Method for adjusting orientation of cutting edge of turning tool
By measuring and adjusting the alignment deviation of the finishing edge of the turning tool relative to the workpiece, the balance between machining surface quality and productivity of the turning tool was solved, resulting in better surface finish and production efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SANDVIK COROMANT
- Filing Date
- 2024-09-13
- Publication Date
- 2026-04-10
AI Technical Summary
When using finishing edges, existing turning tools often fail to achieve the desired surface quality (such as surface roughness), and reducing the feed rate to improve surface quality can negatively impact productivity.
By measuring the morphology of the machined surface, the alignment deviation of the finishing edge relative to the workpiece is determined, and the orientation of the cutting edge is adjusted according to the deviation to ensure that the finishing edge is correctly aligned with the workpiece surface. This includes using measuring equipment such as a surface roughness meter or profilometer, combined with an adjustable cutting head and locking device, to adjust the orientation of the cutting edge.
It significantly improves the surface finish of machined surfaces and enhances turning quality while maintaining productivity.
Smart Images
Figure CN121843779A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to metal cutting, particularly turning. Background Technology
[0002] Turning is a common metal cutting operation in which a turning tool is used to cut a rotating workpiece. Such turning tools typically include cutting inserts made of, for example, carbide. The cutting inserts are usually mounted in a tool holder arranged within the turning tool, for example, using screws or some other fastening mechanism. Some cutting inserts have cutting edges that include not only the tip cutting edge but also a so-called "finishing" edge, which can achieve a better surface finish by smoothing out scallops on the machined surface. The finishing edge typically consists of one or more large-radius, usually nearly straight, cutting segments that follow the tip cutting edge and "finish" the surface behind it.
[0003] Even when using a finishing cutting edge, the quality of the machined surface (e.g., regarding surface roughness) may sometimes fall short of expectations. One way to improve surface roughness is to reduce the feed rate. However, this will negatively impact productivity.
[0004] Therefore, there is a need for turning solutions that can better control the quality of the machined surface, improve machining results, and maintain productivity. Summary of the Invention
[0005] The object of the present invention is to mitigate the disadvantages of the prior art and to provide a method for a turning tool having a cutting edge including a finishing edge, which results in an improved surface finish of the machined surface.
[0006] Therefore, the present invention relates to a method for adjusting the orientation of a cutting edge of a turning tool relative to a workpiece, wherein the cutting edge includes a finishing edge, and wherein the method includes the following steps: - Use the turning tool to machine the surface of the workpiece; - Measure the first morphology of the machined surface; - Based on the first morphology of the processed surface, determine the alignment deviation of the finishing blade relative to the surface; - Adjust the orientation of the cutting edge relative to the workpiece based on the alignment deviation.
[0007] As a result, the cutting edge of the turning tool can be correctly oriented relative to the workpiece, thereby achieving improved surface finish.
[0008] When mounted in a tool holder, the cutting insert is in a fixed position. In this fixed position, the exact position and orientation of the cutting edge, particularly the finishing edge, relative to the turning tool body may not be entirely known, but rather depends on various parameters, such as random variations or defects in the geometry of the cutting insert. Furthermore, additional uncertainties associated with the machine tool or workpiece setup can affect the actual orientation of the cutting edge relative to the machined surface. The inventors have found that such variations, and their negative impacts, are generally greater than the effects of general assumptions. In particular, the inventors have found that the orientation of the finishing edge relative to the workpiece surface is crucial for achieving a good surface finish, and that alignment deviations of the finishing edge relative to the workpiece surface can be determined by measuring and studying the morphology of the machined surface.
[0009] The cutting edge may be part of a replaceable and / or indexable cutting insert arranged in the tool holder of a turning tool. However, it is also envisioned that the cutting edge is an integral part of the turning tool.
[0010] Measuring the morphology of a machined surface can involve using measuring equipment, such as a surface roughness meter or a profilometer, for example using non-contact techniques (e.g., optical methods) or styluses that contact the surface.
