JP2011161519A - Method and device for controlling machine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide method and device for controlling a machine tool, which controls heat displacement in machining to attain high accuracy of machining. <P>SOLUTION: This method for controlling the machine tool includes a temperature acquiring process 52 for acquiring temperatures at a plurality of inspection positions, a temperature distribution preparing process 53 for preparing a temperature distribution of a supporting body 10 based on the temperatures at the plurality of inspection positions, a decision process 54 for deciding that heat displacement occurs in the supporting body 10, an operation route preparing process 55 for preparing a plurality of operation routes, and an operation route changing process 56 for changing the order of the unprocessed operation routes based on the temperature distribution. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a control method and a control apparatus for a machine tool having a support that supports a moving body.

  A machine tool processes a workpiece by controlling the position of each drive shaft by a control device. In machining by this machine tool, the support body that supports the moving body may be thermally deformed due to the thermal effect of the machine tool. Since the thermal deformation of the support affects the position of the moving body, the processing accuracy may be reduced. Thus, for example, Patent Document 1 discloses a method for correcting thermal displacement based on a temperature distribution function calculated by measuring temperatures at a plurality of locations on a support.

JP 2006-281420 A

  However, such a thermal displacement correction method corrects the tip position of the tool and cannot correct the posture of the tool. For example, when the temperature of the support becomes very high, the inclination of the tool accompanying thermal deformation of the support may increase. In such a case, even if the tip position of the tool is corrected, the contact position of the tool with respect to the workpiece is displaced, and the quality may be deteriorated. Therefore, when the amount of thermal displacement due to the thermal deformation of the support body exceeds a predetermined value, it is necessary to notify the operator of an alarm or temporarily stop processing.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a machine tool control method and a control device that can control thermal displacement in machining and achieve high machining accuracy.

(Control method for machine tools)
In order to solve the above problems, the structural features of the invention relating to the method for controlling a machine tool according to claim 1 are:
In a method for controlling a machine tool, which has a support and a movable body supported by the support so as to be movable, and performs processing based on control data,
A temperature acquisition step of acquiring a plurality of inspection position temperatures set on the support;
A temperature distribution creating step for creating a temperature distribution of the support based on temperatures at a plurality of the inspection positions;
When the temperature difference in the temperature distribution exceeds a preset threshold value, a determination step for determining that thermal displacement has occurred in the support,
An operation path creating step of dividing a machining operation in the control data and creating a plurality of operation paths;
A path changing step of changing the order of the unprocessed operation paths based on the temperature distribution when it is determined in the determining step that thermal displacement has occurred in the support;
It is to provide.

  According to a second aspect of the present invention, in the first aspect, the path changing step changes the order of the operation paths based on a connection distance when the unprocessed operation paths are connected. That is.

  According to a third aspect of the present invention, in the configuration of the first or second aspect, the path changing step may change the order of the operation paths based on a temperature state of the unprocessed operation paths in the temperature distribution. Is to change.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the determination step may be configured such that the difference between the highest temperature and the lowest temperature in the partitioned region that divides the temperature distribution is the temperature. It is determined as a difference.

  A structural feature of the invention according to claim 5 is the structural feature according to any one of claims 1 to 4, wherein it is determined in the determination step that thermal displacement has occurred in the support. It is further provided with the operation variable change process which changes the operation variable of processing contained in the changed said operation course.

  The constitutional feature of the invention according to claim 6 is the order in the case where it is determined in any one of claims 1 to 5 that thermal displacement has occurred in the support in the determination step. It is further provided with the process temporary stop process which stops processing based on the changed above-mentioned operation course only for a definite period of time.

  A structural feature of the invention according to claim 7 is that, in any one of claims 1 to 6, the operation path creating step is based on a non-machining command code included in the control data. Is to divide the machining operation and create a plurality of the operation paths.

  A structural feature of the invention according to claim 8 is that, in any one of claims 1 to 7, the temperature distribution creating step creates a temperature distribution in a moving direction of the moving body with respect to the support. It is.

(Control device for machine tools)
In order to solve the above problems, the structural features of the invention relating to the machine tool control device according to claim 9 are:
In a control device of a machine tool that has a support and a movable body that is movably supported by the support, and performs processing based on control data,
Temperature acquisition means for acquiring the temperatures of a plurality of inspection positions set on the support;
Temperature distribution creating means for creating a temperature distribution of the support based on temperatures at a plurality of the inspection positions;
When the temperature difference in the temperature distribution exceeds a preset threshold value, determination means for determining that thermal displacement has occurred in the support,
An operation path creating means for dividing a machining operation in the control data and creating a plurality of operation paths;
A path changing means for changing the order of the unprocessed operation paths based on the temperature distribution when it is determined in the determining means that thermal displacement has occurred in the support;
It is to provide.

  According to the first aspect of the present invention, the path changing step is configured to change the order of the unprocessed operation paths based on the temperature distribution. This operation path is obtained by dividing the machining operation in the control data. That is, the control data is divided in advance into a plurality of operation paths by the operation path creation process. With such a configuration, for example, when it is determined that thermal displacement has occurred in the support of the machine tool, for example, an operation for machining an operation region that is less affected by thermal displacement in an unprocessed operation path. Change the order to prioritize the route. Thereby, since the thermal displacement of the support body is small in the operation path that has been processed earlier, the processing can be performed with high accuracy. Furthermore, even if the part of the support generates heat due to this operation path, the influence on the part where the thermal displacement is generated can be suppressed. Therefore, it is possible to promote heat dissipation from the portion of the support where thermal displacement occurs.

  Further, by applying the control method of the present invention to the thermal displacement correction of the machine tool, it is possible to make the thermal displacement of the support generated in machining by the machine tool uniform. Thereby, the temperature deviation in the temperature distribution is reduced, and the local temperature rise of the support can be suppressed. Therefore, the amount of thermal displacement accompanying the thermal deformation of the support can be reduced. Therefore, it is possible to easily correct the thermal displacement of the support as compared with the conventional case, and to reduce the amount of change in the posture of the tool. With such a configuration, the amount of change in the posture of the tool has increased so far, and even machining operations that have required machining pause must be paused by changing the order of the divided motion paths. It becomes possible to process without. As a result, the processing cycle time can be shortened.

  According to the invention which concerns on Claim 2, a path | route change process is set as the structure which changes the order of an operation path | route based on the connection distance at the time of connecting an unprocessed movement path | route. In the route changing step, the order of a plurality of operation routes created by dividing the machining operation in the control data by the operation route creating step is changed. At this time, for example, the next operation path is changed to an operation path that is separated from a region where the temperature is rising in the temperature distribution. In this case, the order is changed so as to process with priority given to an operation path having a small connection distance connecting the operation paths from the current processing position. Thereby, the time to move between the respective operation paths can be shortened.

