutting insert 4 that protrude radially beyond the cutting tool body are clearly visible.

[0046] 1 shows a diagram of a cutting tool 1, which is based on CAD data. These CAD data are generated on the basis of computer-aided design of the cutting tool. The three-dimensional cutting tool surface is shown, including cutting inserts 3, 4, and 5.

[0047] FIG. 2 shows a diagram of the cutting tool 1, based on data acquired using a surface scanner. This surface scanner is shown in FIG. 14 with reference numeral 59. The surface of the cutting tool 1 is detected from all sides in the sections where the cutting inserts 3, 4, and 5 are located. This results in a three-dimensional cutting tool surface, which is important for implementing the method. According to FIG. 2, the surface of the cutting tool 1 is detected in the sections of the cutting tool 1 that are also shown in FIG. 1 based on CAD data. The surface scanner generates a large number of surface points. In FIG. 2, these surface points are connected to each other by lines to form triangles. FIG. 3 shows an alternative diagram based on the same number of surface points as FIG. 2, but instead of triangles, they are displayed in different grayscales. The shape of the cutting tool 1 is more clearly visible in FIG. 3 than in FIG. 2.

[0048] FIG. 4 shows a cutting tool 1 equipped with cutting inserts 3, 4, and 5, which meet established criteria regarding the position and extension of the cutting edge 10. These criteria are, in particular, established cutting edge target data, such as the position and extension of the cutting edge relative to the cutting tool rotation axis. The cutting inserts 3, 4, and 5 project significantly less radially outward beyond the cutting tool body 2. For example, the second cutting insert 4 is shown with the cutting edge 10 defining a first cutting edge-defining surface 11 and a second cutting edge-defining surface 12. The same applies to the first cutting insert 3 and the third cutting insert 5.

[0049] FIG. 5 shows the cutting tool 1 shown in FIGS. 1 and 2, in which the outer geometry 13 of the cutting tool, defined by the set extension of the cutting edges 10 of the cutting inserts 3, 4, and 5, is marked by lines in the area of ​​the first and second cutting inserts 3 and 5. Thus, the actual and target cutting edge data are evident from this figure. Based on a comparison of these data, it can be seen from the figure that the areas of the cutting inserts 3, 4, and 5 that protrude beyond the outer geometry 13 of the cutting tool 1 must be removed. In particular, post-machining must be performed on the first and / or second cutting edge-defining surfaces 11a and 12a so that they correspond, within tolerance, to the first and / or second cutting edge-defining surfaces 11 and 12 shown in FIG. 4, thereby providing the cutting edge 10 with the set extension.

[0050] To enable machining of the cutting inserts 3, 4, and 5 in the region of the cutting edge-defining surfaces 11a and 12a, the three-dimensional surface of the cutting tool 1 is determined based on CAD data (see FIG. 1) or data acquired by a surface scanner (see FIG. 2). The entire set of determined data is called the three-dimensional cutting tool surface. From this three-dimensional cutting tool surface, subregions that form the surfaces of the cutting inserts 3, 4, and 5 and are located adjacent to the cutting edges are identified. These subregions are called cutting edge-defining surfaces 11a and 12a. The cutting edge-defining surfaces 11a and 12a are generated by comparing the orientation or position of the surfaces with the cutting tool rotation axis 6 or the end face 9 of the cutting tool. For this purpose, the three-dimensional cutting tool surface is divided into a grid of subregions 14. In the diagram shown in FIG. 2, the grid with the subregions 14 corresponds to triangles resulting from the connection of surface points. For each subregion 14, the orientation relative to the geometric cutting tool rotation axis 6 is determined. Alternatively or cumulatively, an orientation relative to the end face 9 of the cutting tool can also be specified for each part surface 14. Adjacent part surfaces 14 having the same orientation are assigned to one common surface. The cutting edge-defining surfaces 11 a, 12 a differ from other surfaces of the cutting tool 1 by having a completely specified set orientation relative to the cutting tool rotation axis 6 or the end face 9.

