Method for measuring cutting tool and coordinate measuring device for implementing method

Abstract

The invention relates to a method and a coordinate measuring device for measuring a cutting tool (1, 21) having a cutting tool body (2, 22) and at least one cutting insert (3, 4, 5, 23) which is fastened to the cutting tool body (2, 22) and which has at least one cutting edge (10, 30). The coordinate measuring device has: a fixing device (51) which receives and fixes the cutting tool (1, 21); a measuring head which is in contact or non-contact with the surface of the cutting tool (1, 21) arranged in the fixing device (51), the measuring head being movable relative to the fixing device (51); and a moving device (53) that moves the cutting tool (1, 21) and the measuring head received in the fixing device (51) relative to each other. The measuring head is moved along a movement path relative to the cutting tool to determine coordinates of the cutting edge limiting surface (11a, 12a, 31a, 32a) at a predetermined measuring point.

Description

[0001] describe

[0002] The invention relates to a method for measuring a cutting tool having a cutting tool body and at least one cutting insert which is fastened to the cutting tool body via at least one cutting edge, and to a device for carrying out the method.

[0003] Cutting tools include cutting tools for machining and tools for cutting machining. They usually have a shaft and a cutting part. The shaft is used to fix the cutting tool, for example in the mechanical interface of the machining tool. The cutting part is mounted on the shaft. The cutting part has at least one cutting edge, through 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. The cutting tool can be a solid tool made entirely of a single material. Alternatively, the cutting part can also have an insert surrounding the cutting edge, wherein the insert is made of a different material from the shaft. Due to the forces acting on the cutting tool and the temperatures generated, the cutting tool is subjected to considerable mechanical and thermal stresses during use. These include mechanical friction, oxidation and wear, as well as diffusion and scaling, especially at high processing speeds. This can lead to wear in the cutting edge area of ​​the cutting tool.

[0004] In order to improve the wear resistance of cutting tools and increase their service life, cutting tools are provided with a harder material in the cutting edge area than in the rest of the cutting tool body. For this purpose, for cutting tools with cutting blades, either the cutting blades are provided with a hard coating or the entire cutting blade is made of a hard material. Such hard or superhard materials include, for example, diamond, such as polycrystalline diamond PCD, single crystal diamond, crystalline diamond or chemical vapor deposited diamond CVD, amorphous carbon, known as diamond-like carbon DLC, cubic boron nitride CBN, titanium or ceramics. If the cutting blade is provided with a coating made of a hard material, it can be applied to the cutting blade using methods such as chemical vapor deposition (CVD).

[0005] Cutting inserts are usually welded directly to the tool body to fix them. Although this connection is characterized by high strength, the welding process is not precise enough to ensure the exact positioning of the cutting insert on the cutting tool body. In addition, there may be certain inaccuracies in the shape, length, width, depth or curvature of the surface of the cutting insert. These inaccuracies of the cutting insert and the inaccurate positioning of the cutting insert on the cutting tool body lead to the associated cutting tool not meeting the specified tolerances and being of poor quality. Cutting edge target data are specified for the cutting edge. These include, for example, the position of the cutting edge relative to the cutting tool binding coordinate system, the geometry of the cutting edge or the course of the cutting edge relative to the cutting edge binding coordinate system. In order to find out whether the cutting edge of the cutting insert has these cutting edge target data after it has been welded to the cutting tool body and how much, if any, the actual cutting edge data deviate from the cutting edge target data, the actual cutting edge data must be recorded. By comparing the actual cutting edge data with the cutting edge target data, it can be determined at which point on the cutting insert how much material must be removed so that the cutting edge meets the specified cutting edge target data within the specified tolerance range after the material removal. Targeted material removal is carried out using a processing device. The material-removing device can be equipped, for example, with a grinding wheel, a laser for generating a laser beam or a device for electrical discharge machining (EDM).

[0006] Before the cutting inserts welded to the cutting tool body are post-processed using a processing device, the exact position of each cutting insert must be determined in three-dimensional space based on the known reference of the cutting tool. In addition, it must be determined whether the surface is flat or curved. If the cutting tool is designed as a rotating tool, which rotates around the cutting tool geometric rotation axis during use, the cutting tool geometric rotation axis can serve as a reference body, for example. Another reference body can be the top side of the cutting tool or the bottom side of the cutting tool.

[0007] Based on the recorded position, orientation and shape of the cutting insert and the comparison of the actual cutting edge data with the target cutting edge data, the path that the material removal device must move relative to the cutting tool is determined to achieve the material removal on the cutting insert required for post-processing.

[0008] As is known, the position of the cutting insert on the cutting tool can be detected using mechanical, electrical or optical measuring probes or measuring heads. The detection can be tactile, i.e. the surface of the cutting insert is touched with the measuring head, or contactless. For this purpose, the measuring head is arranged on a machining device or a coordinate measuring device. The measuring head is moved relative to the cutting tool in order to determine the coordinates of the measuring 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 on the cutting tool, the measuring head must be moved relative to the cutting tool so that it detects the position of the surface relative to a reference body (e.g. the geometrical rotation axis of the cutting tool) at at least three measuring points on each cutting insert. For this purpose, a coordinate system is defined. The coordinates of the measuring points are determined by the measuring head. The control of the relative movement of the measuring head relative to the cutting tool is usually carried out using a computer (e.g. CNC). The software must be created and specified by the responsible operator according to the type, number and approximate position of the cutting inserts. The operator can rely on the technical specifications and drawings of the cutting tool, but these specifications do not include inaccuracies caused by welding of the cutting inserts. Therefore, the operator must enter detailed information into the control system in order to bring the measuring probe to the measuring point of the cutting insert. This requires considerable effort, especially for cutting tools with a large number of cutting inserts. There is also a risk of error when entering the details into the control system.