[0011] As used herein, the morphology of the machined surface should be understood as a measure of the geometry of the machined surface and depends on any measure of the alignment deviation of the finishing blade relative to the machined surface.
[0012] Adjusting the orientation of the cutting edge can be accomplished in many different ways. For example, adjustment may involve adjusting the orientation of the turning tool, but it may also involve adjusting only a portion of the turning tool, including the cutting edge. For example, if the turning tool includes replaceable cutting inserts, adjustment may involve adjusting the orientation of the cutting inserts within the tool holder in which they are mounted. Alternatively, the turning tool may include a cutting head that holds the cutting inserts and is movable relative to the tool body of the turning tool. For example, the cutting head may be slightly rotated or tilted, thereby changing the orientation of the cutting edge relative to the workpiece. Preferably, the cutting head may include a locking device that prevents movement of the cutting head when locked. The turning tool may also include a control device that can be used to change the position of the cutting head when the locking device is unlocked. Preferably, visible graduations are arranged on the cutting head and the tool body to facilitate easy assessment of the position of the cutting head relative to the tool body.
[0013] According to some embodiments, the alignment deviation is defined by an alignment deviation angle corresponding to the angle formed by the finishing blade relative to the surface being processed, and wherein a zero-degree angle corresponds to no alignment deviation.
[0014] As discussed, the finishing edge may not be formed from a perfectly straight edge, but rather from one or more large-radius segments. However, for the purposes of this disclosure, the finishing edge can be considered (i.e., approximately) a straight edge forming a specific angle relative to the surface being machined. If the finishing edge is parallel to the surface being machined, i.e., if the angle is zero, then there is no alignment deviation of the finishing edge relative to the surface.
[0015] According to some embodiments, the morphology can correspond to the profile of the machined surface. The profile of a surface is generally understood as the profile of the surface in a cross-section, preferably a cross-section parallel to the feed direction of the turning tool. The profile can be a raw profile obtained directly by a measuring device (e.g., a profilometer), but it can also be a filtered profile in which variations unrelated to determining the alignment deviation of the finishing edge have been removed. For example, the profile can be a master profile (P-profile) in which the shortest wavelength component is removed from the measured profile by a low-pass filter, or a roughness profile (R-profile) in which a high-pass filter has been applied to the P-profile to remove longer wavelength components, so that the profile includes only surface roughness. For example, the profile of a surface can be determined by a profilometer.
[0016] According to some embodiments, the profile includes a plurality of ridges extending from a nominal machined surface, wherein each ridge includes a rising portion and a subsequent falling portion in the feed direction, wherein the rising portion extends from a valley located at the nominal machined surface between the ridge and a preceding ridge to a ridge peak of the ridge, and the falling portion extends from the ridge peak to a valley located at the nominal machined surface between the ridge and a subsequent ridge, and wherein the alignment deviation of the finishing edge is determined based on the length and inclination of the rising portion and / or the falling portion relative to the nominal machined surface. According to some embodiments, if at least one of the rising portion and the falling portion of each ridge is longer than the adjacent valley, the interior angle between the nominal machined surface and the longest of the rising portion and the falling portion is identified as the alignment deviation angle.
[0017] Therefore, the alignment deviation of the finishing blade can be determined directly from the surface profile, such as the angle of the finishing blade relative to the surface being processed.
[0018] The nominally machined surface should be understood as a surface without any ridges, which corresponds to the desired (expected) machined surface of the workpiece. Therefore, in the profile, the nominally machined surface corresponds to a line that includes all valleys.
[0019] If the valley between the ridges is longer than the rising and falling portions of the ridges (or if there are no ridges at all), this indicates a finishing edge that is well aligned with the surface being machined, i.e., the finishing edge is parallel to the surface being machined. However, if the rising or falling portion of the ridge is longer than the valley, the finishing edge will have a certain degree of alignment deviation, i.e., it will not be parallel to the surface being machined, and this alignment deviation will then correspond to the interior angle formed between the nominal machined surface and the rising or falling portion (the longest of which).