  According to the invention of claim 3, the path changing step is configured to change the order of the operation paths based on the temperature state of the unprocessed operation path in the temperature distribution. In the route changing step, the order of a plurality of operation routes created by dividing the machining operation in the control data into a plurality of pieces by the operation route creating step is changed. At this time, for example, the next operation path is changed to an operation path that is not included in the region where the temperature is rising in the temperature distribution. In this case, the temperature state of each operation path is acquired from the temperature distribution, and the order is changed so as to give priority to the operation path whose temperature in the processing region is low. As a result, it is possible to prevent priority from being placed on an unprocessed operation path that is scheduled to be processed in a region where the temperature has already risen. Therefore, it is possible to make the thermal displacement of the support generated during machining by the machine tool uniform.

  According to the invention which concerns on Claim 4, the determination process is set as the structure which determines the difference of the highest temperature and the lowest temperature in the division area which divided the temperature distribution as a temperature difference. The position and size of this partition region are appropriately set according to various configurations of the machine tool. And a determination process determines with the thermal displacement having arisen in the support body, when the temperature difference in the division area with temperature distribution exceeds the threshold value. Thereby, the temperature deviation of the temperature distribution can be detected. And when there exists a local temperature rise in a support body, it can determine reliably that the thermal displacement has arisen.

  According to the invention which concerns on Claim 5, an operation variable change process WHEREIN: When it determines with the thermal displacement having arisen in the support body in the determination process, the operation variable of the process included in the operation path by which the order was changed is set. The configuration is changed. Thereby, for example, it is possible to change the operation variables such as the machining speed and the feed speed included in the operation path, and set the machining conditions to reduce the load on the machine tool. Therefore, the heat generation in the support can be more reliably suppressed. Therefore, the path change step and the operation variable change step can make the thermal displacement of the support uniform and can easily correct the thermal displacement.

  According to the invention of claim 6, in the processing temporary stop step, when it is determined in the determination step that thermal displacement has occurred in the support, the processing based on the operation path whose order has been changed is performed for a certain period of time. It is configured to stop only. Thereby, for example, when there is a local temperature rise of the support, heat dissipation of the part of the support where thermal displacement occurs can be promoted. Therefore, even if the posture of the tool fluctuates due to thermal deformation of the support, it can be determined that thermal displacement has occurred based on the temperature distribution, and it is possible to prevent the machining accuracy from being lowered.

  According to the seventh aspect of the invention, the operation path creation step is configured to divide the machining operation in the control data and create a plurality of operation paths based on the non-machining command code included in the control data. The control data includes a machining command code for instructing movement to each drive axis so that the tool is brought into contact with the workpiece, and non-machining for instructing movement to each drive axis so that the tool is not in contact with the workpiece. Command code is included. Therefore, the operation path creating step may recognize the non-machining command code and divide the control data into a plurality of motion paths, for example, on the front side or the rear side of the specific non-machining command code. Thereby, the machining operation in the control data can be divided easily at an appropriate position.

  According to the eighth aspect of the invention, the temperature distribution creating step creates a temperature distribution in the moving direction of the moving body relative to the support. The support is deformed by a thermal effect such as machining of the machine tool or change in environmental temperature. In particular, the heat generated by the movement of the supporting moving body greatly affects the deformation of the supporting body. Therefore, when the temperature distribution creating step creates at least the temperature distribution in the moving direction of the moving body, the path changing step can change the operation path as the temperature distribution on the sliding surface of the support. In other words, the present invention can be applied to thermal deformation of the sliding surface of the support, and more appropriate correction of the thermal displacement of the support can be performed.

  According to the ninth aspect of the present invention, the path changing means changes the order of the unprocessed operation paths based on the temperature distribution. With such a configuration, for example, when it is determined that thermal displacement has occurred in the support of the machine tool, for example, an operation for machining an operation region that is less affected by thermal displacement in an unprocessed operation path. Change the order to prioritize the route. Thereby, since the thermal displacement of the support body is small in the operation path that has been processed earlier, the processing can be performed with high accuracy. Furthermore, even if the part of the support generates heat due to this operation path, the influence on the part where the thermal displacement is generated can be suppressed. Therefore, it is possible to promote heat dissipation from the portion of the support where thermal displacement occurs.

  Further, by applying the control device of the present invention to the correction of the thermal displacement of the machine tool, it is possible to make the thermal displacement of the support generated in machining by the machine tool uniform. Accordingly, it is possible to easily correct the thermal displacement of the support body as compared with the conventional case, and it is possible to reduce the amount of change in the posture of the tool. That is, by suppressing the local temperature rise of the support, the amount of thermal displacement associated with the thermal deformation of the support can be reduced as a whole. Therefore, even if the operation path has been required to be temporarily stopped, it is possible to perform processing without pausing by changing the operation path, and the cycle time can be shortened.

  Further, the other characteristic portions of the machine tool control method of the present invention can be similarly applied to the machine tool control device of the present invention. And the effect in this case also has the same effect as the effect as the control method of the machine tool.

1 is an overall view of a machine tool 1. 3 is a block diagram showing a control device 50. FIG. 4 is a flowchart for explaining thermal displacement control by a control device 50. It is a figure which shows the relationship between an operation path | route and temperature distribution. (A) is a figure which shows the positional relationship of the operation path | route in the movable range of the saddle 20, (b) is a figure which shows the high temperature area | region and normal temperature area | region in temperature distribution.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of a machine tool control method and a control device according to the invention will be described with reference to the drawings. As a machine tool, a three-axis machining center will be described as an example. That is, the machine tool is a machine tool having three rectilinear axes (X, Y, Z axes) orthogonal to each other as drive axes.

<Embodiment>
A thermal displacement correction device for a machine tool 1 according to a first embodiment will be described with reference to FIGS. FIG. 1 is an overall view of the machine tool 1. FIG. 2 is a block diagram showing the control device 50.

(Configuration of machine tool 1)
As shown in FIG. 1, the machine tool 1 includes a bed 2, a column 10 (corresponding to a “supporting body” of the present invention), a saddle 20 (corresponding to a “moving body” of the present invention), a spindle base body. 30, a table 40, and a control device 50. The bed 2 has rails in the Z-axis direction (direction parallel to the floor surface) formed on the upper surface, and is installed on the floor surface. The workpiece W is a workpiece to be processed by the machine tool 1.