[0009] The object of the present invention is to provide a method and a coordinate measuring device for measuring a cutting insert after it has been welded to a cutting tool, wherein the measurement is performed automatically and collisions of the coordinate measuring device with the cutting tool are avoided.

[0010] This object is achieved by a method having the features of claim 1 and a coordinate measuring device having the features of claim 15. The coordinate measuring device is equipped with:

[0011] - a fixture for holding and securing the cutting tool,

[0012] a measuring head which is in contact or out of contact with a surface of a cutting tool arranged in a fixture, wherein the measuring head is movable relative to the fixture, and

[0013] - A moving device for moving the cutting tool fixed in the fixing device relative to the measuring head.

[0014] The method is characterized by the following steps:

[0015] a) Specify the measuring head geometry data, including the shape and size of the measuring head.

[0016] b) Secure the cutting tool in a fixture.

[0017] c) Define a three-dimensional coordinate system with a zero point and coordinate axes.

[0018] d) A three-dimensional surface of the cutting tool arranged in the fixture is specified at least in those parts of the cutting tool comprising the cutting insert, the surface being defined as the cutting tool three-dimensional surface. The surface may be specified in a three-dimensional coordinate system.

[0019] e) Determining those sub-regions of the three-dimensional surface of the cutting tool which form the surface of the cutting insert and are arranged adjacent to the cutting edge of the cutting insert, whereby these sub-regions are defined as cutting edge limiting surfaces.

[0020] f) The measuring point is located on the cutting edge limiting surface.

[0021] g) determining a moving path of a moving device for relative movement of a measuring head and a cutting tool, wherein the moving path is determined by geometric data of the measuring head, a limiting surface of a cutting edge and measuring points, so that during the relative movement of the measuring head and the cutting tool along the moving path, the coordinates of the cutting tool at the measuring point are recorded by a coordinate measuring device, and collision between the cutting tool and the measuring head during the relative movement is excluded.

[0022] h) The measuring head is moved along the movement path relative to the cutting tool.

[0023] i) Using a coordinate measuring device, the coordinates of the measuring points on the cutting edge limiting surface are recorded relative to the coordinate system.

[0024] j) Finally, the cutting edge limiting surface is adjusted to the recorded measuring point coordinates so that the recorded coordinates are located on the adjusted cutting edge limiting surface.

[0025] For example, the measuring point is specified in such a way that one or two coordinates of the measuring point are determined and the movement device positions the measuring head relative to the cutting edge limiting surface relative to the specified coordinate or coordinates. The measuring head then detects the missing coordinates of the cutting edge limiting surface.

[0026] Coordinates refer to a given coordinate system. Advantageously, it is a cutting tool bound coordinate system. The cutting tool bound coordinate system comprises the coordinate axes passing through the cutting tool and a zero point in or on the cutting tool. When the cutting tool moves, the cutting tool bound coordinate system moves with it. When the cutting tool moves, the cutting edge position coordinates and the cutting edge path coordinates do not change in this cutting tool bound coordinate system.

[0027] In principle, the cutting insert not only has a surface that is a part of the cutting tool surface and is arranged near the cutting edge of the cutting insert. For example, the cutting insert also includes those surfaces where the cutting insert is welded to the cutting tool body. Assuming that those surfaces of the cutting insert are a part of the cutting tool surface and the surface adjacent to the cutting edge of the cutting insert is particularly important for the quality of the cutting tool, this is why the inspection and post-processing of this area are particularly important. If necessary, of course, it is also possible to measure on the surface of the non-adjacent cutting edge of the cutting insert. Usually, the back measurement is not carried out in those parts where the cutting insert is welded to the cutting tool body, because these parts are not exposed and therefore at least do not directly affect the performance of the cutting edge, and because processing in these parts may cause the cutting insert to break away from the cutting tool body. In addition to these mounting portions and the surface that limits the cutting edge, the cutting insert can also have other surfaces that can be measured.

[0028] The three-dimensional surface of the cutting tool is specified in such a way that the data does not need to be manually entered into the coordinate measuring device. For example, the three-dimensional surface of the cutting tool can be generated and specified using known cutting tool CAD data. The CAD data can contain two-dimensional or three-dimensional cutting tool surfaces. For example, the surface of the cutting tool body can be specified in three dimensions, while the surface of the cutting blade can be specified in two dimensions. The three-dimensional surface of the cutting tool is then determined based on these data. In this case, the three-dimensional surface of the cutting tool corresponds to or is a part of the theoretical geometric surface of the cutting tool generated from the CAD design of the cutting tool. Alternatively, a surface scanner based on a cutting tool clamped in a fixture and entered into the device can be used to generate the three-dimensional surface. In this case, the three-dimensional surface of the cutting tool corresponds to the actual surface of the cutting tool after the cutting blade is welded. In both cases, there is no need to manually enter the surface data into the system. Therefore, the process is no longer so complicated and error-prone for the user.

[0029] By evaluating the three-dimensional surface of the cutting tool, those sub-areas that form the cutting blade surface and are arranged near the cutting edge can be determined. These sub-areas are characterized by their specific orientation relative to a reference body of the cutting tool, for example relative to the geometric rotation axis of the cutting tool, the bottom surface or the top surface of the cutting tool. This characteristic of the cutting blade surface can be used when determining the properties of the cutting blade. With the method according to the invention, the cutting edge limiting surface can be determined no matter how and in what way the three-dimensional surface of the cutting tool is specified. The user does not need to enter any data or information.

[0030] By evaluating the three-dimensional surface of the cutting tool and determining the cutting edge limiting surface, the position, orientation, possible curvature of the surface and the length, width or depth of the cutting insert can be determined.