[0020] According to some embodiments, if the descending portion is longer than the ascending portion, the angle of the alignment deviation is identified as negative, and if the ascending portion is longer than the descending portion, the angle of the alignment deviation is identified as positive. Therefore, the direction of the alignment deviation of the finishing blade relative to the workpiece can also be determined.
[0021] According to some embodiments, the morphology can be defined by a parameter of surface roughness, such as the arithmetic mean roughness Ra or the mean roughness depth Rz of the surface profile. As is known in the art, the arithmetic mean roughness Ra is defined as the arithmetic mean of the deviations from the profile height of the average line of the profile, while the mean roughness depth Rz is the average height from the largest ridge to the valley of the profile.
[0022] If the parameters of the surface roughness that a perfectly aligned finishing edge can expect are known, alignment deviations can be easily identified by detecting roughness that differs from the expected roughness, and the orientation of the cutting edge can be adjusted accordingly. The parameters identified by the surface roughness that deviates from the expected value may not indicate in what direction the finishing edge has an alignment deviation relative to the workpiece. Therefore, in embodiments where the surface roughness parameter is used as a measure of morphology, it may be necessary to reorient the cutting edge multiple times in different directions to identify the optimal orientation of the cutting edge (where there is no orientation of the finishing edge relative to the machined surface with respect to alignment deviation). If the surface roughness that a perfectly aligned finishing edge can expect is unknown, the method can still be used and will involve multiple reorientations of the cutting edge in different directions. Therefore, according to some embodiments, the method further includes performing one or more of the following steps after measuring the first morphology of the surface and before determining the alignment deviation: - Change the orientation of the cutting edge relative to the workpiece. - Use turning tools to machine the surface of the workpiece. - Measure the reference morphology of the processed surface. Furthermore, the alignment deviation of the polishing blade is determined based on the difference between the first morphology and one or more control morphologies.
[0023] Therefore, more than one (e.g., at least three) cuts will be required before the correct orientation of the cutting edge is found. However, multiple cuts with different orientations may not necessarily be a problem, as many parts are inherently machined through multiple passes, in which a small amount of material is removed from the workpiece in each pass of the turning tool.
[0024] This trial-and-error method, after multiple reorientations of the cutting edge, can determine the alignment deviation of the finishing edge relative to the surface; that is, the difference between the orientation used to obtain the first profile and the orientation found to yield the best control profile (or at least a control profile as a result of a finishing edge used to produce the first profile). Based on this, the orientation of the cutting edge can be adjusted accordingly before the final pass of the turning tool.
[0025] The above embodiments involving parameters relating to the geometry or roughness of ridges in an analytical profile are based on an evaluation of one or more profiles of a surface, for example, measured by a profilometer or similar measuring device. In other embodiments, other measures of the topography of the processed surface may be used. Attached Figure Description
[0026] The solution will now be described in more detail with reference to exemplary embodiments and the accompanying drawings, in which: Figure 1 A turning tool that can be used in accordance with the method according to the invention is shown.
[0027] Figure 2 This is an enlarged view of the cutting insert mounted in the tool holder of a turning tool.
[0028] Figure 3 This is a top view of a turning tool.
[0029] Figure 4 The machined surface of the workpiece and the orientation of the turning tool corresponding to the absence of alignment deviation of the finishing edge are shown.
[0030] Figure 5 The orientation of the machined surface of the workpiece and the turning tool corresponding to a negative alignment deviation of the finishing edge is shown.
[0031] Figure 6 The orientation of the machined surface of the workpiece and the turning tool corresponding to a positive alignment deviation of the finishing edge is shown.
[0032] Figure 7 This is a flowchart illustrating the method according to the present invention.
[0033] All accompanying drawings are schematic and not necessarily drawn to scale, and generally only show components necessary to illustrate the corresponding embodiments, while other components may be omitted or merely implied. Unless otherwise stated, the same reference numerals denote the same components in different figures. Detailed Implementation
[0034] Figures 1 to 3 A turning tool including a tool body 10 and a cutting insert 1 having a cutting edge 3 is shown. The cutting insert 1 is located on a cutting head 2, which is arranged in an adjustable manner relative to the tool body 10. The cutting insert 1 is mounted in an insert holder on the cutting head 2 by fastening screws 5.