  The column 10 is a support that is fixed so as to stand on the upper surface of the bed 2 and supports the saddle 20. Since the column 10 is deformed due to thermal effects such as machining of the machine tool 1 and changes in environmental temperature, the saddle 20 may be thermally displaced due to thermal deformation of the column 10. Therefore, the control device 50 performs thermal displacement control such as changing the operation path so as to suppress thermal deformation of the column 10 and thermal displacement of the saddle 20. Details will be described later.

  The column 10 has a plurality of temperature sensors 11 and rails 12. A plurality of temperature sensors 11 are arranged inside the column 10 in order for the control device 50 to perform thermal displacement control. The plurality of temperature sensors 11 are arranged at inspection positions set in a total of 15 places, that is, three places in the X-axis direction of the column 10 and five places in the Y-axis direction. Each temperature sensor 11 detects the temperature at each inspection position in the column 10 and outputs a signal corresponding to the temperature to the control device 50.

  The rail 12 is formed on the side surface of the column 10 so as to extend in the Y-axis direction (direction perpendicular to the floor surface). The saddle 20 is a moving body that is provided on the rail 12 of the column 10 and is movable with respect to the column 10 in the Y-axis direction. The saddle 20 slides in the Y-axis direction by a rotational drive of a Y-axis motor (not shown) fixed to the column 10. In this embodiment, the side surface of the column 10 on which the rail 12 in the Y-axis direction is formed is a sliding surface 10a of the column 10 on which the saddle 20 slides. The saddle 20 has a rail 21 formed on its side surface so as to extend in the X-axis direction (a direction parallel to the floor surface).

  The main spindle base 30 has a main spindle head 31, a rotary main spindle 32, and a tool 33, and is provided on the rail 21 of the saddle 20. The main spindle base 30 is a feed base that can move in the X-axis direction with respect to the saddle 20. The spindle head 31 is formed with a guide groove in the X-axis direction and is slidably fitted to the rail 21 of the saddle 20. The spindle head 31 moves the entire spindle base 30 in the X-axis direction by rotational driving of an X-axis motor (not shown) fixed to the saddle 20.

  The rotation spindle 32 is rotatably provided by a spindle motor housed in the housing of the spindle head 31 and supports a tool 33. The tool 33 is fixed to the tip of the rotary main shaft 32 of the main shaft base 30. That is, the tool 33 rotates with the rotation of the rotation spindle 32. The tool 33 is, for example, a ball end mill, an end mill, a drill, a tap, or the like. That is, the machine tool 1 that is the three-axis machining center can move the tool 33 in the X-axis direction and the Y-axis direction with respect to the bed 2. The machine tool 1 can move the workpiece W in the Z-axis direction.

  The table 40 is a feed base that is provided on a rail in the Z-axis direction of the bed 2 and is movable in the Z-axis direction with respect to the bed 2. The table 40 is moved in the Z-axis direction by a rotational drive of a Z-axis motor (not shown) fixed to the bed 2. The table 40 is provided with a jig 41 for fixing the workpiece W at a predetermined position.

  Thereby, the workpiece W moves in the Z-axis direction with respect to the bed 2 as the table 40 moves in the Z-axis direction. In such a machine tool 1, the saddle 20, the spindle base 30, and the table 40 are controlled to move to the command position based on the command position by the control device 50. Thereby, the tool 33 is moved relative to the workpiece W for processing.

  The control device 50 controls each shaft motor, main shaft motor, and the like based on the control data. Thereby, the process by the machine tool 1 is performed. The control data is machining data such as NC data input to the machine tool 1, and includes machining operation variables, machining command codes, non-machining command codes, and the like. Machining operation variables include machining conditions such as machining speed, feed speed, and spindle rotation speed. Such control data includes the command position of the saddle 20 and the spindle base 30, and these constitute the machining operation of the saddle 20 as a moving body.

  Further, the control device 50 is a control device that controls thermal displacement in each part of the column 10 due to the thermal effect of the machine tool 1. Therefore, the control device 50 controls the thermal displacement by changing the order of a plurality of operation paths created by dividing the machining operation in the control data in advance according to the temperature distribution of the column 10. In other words, processing is performed with priority given to an operation path that processes an operation region that is less affected by thermal displacement among unprocessed operation paths, thereby suppressing thermal displacement and increasing the accuracy of the processing. Hereinafter, the structure of the characteristic part of this invention among the control apparatuses 50 of the machine tool 1 is demonstrated.

  As illustrated in FIG. 2, the control device 50 includes a control unit 51, a temperature acquisition unit 52, a temperature distribution creation unit 53, a determination unit 54, an operation path creation unit 55, an operation path change unit 56, an operation This is a numerical control device having a variable change unit 57 and a machining temporary stop unit 58. Here, the control unit 51, the temperature acquisition unit 52, the temperature distribution generation unit 53, the determination unit 54, the operation path generation unit 55, the operation path change unit 56, the operation variable change unit 57, and the machining temporary stop unit 58 are individually provided. It can be configured by hardware, or can be realized by software.

  The control unit 51 controls each axis motor, main shaft motor, and the like based on the input control data. Thus, the control device 50 controls the saddle 20, the main spindle base 30, and the table 40 to move, and performs processing by relatively moving the tool 33 that is rotationally driven with respect to the workpiece W.

  The temperature acquisition unit 52 is a temperature acquisition unit that acquires temperatures at a plurality of inspection positions set in the column 10. That is, the temperature measured by the temperature sensor 11 arranged at each inspection position is acquired. The temperature distribution creation unit 53 is a temperature distribution creation unit that creates the temperature distribution of the column 10 based on the temperatures at the plurality of inspection positions acquired by the temperature acquisition unit 52. In the present embodiment, this temperature distribution corresponds to the temperature of the sliding surface 10 a of the column 10. This is because, as shown in FIG. 1, the saddle 20, which is a moving body, has rails 21 and supports the spindle base 30. That is, in the thermal displacement control of the present embodiment, the temperature distribution corresponding to the sliding surface 10a (XY plane) of the column 10 is created in consideration of the heat generated by the main spindle base 30 sliding with respect to the saddle 20. ing.

  The determination unit 54 is a determination unit that determines that thermal displacement has occurred in the column 10 when the temperature difference in the temperature distribution exceeds a preset threshold value. The determination unit 54 sets a difference between the highest temperature and the lowest temperature in the partitioned area where the temperature distribution is divided as a temperature difference in the temperature distribution. The position and size of the partition area are appropriately set according to various configurations of the machine tool 1 and the operation area of the column 20 in the control data. In the present embodiment, the partition region is a region in which the sliding surface 10a of the column 10 is partitioned into 24 equal parts. That is, when the temperature difference in the partition region exceeds the threshold value, there is a temperature deviation in the temperature distribution. On the other hand, even when the overall temperature is higher than room temperature, a relatively uniform temperature distribution is obtained when the temperature difference in the partitioned region is equal to or less than the threshold value.