[0031] The cutting edge limiting surface determined from the three-dimensional surface of the cutting tool is adapted to the coordinates obtained during probing with the measuring head. If the measuring point at which the coordinates were recorded is already on the cutting edge limiting surface, the cutting edge limiting surface does not need to be changed. If the measuring point at which the coordinates were recorded is not located on the cutting edge limiting surface, the cutting edge limiting surface must be changed so that the measuring point is located on the changed cutting edge limiting surface. Based on the cutting edge limiting surface, it can be determined, if necessary by adjustment using the scan data, how the material removal device must be moved relative to the cutting tool in order to remove material from the cutting insert in a targeted manner, so that the welded cutting insert can be post-processed and the cutting tool then meets the specifications regarding the position, orientation and course of the cutting edge and the surface limited by the cutting edge within a certain tolerance range.

[0032] When determining the movement path of the measuring head and the cutting tool for relative movement, the geometry and dimensions of the measuring head and the cutting tool are taken into account so that the relative movement does not cause a collision.

[0033] The following surfaces can be assigned to a cutting tool:

[0034] 1. The theoretical geometric three-dimensional surface obtained from the cutting tool design; if the cutting tool is designed using CAD, the theoretical geometric three-dimensional surface of the cutting tool can be derived from the CAD data. This surface must not contain any inaccuracies caused by the manufacture of the cutting insert and the welding of the cutting insert.

[0035] 2. The actual three-dimensional surface of the cutting tool after welding the cutting insert; this surface includes inaccuracies caused by the manufacture of the cutting insert and the welding of the cutting insert; for example, the surface can be determined using a surface scanner covering the entire surface of the cutting tool; the surface determined by the surface scanner is checked at specified measuring points by detection with a measuring head. Alternatively, the surface can be checked using the data obtained in item 1, and then the surface of the cutting insert is detected at specified measuring points using a measuring head. In both cases, the specific surface of the cutting insert is corrected so that the coordinates of the measuring points determined by detection are located on the surface of the cutting insert. The number of measuring points depends on the accuracy of the given three-dimensional surface. The higher the accuracy of the given surface, the fewer measuring points are required. The three-dimensional surface of the cutting tool according to claim 1 can be derived from a theoretical three-dimensional surface according to item 1 or from an actual three-dimensional surface according to item 2.

[0036] 3. The cutting edge limiting surface determined based on the three-dimensional surface of the cutting tool; the cutting edge limiting surface can be determined from the theoretical geometric three-dimensional surface of the cutting tool according to item 1 above, or from the actual three-dimensional surface of the cutting tool after welding the cutting blade according to item 2 above.

[0037] 4. The measuring points are located on the cutting edge limiting surfaces. The surface of the cutting tool mounted in the fixture is measured at these measuring points using the measuring head. This helps to adapt the theoretical cutting edge limiting surfaces to reality. The cutting edge limiting surfaces are adjusted so that the coordinates of the measuring points recorded with the measuring head are located on the cutting edge limiting surfaces. These cutting edge limiting surfaces have actual data of the cutting edge.

[0038] In the method according to the invention, a three-dimensional cutting tool surface is specified according to item 1 above or according to item 2 above, and a cutting edge limiting surface is determined therefrom according to item 3 above. It is assumed that the cutting edge limiting surfaces adjusted according to item 4 correspond to corresponding actual surfaces on a cutting tool clamped in a fixture and to be machined, and have actual cutting edge data. Starting from these cutting edge limiting surfaces, material removal can be carried out as required in order to adapt the cutting edge to the specified cutting edge target data.

[0039] The data required to measure the cutting insert on the cutting tool is automatically determined from the cutting tool surface, eliminating the need for manual input by the operator and the need for the operator to determine the measurement data. This makes the measurement process much simpler. The measurement is also more accurate because input errors cannot occur.

[0040] The measuring range and the machine coordinate system are determined by the moving axes of the moving device and its guides, drives and incremental measuring systems. The machine coordinate system does not match the cutting tool-bound coordinate system. However, it is possible to transform the coordinates of the machine coordinate system into the cutting tool-bound coordinate system. Moving devices with x, y and z axes usually use a Cartesian machine coordinate system. However, moving devices with cylindrical or spherical coordinate systems are also common. They are used in combination with incremental displacement and angle sensors.

[0041] The measuring head can be equipped with switches and measuring sensors. When recording a measuring point, the switch sensor only issues a trigger signal, which initiates the reading of the length measuring system. The measuring sensor, on the other hand, has its own internal measuring range of a few millimeters. The internally measured sensor value is superimposed on the sensor position determined by the length measuring system.

[0042] In order to avoid unnecessary collisions between the material removal device and the cutting tool, the measuring head geometry data, including the shape and size of the measuring head, are taken into account when determining the movement path. This can be achieved using known collision avoidance calculation methods. The specific data of the cutting tool and the measuring head are taken into account. Known collision avoidance calculation methods can be used. For example, the Minkowski addition method can be used for this purpose. Other calculation methods are also possible.

[0043] According to an advantageous embodiment of the invention, the coordinate system is a cutting tool bound coordinate system.

[0044] According to another advantageous embodiment of the invention, the cutting tool is a rotary cutting tool which rotates around a cutting tool geometrical rotation axis during use. The cutting tool geometrical rotation axis corresponds to the axis around which the cutting tool rotates in its subsequent use position. Advantageously, the cutting tool designed as a rotary tool is received in a fixture so that it rotates around the cutting tool geometrical rotation axis with the mobile device. One of the coordinate axes of the coordinate system coincides with the cutting tool rotation axis.

[0045] According to another advantageous embodiment of the invention, the orientation of the cutting edge limiting surface is determined relative to the geometrical rotation axis of the cutting tool. This makes use of the fact that the cutting insert usually has a certain orientation relative to the geometrical rotation axis of the cutting tool. This orientation is a prerequisite for the cutting insert to achieve the desired material removal at the position where the cutting tool is subsequently used.