[0051] From the cutting edge defining surface, cutting edge actual data is identified, the cutting edge actual data relating to at least one characteristic of the cutting edge, i.e., cutting edge position relative to a coordinate system relative to the cutting tool, cutting edge geometry, or cutting edge extension relative to a coordinate system relative to the cutting edge.

[0052] For the cutting tool, cutting edge target data is set. The cutting edge target data is related to a corresponding characteristic from the group of characteristics described above, i.e., the cutting edge position relative to the coordinate system for the cutting tool, the cutting edge geometry, or the cutting edge extension relative to the coordinate system for the cutting edge. The cutting tool shown in Figure 4 has this cutting edge target data.

[0053] The cutting edge actual data is compared with the cutting edge target data, and based on this comparison it is known whether and how much material must be removed at the detected cutting edge defining surfaces 11 a, 12 a so that the cutting edge 10 has the cutting edge target data and a set extension shape with a set outer geometric shape 13.

[0054] To determine the coordinates of the cutting edge-defining surfaces at the measurement points 16, a motion trajectory 15 is determined from the geometric measuring head data, the cutting edge-defining surfaces 11a, 12a, 31a, 32a, and the measurement points 16 shown in FIG. 7, along which the measuring head is moved relative to the cutting tool by means of a motion device. In FIG. 6, this motion trajectory 15 is shown for the first cutting insert 3, the second cutting insert 4, and the third cutting insert 5. The motion trajectory 15 extends beyond the cutting edge-defining surfaces 11a, 12a, thereby ensuring that the entire cutting edge surfaces 11a, 12a are scanned. The motion trajectory is set so that the coordinates of all set measurement points are detected without the measuring head colliding with the cutting tool.

[0055] If the three-dimensional cutting tool surface resulting from the CAD data shown in FIG. 1 does not sufficiently reflect reality, or if checking of the three-dimensional cutting tool surface shown in FIG. 1, 2, or 3 is desired, measurement points are identified on at least one cutting edge-defining surface 11a, and the coordinates of the cutting edge-defining surface at these measurement points are determined using a coordinate measuring device. In this case, three measurement points 16 are set on the first cutting edge-defining surface 11a. The coordinate measuring device is then used to determine the coordinates of the cutting edge-defining surface at these three measurement points 16. The measurement data obtained based on this are compared with the cutting edge-defining surface 11a at these measurement points 16. If there are differences, the cutting edge-defining surface 11a is correspondingly corrected and adapted so that the coordinates of the measurement points are on the cutting edge-defining surface 11a. Such checking of the cutting edge-defining surfaces 11a, 12a can also be performed when the three-dimensional cutting tool surface is identified using a surface scanner as shown in FIG. 2 or 3. It is assumed that in this case a check is necessary for inspection purposes, since the surface scanner has already detected the surface of the actual cutting tool.

[0056] Figure 8 shows a comparison of the three-dimensional cutting tool surface 17 determined using CAD data and the three-dimensional cutting tool surface 18 obtained using a surface scanner. In the light grey areas, the three-dimensional cutting tool surface 18 obtained using the surface scanner protrudes from the three-dimensional cutting tool surface 17 determined using CAD data. In the dark grey areas, this is exactly the opposite.

[0057] 9-13 illustrate a second embodiment of a cutting tool 21 measured by the method according to the present invention. FIGS. 9 and 10 show the cutting tool 21. FIG. 9 corresponds to a diagram of CAD data for the cutting tool 21, which was established by designing the cutting tool using CAD. FIG. 10 corresponds to a diagram of data acquired using a surface scanner. The cutting tool 21 includes a cutting tool body 22 in which multiple cutting inserts 23 are arranged. The cutting tool is a rotary tool that is rotated around a geometric cutting tool rotation axis 26 at the point of use. Unlike the first embodiment of the cutting tool shown in FIGS. 1-8, in the cutting tool 21 according to the second embodiment, all cutting inserts 23 are arranged in the cutting tool body 22 at the same axial position relative to the cutting tool rotation axis 26 and with the same orientation relative to the cutting tool rotation axis 26.

