Numerical control device and method for controlling machine tool

Abstract

The purpose of the present invention is to provide a numerical control device and a control method of a machine tool with which it is possible to prevent a processing failure or a tool from being damaged due to setting of incorrect tool data by a user for a plurality of main shafts. A numerical control device (1) comprises a tool data error determination unit (10) that calculates the degree of divergence between tool data in two or more main shafts with respect to tool data including any one of the length of a tool attached to the main shaft, the diameter of the tool, the amount of correction with respect to the length of the tool, and the amount of correction with respect to the diameter of the tool, determines an error in the tool data on the basis of the degree of divergence and a threshold, and outputs a determination result. The numerical control device (1) further comprises at least one of a notification unit (12) that receives the determination result from the tool data error determination unit (10) and outputs the determination result to the outside, and a control unit (14) that receives the determination result from the tool data error determination unit and stops or continues the operation of the machine tool on the basis of the determination result.

Description

Numerical control device and machine tool control method

[0001] The present disclosure relates to a numerical control device and a method for controlling a machine tool.

[0002] There are machine tools equipped with multiple spindles, such as multi-spindle machining centers. In these machine tools, productivity is improved by simultaneously machining a workpiece into the same shape using each spindle. Patent Document 1 discloses a multi-axis synchronous control device that monitors the rotation of multiple rotating axes and controls the rotation speed of each axis.

[0003] JP 2002-172542 A

[0004] In a machine tool equipped with multiple spindles, it is necessary to set the tool length (tool length), tool diameter (tool diameter), tool length compensation amount (compensation amount), and tool diameter compensation amount (compensation amount) for each tool attached to the multiple spindles in the machine tool. Data including any of the tool length, tool diameter, and compensation amount is called tool data. When a machine tool user sets tool data in the machine tool, there is a possibility that the user may set it incorrectly (misconfiguration). Misconfiguration may result in poor machining or tool damage.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a numerical control device and a machine tool control method that can prevent machining defects or tool damage caused by the user setting incorrect tool data for multiple spindles.

[0006] The numerical control device disclosed herein is a numerical control device for controlling a machine tool equipped with two or more spindles, and includes a tool data error determination unit that calculates a degree of deviation between tool data for the two or more spindles for tool data including one of the length of a tool attached to the spindle, the diameter of the tool, the amount of correction for the tool length, and the amount of correction for the tool diameter, determines an error in the tool data based on the degree of deviation and a threshold value, and outputs the determination result, and further includes at least one of a notification unit that receives the determination result from the tool data error determination unit and outputs the determination result to the outside, and a control unit that receives the determination result from the tool data error determination unit and stops or continues operation of the machine tool based on the determination result.

[0007] The machine tool control method disclosed herein includes the steps of: calculating a degree of deviation between tool data for two or more spindles of a machine tool equipped with two or more spindles, the tool data including any one of the length of a tool attached to the spindles, the diameter of the tool, the amount of correction for the tool length, and the amount of correction for the tool diameter; and determining whether there is an error in the tool data based on the degree of deviation and a threshold value; and outputting a determination result, or stopping or continuing operation based on the determination result.

[0008] According to the numerical control device of the present disclosure, it is possible to provide a numerical control device and a machine tool control method that can prevent poor machining or tool damage caused by the user setting incorrect tool data for multiple spindles.

[0009] Fig. 1 is a block diagram showing a schematic configuration of a numerical control device according to an embodiment of the present disclosure. Fig. 2 is a flow chart showing a processing flow of a machine tool control method according to an embodiment of the present disclosure. Fig. 3 is a diagram for explaining a determination example of Example 1. Fig. 4 is a diagram for explaining a determination example of Example 2. Fig. 5 is a diagram for explaining a display example of Example 3.

[0010] (Numerical Control Device) An embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a numerical control device 1 according to an embodiment of the present disclosure. The numerical control device 1 is a device for controlling a machine tool 50 equipped with two or more spindles. The numerical control device 1 is connected to the machine tool 50. The numerical control device 1 detects erroneous settings based on the degree of deviation between tool data in the machine tool 50 equipped with multiple spindles. The numerical control device 1 and the machine tool 50 form part of a machining system 100.

[0011] 1 , the numerical control device 1 includes, in addition to a conventional numerical control device, a tool data error determination unit 10, a notification unit 12, and a control unit 14. The tool data error determination unit 10 is a part that determines whether there is an error in the set tool data and outputs the determination result to the notification unit 12 or the control unit 14.

