How to operate a machine tool

Abstract

The invention relates to a method for operating a machine tool (1) configured to machine a work blank (7) using a tool (2), comprising the steps of determining geometric data of the work blank (7), determining geometric data of a tool (2) for use in machining the work blank (7), dividing a tool path for machining the work blank (7) into a plurality of path units, simulating material removal on the work blank (7) by the tool (2) for each path unit, and calculating an engagement rate of the work blank (7) with the tool (2) for each path unit to determine an engagement parameter, wherein an advance and / or a rotational speed of the tool (2) relative to the work blank (7) is adjusted depending on the calculated engagement parameter.

Description

[Technical Field]

[0001] The present invention relates to a method for operating a machine tool, particularly a machine tool for milling or grinding, and a machine tool configured to perform the method. [Background technology]

[0002] Various embodiments of machine tools and their operating methods have been known for a long time. NC (numerical control) machine tools and CNC (computer numerical control) machine tools are well known, and they process commands sequentially based on a control program to perform various machining operations on a workpiece. While this type of machining operation has been demonstrated in practice, there are also use cases where high-precision machining or extremely high surface quality is required. Furthermore, if the programming of the control program is not ideal, the tool or the machine's mandrel may be overloaded. [Overview of the project] [Problems that the invention aims to solve]

[0003] Therefore, the object of the present invention is to provide a machine tool operating method and machine tool that enable a significant improvement in the machining accuracy and / or surface quality of a workpiece with a simple design and easy operation, and that prevent overloading of the mandrel and tools. [Means for solving the problem]

[0004] This objective is achieved by a method having the features of claim 1 and a machine tool having the features of claim 14. Dependent claims relate to advantageous developments of the present invention.

[0005] The method of the present invention having the features of claim 1 has the advantages of enabling high-precision machining of work blanks using tools and / or achieving a better surface compared to the prior art, and avoiding overloading of the mandrel and / or tool. In this case, a particularly great advantage is obtained when it is necessary to manufacture workpieces multiple times in succession. In this case, the method of the present invention takes into account the shape data of the work blank and the shape data of the tool used for machining. In this case, the method of the present invention includes the steps of determining the shape data of the work blank and determining the shape data of the tool used for machining the work blank. Preferably, the shape data of the work blank is provided by detecting the dimensions of the work blank using a measurement technique prior to machining. Alternatively, the shape data of the work blank can also be obtained from the memory of a CAD system and / or machine tool controller. In this case, detecting the dimensions of the work blank by a measurement technique enables the most precise machining. Furthermore, it is preferable that the shape data of the tool used for machining is also obtained from memory. Alternatively, the detection of the shape data of the tool to be used is performed by a measurement technique.

[0006] The method of the present invention further includes the step of dividing the tool path for machining a work blank into a plurality of path units. In this case, the size of each path unit can be freely selected. Preferably, the path units are selected to be short enough to correspond only to the path that the tool travels during a maximum of five rotations, one or more times relative to the workwork, at a predetermined path speed (predetermined forward distance) of the path in which the tool and the work blank move relative to each other and a predetermined rotational speed of the tool.

[0007] Furthermore, according to the present invention, the removal of material from the work blank by the tool is simulated for each path unit. Subsequently, based on the simulation, the engagement ratio between the work blank and the tool is calculated for each path unit, and the relative movement between the tool and the work blank, in particular the amount of advancement of the tool relative to the work blank and / or rotational speed, is adjusted according to the obtained engagement parameters.

[0008] As a result, the method of the present invention makes it possible to manufacture workpieces that precisely meet predetermined dimensions and requirements by significantly improving the machining accuracy and / or surface quality of the workpiece blank and by avoiding overloading of the machine tool components.

[0009] The method of the present invention is particularly preferably implemented directly within the controller of a machine tool.

[0010] According to a preferred embodiment of the present invention, the length of the path unit corresponds to the path the tool travels during 1 to 5 rotations, given a predetermined path speed and rotational speed. By selecting such relatively small path units, it becomes possible to perform a very good simulation of material removal by the tool, in particular, taking into account a pre-calculated engagement ratio between the workpiece blank and the tool.

[0011] This engagement ratio is preferably determined based on the amount of material removed by the tool from the work blank as the tool and work blank move relative to each other along a path unit.

[0012] The engagement ratio is more preferably determined based on the penetration depth of the tool into the workpiece blank. The penetration depth corresponds to the difference between the lowest and highest contact points of the tool in the workpiece blank material in the direction of the tool's axis of rotation.