  The operation path creation unit 55 is an operation path creation unit that creates a plurality of operation paths by dividing the machining operation in the control data. The operation path is a part of control data divided as a machining operation pattern according to a predetermined condition for a machining operation in which the tool 33 moves relative to the workpiece W according to a machining command code of the control data. The predetermined condition for creating a plurality of operation paths may be divided on the basis of the presence or absence of a specific command code included in the control data.

  Therefore, the operation path creation unit 55 of the present embodiment is configured to create a plurality of operation paths based on the non-machining command code included in the control data. The control data includes a machining command code for instructing each drive shaft to move to bring the tool 33 into contact with the workpiece W, and a movement to each drive shaft so that the tool 33 is not in contact with the workpiece W. The non-machining command code to command is included. Therefore, the operation path creation unit 55 divides the machining operation in the control data by recognizing a positioning G code (G00) that is a non-machining command code and is used for fast-forwarding.

  The operation path changing unit 56 is a path changing unit that changes the order of the unprocessed operation paths based on the temperature distribution when the determination unit 54 determines that a thermal displacement has occurred in the column 10. For example, it is assumed that a thermal displacement of the column 10 occurs when the machine tool 1 is machining based on control data divided into a plurality of operation paths. At this time, the operation path changing unit 56 changes the order so that the operation path suitable for the next processing among the unprocessed operation paths is prioritized. As an operation path suitable for the next processing, for example, an operation path that is separated from the current processing position and that processes an operation region where the influence of the generated thermal displacement of the column 10 is small is given priority.

  Furthermore, the operation path changing unit 56 is configured to change the order of the operation paths based on the connection distance when unprocessed operation paths are connected. In other words, when there are multiple motion paths that are separated from the current machining position, the movement distance of each drive shaft while controlling the thermal displacement so that the time required when machining an unmachined motion path is shortened Is to minimize. Details of the change of the order of the operation paths by the operation path changing unit 56 will be described later.

  The operation variable changing unit 57 is an operation variable changing unit that changes the operation variable of the machining included in the operation path whose order has been changed when the determination unit 54 determines that a thermal displacement has occurred in the column 10. is there. For example, it is assumed that a thermal displacement of the column 10 occurs when the machine tool 1 is machining based on a predetermined operation path. At this time, the operation variable changing unit 57 changes the operation variable of the processing step by step so as to suppress the heat generation in the processing of the operation path. As the change of the operation variable, for example, an override of the machining speed or a change of the rotation speed of the spindle can be considered. In addition, when the determination unit 54 determines that the thermal displacement amount of the thermal displacement of the column 10 has decreased, the operation variable change unit 57 returns the changed operation variable to the original setting value included in the control data. Change as follows.

  The machining pause unit 58 is a machining pause unit that stops machining based on the operation path whose order has been changed for a certain period of time when the determination unit 54 determines that thermal displacement has occurred in the column 10. It is. For example, it is assumed that a thermal displacement of the column 10 occurs when the machine tool 1 is machining based on a predetermined operation path. At this time, the machining temporary stop unit 58 stops the machining for a certain period of time so as to promote the heat radiation of the portion of the column 10 where the thermal displacement occurs. This fixed time is appropriately set in consideration of the state of heat dissipation by various configurations of the machine tool 1, and is set between ten and a few seconds in this embodiment.

(Thermal displacement control)
Hereinafter, thermal displacement control of the machine tool 1 by the control device 50 will be described with reference to FIGS. FIG. 3 is a flowchart for explaining thermal displacement control by the control device 50. FIG. 4 is a diagram illustrating the relationship between the operation path and the temperature distribution. 4A is a diagram showing the positional relationship of the operation path in the operation region of the saddle 20, and FIG. 4B is a diagram showing a high temperature region and a normal temperature region in the temperature distribution. Further, the thermal displacement control in the present embodiment will be described with the thermal displacement of the saddle 20 accompanying the thermal deformation of the column 10 due to thermal influence as the control target.

  First, in the operation path creation step, the control data input to the control device 50 of the machine tool 1 is divided into a plurality of operation paths (S11). Therefore, the operation path creation unit 55 searches for a non-machining command code included in the control data as a candidate for a division position of the control data. Then, based on the non-machining command code in the control data, the machining operation in the control data is appropriately divided to create a plurality of operation paths that are a part of the control data. At this time, the order of the plurality of operation paths remains in the state included in the control data and has not been changed.

  Further, at this time, the motion path creation unit 55 determines, for each motion path, which range in the sliding surface 10a of the column 10 the processing motion area by the motion path is, as shown in FIG. It is related. Thereby, each operation area is positioned with respect to the movable range of the saddle 20. In the control device 50, after a plurality of motion paths are created in the motion path creation step, the control unit 51 controls each axis motor and the spindle motor based on the first motion path and starts machining the workpiece W.

  Next, in the temperature acquisition step and the temperature distribution creation step, as shown in FIG. 4B, the temperature at the plurality of inspection positions set in the column 10 is obtained and the temperature distribution of the column 10 is created (S12). The temperature acquisition unit 52 acquires temperatures measured by the plurality of temperature sensors 11 during processing. The temperature distribution creation unit 53 creates a temperature distribution by appropriately interpolating the temperatures between the inspection positions based on the temperatures at the inspection positions. This temperature distribution corresponds to the temperature of the sliding surface 10a of the column 10, that is, the movable range of the saddle 20.

  Subsequently, in the determination step, the temperature difference in the temperature distribution is compared with a preset threshold value Th to determine the presence or absence of thermal displacement in the column 10 (S13). Therefore, the determination unit 54 compares the temperature difference in each partition region with the threshold Th, using the difference between the maximum temperature and the minimum temperature in the partition region where the temperature distribution is partitioned as a temperature difference. As a result, if the temperature difference in any of the divided areas is also equal to or smaller than the threshold Th (S13: Yes), it is determined that the thermal displacement control is unnecessary, and the next step is completed when the machining by the machining path currently being machined is completed. It shifts to machining end determination (S14).