[0012] A tool is attached to each of the multiple spindles of the machine tool 50. The attached tool is the same for each spindle. When a tool is attached to a spindle, the tool attachment status may differ between spindles. The tool attachment status includes the position at which the tool is attached. In other words, there may be tool attachment errors between spindles. For this reason, the user needs to set the tool length, tool diameter, correction amount for the tool length, correction amount for the tool diameter, etc. in the numerical control device 1.

[0013] Here, data including at least one of the tool length, tool diameter, correction amount for the tool length, and correction amount for the tool diameter is referred to as tool data. The tool length is referred to as the tool length. The tool diameter is referred to as the tool diameter. The correction amount for the tool length and the correction amount for the tool diameter are simply referred to as the correction amount.

[0014] When a user sets tool data in the numerical control device 1, an incorrect value may be input. Therefore, the numerical control device 1 calculates the degree of deviation between the tool data for two or more spindles. The numerical control device 1 determines whether the input tool data is incorrect based on the calculated degree of deviation and a threshold value. If the degree of deviation is within the threshold value, the numerical control device 1 determines that the input tool data is not incorrect. If the degree of deviation is outside the threshold value, the numerical control device 1 determines that the input tool data contains an error. This is because if the degree of deviation between the tool data is greater than a predetermined value, there is a high probability that one of the tool data contains an error, such as an input error. The numerical control device 1 outputs the determination result to the notification unit 12 and the control unit 14.

[0015] In the above description, an example has been described in which the tool data and thresholds are set in the numerical control device 1 by a user or the like. In this example, the tool data and thresholds are set in the numerical control device 1 by external input. However, the setting of the tool data and thresholds is not limited to the above-described method. The tool data and the thresholds may be set in a machining program. Alternatively, the tool data and the thresholds may be set in advance on the numerical control device 1.

[0016] (Contents of Deviation) An example of the deviation will be described. The deviation may be anything that represents the degree of difference between tool data for two or more spindles. The deviation may be, for example, the difference between the tool data, the ratio when one piece of tool data is divided by the largest piece of tool data, or the ratio when one piece of tool data is divided by the smallest piece of tool data.

[0017] (Notification unit) The notification unit 12 is a part that outputs the judgment result judged by the numerical control device 1. The notification unit 12 can output the judgment result to the outside of the numerical control device 1. The notification unit 12 receives the judgment result from the numerical control device 1. The notification unit 12 can output the judgment result by displaying it. The notification unit 12 may output the judgment result as a signal to another device, etc. The notification unit 12 may also print out the judgment result.

[0018] The notification unit 12 may display the determination result on a display device, etc. When the notification unit 12 displays the determination result on a display device, etc., the content determined to be an error may be highlighted.

[0019] (Control Unit) Control unit 14 is a part that stops or continues operation of machine tool 50 based on the judgment result judged by numerical control device 1. Control unit 14 receives the judgment result from numerical control device 1. If the received judgment result is that "there is an error in the input tool data", control unit 14 stops operation of machine tool 50. If the received judgment result is that "there is no error in the input tool data", control unit 14 continues operation of machine tool 50.

[0020] (Processing Flow) The processing flow of the machine tool control method of this embodiment will be described. Fig. 2 is a flow chart showing the processing flow of the machine tool control method of the embodiment of the present disclosure. In Fig. 2 and the following description, S1 indicates step 1. The same applies to the other steps.

[0021] (S1) S1 is a step of setting tool data and thresholds. The tool data and thresholds are set in the numerical control device 1 by a machining program or external input. Alternatively, the tool data and thresholds may be set in advance on the numerical control device 1.

[0022] (S2) S2 is a step of calculating the degree of deviation between tool data for two or more spindles. The degree of deviation can be the difference between tool data within the same block, the ratio when one piece of tool data is divided by the largest piece of tool data, or the ratio when one piece of tool data is divided by the smallest piece of tool data.

[0023] (S3) S3 is a step of comparing the deviation calculated in S2 with a threshold value, which is the value set in S1.

[0024] (S4) S4 is a step for determining whether or not there is an error in the tool data. When the deviation is outside the threshold range in the comparison with the deviation threshold in S3, it is determined that there is an error in the tool data. When the deviation is within the threshold range, it is determined that there is no error in the tool data. If it is determined that there is an error in the tool data, the process proceeds to step S5. If it is determined that there is no error in the tool data, the process proceeds to step S6.