[0058] For each cutting insert 23 arranged in the cutting tool body 22, a reference for the extension and position of the cutting edge 30 of the cutting insert 23 relative to the cutting tool rotation axis 26 of the cutting tool is set as cutting edge target data. This set cutting edge 30 is shown in FIG. 13. The set cutting edge 30 defines a first cutting edge-defining surface 31 and a second cutting edge-defining surface 32. The extension and positions of the cutting edges 30 of all cutting inserts 23 of the cutting tool 21 set an outer geometry 33 of the cutting tool 21. This outer geometry 33 is marked by lines in FIGS. 9 and 10.

[0059] To implement the method, the cutting edge defining surfaces 31a, 32a of the cutting insert 23 are identified from the three-dimensional cutting tool surface of the CAD data shown in FIG. 9 or data acquired using a surface scanner shown in FIG. 10, and actual cutting edge data is derived based on this. The actual cutting edge data is compared with the set cutting edge target data. FIGS. 11 and 12 exemplarily show two cutting edge defining surfaces 31a, 32a of one cutting insert 23. Based on the comparison with the settings for the cutting edge 30, the first cutting edge defining surface 31, and the second cutting edge defining surface 32, it becomes clear what material removal must be performed and how much material removal must be performed. Based on the acquired data, the processing device can be controlled so that the corresponding material is removed and the cutting edge 30 meets the settings shown in FIG. 13.

[0060] Determining the position and orientation of the cutting edge defining surfaces 31a, 32a based on the three-dimensional cutting tool surface corresponds to the first embodiment shown in Figures 1-8.

[0061] 14 shows a coordinate measuring machine 50 for carrying out the method. The coordinate measuring machine is combined with a laser 56 for material removal. The coordinate measuring machine includes a workpiece fixing device 51 for receiving and fixing the cutting tool 1, a movement device 53 for moving the cutting tool 1 arranged in the fixing device relative to the machine base 55, a laser 56 for generating a laser beam 52, and a laser beam deflector 57 for guiding the laser beam 52. In this case, the movement device 53 has three linear axes X, Y, and Z and two rotation axes B and C. The rotation axis C serves to rotate the cutting tool 1 arranged in the workpiece fixing device 51 around a geometric cutting tool rotation axis extending through the cutting tool.

[0062] The coordinate measuring device 50 further comprises a surface scanner 59, which detects the surface of the cutting tool 1 arranged in the position fixing device 51 and stores the determined three-dimensional cutting tool surface. This three-dimensional cutting tool surface is sent to the control device 58, which determines the cutting edge-defining surface of the cutting insert based on this three-dimensional cutting tool surface.

[0063] The coordinate measuring device 50 includes a measuring head 60 for detecting the surface of the cutting tool 1, which is arranged in a fixed positioning device, at set measurement points and assigning them to coordinates in a coordinate system. The detected coordinates are then checked to see if they lie on the set cutting edge defining surface. If the coordinates are not on the set cutting edge defining surface, the cutting edge defining surface is corrected so that the coordinates of the measurement points lie on the adapted cutting edge defining surface. The measuring head 60 is controlled and moved in such a way that collisions between the cutting tool and the measuring head are avoided. The relative movement between the cutting tool 1 and the measuring head is performed using a motion device 53.

[0064] If, based on the measurements of the cutting tool, it is clear that material needs to be removed at the cutting insert, this material removal can be carried out using a laser. A laser beam deflector 57 moves and guides the laser beam 52 in three different directions in space. In doing so, the laser beam 52 is moved relative to the cutting tool 1 along a laser path (not shown). A control device 58 controls the position fixing device 51, the movement device 53 and the laser beam deflector 57 in order to intentionally remove material at the cutting tool.

[0065] Thus, the control device 58 not only controls the movement device 53 and the measuring head 60, but also the laser 56. Based on the cutting edge actual data and the cutting edge target data, the material to be removed is determined. The laser and the movement device are controlled to intentionally remove this material from the cutting insert of the cutting tool 1.