  On the other hand, when the temperature difference in the plurality of partitioned regions exceeds the threshold Th (S13: No), it is determined that thermal displacement has occurred in the column 10, and the path is changed to perform thermal displacement control (S21). Migrate to Further, the threshold value Th in the determination step is set to a value for determining that the thermal displacement to the extent that the thermal displacement control by the control device 50 is required is occurring in the column 10.

  In the processing end determination in S14, it is determined whether the processing based on the input control data has been completed based on the presence or absence of an unprocessed motion path. When the processing is finished for all the operation paths (S14: Yes), the processing and the thermal displacement control are finished. On the other hand, when an unprocessed operation path remains (S14: No), processing by the next operation path is started, and the process returns to the temperature distribution creation of S12.

  Here, it is assumed that the processing based on the plurality of operation paths as described above is performed and the column 10 is thermally displaced. Then, in the determination step of S13, the temperature difference in the temperature distribution exceeds the threshold Th, and it is determined that thermal displacement has occurred in the column 10 (S13: No), and the path is changed to perform thermal displacement control. The process proceeds to (S21). Further, for example, if the number of unprocessed operation paths remaining at this time is 6, the order is the operation paths Pt1 to Pt6 in the order of the processing operations in the original control data. Each operation path Pt1 to Pt6 is associated with the sliding surface 10a of the column 10 by the operation path creation unit 55, and has a positional relationship as shown in FIG.

  In the processing by the machine tool 1, when thermal displacement occurs in the column 10, the order of the unprocessed operation paths is changed based on the temperature distribution in the path changing step (S21). That is, since the operation path changing unit 56 generates thermal displacement in the operation area of the operation path that is currently being processed, the operation path changing unit 56 sets the order so that the operation path that processes the operation area that is less affected by the heat displacement is given priority. change. In this manner, the control device 50 performs heat displacement control so as to promote heat dissipation in the operation region where the thermal displacement has occurred and to increase the accuracy of the operation path to be processed next. Further, the operation path changing unit 56 changes the order of the operation paths based on the connection distance when the unprocessed operation paths are connected.

  Here, the change in the order of the operation paths in S21 will be described with reference to FIGS. 4 (a) and 4 (b). Further, in FIG. 4B, in the high temperature region Ht, a higher temperature inspection position is indicated by an ellipse with a dense oblique line, and other inspection positions are indicated by an ellipse with a loose oblique line. The inspection position in the normal temperature region Nt is indicated by an ellipse without hatching.

  The operation path changing unit 56 divides the acquired temperature distribution into a high temperature region Ht that is a region that is equal to or higher than a predetermined temperature and a normal temperature region Nt that is a region where the other temperatures are not rising. Thus, the unprocessed operation paths Pt1 to Pt3 belong to the high temperature range Ht, and the operation paths Pt4 to Pt6 belong to the normal temperature range Nt. Therefore, the operation path changing unit 56 changes the order so that the operation paths Pt4 to Pt6 have priority. The operation path changing unit 56 detects the operation path closest to the high temperature region Ht from the operation paths Pt4 to Pt6. Here, as shown in FIG. 4B, since the operation path Pt4 is closest to the high temperature region Ht, the operation path changing unit 56 processes the operation path Pt4 last among the operation paths Pt4 to Pt6. Set the order to

  Next, the operation path changing unit 56 detects the operation path closest to the operation path Pt4 set to be processed last among the operation paths belonging to the normal temperature range Nt. Here, as shown in FIG. 4B, since the operation path Pt6 is closest to the operation path Pt4, the operation path changing unit 56 uses the operation path Pt6 as the operation path Pt4 among the operation paths Pt5 and Pt6. Set the order to process immediately before. Similarly, the operation path changing unit 56 detects an operation path closest to the operation path Pt6 in which the order is set as described above, among the operation paths belonging to the normal temperature range Nt. Here, the remaining operation path Pt5 is detected, and the operation path changing unit 56 sets the order so as to process the operation path Pt5 immediately before the operation path Pt6. As a result, the operation path belonging to the normal temperature region Nt is changed to be in the order of the operation path Pt5, the operation path Pt6, and the operation path Pt4.

  Subsequently, the operation path changing unit 56 changes the order of the operation paths Pt1 to Pt3 belonging to the high temperature region Ht as in the normal temperature region Nt. In this case, the operation path changing unit 56 detects the operation path that is closest to the central portion C of the high temperature region Ht or the highest temperature region from the operation paths Pt1 to Pt3. This central portion C corresponds to the center of the circumscribed circle of the inspection position included in the high temperature region Ht. Here, as shown in FIG. 4B, since the operation path Pt2 is closest to the center C of the high temperature region Ht, the operation path changing unit 56 operates the operation path Pt2 among the operation paths Pt1 to Pt3. Set the order so that is processed last. Similarly, the operation path changing unit 56 sets the order for the remaining operation paths Pt1 and Pt3. As a result, the operation path belonging to the high temperature region Ht is changed to be in the order of the operation path Pt1, the operation path Pt3, and the operation path Pt2.

  As described above, in S21, the operation path changing unit 56 changes the order by giving priority to the operation path belonging to the normal temperature range Nt over the operation path belonging to the high temperature range Ht. Furthermore, the operation path changing unit 56 sets the order of changing so that the connection distance when the unprocessed operation paths are connected is minimized.

  The path changing step for changing the order of the operation paths in S21 is executed before finishing the processing based on the current operation path. Then, when the machining by the operation path is completed, the machining by the operation path Pt5 that is prioritized in the path change of S21 is started. When processing by the operation path Pt5 is started, in the temperature acquisition step and the temperature distribution creation step, the temperatures at a plurality of inspection positions are obtained and the temperature distribution of the column 10 is created (S22), as in S12.

  Then, in the determination step, the temperature difference in the temperature distribution is compared with a preset threshold value Th, and the presence or absence of thermal displacement in the column 10 is determined in the operation region of the operation path Pt5 that is currently being processed (S23). Therefore, the determination unit 54 compares the temperature difference in the partitioned area to which the operation path Pt5 belongs out of the partitioned areas partitioned from the temperature distribution with the threshold Th. Here, since the operation path Pt5 is an operation path that belongs to the normal temperature region Nt, the temperature difference is determined to be equal to or less than the threshold Th (S23: Yes). Then, when the machining by the operation path Pt5 is completed, the process proceeds to the machining end determination (S14) as the next step.

  In the processing end determination in S14, since the unprocessed operation paths Pt1 to Pt4 and Pt6 remain, the processing by the next operation path Pt6 is started, and the process proceeds to S12 for temperature distribution creation. In the temperature acquisition process and the temperature distribution creation process of S12, the temperatures at a plurality of inspection positions are acquired and the temperature distribution is updated and created. Next, in the determination step of S13, it is determined whether thermal displacement has occurred in the column 10 based on the updated temperature distribution.