[0035] The cutting edge 3 includes a tip cutting edge 31 and a finishing edge 32, such as... Figure 2 As shown.
[0036] In the illustrated embodiment, the position of the cutting head 2 relative to the tool body 10 can be adjusted by first loosening the two locking screws 6 and then controlling the adjusting screw 7, which is arranged to contact the stop surface 8 formed inside the recess within the cutting head 2. Therefore, the end portion of the adjusting screw 7 constitutes a stop that restricts the position of the cutting head 2. Thus, when the adjusting screw 7 is positioned as desired and the cutting head has been rotated such that the stop surface 8 engages the front end of the adjusting screw 7, the locking screws 6 secure the cutting head 2, making it immovable relative to the tool body 10.
[0037] As a result of this adjustment, the orientation of the cutting edge 3 relative to the tool body is changed, particularly the orientation of the finishing edge 32 relative to the tool body. In this way, when a turning tool is mounted on a machine tool and arranged for machining a workpiece, the orientation of the cutting edge, and especially the orientation of the finishing edge, can be adjusted relative to the surface of the workpiece to be machined.
[0038] The position of the cutting head 2 relative to the tool body 10 is visibly indicated by a scale 9 applied to both the tool body 10 and the cutting head 2. In the illustrated embodiment, the scale 9 is a vernier scale. For clarity, the scale 10 is... Figure 3 Omitted and only in Figure 1 As shown in the image.
[0039] The resulting surface morphology caused by the different orientations of the finishing blade 32 Figures 4 to 6The diagram shows the orientation of the cutting insert 1 relative to the machined surface 20 of the workpiece and the corresponding resulting morphology of the machined surface 20, shown in this case as a roughness profile 30 of the machined surface 20. The roughness profile 30 includes grooves separated by ridges 21 caused by the tool feed during workpiece rotation. Random variations and noise have been removed by filtering the signal obtained from the measurement of the profile.
[0040] Each profile 30 includes multiple repeating ridges 21, each repeating ridge 21 including a rising portion 22, a falling portion 23, and a ridge peak 24 in the feed direction of the turning tool. Between the ridges, there are valleys 25 located at the nominal machined surface 26.
[0041] In the illustrated embodiment, the alignment deviation angle θ formed by the finishing blade relative to the surface being processed is... w Used as a measure of the alignment deviation of the finishing blade relative to the workpiece. Alignment deviation angle θ w Equal to zero, such as Figure 4 As shown, the finishing blade extends parallel to the surface being processed, corresponding to no alignment deviation. For example, in... Figure 4 As seen in the resulting profile 30 of the surface shown, the machined surface is quite smooth, with valleys 25 being much wider than ridges 21. The width of ridges 21 will depend on the feed rate related to the length of the finishing edge. In practice, finishing edges typically have a slight curvature (i.e., a large radius of curvature), making it impossible to obtain a surface that perfectly corresponds to the nominal machined surface 26. However, for the purposes of this invention, and as shown, the finishing edge can be approximated by a straight line. Moreover, by using a finishing edge with a larger radius of curvature (i.e., closer to a straight line) than conventionally used, it can be advantageous to use a solution according to this disclosure in which the orientation of the cutting edge is adjusted. Therefore, if the finishing edge 32 in the illustrated embodiment is considered to be perfectly straight, then in Figure 4 The resulting ridge 21 shown is a result of using an excessively short finishing edge and / or an excessively high feed rate during machining. However, it may not always be desirable to completely eliminate the ridge 21, as this may require an unreasonably low feed rate and / or an extension of the finishing edge, which would result in excessive cutting forces.
[0042] When the alignment deviation angle θ w When the value is non-zero, a less smooth surface morphology will be produced, in which the ridges 21 are asymmetrical, higher, and wider. Therefore, by analyzing the morphology of the machined surface, and especially... Figures 4 to 6 The contour 30 shown can be used to estimate the alignment deviation angle θ. w This refers to the alignment deviation of the finishing blade relative to the surface being processed.