[0013] According to a more preferred embodiment of the present invention, the engagement ratio is determined based on lapping. This lapping identifies the angular region in which the cutting edge of the tool engages with the material of the workpiece blank during the rotation of the tool. For example, in the case of a so-called full cut, where the tool forms a groove in the workpiece blank, the lapping is up to 180°.

[0014] The engagement ratio is more preferably determined based on the size of the surface that contacts the material of the workpiece blank. In this case, the surface is defined by the boundary volume of the tool created by the rotation of the tool.

[0015] According to a more preferred embodiment of the present invention, the engagement ratio is determined based on the angle of the path between the tool and the workpiece blank with respect to the rotation axis of the tool. If this angle is less than 90°, the tool is embedded into the workpiece blank. In this case, the tool is embedded into the workpiece in the axial direction. If the angle is greater than 90°, the workpiece blank is pulled out.

[0016] Therefore, for each path unit, the machine tool controller can calculate one or more engagement parameters for the engagement rate.

[0017] It is preferable that the calculation of the engagement parameter for each individual path unit is performed first, before the tool is moved along the calculated path units relative to the workpiece blank. The controller can adjust the forward movement and / or rotational speed before machining along the calculated path units by determining the engagement parameter for each individual path unit a little earlier. This allows the controller to change the forward movement and / or rotational speed parameters essential for machining, even immediately before machining along the path units. As a result, machining accuracy can be improved, for example, by reducing the forward movement and / or rotational speed along path units with greater material removal. In particular, if the engagement parameter along the path unit is too large, undesirable vibrations leading to inaccuracies and poor surface finishes can be prevented. This also prevents tool overload. Therefore, in the case of machining workpiece blanks, machining adjustments can be made and particularly optimized.

[0018] For example, if the amount of material removed along a single path unit is large, the tool's forward movement and / or rotational speed can be reduced to lessen the load on the tool and mandrel of the machine tool.

[0019] For example, if the amount of material removed along a single path unit is particularly small, a larger tool advance and / or rotational speed can be selected to reduce machining time.

[0020] It is particularly preferable that one or more characteristic curves for engagement parameters are stored in the machine tool controller for each tool used to machine the workpiece blank. In this case, the characteristic curves show how the amount of tool advance relative to the workpiece and / or rotational speed are adjusted for individual calculated engagement parameters, such as the amount of material and / or penetration depth and / or lapping and / or engaged boundary volume and / or path angle between the tool and the workpiece blank. The characteristic curves determine the amount of advance and / or rotational speed in accordance with the engagement rate that occurs during machining along the path unit and is recalculated for each path unit.

[0021] In the method according to the present invention, it is even more preferable to detect vibration and / or machining force during machining, calculated from the motor current of at least one electrically driven unit, specifically at least one forward shaft or mandrel shaft. This is done, for example, by a sensor on the mandrel, or indirectly by a path measuring sensor in the shaft of the machine tool. If the measured vibration and / or calculated machining force are low, the amount of forward movement and / or rotational speed can be increased without compromising the machining results or overloading the mandrel or tool. In the case of machining, if the measured vibration and / or calculated machining force of the machining process, mandrel, or tool is high, it is necessary to reduce the amount of forward movement and / or rotational speed. If it is not possible to change the amount of forward movement and / or rotational speed for a path unit where the measured vibration and / or calculated machining force values ​​are high or low, since machining has already been performed, it is preferable instead to adjust the characteristic curve of the tool currently in use with the controller for that one or more engagement parameters. When the measured vibration and / or calculated machining force is large, the characteristic curves of tool advance and / or rotational speed within the range of the calculated engagement parameter will decrease as the controller reduces the advance and / or rotational speed for subsequent path units of the tool path where the calculated engagement parameter is the same magnitude, so that machining can be performed according to the modified characteristic curve. When the measured vibration and / or calculated machining force is low, the characteristic curve will rise accordingly in the range of the calculated engagement parameter. Thus, a self-optimizing, self-learning system is realized. In addition to dividing the measured vibration and / or calculated machining force into high and low values ​​so that the characteristic curve does not change continuously during machining, it is also possible to define a central region, especially a deviation of ±5%, which may be appropriate, for example. When the measured vibration and / or calculated machining force falls within this region, the characteristic curve does not change. During machining, the calculated engagement parameter usually changes within a specific range of values, so one or more characteristic curves of advance and / or rotational speed are automatically optimized for this range.After a short machining time, only appropriate values for the measured vibrations and / or the calculated machining forces should be obtained for the various engagement parameters calculated.