  Here, when thermal displacement has occurred in the column 10 due to the processing up to the operation path Pt6 (S13: No), the process proceeds to the path change in S21, and the order of the operation paths is further changed based on the updated temperature distribution. . Here, it is determined that thermal displacement has occurred in the high temperature region Ht due to the processing up to the previous operation path (S13: No). However, if the thermal displacement is not newly generated in the column 10 due to the processing along the operation path Pt6, the order of the operation paths is changed as described above. That is, as a result, the raw motion path is in the same order as the order changed earlier.

Then, when the machining by the operation path Pt6 is completed, the machining by the operation path Pt4 that is prioritized in the path change of S21 is started.
When processing by the operation path Pt4 is started, in the temperature acquisition step and the temperature distribution creation step, the temperatures at a plurality of inspection positions are obtained and the temperature distribution of the column 10 is created (S22). Here, similarly to the operation path Pt5, in the determination step of S23, the temperature difference in the partitioned region to which the operation path Pt4 belongs is determined to be equal to or less than the threshold Th (S23: Yes). Then, when the machining by the operation path Pt4 is completed, the process proceeds to a machining end determination (S14) as the next step.

  In the processing end determination of S14, since unprocessed operation paths Pt1 to Pt3 remain, the processing by the next operation path Pt1 is started, and the process proceeds to S12 for temperature distribution creation. In the temperature acquisition process and the temperature distribution creation process of S12, the temperatures at a plurality of inspection positions are acquired and the temperature distribution is updated and created. Next, in the determination step of S13, it is determined whether thermal displacement has occurred in the column 10 based on the updated temperature distribution.

  Here, the high temperature region Ht may be sufficiently dissipated during the processing by the operation paths Pt4 to Pt6 belonging to the normal temperature region Nt. In this case, the temperature is lowered and no thermal displacement of the column 10 occurs (S13: Yes), and the machining by the operation path Pt1 is completed, and the process shifts to the machining end determination (S14) again. Here, it is determined that the temperature difference in any partition region in the temperature distribution exceeds the threshold Th, that is, it is determined that the thermal displacement of the column 10 has occurred (S13: No), and the path change (S21) is performed. Transition.

  In S21, the order of the unprocessed operation paths Pt2 and Pt3 is changed in the same manner as described above. Here, it is assumed that the operation path Pt3 and the operation path Pt2 are set in the same order as before. Then, when the processing by the operation path Pt1 is completed, the processing by the operation path Pt3 that is prioritized in the path change of S21 is started. When processing by the operation path Pt3 is started, in the temperature acquisition step and the temperature distribution creation step, the temperatures at a plurality of inspection positions are obtained and the temperature distribution of the column 10 is created (S22).

  Then, in the determination step, the temperature difference in the temperature distribution is compared with a preset threshold Th, and the presence / absence of thermal displacement in the column 10 is determined in the operation region of the operation path Pt3 currently being processed (S23). Therefore, the determination unit 54 compares the temperature difference in the partitioned area to which the operation path Pt3 belongs out of the partitioned areas where the temperature distribution is partitioned with the threshold Th. Here, it is determined that the operation path Pt3 is an operation path in which the operation region Pt3 belongs to the high temperature region Ht, and that the temperature difference exceeds the threshold Th due to heat generated by the processing along the operation path Pt1. Therefore, it is determined that thermal displacement has occurred in the column 10 (S23: No), and the process proceeds to the next step, variable operation variable (S31).

  Next, in the operation variable changing step, the operation variable for machining included in the operation path Pt3 whose order has been changed is changed (S31). Therefore, the operation variable changing unit 57 acquires the temperature in the processing range of the operation path Pt3 based on the temperature distribution updated and created in S22. Then, the operation variable changing unit 57 reduces the machining speed by applying an override corresponding to the acquired temperature to the machining speed that is the operation variable of the operation path Pt3. In this way, the control device 50 suppresses heat generation in the processing of the operation path Pt1, and prevents the amount of thermal displacement of the column 10 from increasing.

  Subsequently, when the machining by the operation path Pt3 in which the machining operation variable is changed is finished, the process proceeds to the machining finish determination (S32) which is the next step. In the machining end determination in S32, it is determined whether the machining based on the input control data is completed based on the presence / absence of an unprocessed operation path as in S14. When the processing is finished for all the operation paths (S32: Yes), the processing and the thermal displacement control are finished. Here, since the unprocessed operation path Pt2 remains (S32: No), processing by the next operation path Pt2 is started.

  Then, in the temperature acquisition step and the temperature distribution creation step, as in S12 and S22, the temperatures at a plurality of inspection positions are acquired and the temperature distribution of the column 10 is created (S33). Then, in the determination step, the temperature difference in the temperature distribution is compared with a preset threshold Th, and the presence or absence of thermal displacement in the column 10 is determined in the operation region of the operation path Pt2 currently being processed (S34). Accordingly, the determination unit 54 compares the temperature difference in the partitioned region to which the operation path Pt2 belongs among the partitioned regions partitioned from the temperature distribution with the threshold Th.

  In the determination step of S34, when it is determined that the temperature difference is equal to or less than the threshold Th (S34: Yes), the process proceeds to the operation variable return process (S35) as the next step. In such a determination, it is considered that the amount of thermal displacement in the machining region of the motion path currently being machined has decreased. Therefore, in S35, the operation variable changing unit 57 performs a process of changing the operation variable changed in S31 to the original set value based on the temperature distribution updated in S33. Here, when the amount of thermal displacement is sufficiently reduced, the machining operation variable is changed to return to the original set value. On the other hand, when the thermal displacement amount is only slightly decreased, the machining operation variable is changed so as to slightly return to the original set value.

  When the processing variable return process is performed by the operating variable changing unit 57, it is determined whether or not the operating variable is equal to the initial set value (S36). When the operation variable is equal to the initial set value (S36: Yes), the operation variable changing process is ended when the processing by the operation path Pt2 currently being processed is completed, and the process proceeds to the processing end determination S37, which is the next step. If it is determined in S36 that the operation variable is not equal to the initial set value (S36: No), the process is performed by the operation path Pt2 in a state where the operation variable is changed. After the process is completed, the process in S32 is performed. Return to end determination.

  In the processing end determination in S37, it is determined whether the processing based on the input control data has been completed based on the presence or absence of an unprocessed motion path, as in S14 and S32. Here, since the machining is completed for all the operation paths (S37: Yes), the machining and the thermal displacement control are finished. On the other hand, when the unprocessed operation path remains (S32: No), the processing by the next operation path is started, and the process proceeds to the temperature distribution creation of S22 again.