[0046] According to another advantageous embodiment of the invention, the position of the cutting edge limiting surface is determined relative to the cutting tool geometrical rotation axis. This utilizes the fact that the cutting insert usually has a specific position relative to the cutting tool geometrical rotation axis.

[0047] According to another advantageous embodiment of the invention, the position of the cutting edge limiting surface is determined relative to the front side of the cutting tool. If the cutting tool is designed as a rotating tool, which rotates around the cutting tool rotation axis at the place of use, and which extends along the cutting tool rotation axis from a first end to a second end, the end face is preferably a surface of the cutting tool at the first end or the second end, which is perpendicular to the cutting tool rotation axis.

[0048] According to another advantageous embodiment of the invention, the coordinates of the recorded measuring points are used to check whether the cutting edge limiting surfaces are curved or flat. For example, if it is determined that one of the cutting edge limiting surfaces has a curvature that results in an undesired curvature of the cutting edge, the corresponding cutting edge limiting surface can be smoothed and converted into a flat surface by post-processing so that the cutting edge has a predetermined course. If the cutting edge limiting surface has a specified curvature, more than three measuring points must be specified.

[0049] According to another advantageous embodiment of the invention, the cutting insert is made of a superhard material, such as polycrystalline diamond (PCD), cubic boron nitride (CBN), chemical vapor deposition (CVD) diamond, single crystal diamond or ceramic. If a coating is required, it can be applied by CVD. Alternatively, diamond-like amorphous carbon (DLC) can also be used.

[0050] According to another advantageous embodiment of the present invention, the three-dimensional surface of the cutting tool is determined according to the specified CAD data of the cutting tool. By computer-aided design and manufacturing of a cutting tool having at least one cutting blade, a geometric model of the cutting tool can be obtained as a digital data set. The CAD data contains the digital data set. By calculation, the theoretical cutting tool geometric three-dimensional surface can be determined from the CAD data. Since the CAD data is derived from the geometric model, it does not contain inaccuracies caused by the manufacture of the cutting blade and the welding of the cutting blade with the cutting tool body. Therefore, they do not reflect reality in the same way. Therefore, it may be advantageous to determine the measuring points on the surface of the cutting blade, detect the actual real cutting edge limiting surface by scanning the measuring points with a measuring head, and adapt the cutting edge limiting surface to the scanned data.

[0051] According to another advantageous embodiment of the invention, the three-dimensional surface of the cutting tool is generated using a surface scanner. The surface scanner is equipped with one or more sensors that can systematically and regularly scan or measure the cutting tool. A large number of individual measurement results form an overall image of the cutting tool. The measurement values ​​recorded by the sensor are converted into digital data and processed by a computer. Based on these data, the three-dimensional surface of the cutting tool can be determined by calculation. The three-dimensional surface of the cutting tool captured with the surface scanner may well reproduce the real surface of the cutting tool. In this case, measuring points are defined on the surface of the cutting blade and the surface is measured at these measuring points using a measuring head to check the quality of the surface captured by the scanner. The detection is for control purposes. For example, if such an inspection of the surface of the cutting blade shows that the coordinates recorded with the measuring head are part of the three-dimensional surface of the cutting tool recorded with the surface scanner, further inspection of the remaining surface of the cutting blade may not be required. However, if deviations are found, the inspection can continue.

[0052] According to another advantageous embodiment of the invention, a grid of sub-surfaces is placed on the three-dimensional surface of the cutting tool. For each sub-surface, the orientation is determined relative to a reference body, for example relative to the geometrical rotation axis of the cutting tool. The cutting edge limiting surface is thereby determined.

[0053] According to another advantageous embodiment of the invention, the sub-surface is a triangle. Alternatively, the sub-surface can also be a quadrilateral or other polygon.

[0054] According to another advantageous embodiment of the invention, the orientations of two adjacent sub-surfaces are compared with one another. The cutting edge limiting surface is thereby determined. This utilizes the fact that adjacent sub-surfaces having the same or similar orientation belong to the same cutting edge limiting surface.

[0055] According to another advantageous embodiment of the invention, the coordinates of the measuring points of the cutting edge limiting surface are detected by contact with a tactile sensor of the measuring head. Such sensors are also called mechanical sensors.

[0056] According to a further advantageous embodiment of the invention, the coordinates of the measuring points of the cutting edge limiting surface are recorded contactlessly by means of an optical or electrical sensor of the measuring head.

[0057] According to another advantageous embodiment of the invention, the collision-free movement path is determined by Minkowski addition.Other methods can also be used to calculate the collision-free movement path.

[0058] The coordinate measuring device according to the present invention is characterized in that it is equipped with a control device which controls the fixing device, the measuring head and the moving device so that they carry out the method according to the present invention.

[0059] Further advantages and advantageous embodiments of the invention can be found in the following description, the drawings and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The accompanying drawings show embodiments of the present invention, in which:

[0061] Figure 1 is a perspective view of a first embodiment of a cutting tool measured using the method according to the present invention, represented based on CAD data;

[0062] Figure 2 is based on Figure 1 A perspective view of the cutting tool shown, represented using triangles based on data obtained by a surface scanner;

[0063] Figure 3 is based on Figure 2 Use different grayscale representations;

[0064] Figure 4 is based on Figure 1 , 2 and 3 , a perspective view of the cutting tool after processing is completed;

[0065] Figure 5 is based on Figure 1 The cutting tool represented is labeled with the external cutting tool geometry;

[0066] Figure 6 yes Figure 1 Schematic diagram of the moving path of the cutting tool and the measuring head shown;

[0067] Figure 7 is based on Figure 1 A cutting tool represented by a measuring head, wherein measuring points are marked on the surface of the cutting insert by scanning the measuring head;