[0043] exist Figure 5In the middle, the alignment deviation angle θ w The angle is -5°, resulting in a roughness profile where the valley 25 is shorter and the ridge 21 is asymmetrical, with the ridge 21 having a shorter rising portion 22 but a longer falling portion 23. The interior angle θ formed between the falling portion 23 and the nominal machined surface 26... d The corresponding negative alignment deviation angle θ between the finishing blade and the machined surface 20 of the workpiece. w In other words, after determining that the descending portion 23 is longer than the ascending portion 22, the alignment deviation angle θ can be derived. w = -θ d The conclusion.
[0044] exist Figure 6 In the middle, the alignment deviation angle θ w The angle is 5°, resulting in a roughness profile where the valley 25 is shorter and the ridge 21 is asymmetrical, with the ridge 21 having a longer rising portion 22 but a shorter falling portion 23. The interior angle θ formed between the rising portion 22 and the nominal machined surface 26... a The positive alignment deviation angle θ between the finishing blade and the machined surface 20 of the workpiece. w In other words, after determining that the rising portion 22 is longer than the rising portion 23, the alignment deviation angle θ can be derived. w = θ a The conclusion.
[0045] Therefore, the magnitude and direction of the alignment deviation can be determined from the roughness profile. Thus, the orientation of the cutting edge can be correctly adjusted based solely on the profile 30 corresponding to the first morphology for subsequent machining of the workpiece.
[0046] Alternatively, there may be different methods that do not require detailed profile analysis but are based on roughness parameters. Therefore, such alternative methods may require less complex profile analysis. On the other hand, additional machining operations with different cutting edge orientations may be necessary.
[0047] For example, the mean roughness depth Rz can be considered for analysis. For illustrative purposes, the mean roughness depth Rz is... Figures 4 to 6 The depth is shown as a single depth. However, this parameter is calculated as the average of multiple ridges along the contour.
[0048] By first measuring the mean roughness depth Rz of the profile (corresponding to the first morphology), then adjusting the orientation of the cutting edge and machining the workpiece, and measuring the mean roughness depth Rz again (corresponding to the control morphology), the alignment deviation of the finishing edge can be determined and the orientation of the cutting edge adjusted accordingly, although this process may need to be repeated many times.
[0049] In the following text, reference will be made to Figure 7 Describe the method according to the present invention. Figure 7 This is a flowchart indicating the steps of the method. Optional steps are shown by dashed lines.
[0050] In the first step 701, a turning tool is used to machine the surface of the workpiece. The machining can, for example, correspond to a single pass of a longitudinal external turning operation, i.e., in which the turning tool moves in a direction parallel to the axis of rotation of the workpiece, while the cutting edge of the turning tool engages the outer side of the rotating workpiece.
[0051] In the second step 702, a first morphology of the machined surface is measured. For example, this can be achieved by using a profilometer to detect one or more profiles of the machined surface in a direction parallel to the axis of rotation of the workpiece. In this case, the first morphology under consideration can be a measured profile or a filtered profile, or a roughness parameter of such profile, such as Ra or Rz.
[0052] If the roughness parameter is measured and considered as the first morphology, and in particular if the roughness that can be obtained using a perfectly aligned finishing edge is unknown, the method will include, in the third step 703, adjusting the orientation of the cutting edge relative to the workpiece, and in the fourth step 704, using a turning tool to machine the surface of the workpiece, and in the fifth step 705, measuring the reference morphology of the new machined surface, i.e., the roughness parameter.
[0053] In step 703, the direction and amount of adjustment to the cutting edge orientation can be determined by the machine operator based on his or her knowledge and experience. A predefined guideline of what adjustment to apply can also be used. Step 703 of adjusting the orientation, step 704 of machining the workpiece, and step 705 of measuring the reference morphology can be repeated multiple times as needed. Preferably, the direction and amount of adjustment for this further adjustment of the cutting edge orientation are based on the previously measured reference morphology and its relationship to the first morphology. For example, if the reference morphology indicates that the finishing edge is better aligned than the first morphology, further adjustment of the cutting edge orientation in the same direction can be applied.