[0025] (S5) S5 is a step of stopping the operation of the machine tool. If it is determined that there is an error in the tool data, the control unit of the numerical control device stops the operation of the machine tool. This makes it possible to prevent machining defects and tool damage caused by incorrect setting of tool data.

[0026] (S6) S6 is a step of continuing the operation of the machine tool. If it is determined that there is no error in the tool data, the control unit of the numerical control device continues the operation of the machine tool.

[0027] This completes the process of the machine tool control method. In the above description, the control unit stops or continues the operation of the machine tool based on the determination result. The numerical control device may also output the determination result from the notification unit.

[0028] As described above, the numerical control device 1 of this embodiment can suppress the occurrence of machining defects and tool damage caused by incorrect settings made by the user for multiple spindles.

[0029] Example 1 Example 1 of the numerical control device 1 of this embodiment will be described. FIG. 3 is a diagram for explaining a judgment example of Example 1. FIG. 3 shows a machining program, a tool length, and a judgment result. In Example 1, the deviation is calculated based on the difference between tool data. The difference between tool data is calculated among the tool data included in one block. The tool data included in the combination of tool data when calculating the difference between tool data is the tool data included in the same block.

[0030] The machining program excerpt 301 shows an excerpted portion of the machining program. The machining program is automatically operated in the direction of the arrow 221. The machining program excerpt 301 shows the machining program divided into blocks.

[0031] In the machining program excerpt 301, the H in H1=11, H2=21, and H3=31 is a command for correcting the tool length, and the number following the H indicates the spindle number. Also, "11" in H1=11, "21" in H2=21, "31" in H3=31, "12" in H1=12, "22" in H2=22, and "33" in H3=33 each indicate a tool compensation number. As shown in the machining program excerpt 301, the tool compensation number to be used is specified for each spindle in the machining program.

[0032] The tool length correspondence table 302 shows tool compensation numbers and corresponding tool lengths. As indicated by arrows 201 and 202, the tool length correspondence table 302 shows the tool compensation numbers and tool lengths for the tool compensations included in block N30 and block N60. For example, the tool length of tool compensation number 11 included in block N30 is 99.825. Similarly, the tool length of tool compensation number 33 included in block N60 is 78.323. The tool data error determination unit 10 reads out the tool length based on the tool compensation number specified in the machining program.

[0033] The decision table 303 shows the results of determining whether there is a tool data error based on the differences between the tool data. The decisions in the decision table 303 are the results of calculating the tool data differences (absolute values) for each combination of any two axes of two or more spindles and determining whether there is a tool data error. As indicated by the arrow 211, for block N30, differences were calculated for all possible combinations of tool compensation numbers 11-21, 11-31, and 21-31, including tool compensation numbers 11, 21, and 31. The calculated differences were then compared with a threshold value of 0.5 to determine whether there is a tool data error. For all of the tool compensation number combinations 11-21, 11-31, and 21-31, the absolute values ​​of the differences were not greater than the threshold value. Therefore, the determination was OK for all of the tool compensation number combinations 11-21, 11-31, and 21-31, i.e., "there is no error in the tool data." As a result, operation of block N30 continues.

[0034] Next, block N60 will be described. As indicated by arrow 212, for block N60, as with block N30, differences were calculated for all possible combinations of tool compensation numbers included in the block, namely 12-22, 12-33, and 22-33. When the calculated differences were compared with a threshold, the difference for the combination of tool compensation numbers 12-22 was not greater than the threshold. Therefore, the judgment was OK, that is, "there is no error in the tool data."

[0035] In contrast, for the combinations of tool compensation numbers 12-33 and 22-33, the difference was greater than the threshold value. Therefore, the judgment was NG, that is, "there is an error in the tool data." It is believed that the settings of block N60 contain an error. Therefore, operation of block N60 is stopped. If a block contains even one combination that is judged as NG, operation of that block is stopped even if the judgments of other combinations are OK.

[0036] As shown in the judgment table 303, the differences are checked for combinations of tool compensation numbers, and operation of a block containing a combination where the absolute value of the difference is greater than the threshold value is stopped. Note that the combinations can be any combination of two axes in two or more spindles. In the example shown in FIG. 3, differences are calculated for all possible combinations. The calculation of differences can be performed for only some combinations. For example, for combinations where the judgment result is clear and there is no need to compare with the threshold value, checking the differences may be omitted.