[0068] Figure 8 is based on Figures 1 to 7Cutting tools, comparing CAD data with data determined using surface scanners;

[0069] Fig. 9 is a perspective view of a second embodiment of a cutting tool measured using the method according to the present invention, represented based on CAD data;

[0070] Fig.10 is based on Fig. 9 a perspective view of the cutting tool shown, the view being based on data obtained from a surface scanner;

[0071] Fig.11 yes Fig. 9 Details in;

[0072] Fig.12 yes Fig.11 Details in;

[0073] Fig.13 is based on Fig. 9 and Fig.10 The cutting tool portion after finishing;

[0074] Fig.14 is a coordinate measuring device for performing the method. DETAILED DESCRIPTION

[0075] Figures 1 to 8 A first cutting tool measured using the method according to the invention is shown. A coordinate measuring device such as Fig.14 shown. Figure 1 and Figure 2 The cutting tool before measurement is shown. Figure 1 Corresponds to a representation of the CAD data of the cutting tool, which data is specified by designing the cutting tool using CAD. Figure 2 Represents data obtained using a surface scanner. The cutting tool 1 comprises a cutting tool body 2 on which a total of six cutting blades 3, 4, 5 are arranged. The cutting tool is a rotating tool which rotates about a cutting tool geometric rotation axis 6 in a use position. The cutting tool is not fully shown in the figure. For the sake of clarity, only a portion of the axis 7 is shown, which is used to fix the cutting tool 1 in a machine not shown. No cutting blades are arranged in the not shown part of the cutting tool. Therefore, the not shown part of the cutting tool will not be measured when using this process. The part of the cutting tool 1 on which the cutting blades 3, 4, 5 are arranged on the cutting tool body 2 is defined as the three-dimensional surface of the cutting tool. In Figure 1 and Figure 2 In the example, the three-dimensional surface of the cutting tool is visible, at least in the area facing the observer. Figure 1 and Figure 2In the figure, the part of the three-dimensional surface of the cutting tool facing away from the observer is hidden by the cutting tool body 2.

[0076] The cutting blades 3, 4, 5 are arranged offset relative to the axis of rotation of the cutting tool. The first two cutting blades 3 are located at one end 8 of the cutting tool. They are arranged 180o apart from each other on the cutting tool body 2 and are inclined at an angle α relative to the axis of rotation of the cutting tool. The two second cutting blades 4 are arranged axially relative to the axis of rotation 6 of the cutting tool, keeping a certain distance from the end 8 and the two first cutting blades 3. They are mounted on the cutting tool body in an axially offset manner from the first cutting blade 3. The angular distance between the two second cutting blades is also 180o. The two third cutting blades 5 are located between the two first and second cutting blades 3, 4 relative to their axial position and relative to their angular position. In the figure, only one of the two third cutting blades 5 is visible because the other third cutting blade 5 is covered by the cutting tool body 2.

[0077] The first, second and third cutting inserts 3, 4, 5 are welded to the cutting tool body 2. After welding, the cutting inserts 3, 4, 5 initially protrude radially outwards beyond the cutting tool body 2. Figure 1 and Figure 2 The cutting tool is shown after welding of the cutting inserts 3, 4, 5. In particular in the case of the first cutting insert 3 and the second cutting insert 4, the parts protruding radially beyond the cutting tool body are clearly visible.

[0078] Figure 1 A representation of a cutting tool 1 based on CAD data is shown. These CAD data originate from a computer-aided design of a cutting tool. Shown in the figure is a three-dimensional surface of the cutting tool, including cutting inserts 3, 4, 5.

[0079] Figure 2 A representation of a cutting tool 1 is shown, which is based on data obtained by a surface scanner. The surface scanner Fig.14 59. The surface scanner scans the surface of the cutting tool 1 from all sides in the area where the cutting inserts 3, 4, 5 are arranged. This generates a three-dimensional surface of the cutting tool, which is essential for performing the process. Figure 2 Based on the CAD data, the surface of the cutting tool 1 can be accurately captured (the surface is also shown in Figure 1 ). The surface scanner generates many surface points. Figure 2 In the figure, they are connected by lines to form triangles. Figure 3 Shows the Figure 2 Alternative representation of the same set of surface points, but showing different grayscale levels instead of triangles. Figure 2 In comparison, the shape of the cutting tool 1 in this figure is clearer.

[0080] Figure 4 A cutting tool 1 is shown with cutting inserts 3, 4, 5, wherein the cutting inserts meet predetermined criteria regarding the position and course of their cutting edges 10. This relates in particular to predefined cutting edge target data, such as the position and course of the cutting edges relative to the axis of rotation of the cutting tool. The cutting inserts 3, 4, 5 protrude radially outwards from the cutting tool body 2 to a significantly lesser extent. By way of example, the second cutting insert 4 shows a cutting edge 10 that delimits a first cutting edge limiting surface 11 and a second cutting edge limiting surface 12. The same is true for the first cutting insert 3 and the third cutting insert 5.

[0081] Figure 5 Shown according to Figure 1 and Figure 2 A cutting tool 1, wherein the outer geometry 13 of the cutting tool is marked by lines in the region of the first cutting insert 3 and the second cutting insert, the outer geometry 13 being defined by the predetermined course of the cutting edges 10 of the cutting inserts 3, 4, 5. The figure thus illustrates actual cutting edge data and target cutting edge data. By comparing these data, it can be seen from the illustration that the regions of the cutting inserts 3, 4, 5 that protrude beyond the outer geometry 13 of the cutting tool 1 must be removed. In particular, the first cutting edge limiting surface 11a and / or the second cutting edge limiting surface 12a must be post-processed so that they are within the tolerance range and are aligned with the outer geometry 13 of the cutting tool 1. Figure 4 The first cutting edge limiting surface 11 and the second cutting edge limiting surface 12 in the embodiment correspond to each other, and the cutting edge 10 thus has a predetermined course.