[0066] All of the features of the invention may be important to the invention both individually and in any combination with one another. [Explanation of symbols]

[0067] 1 cutting tool 2 Cutting tool body 3 First cutting insert 4 Second cutting insert 5 Third cutting insert 6 Cutting tool rotation axis 7 Shank 8 End 9 End face 10 Cutting Edge 11 First cutting edge defining surface after machining 11a: First cutting edge defining surface before machining 12 Second cutting edge defining surface after machining 12a: Second cutting edge defining surface before machining 13 External geometry of cutting tools 14 partial surfaces 15 Measurement head movement trajectory 16 measurement points 17 Three-dimensional cutting tool surface identified using CAD data 18 Three-dimensional cutting tool surface identified using a surface scanner 21 Cutting tools 22 Cutting tool body 23 Cutting Insert 26 Cutting tool rotation axis 30 cutting edges 31 first cutting edge defining surface after machining 31a: first cutting edge defining surface before machining 32 Second cutting edge defining surface after machining 32a: Second cutting edge defining surface before machining 33 External geometry of cutting tools 50 Coordinate Measuring Device 51 Position fixing device 52 Laser Beam 53 Exercise equipment 55 Device base 56 Laser 57 Laser beam deflector 58 Control Device 59 Surface Scanner 60 measuring heads

Claims

1. A method for measuring a cutting tool (1, 21), wherein the cutting tool (1, 21) comprises a cutting tool body (2, 22) and at least one cutting insert (3, 4, 5, 23) attached to the cutting tool body (2, 22) having at least one cutting edge (10, 30), and the measurement is performed using a coordinate measuring device (50), wherein the coordinate measuring device (50) - A position fixing device (51) that houses and fixes the cutting tools (1, 21), - A measuring head that scans the surface of the cutting tools (1, 21) arranged within the position fixing device (51) by contact or in a non-contact manner, wherein the measuring head is movable relative to the position fixing device (51), - A motion device (53) that moves the cutting tools (1, 21) and the measuring head housed in the position fixing device (51) relative to each other. In a method having, a) A step of setting geometrical measurement head data, including the shape and size of the measurement head, b) The step of fixing the cutting tools (1, 21) in position within the position fixing device (51), c) A step of determining a three-dimensional coordinate system having zeros and coordinate axes, d) A step of setting a three-dimensional surface of the cutting tool (1, 21) located within the position fixing device (51) in a portion of the cutting tool (1, 21) that includes the cutting inserts (3, 4, 5, 23), wherein the surface is defined as a three-dimensional cutting tool surface (17, 18). e) A step of identifying a subregion of the three-dimensional cutting tool surface (17, 18) that forms one surface of the cutting insert (3, 4, 5, 23) and is located adjacent to the cutting edge (10, 30) of the cutting insert (3, 4, 5, 23), wherein the subregion is defined as a cutting edge defining surface (11a, 12a, 31a, 32a). f) A step of identifying a measurement point (16) on the cutting edge defining surface (11a, 12a, 31a, 32a), g) A step of determining the motion trajectory of the motion device for the relative motion of the measuring head and the cutting head (1, 21), wherein the coordinates of the cutting tool (1, 21) are detected at the measurement point (16) by the coordinate measuring device during the relative motion of the measuring head and the cutting tool (1, 21) along the motion trajectory, and the motion trajectory is determined based on the geometric measuring head data, the cutting edge defining surfaces (11a, 12a, 31a, 32a), and the measurement point (16) such that collisions between the cutting tool (1, 21) and the measuring head during the relative motion are eliminated. h) A step of moving the measuring head relative to the cutting tool (1, 21) along the motion trajectory, i) A step of detecting the coordinates of the measurement points (16) on the cutting edge defining surfaces (11a, 12a, 31a, 32a) using the coordinate measuring device in relation to the coordinate system, j) A step of fitting the cutting edge defining surfaces (11a, 12a, 31a, 32a) to the detected coordinates of the measurement point (16), wherein the detected coordinates are located on the fitted cutting edge defining surfaces (11a, 12a, 31a, 32a). A method characterized by having

2. The method according to claim 1, characterized in that the coordinate system is a coordinate system relating to a cutting tool.

3. The method according to claim 1, characterized in that the cutting tool (1, 21) is a rotary cutting tool, which is rotated about a geometric cutting tool rotation axis (6, 26) when in use, and one of the multiple coordinate axes of the coordinate system coincides with the cutting tool rotation axis.