[0022] During machining, if the vibrations and / or machining forces calculated from the motor current of the electric drive of the feed shaft or mandrel shaft are detected, in particular by sensors, and a predetermined limit value is not met, when machining is carried out along a path unit, if the engagement parameters are recalculated with the same magnitude, it is further preferable that the characteristic curve of the tool used rises in the region of the engagement parameters calculated for the feed and / or rotational speed in order to increase the machining speed with a constant machining quality in the future. If the detected value of the vibrations and / or machining forces exceeds a predetermined limit value, the characteristic curve of the tool used falls in the region of the engagement parameters calculated for the feed and / or rotational speed in order to reduce the machining speed in the future when the engagement parameters are recalculated with the same magnitude when machining is carried out along a path unit.

[0023] It is further preferable that the characteristic curve depends on the material properties. When one tool is used for different materials or for one material with different hardnesses, separate characteristic curves are stored for each tool and each material property, for example for each material or each hardness. Separate characteristic curves are defined for each material property of the workpiece blank in relation to the tool, and it is preferable that the characteristic curve is adjusted to the engagement parameters calculated for future machining.

[0024] It is further preferred that a region for determining whether the measured vibration and / or the calculated machining force is high, low, or appropriate is defined individually for each tool. Of course, large tools for pre-machining can be used with a considerably higher load with respect to the measured vibration and / or the calculated machining force compared to the delicate tools for final machining. Therefore, in addition to the characteristic curve of each individual tool for setting the feed rate and / or the rotational speed, it is also convenient to store in the controller the limit values for distinguishing the measured vibration and / or the calculated machining force as high, appropriate, or low for each tool and optionally for each workpiece material.

[0025] It is even more preferred that the characteristic curve optimized during machining is stored in the controller so that it can be used later to machined further workpieces using the same tool.

[0026] According to a further preferred embodiment of the invention, the possibility of tool wear is determined. If the measured vibration and / or the calculated machining force is neither high nor low and is appropriate during machining along a path unit, it can be assumed that machining is already being carried out at the optimum values of the feed rate and / or the rotational speed. As described above, the characteristic curve is not changed any more in this region for the calculated engagement parameters and can be further specified to be optimized in that region. At a later point during machining, the calculated engagement parameters enter the region of the characteristic curve specified as optimized, but the measured vibration and / or the calculated machining force is no longer appropriate, but rather deviates, for example, being high or low. From this, it can be concluded that the overall machining is not proceeding optimally, specifically, that the values of the measured vibration and / or the calculated machining force have deteriorated due to tool wear.

[0027] In response to this, the controller may exhibit different reactions depending on the machining task. According to a preferred embodiment, machining of a workpiece using a tool can be interrupted and, in some cases, continued using a new tool or an intact sister tool. Alternatively, if the measured vibration and / or calculated machining force is only slightly exceeded, for example, by ±2% within a suitable range, machining can continue using the temporarily reduced second characteristic curve of that tool until the difference with machining using an unworn tool becomes too large, and only then is machining interrupted.

[0028] Such wear monitoring works particularly well when the characteristic curve has already been properly optimized through prior machining work. In this case, wear monitoring can not only detect tool wear but also other abnormalities in the machining process, such as when the tool is very unbalanced, causing excessive vibration and compromising the machining results.

[0029] Therefore, by combining the calculation of engagement parameters with the determination of measured vibrations and / or calculated machining forces, it becomes possible to monitor the machining process very effectively.

[0030] Tool and mandrel overloads and collisions can be prevented by calculating engagement parameters in advance along the tool path. When calculating engagement parameters, if it is determined that the cutting edge actually needs to perform material removal using, for example, a part n of the tool not located on the tool shaft, a collision can be identified as a potential occurrence, and the controller can stop the machine before the collision occurs. Similarly, if the engagement parameters are determined to be too high and unacceptable for the tool or mandrel, tool and mandrel overloads can be prevented, for example, by calculating engagement parameters in advance. The controller can also stop the machine before the tool or mandrel becomes overloaded.

[0031] Conversely, if the characteristic curve has already been optimized within the calculated engagement parameter range, but the newly measured vibration value is significantly lower than the appropriate value, a machining error can be detected. In this case, for example, engagement may not occur due to tool interruption.