[0082] In order to be able to machine the cutting inserts 3, 4, 5 in the region of the cutting edge limiting surfaces 11a, 12a, a Figure 1 CAD data or use according to Figure 2 The three-dimensional surface of the cutting tool 1 is specified by the data determined by the surface scanner. The sum of these given data is called the three-dimensional cutting tool surface. From this three-dimensional cutting tool surface, those sub-areas that form the surface of the cutting inserts 3, 4, 5 and are arranged near the cutting edges are determined. These are called cutting edge limiting surfaces 11a, 12a. They are obtained by comparing the orientation or position of the surface with the cutting tool rotation axis 6 or the front side 9 of the cutting tool. For this purpose, the three-dimensional cutting tool surface is divided into a grid of sub-surfaces 14. In accordance with Figure 2In the representation of , the mesh with sub-surfaces 14 corresponds to the triangles generated by connecting the surface points. For each sub-surface 14, the orientation relative to the geometric rotation axis 6 of the cutting tool is determined. Alternatively or cumulatively, the orientation relative to the front side 9 of the cutting tool can also be determined for each sub-surface 14. Adjacent sub-surfaces 14 with the same orientation are assigned to a common surface. The cutting edge limiting surfaces 11a, 12a differ from the other surfaces of the cutting tool 1 in that they have a very specific predetermined orientation relative to the cutting tool rotation axis 6 or the front side 9.

[0083] The actual cutting edge data are determined based on the cutting edge limiting surface. They relate to at least one property of the cutting edge, namely the cutting edge position relative to the cutting tool binding coordinate system, the cutting edge geometry or the cutting edge path relative to the cutting edge binding coordinate system.

[0084] The cutting tool is assigned cutting edge target data, which is related to the corresponding attributes in the above attribute set: the cutting edge position relative to the cutting tool binding coordinate system, the cutting edge geometry, and the cutting edge path relative to the cutting edge binding coordinate system. Figure 4 The cutting tool shown has these cutting edge target data.

[0085] The actual cutting edge data are compared with the cutting edge target data. The comparison determines whether and how much material must be removed from the detected cutting edge limiting surfaces 11a, 12a so that the cutting edge 10 has the cutting edge target data and has the specified course with the specified outer geometry 13.

[0086] according to Figure 7 The illustrated measuring head geometry, the cutting edge limiting surfaces 11a, 12a, 31a, 32a and the measuring point 16 define a movement path 15 along which the measuring head is moved relative to the cutting tool by means of a movement device in order to determine the coordinates of the cutting edge limiting surfaces at the measuring point 16. Figure 6 In the embodiment of the present invention, the movement path 15 is shown on the first, second and third cutting inserts 3, 4, 5. The movement path 15 extends beyond the cutting edge limiting surfaces 11a, 12a, thereby ensuring that the entire cutting edge surface 11a, 12a is contacted when necessary. The movement path is specified in such a way that the measuring head does not collide with the cutting tool and records the coordinates of all specified measuring points.

[0087] If according to Figure 1 The three-dimensional surface of the cutting tool obtained from the CAD data cannot fully reflect the actual situation, or needs to be checked according to Figure 1 , 2If the three-dimensional surface of a cutting tool is 3 or 3, then a measuring point can be determined on at least one cutting edge limiting surface 11a, and the coordinates of the cutting edge limiting surface can be recorded using a coordinate measuring device. In this example, three measuring points 16 are determined on the first cutting edge limiting surface 11a. Subsequently, the coordinates of the cutting edge limiting surface at these three measuring points 16 are recorded using a coordinate measuring device. The obtained measurement data are compared with the cutting edge limiting surface 11a at these measuring points 16. If there is a deviation, the cutting edge limiting surface 11a is corrected and adjusted so that the coordinates of the measuring point are located on the cutting edge limiting surface 11a. If according to Figure 2 Or 3 using a surface scanner to determine the three-dimensional surface of the cutting tool, such an inspection can also be performed on the cutting edge limit surfaces 11a, 12a. Since the surface scanner has captured the surface of the real cutting tool, it is assumed that in this case an inspection is only required in special cases or for control purposes.

[0088] Figure 8 A comparison of a three-dimensional cutting tool surface 17 determined using CAD data and a three-dimensional cutting tool surface 18 determined using a surface scanner is shown. In the light grey area, the three-dimensional cutting tool surface 18 determined using the surface scanner protrudes from the three-dimensional cutting tool surface 17 determined using CAD data. The opposite is true in the dark grey area.

[0089] Figures 9 to 13 A second embodiment of a cutting tool 21 measured using the method according to the invention is shown. Fig. 9 and Fig.10 A cutting tool 21 is shown. Fig. 9 This corresponds to the representation of the CAD data of the cutting tool 21, which is specified by designing the cutting tool using CAD. Fig.10 represents data obtained using a surface scanner. The cutting tool 21 comprises a cutting tool body 22 on which a plurality of cutting inserts 23 are arranged. The cutting tool is a rotary tool which rotates about a cutting tool geometric rotation axis 26 in a use position. Figures 1 to 8 Compared to the first embodiment of the cutting tool, in the cutting tool 21 according to the second embodiment, all cutting blades 23 are arranged at the same axial position on the cutting tool body 22 relative to the cutting tool rotation axis 26 and have the same orientation relative to the cutting tool rotation axis 26.

[0090] For each cutting insert 23 arranged on the cutting tool body 22, the criteria for the path and position of the cutting edge 30 of the cutting insert 23 relative to the cutting tool rotation axis 26 of the cutting tool are specified as cutting edge target data. Fig.13The predetermined cutting edge 30 defines a first cutting edge limiting surface 31 and a second cutting edge limiting surface 32. The paths and positions of the cutting edges 30 of all cutting inserts 23 of the cutting tool 21 determine the outer geometry 33 of the cutting tool 21. The outer geometry 33 is Fig. 9 and 10 Marked with a line.