[0054] In step 706, the alignment deviation of the cutting edge is determined (i.e., the alignment deviation of the initially oriented cutting edge, resulting in a first morphology). Referring to an example where the roughness parameter is considered as a morphology, the alignment deviation may correspond to the difference between the cutting edge orientation that provides the first morphology and the cutting edge orientation that is found to provide the best-matching morphology (e.g., the minimum roughness parameter).
[0055] In step 707, the orientation of the cutting edge relative to the workpiece is adjusted based on the determined alignment deviation. Therefore, referring again to the roughness parameter as an example of the topography, if the orientation used last is also the orientation that yields the minimum roughness parameter, then there is no need to adjust the orientation of the cutting edge.
[0056] While the above description includes several specific features, these should not be construed as limiting the scope of the concepts described herein, but rather as providing illustrations of some exemplary embodiments of the described concepts. It should be understood that the scope of the concepts currently described fully encompasses other embodiments that will be obvious to those skilled in the art, and therefore the scope of the concepts currently described is not limited.
Claims
1. A method for adjusting the orientation of the cutting edge (3) of a turning tool relative to the workpiece (20), wherein, The cutting edge (3) includes a finishing edge (32), and the method includes the following steps: - Use the turning tool to machine (701) the surface of the workpiece (20); - Measure the first morphology of the surface processed by (702); - Determine (706) the alignment deviation of the finishing blade (32) relative to the surface based on the first morphology of the processed surface; and - Adjust (707) the orientation of the cutting edge (3) relative to the workpiece (20) based on the alignment deviation.
2. The method according to claim 1, wherein, The alignment deviation is determined by the alignment deviation angle (θ). w The alignment deviation angle (θ) is defined as follows: w The angle corresponds to the angle formed between the finishing blade and the processed surface, and the zero-degree angle corresponds to no alignment deviation.
3. The method according to any one of the preceding claims, wherein, The first morphology corresponds to the contour (30) of the surface.
4. The method according to claim 3, wherein, The profile includes a plurality of ridges (21) extending from a nominal machining surface (26), wherein each ridge (21) includes a rising portion (22) and a subsequent falling portion (23) in the feed direction (F), wherein the rising portion (22) extends from a valley (25) located at the nominal machining surface (26) between the ridge (21) and the preceding ridge to the ridge peak (24) of the ridge (21), and the falling portion (23) extends from the ridge peak (24) of the ridge (21) to a valley located at the nominal machining surface (26) between the ridge (21) and the following ridge, and wherein the alignment deviation of the finishing blade (32) is determined based on the length and inclination of the rising portion (22) and / or the falling portion (23) relative to the nominal machining surface (26).
5. The method according to claims 2 and 4, wherein, If at least one of the rising and falling portions of each ridge is longer than the adjacent valley, then the interior angle (θ) between the nominal machined surface and the longest of the rising and falling portions... a θ d The alignment deviation angle (θ) is identified as the alignment deviation angle. w ).
6. The method according to claim 5, wherein, If the descending portion is longer than the ascending portion, the alignment deviation angle (θw) is negative, and if the ascending portion is longer than the descending portion, the alignment deviation angle is positive.
7. The method according to any one of claims 1 or 2, wherein, The first morphology is defined by a parameter of the surface roughness.
8. The method according to claim 7, wherein, The parameter of the surface roughness is the arithmetic mean roughness Ra or the mean roughness depth Rz of the surface profile.
9. The method according to any one of the preceding claims, wherein, The method further includes performing one or more of the following steps after measuring the first topography of the surface and before determining the alignment deviation: - Change the orientation of the cutting edge (703) relative to the workpiece; - Use the turning tool to machine (704) the surface of the workpiece; as well as - Measure the comparative morphology of the machined surface described in (705); Furthermore, the alignment deviation of the polishing blade is determined based on the difference between the first morphology and one or more control morphologies.