[0032] Of course, the characteristic curves for forward movement and / or rotational speed may depend on one or more calculated engagement parameters and may differ for each individual tool.

[0033] The present invention further relates to a machine tool configured to carry out the method of the present invention. The machine tool preferably includes a controller and memory, and preferably the method of the present invention is carried out, an engagement parameter of the engagement rate is calculated, characteristic curves of the forward movement and / or rotational speed are stored according to the calculated engagement parameter and vary according to the measured vibration and / or calculated machining force.

[0034] In the method of the present invention, it is particularly preferable to keep the ratio of rotational speed to forward movement constant. That is, the forward movement and rotational speed always change proportionally so that the quotient obtained by dividing the rotational speed by the forward movement remains constant. Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. [Brief explanation of the drawing]

[0035] [Figure 1] This is a schematic diagram of a method according to the present invention for operating a machine tool according to a preferred embodiment of the present invention. [Figure 2] This is a schematic perspective view of a machine tool for carrying out the method according to the present invention. [Figure 3] This graph shows characteristic curves for rotational speed and / or forward movement for each path unit, corresponding to the calculated engagement parameters. [Figure 4] This graph shows characteristic curves for rotational speed and / or forward movement for each path unit, corresponding to the calculated engagement parameters. [Figure 5]This graph shows characteristic curves for rotational speed and / or forward movement for each path unit, corresponding to the calculated engagement parameters. [Modes for carrying out the invention]

[0036] The following diagram shows the operation procedure for machine tool 1, referring to Figures 1 to 5.

[0037] Figure 2 is a schematic perspective view of a machine tool 1 for carrying out the method of the present invention. The machine tool 1 comprises a mandrel 3 having a fixed tool 2 for machining a work blank 7. A sensor 6 is positioned on the mandrel 3 to detect vibrations. The machine tool 1 further comprises a controller 10 having memory.

[0038] In this method (see Figure 1), the shape data of the work blank 7 is determined in the first step S1. This shape data can be determined in advance by detecting the dimensions of the work blank 7, obtained from a construction system (CAD), or stored in memory beforehand and retrieved from there.

[0039] In step S2, the shape data of the tool 2 used to machine the work blank 7 is determined. This shape data can preferably be obtained from memory or determined by measuring the tool 2.

[0040] Steps S1 and S2 can be executed simultaneously, or step S2 can be executed before step S1.

[0041] In the third step S3, the tool path for machining the work blank 7 is divided into several smaller path units. In this case, it is preferable that the path units are short so as to correspond only to the path that the tool 2 travels during the time it rotates around the work blank 7 for one or a few rotations, up to a maximum of five times, at a predetermined path speed and rotational speed of the tool 2 relative to the work blank 7.

[0042] Step S3 can be executed simultaneously with steps S1 and S2, or it can be specified in advance to the controller.

[0043] In step S4, the removal of material from the work blank 7 by the tool 2 is simulated for each path unit. For each path unit whose length has been determined in this way, the controller calculates, in step S5, the engagement ratio between the tool 2 and the work blank 7, based on the simulation, which is the ratio of material removed over the length of the path unit by the relative movement of the tool 2 and the work blank 7.

[0044] Next, in step S6, the relative movement speed between tool 2 and work blank 7, and / or the rotational speed of tool 2 are adjusted according to the engagement parameters calculated for machining the work blank 7.

[0045] Thus, according to the present invention, high-precision machining is possible based on the simulation results of the engagement ratio between the work blank 7 and the tool 2. In this case, the engagement ratio can be determined based on various parameters. For example, the amount of material removed by the tool 2, and / or the penetration depth of the tool 2 into the work blank 7, and / or the lapping that engages the cutting edge of the tool 2 with the work blank 7 during rotation, and / or the surface size of the boundary volume of the tool 2 created by the rotation of the tool, and / or the angle of the path between the tool 2 and the work blank 7 with respect to the rotation axis of the tool 2. The degree It can be done.

[0046] In this case, the more parameters of the engagement ratio that are calculated, the more precisely the work blank 7 can be machined.

[0047] It is particularly preferable that, in order to actually perform machining, the engagement parameter for the engagement rate of each individual path unit is calculated first in time before the controller moves the shaft of the machine tool 1 along the path unit. Then, the machining of each path unit can be optimized by adjusting it based on the calculation results of the engagement parameter.