[0091] In order to implement this method, according to Fig. 9 The three-dimensional surface of the cutting tool shown in the CAD data or according to Fig.10 The data determined by the surface scanner are shown to determine the cutting edge limiting surfaces 31a, 32a of the cutting insert 23 and to derive actual cutting edge data therefrom. These are compared with specified cutting edge target data. Fig.11 and 12 As an example, two cutting edge limiting surfaces 31a and 32a on the cutting insert 23 are shown. By comparing the specifications of the cutting edge 30, the first cutting edge limiting surface 31 and the second cutting edge limiting surface 32, it can be concluded that material removal must occur and to what extent. Based on the determined data, the machining device can be controlled so that the corresponding material is removed and the cutting edge 30 meets the requirements. Fig.13 Specifications shown.

[0092] according to Figures 1 to 8 The first embodiment of the invention determines the position and orientation of the cutting edge limiting surfaces 31a, 32a relative to the three-dimensional surface of the cutting tool.

[0093] Fig.14 A coordinate measuring device 50 for implementing the method is shown. The coordinate measuring device is combined with a laser 56 for material removal. The coordinate measuring device comprises a fixture 51 for receiving and fixing a cutting tool 1, a moving device 53 for moving the cutting tool 1 arranged in the fixture relative to a device base 55, a laser 56 for generating a laser beam 52, and a laser beam deflection device 57 for guiding the laser beam 52. In this example, the moving device 53 has three linear axes X, Y, Z and two rotation axes B and C. The rotation axis C ensures that the cutting tool 1 arranged in the workpiece fixture 51 rotates around a cutting tool geometric rotation axis extending through the cutting tool.

[0094] The coordinate measuring device 50 is also equipped with a surface scanner 59, which detects the surface of the cutting tool 1 arranged in the fixture 51 and stores the three-dimensional surface of the cutting tool determined in this way. The three-dimensional surface of the cutting tool is output to the control device 58, and the control device 58 uses the three-dimensional surface of the cutting tool to determine the cutting edge limit surface of the cutting insert.

[0095] The coordinate measuring device 50 is equipped with a measuring head 60 so as to detect the surface of the cutting tool 1 arranged in the fixture at a predetermined measuring point and assign the coordinates of the coordinate system. It is then checked whether these recorded coordinates are located on the specified cutting edge limit surface. If not, the cutting edge limit surface is corrected so that the coordinates of the measuring point are located on the adjusted cutting edge limit surface. The measuring head 60 is controlled and moved so as to avoid collisions between the cutting tool and the measuring head. The relative movement between the cutting tool 1 and the measuring head is achieved by the moving device 53.

[0096] If the measurement of the cutting tool indicates that material needs to be removed from the cutting insert, the laser can be used for material removal. The laser beam deflection device 57 moves in three different directions in space and guides the laser beam 52. The laser beam 52 moves along a laser path (not shown) relative to the cutting tool 1. The control device 58 controls the fixing device 51, the moving device 53 and the laser beam deflection device 57 so as to remove material from the cutting tool in a targeted manner.

[0097] Therefore, the control device 58 controls not only the moving device 53 and the measuring head 60, but also the laser 56. The material to be removed is determined according to the actual cutting edge data and the cutting edge target data. The laser and the moving device are controlled in such a way that the material is exclusively removed by the cutting blade of the cutting tool 1.

[0098] All features of the invention may be essential to the invention individually or in any combination with one another.

[0099] Reference Number:

[0100] 1 Cutting tools

[0101] 2 Cutting tool body

[0102] 3 First cutting blade

[0103] 4 Second cutting blade

[0104] 5 Third cutting blade

[0105] 6 Cutting tool rotation axis

[0106] 7 Axis

[0107] 8 terminals

[0108] 9 Front

[0109] 10 Cutting edge

[0110] 11 The first cutting edge limiting surface after machining

[0111] 11a The first cutting edge limiting surface before machining

[0112] 12 Machined second cutting edge limiting surface

[0113] 12a Second cutting edge limiting surface before machining

[0114] 13 External geometry of cutting tools

[0115] 14 Sub-areas

[0116] 15 Measuring head moving path

[0117] 16 measuring points

[0118] 17 Determine the three-dimensional surface of the cutting tool using CAD data

[0119] 18 Determine the three-dimensional surface of cutting tools using surface scanners