  Here, in S34, when the determination unit 54 determines that the temperature difference in the partitioned region to which the operation path Pt2 belongs exceeds the threshold Th (S34: No), the machining by the machine tool 1 is temporarily stopped (S41). ). Therefore, the machining temporary stop unit 58 stops the machining based on the operation path Pt2 whose order has been changed for a certain period of time. This is considered to be a case in which the amount of thermal displacement exceeds a certain value and the posture of the tool 33 varies greatly even when the operation variable of the processing is changed in the processing along the operation path Pt2. Thus, the heat dissipation of the column 10 is promoted by temporarily stopping the processing based on the operation path Pt2. In S34, the machine tool 1 resumes the machining by the operation path Pt2 after the temporary stop, and returns to the machining end determination in S32 after the machining is completed.

As described above, the operation variable changing step and the processing suspension step are executed, and the processing is sequentially performed on the unprocessed operation path.
Then, when all of the unprocessed machining paths Pt1 to Pt6 are finished, it is determined by any of the machining end determinations (S14, S32, S37), and the machining by the machine tool 1 and the thermal displacement control by the control device 50 are performed. finish. In the thermal displacement control determination step (S13, S23, S34) described above, the temperature difference is compared with a preset threshold value Th. On the other hand, the threshold value Th in each determination step may be set to a different value.

(Effect of the control device 50)
According to the control device 50 of the machine tool 1 described above, the operation path changing unit 56 is configured to change the order of the unprocessed operation paths based on the temperature distribution. With such a configuration, when it is determined that thermal displacement has occurred in the column 10 of the machine tool 1, an operation path that processes an operation region that is less affected by thermal displacement among unprocessed operation paths. The order is changed to give priority to Pt4 to Pt6. As a result, in the operation path that was previously processed, the thermal displacement of the column 10 is small, so that the processing can be performed with high accuracy. Furthermore, even if the part of the column 10 generates heat by this operation path, the influence on the part where the thermal displacement is generated can be suppressed. Therefore, it is possible to promote the heat radiation of the portion of the column 10 where the thermal displacement occurs.

  In addition, by applying the control method of the present invention to the thermal displacement correction of the machine tool 1, the thermal displacement of the column 10 that occurs during machining by the machine tool 1 can be made uniform. Thereby, the temperature deviation in the temperature distribution is reduced, and the local temperature rise of the column 10 can be suppressed. Therefore, the amount of thermal displacement accompanying the thermal deformation of the column 10 can be reduced. Therefore, it is possible to easily correct the thermal displacement of the column 10 as compared with the conventional case, and it is possible to reduce the amount of change in the posture of the tool 33. With such a configuration, the amount of change in the posture of the tool 33 has increased so far, and even a machining operation that has required a pause in machining is suspended by changing the order of the divided movement paths. It becomes possible to process without. As a result, the processing cycle time can be shortened.

  The operation path changing unit 56 is configured to change the order of the operation paths based on the connection distance when unprocessed operation paths are connected. When changing the order of the plurality of operation paths, the operation path changing unit 56 gives priority to an operation path having a small connection distance connecting the operation paths from the current processing position with respect to the operation paths Pt4 to Pt6 belonging to the normal temperature range Nt. And change the order to process. Thereby, the time to move between the respective operation paths can be shortened.

  The determination unit 54 is configured to determine the difference between the highest temperature and the lowest temperature in the partitioned area where the temperature distribution is partitioned as a temperature difference. Thereby, the temperature deviation of the temperature distribution can be detected. When the column 10 has a local temperature rise, it can be reliably determined that a thermal displacement has occurred.

  The operation variable change unit 57 is configured to change the operation variable of machining included in the operation path whose order has been changed when the determination unit 54 determines that a thermal displacement has occurred in the column 10. Thereby, it is possible to change the operation variables such as the machining speed and the feed speed included in the operation path, and to set the machining conditions to reduce the load on the machine tool 1. Therefore, the heat generation in the column 10 can be more reliably suppressed. Therefore, the operation path changing unit 56 and the operation variable changing unit 57 can make the thermal displacement of the column 10 uniform and easily correct the thermal displacement.

  The processing temporary stop unit 58 is configured to stop the processing based on the operation path whose order has been changed for a certain period of time when the determination unit 54 determines that thermal displacement has occurred in the column 10. Thereby, when there is a local temperature rise in the column 10, it is possible to promote the heat radiation of the portion of the column 10 where the thermal displacement is generated. Therefore, even if the posture of the tool 33 fluctuates due to the thermal deformation of the column 10, it can be determined that the thermal displacement has occurred based on the temperature distribution, and the processing accuracy can be prevented from being lowered.

  The operation path creation unit 55 is configured to divide the machining operation in the control data and create a plurality of operation paths based on the non-machining command code included in the control data. The control data includes a machining command code and a non-machining command code. Therefore, the operation path creation unit 55 recognizes this non-machining command code, and divides the machining operation in the control data into a plurality of operation paths on the front side or the rear side of the detected non-machining command code. Thereby, the machining operation in the control data can be divided easily at an appropriate position.

  The temperature distribution creating unit 53 is configured to create a temperature distribution in the moving direction of the saddle 20 with respect to the column 10. The column 10 is deformed due to thermal effects such as machining of the machine tool 1 and changes in environmental temperature. In particular, heat generated by the movement of the supporting saddle 20 greatly affects the deformation of the column 10. Therefore, when the temperature distribution creating unit 53 creates at least the temperature distribution in the moving direction of the saddle 20, the operation path changing unit 56 can change the operation path as the temperature distribution on the sliding surface 10a of the column 10. In other words, the control device 50 can correct the thermal displacement of the column 10 more appropriately with the thermal displacement accompanying the thermal deformation of the sliding surface 10a of the column 10 as a control target.

<Modification of Embodiment>
In the embodiment, the operation path changing unit 56 is configured to change the order of the operation paths based on the connection distance when the unprocessed operation paths are connected. On the other hand, the operation path changing unit 56 may be configured to change the order of the operation paths based on the temperature state of the unprocessed operation paths in the temperature distribution. For example, when changing the order of a plurality of operation paths, the operation path change unit 56 changes the operation path to an operation path that is not included in the region where the temperature is rising in the temperature distribution.