[0048] Figures 3 to 5 show characteristic curves of rotational speed and / or forward movement (path speed) corresponding to the calculated engagement parameters. In this embodiment, the calculated amount of material removed per path is shown as the calculated engagement parameter. For simplicity, in this embodiment, the characteristic curve is evaluated using only the calculated amount of material as a single calculated engagement parameter. In practice, it is preferable to determine the characteristic curve from multiple calculated engagement parameters. In this case, it is also possible to weight the calculated engagement parameters. Figure 3 shows the forward movement V or rotational speed D against the amount of material M, recorded for each path. From the characteristic curve K1 of the illustrated engagement parameter, it can be seen that as the amount of material M increases, the forward movement V and / or rotational speed D decrease. In this case, it is preferable that the ratio of forward movement V to rotational speed D remains constant. Maximum forward movement V max and / or maximum rotational speed D max This exists when the amount of material M is close to zero. Furthermore, as can be seen from Figure 3, according to the characteristic curve K1, as the amount of material M per path unit increases, the forward distance V and / or rotational speed D decrease. G This indicates the limit of the amount of material that can reach the maximum allowable load of the tool and / or mandrel used for machining. Since characteristic curve K1 intersects the horizontal axis of material amount M, a material amount M greater than this is not permitted.

[0049] Nevertheless, the amount of material M for one path unit is the allowable limit amount of material M G If the calculation is greater than this, machining will not be performed on this path unit by the machine tool. The machine tool controller stops the tool before it is determined in the calculation of engagement parameters performed in advance that an unacceptable load will be placed on the tool and / or mandrel.

[0050] In Figure 3, the characteristic curve K1' is shown as a dashed line, and in this curve, the amount of material Mb calculated for each path unit is within the acceptable range of the stored characteristic curve K1, i.e., M Gis smaller. And for each path unit, machining is performed at a feed rate and / or a rotational speed predetermined by the characteristic curve K1'. In this case, it is evaluated whether the measured vibration and / or the calculated machining force is too large, suitable, or too small for the tool to be used. FIG. 3 shows the case where the measured vibration or the calculated machining force is large. For this reason, in the region M indicated by the broken line K1' in FIG. 3 b the characteristic curve drops by a few percent. When the characteristic curve drops, it is preferable to ensure that the gradient of the characteristic curve always remains negative. That is, as shown in FIG. 3, the characteristic curve K1' steadily drops as the material volume M increases.

[0051] FIG. 4 shows the opposite case to FIG. 3, where machining is performed on the material volume Mb calculated for each path unit, and the measured vibration and / or the calculated machining force is small. For this reason, the characteristic curve K2 rises by a few percent in the region M indicated by the broken line K2' in FIG. 4. Also in this case, the gradient of the adjusted characteristic curve K2' with respect to the material volume M is negative overall. b

[0052] Furthermore, FIG. 5 shows that the change in the characteristic curve K3' due to the measured vibration and / or the calculated machining force can also affect the maximum allowable material volume M for each path unit. The material volume M calculated for each path unit G is relatively close to the maximum allowable material volume M b . The subsequent machining of the workpiece is performed at a feed rate resulting from the characteristic curve and / or the resulting rotational speed, and the measured vibration and / or the calculated machining force increases. Therefore, the characteristic curve K3 drops in the region M G . This is shown by the broken-line characteristic curve K3' in FIG. 5. As a result, since the characteristic curve K3' already coincides with the horizontal axis at a smaller material volume M per path unit, a new maximum allowable material volume M b occurs and cannot be exceeded. Thereby, a new maximum allowable material volume M GN GN ​​This represents a new upper limit on the allowable amount of material M per route unit. Processing operations that require the calculation of large amounts of material per route unit will be interrupted. [Explanation of symbols]

[0053] 1 Machine tools 2 tools 3 Mandrels 6 sensors 7 Work Blank 10 Controllers D Rotation speed V: Forward movement (path velocity) K characteristic curve K' Adjusted Characteristic Curve Material quantity per M path unit M G Maximum material quantity M GN Maximum permissible limit material quantity