[0120] 21 Cutting tools

[0121] 22 Cutting tool body

[0122] 23 Cutting inserts

[0123] 26 Cutting tool rotation axis

[0124] 30 Cutting Edge

[0125] 31 First cutting edge limiting surface after machining

[0126] 31a The first cutting edge limiting surface before machining

[0127] 32 Machined second cutting edge limiting surface

[0128] 32a Second cutting edge limiting surface before machining

[0129] 33 External geometry of cutting tools

[0130] 50 Coordinate measuring device

[0131] 51 Fixtures

[0132] 52 Laser Beam

[0133] 53 Mobile Devices

[0134] 55 Device base

[0135] 56 Laser

[0136] 57 Laser beam deflection device

[0137] 58 Control Device

[0138] 59 Surface Scanner

[0139] 60 Measuring head

Claims

1. A method for measuring a cutting tool (1, 21), the cutting tool (1, 21) having a cutting tool body (2, 22) and at least one cutting insert (3, 4, 5, 23), the cutting insert (3, 4, 5, 23) being fixed to the cutting tool body (2, 22) and having at least one cutting edge (10, 30), wherein: The measurement is performed using a coordinate measuring device (50), wherein the coordinate measuring device (50) has: - a fixing device (51), which receives and fixes the cutting tool (1, 21); a measuring head, which is in contact or not in contact with a surface of the cutting tool (1, 21) arranged in the fixture (51), and which is movable relative to the fixture (51); - a moving device (53) for relatively moving the cutting tool (1, 21) received in the fixing device (51) and the measuring head; It is characterized by the following process steps: a) specifying the measuring head geometric data, including the shape and size of the measuring head; b) fixing the cutting tool (1, 21) in the fixing device (51); c) defining a three-dimensional coordinate system having a zero point and coordinate axes; d) predetermining a three-dimensional surface of the cutting tool (1, 21) mounted in the fixture (51) at least in those parts of the cutting tool (1, 21) comprising the cutting insert (3, 4, 5, 23), the three-dimensional surface being defined as the cutting tool three-dimensional surface (17, 18); e) determining a sub-region of the three-dimensional surface (17, 18) of the cutting tool, the sub-region forming the surface of the cutting insert (3, 4, 5, 23) and arranged adjacent to the cutting edge (10, 30) of the cutting insert (3, 4, 5, 23), wherein the sub-region is defined as a cutting edge limiting surface (11a, 12a, 31a, 32a); f) determining a measuring point (16) on the cutting edge limiting surface (11a, 12a, 31a, 32a), g) determining a movement path of the moving device for relative movement of the measuring head and the cutting tool (1, 21), wherein the movement path is determined by the measuring head geometric data, the cutting edge limiting surface (11a, 12a, 31a, 32a) and the measuring point (16), so that during the relative movement of the measuring head and the cutting tool (1, 21) along the movement path, the coordinates of the cutting tool (1, 21) at the measuring point (16) are recorded by the coordinate measuring device, and collision between the cutting tool (1, 21) and the measuring head is excluded during the relative movement; h) moving the measuring head relative to the cutting tool (1, 21) along the movement path; i) determining the coordinates of the measuring point (16) of the cutting edge limiting surface (11a, 12a, 31a, 32a) relative to a coordinate system using the coordinate measuring device; j) adapting the cutting edge limiting surface (11a, 12a, 31a, 32a) to the detection coordinates of the measuring point (16) so that the detection coordinates are located on the adapted cutting edge limiting surface.

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

3. The method according to claim 1 or 2, characterized in that: The cutting tool (1, 21) is a rotating cutting tool which rotates around a geometric rotation axis (6, 26) of the cutting tool during use, and one of the 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 limiting surface (11a, 12a, 31a, 32a) is determined relative to the geometrical rotation axis (6, 26) of the cutting tool.

5. The method according to claim 3 or 4, characterized in that: The position of the cutting edge limiting surface (11a, 12a, 31a, 32a) is determined relative to the geometrical rotation axis (6, 26) of the cutting tool.

6. The method according to any one of the preceding claims, characterized in that The detected measuring point coordinates are used to check whether the cutting edge limiting surface (11a, 12a, 31a, 32a) is curved or flat.

7. The method according to any one of the preceding claims, characterized in that The three-dimensional surface (17) of the cutting tool is determined based on predetermined CAD data of the cutting tool (1, 21).

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

9. The method according to any one of the preceding claims, characterized in that A grid of sub-surfaces (14) is placed on the three-dimensional surface (17, 18) of the cutting tool, the orientation of each sub-surface (14) relative to the geometric rotation axis (6, 26) of the cutting tool is determined, and the cutting edge limiting surface (11a, 12a, 31a, 32a) is thereby determined.

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

11. The method according to claim 9 or 10, characterized in that: The orientations of two adjacent partial surfaces (14) are compared with one another and the cutting edge limiting surface (11a, 12a, 31a, 32a) is determined therefrom.

12. The method according to any one of the preceding claims, characterized in that The coordinates of the measuring point (16) of the cutting edge limiting surface (11a, 12a, 31a, 32a) are detected by contact with a tactile sensor of the measuring head.

13. The method according to any one of claims 1 to 11, characterized in that The coordinates of the measuring point (16) of the cutting edge limiting surface (11a, 12a, 31a, 32a) are detected contactlessly with an optical or electrical sensor of a measuring head.

14. The method according to any of the preceding claims, characterized in that The collision-free movement path is determined by Minkowski addition.

15. A coordinate measuring device for measuring a cutting tool (1, 21), the cutting tool (1, 21) having a cutting tool body (2, 22) and at least one cutting insert (3, 4, 5, 23), the cutting insert (3, 4, 5, 23) being fixed to the cutting tool body (2, 22) and having at least one cutting edge (10, 30), wherein the coordinate measuring device (50) comprises: - a fixing device (51) which receives and fixes the cutting tool (1, 21), a measuring head which is in contact or not in contact with a surface of the cutting tool (1, 21) arranged in the fixture (51), the measuring head being movable relative to the fixture (51), - a moving device (53) for relatively moving the cutting tool (1, 21) received in the fixing device (51) and the measuring head, It is characterized in that The coordinate measuring device (50) comprises a control device (58) which is designed to control the fixing device (51), the measuring head and the movement device (53) so that they carry out the method according to one of the preceding claims on the cutting tool (1, 21).

16. The coordinate measuring device according to claim 14, characterized in that: It is equipped with a surface scanner (59) which detects the surface of the cutting tool (1, 21) at least in those parts of the cutting tool (1, 21) which comprise the cutting insert (3, 4, 5, 23).

17. The coordinate measuring device according to claim 15 or 16, characterized in that: The measuring head comprises at least one tactile sensor which detects 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 or 16, characterized in that: The measuring head comprises at least one sensor which detects the surface of the cutting insert (3, 4, 5, 23) at the measuring point in a contactless manner.

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

20. The coordinate measuring device according to any one of claims 15 to 19, characterized in that The control device is a CNC control device.

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