4. The method according to claim 3, characterized in that the orientation of the cutting edge defining surfaces (11a, 12a, 31a, 32a) relative to the geometric cutting tool rotation axis (6, 26) is specified.

5. The method according to claim 3 or 4, characterized in that the positions of the cutting edge defining surfaces (11a, 12a, 31a, 32a) relative to the geometric cutting tool rotation axis (6, 26) are determined.

6. The method according to any one of claims 1 to 4, characterized in that the detected coordinates of the measurement points are used to check whether the cutting edge defining surfaces (11a, 12a, 31a, 32a) are curved or flat.

7. The method according to any one of claims 1 to 4, characterized in that the cutting tool surface (17) for the three-dimensional cutting is identified from the set CAD data of the cutting tools (1, 21).

8. The method according to any one of claims 1 to 4, characterized in that the three-dimensional cutting tool surface (18) is generated using a surface scanner (59) that scans the surface of the cutting tool.

9. The method according to claim 3, characterized in that a grid consisting of partial surfaces (14) is placed over the three-dimensional cutting tool surface (17, 18), an orientation relative to the geometric cutting tool rotation axis (6, 26) is specified for each partial surface (14), and the cutting edge defining surfaces (11a, 12a, 31a, 32a) are specified based on this.

10. The method according to claim 9, characterized in that the partial surface (14) is triangular.

11. The method according to claim 9 or 10, characterized by comparing the orientations of two adjacent subsurfaces (14) with each other and identifying the cutting edge defining surfaces (11a, 12a, 31a, 32a) based thereon.

12. The method according to any one of claims 1 to 4, characterized in that the coordinates of the measurement points (16) on the cutting edge defining surfaces (11a, 12a, 31a, 32a) are detected by contact with the measuring head by a tactile sensor.

13. The method according to any one of claims 1 to 4, characterized in that the coordinates of the measurement points (16) on the cutting edge defining surfaces (11a, 12a, 31a, 32a) are detected non-contact by an optical or electrical sensor of the measuring head.

14. The method according to any one of claims 1 to 4, characterized in that a collision-free motion trajectory is identified using Minkowski addition.

15. A coordinate measuring device for measuring a cutting tool (1, 21), wherein the cutting tool (1, 21) has a cutting tool body (2, 22) and at least one cutting insert (3, 4, 5, 23) attached to the cutting tool body (2, 22), each having at least one cutting edge (10, 30), and the coordinate measuring device (50) - A position fixing device (51) that houses and fixes the cutting tools (1, 21), - A measuring head that scans the surface of the cutting tools (1, 21) arranged within the position fixing device (51) by contact or in a non-contact manner, wherein the measuring head is movable relative to the position fixing device (51), - A motion device (53) that moves the cutting tools (1, 21) and the measuring head housed in the position fixing device (51) relative to each other. In a coordinate measuring device having, A coordinate measuring device characterized in that the coordinate measuring device (50) includes a control device (58), the control device (58) is configured to control the position fixing device (51), the measuring head, and the motion device (53) so that the position fixing device (51), the measuring head, and the motion device (53) carry out the method described in any one of claims 1 to 4 in the cutting tool (1, 21).

16. The coordinate measuring device according to claim 15, wherein the coordinate measuring device comprises a surface scanner (59), and the surface scanner (59) detects the surface of the cutting tool (1, 21) in at least the portion of the cutting tool (1, 21) that includes the cutting inserts (3, 4, 5, 23).

17. The coordinate measuring device according to claim 15, wherein the measuring head includes at least one tactile sensor, the tactile sensor scans the surface of the cutting insert (3, 4, 5, 23) at the measuring point (16) by contact.

18. The coordinate measuring device according to claim 15, wherein the measuring head includes at least one sensor, the sensor non-contact scanning the surface of the cutting insert (3, 4, 5, 23) at the measuring point.

19. The coordinate measuring device according to claim 18, characterized in that the sensor is an electrical or optical sensor.

20. The coordinate measuring device according to claim 15, characterized in that the control device is a CNC control device.

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