  That is, the order of the operation paths Pt4 to Pt6 belonging to the normal temperature range Nt exemplified in the embodiment is changed in consideration of the temperature in the processing region of each operation path. This is because, for example, there is a case where the temperature in any processing region of the unprocessed operation paths Pt4 to Pt6 has already risen due to the processing so far, and such operation paths are prevented from being given priority. Because. Even in such a configuration, the same effect can be obtained. Further, the thermal displacement of the column 10 that occurs during machining by the machine tool 1 can be made uniform.

  In addition, the operation path changing unit 56 may analyze a machining command code included in the operation path and predict a load and heat generation of the machine tool 1 through the operation path. As described above, when changing the order of the unprocessed motion paths, the motion path changing unit 56 weights various elements such as the connection distance and the temperature of the processing area of the motion path, and appropriately changes the order. It may be a thing. With such a configuration, the thermal displacement in the target of thermal displacement control can be made uniform, and the processing cycle time can be shortened.

  In the embodiment, the determination unit 54 sets the difference between the highest temperature and the lowest temperature in the partitioned area in which the temperature distribution is divided into 24 equal parts as the temperature difference in the temperature distribution. On the other hand, the determination unit 54 may appropriately set the position and size of the partition area and compare the temperature difference in the temperature distribution with the threshold Th. Moreover, the determination part 54 may determine the difference with the minimum temperature contained in the predetermined area | region centering on the site | part of the highest temperature in temperature distribution as a temperature difference, for example. In addition, the determination unit 54 may determine the presence or absence of thermal displacement in the support based on the interval between isotherms formed in the temperature distribution. In such a configuration as well, the temperature deviation of the temperature distribution can be detected. And when there exists a local temperature rise in a support body, it can determine reliably that the thermal displacement has arisen.

  In the embodiment, the operation path creation unit 55 is configured to divide the machining operation in the control data into a plurality of operation paths on the front side or the rear side of the non-machining command code. On the other hand, the operation path creation unit 55 may use a tool change code, a sub program call code, a fixed cycle call code, and the like as the non-machining command code in addition to the positioning G code (G00). . In addition, a machining time, a machining distance, and the like may be calculated based on the machining command code and machining operation variables, and the machining operation in the control data may be divided into a plurality of operation paths based on these. Even in such a configuration, the same effect can be obtained.

  In the embodiment, the motion path creation unit 55 creates a plurality of motion paths before starting machining by the machine tool 1. In contrast, for example, the thermal displacement of the support may be detected based on the temperature distribution during processing, and the processing operation in the control data input at that time may be divided into a plurality of operation paths. Thereby, while having the same effect, it can respond dynamically to environmental changes and heat generation due to processing.

  In the embodiment, the temperature distribution creating unit 53 creates a temperature distribution corresponding to the sliding surface 10 a of the column 10. On the other hand, for example, in the case of a mechanical configuration in which the main spindle base is fixed to the moving body, it is only necessary to create a temperature distribution only in the moving direction of the moving body. Even in such a configuration, the same effect can be obtained by applying the control method and the control device of the present invention.

  Further, the thermal displacement control by the control device 50 has been described with the support body that is thermally deformed as the column 10 and the moving body supported by the support body as the saddle 20. On the other hand, the control method and the control device for performing the thermal displacement control of the present invention can be applied as long as the member supports the tool 33 or the workpiece W and causes thermal displacement due to the thermal influence of the machine tool 1. . In addition, the machine tool 1 has been described by taking a three-axis machining center as an example. On the other hand, the machine tool 1 may be, for example, a 5-axis machining center having a rotation axis (A, B axis). Even in such a configuration, the same effect can be obtained.

1: Machine tool 2: Bed 10: Column (support) 10a: Sliding surface 11: Temperature sensor 12: Rail 20: Saddle (moving body) 21: Rail 30: Spindle base 31: Spindle head 32: Rotating spindle 33: Tool 40: Table 41: Jig 50: Control device 51: Control unit 52: Temperature acquisition unit 53: Temperature distribution generation unit 54: Determination unit 55: Operation path generation unit 56: Motion path changing unit 57: Motion variable changing unit 58: Machining temporary stop unit W: Workpiece, Pt1 to Pt6: Motion path, Th: Threshold

Claims (9)

In a method for controlling a machine tool, which has a support and a movable body supported by the support so as to be movable, and performs processing based on control data,
A temperature acquisition step of acquiring a plurality of inspection position temperatures set on the support;
A temperature distribution creating step for creating a temperature distribution of the support based on temperatures at a plurality of the inspection positions;
When the temperature difference in the temperature distribution exceeds a preset threshold value, a determination step for determining that thermal displacement has occurred in the support,
An operation path creating step of dividing a machining operation in the control data and creating a plurality of operation paths;
A path changing step of changing the order of the unprocessed operation paths based on the temperature distribution when it is determined in the determining step that thermal displacement has occurred in the support;
A machine tool control method comprising: In claim 1,
The path change step changes the order of the operation paths based on a connection distance when the unprocessed operation paths are connected. In claim 1 or 2,
The path change step changes the order of the operation paths based on a temperature state of the unprocessed operation paths in the temperature distribution. In any one of Claims 1-3,
The determining step determines a difference between the highest temperature and the lowest temperature in the partitioned area where the temperature distribution is partitioned as the temperature difference. In any one of Claims 1-4,
When it is determined in the determination step that thermal displacement has occurred in the support body, the method further comprises an operation variable changing step of changing an operation variable of processing included in the operation path whose order has been changed. A control method for machine tools. In any one of Claims 1-5,
When it is determined that thermal displacement has occurred in the support in the determination step, the method further includes a processing pause step for stopping the processing based on the operation path whose order has been changed for a certain period of time. A method for controlling a machine tool. In any one of Claims 1-6,
The operation path creating step divides a machining operation in the control data based on a non-machining command code included in the control data to create a plurality of the operation paths. In any one of Claims 1-7,
The temperature distribution creating step creates a temperature distribution in a moving direction of the moving body with respect to the support body. In a control device of a machine tool that has a support and a movable body that is movably supported by the support, and performs processing based on control data,
Temperature acquisition means for acquiring the temperatures of a plurality of inspection positions set on the support;
Temperature distribution creating means for creating a temperature distribution of the support based on temperatures at a plurality of the inspection positions;
When the temperature difference in the temperature distribution exceeds a preset threshold value, determination means for determining that thermal displacement has occurred in the support,
An operation path creating means for dividing a machining operation in the control data and creating a plurality of operation paths;
A path changing means for changing the order of the unprocessed operation paths based on the temperature distribution when it is determined in the determining means that thermal displacement has occurred in the support;
A machine tool control device comprising:

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