Claims

1. A method of operating a machine tool (1) configured to process a work blank (7) using a tool (2), The process of determining the shape data of the work blank (7), A step of determining the shape data of the tool (2) used to process the work blank (7), A step of dividing the tool path for machining the work blank (7) into multiple path units, A step of simulating material removal from the work blank (7) using the tool (2) for each of the aforementioned path units, A step of calculating engagement parameters for determining the engagement ratio between the work blank (7) and the tool (2) for each of the aforementioned path units, Equipped with, The amount of advancement and / or rotational speed of the tool (2) relative to the work blank (7) is adjusted according to the calculated engagement parameters. For each tool (2), one or more characteristic curves of engagement parameters for each path unit are stored in the controller (10), and it is specified how the forward amount and / or rotational speed are adjusted for each engagement parameter related to the stored characteristic curve. During machining, vibrations of the mandrel shaft and tool (2) are detected, and / or the machining force is calculated from the motor current of the electric drive unit of the forward shaft or mandrel shaft. If the detected vibration and / or calculated machining force falls below a predetermined limit value in the controller (10), the characteristic curve of the tool (2) used increases in the region of the engagement parameter calculated for the amount of forward movement and / or rotational speed, and in machining along the path unit, if the engagement parameter is recalculated at the same magnitude, the machining speed will be increased in the future while maintaining a constant machining quality. If the detected vibration and / or calculated machining force exceeds a predetermined limit value in the controller (10), the characteristic curve of the tool (2) used will decrease in the region of the engagement parameter calculated for the amount of forward movement and / or rotational speed, and if the engagement parameter is recalculated at the same magnitude in machining along the path unit, it will reduce the machining speed in the future. method.

2. The method according to claim 1, wherein the length of the path unit corresponds to the path along which the tool (2) moves at a predetermined path speed and a predetermined rotational speed during 1 to 5 rotations.

3. The method according to claim 1, wherein the engagement ratio is determined based on the amount of material removed from the work blank (7) by the tool (2) during the relative movement of the tool (2) and the work blank (7) along a path unit.

4. The method according to claim 1, wherein the engagement ratio is determined based on the penetration depth of the tool (2) into the work blank (7), which corresponds to the difference between the lowest and highest contact points of the tool (2) with the material of the work blank (7) in the direction of the rotation axis of the tool (2).

5. The method according to claim 1, wherein the engagement ratio is determined based on lapping that identifies an angular region in which the cutting edge of the tool (2) engages with the material of the work blank (7) during rotation of the tool (2).

6. The method according to claim 1, wherein the engagement ratio is determined based on the size of the surface on which the boundary volume of the tool (2) generated by the rotation of the tool (2) engages with the material of the work blank (7).

7. The method according to claim 1, wherein the engagement ratio is determined based on the angle of the path between the tool (2) and the work blank (7) with respect to the rotation axis of the tool (2).

8. The method according to claim 1, wherein the calculation of the engagement parameter of the engagement rate for each individual path unit is performed first in time before the tool (2) is moved with respect to the work blank (7) along the path unit for which the engagement parameter has been calculated.

9. If the detected vibration and / or calculated machining force falls below a predetermined limit value set by the controller (10), the forward distance and / or rotational speed are increased in order to increase the machining speed while maintaining a certain machining quality. If the detected vibration and / or calculated machining force exceeds a predetermined limit value set by the controller (10), the forward movement and / or rotational speed are reduced in order to reduce the machining speed. The method according to claim 1.

10. The method according to claim 1, wherein a separate characteristic curve is defined for each material property of the work blank (7) to be machined using the tool (2), and the characteristic curve is adjusted based on engagement parameters for future machining.

11. The method according to claim 1, wherein predetermined limit values ​​for vibration and / or calculated machining forces are defined separately for each tool.

12. The method according to claim 1, wherein the characteristic curve is designated as optimized when the vibration detected and / or the calculated machining force in the controller (10) is within the normal range.

13. The method according to claim 12, wherein tool wear monitoring is performed by monitoring vibrations detected in the controller (10) against a limit value during machining using calculated engagement parameters and optimized characteristic curves for set forward movement and / or rotational speed.

14. The method according to claim 13, wherein if the vibration detected by the controller (10) and / or the deviation of the calculated machining force deviates from a limit value during machining at a forward amount and / or rotational speed value set according to the calculated engagement parameter and optimized characteristic curve, machining is interrupted.

15. The method according to claim 14, wherein if the vibration and / or deviation of the calculated machining force detected by the controller (10) deviates from a limit value during machining at a forward amount and / or rotational speed value set according to the calculated engagement parameter and optimized characteristic curve, it is replaced with a new sister tool.

16. The method according to claim 1, wherein the controller (10) determines that tool wear occurs when the vibration detected and / or the deviation of the calculated machining force exceeds a predetermined upper limit value or falls below a predetermined lower limit value.

17. A machine tool (1) configured to perform the method described in any one of claims 1 to 16.

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