[0037] (Example 2) Example 2 of the numerical control device 1 of this embodiment will be described. FIG. 4 is a diagram for explaining a judgment example of Example 2. Regarding Example 2, differences from Example 1 will mainly be described. Items not specifically described in Example 2 are the same as those in Example 1. In Example 1, the deviation is calculated based on the difference between the tool data. In Example 2, the deviation is calculated based on the ratio between the tool data. The tool data included in the combination of tool data when calculating the ratio between the tool data is the tool data included in the same block, as in Example 1.

[0038] The ratio between tool data includes the ratio when one piece of tool data is divided by the other piece of tool data that is the largest among the tool data, and the ratio when one piece of tool data is divided by the other piece of tool data that is the smallest among the tool data. In the following description, the ratio is defined as the ratio when one piece of tool data is divided by the other piece of tool data that is the largest among the tool data.

[0039] The machining program excerpt 301 and the tool length correspondence table 302 in Fig. 4 are the same as the machining program excerpt 301 and the tool length correspondence table 302 in Fig. 3. Unlike the differences in the judgment table 303 in Fig. 3, the judgment table 303 in Fig. 4 lists ratios. The judgment threshold is 0.95. If the ratio is not smaller than the threshold, the judgment is OK, that is, it is judged that "there is no error in the tool data." If the ratio is smaller than the threshold, the judgment is NG, that is, it is judged that "there is an error in the tool data."

[0040] The result of the determination in Example 2 is that the determination is OK for all of the combinations of tool offset numbers 11-21, 11-31, and 21-31 for block N30, that is, there is no error in the tool data. As a result, operation of block N30 continues.

[0041] For block N60, the ratio of the combination of tool offset numbers 12-22 was not smaller than the threshold value. Therefore, the judgment was OK, that is, there was no error in the tool data. However, the ratios of the combinations of tool offset numbers 12-33 and 22-33 were smaller than the threshold value. Therefore, the judgment was NG, that is, there was an error in the tool data. It is believed that the settings of block N60 contain an error. Therefore, operation of block N60 is stopped. If a block contains even one combination that is judged as NG, operation of that block is stopped even if the judgments of other combinations are OK.

[0042] As described above, in the second embodiment, the ratio is checked, and if the ratio is smaller than the threshold value, the operation is stopped.

[0043] The above description has been given using an example in which the ratio is the ratio obtained by dividing one piece of tool data by the largest piece of tool data. Even if the ratio is the ratio obtained by dividing one piece of tool data by the smallest piece of tool data, it is possible to determine whether the tool data is incorrect in the same way. In this case, if the ratio is greater than a predetermined threshold value when checking the ratio, it is possible to determine that the tool data is incorrect.

[0044] (Example 3) Example 3 of the numerical control device 1 of this embodiment will be described. Fig. 5 is a diagram for explaining a display example of Example 3. The judgment of tool data errors in Example 3 is the same as in Example 1. Example 3 and Example 1 differ in the display manner when the judgment results are displayed on a screen or the like. In Example 3, tool compensation numbers for which the judgment result is NG are highlighted.

[0045] For example, consider a case where the notification unit 12 outputs the judgment result to the screen. Assume that the machining program excerpt 301 in FIG. 5 is displayed on the screen. In the third embodiment, as shown in the judgment table 303, among the combinations of tool offset numbers in block N60, the judgment for 12-22 is OK, while the judgments for 12-33 and 22-33 are NG. From this judgment result, it can be determined that the tool data for tool offset number 33 is incorrect. Therefore, as shown by arrow 222, tool offset number 33 is highlighted in the machining program of the machining program excerpt 301. Methods of highlighting include changing the color of the character from other characters, making the character bolder than the other characters, and changing the font of the character from other characters.

[0046] The notification unit 12 may output the determination result by printing. When the notification unit 12 prints the determination result, the result may be highlighted in the printout.

[0047] As described above, in the numerical control device 1 of this embodiment, when the notification unit 12 or the like displays the judgment result, the display of the tool data judged to be erroneous may be emphasized. Furthermore, when the notification unit 12 or the like prints and outputs the judgment result, the printing of the tool data judged to be erroneous may be emphasized.

[0048] As described above, in the numerical control device 1 of this embodiment, the tool data error determination unit 10 calculates the deviation from the combination of two spindles for the input multiple pieces of tool data (tool length, tool diameter, compensation amount, etc.). The deviation is calculated as a difference or a ratio. The deviation is then compared with the input threshold value as follows to determine whether there is an error. That is, if the deviation is within the threshold range, it is determined that there is no error, and if the deviation is outside the threshold range, it is determined that there is an error.

[0049] In addition, in the numerical control device of this embodiment, the judgment result is output to the notification unit or the control unit. The notification unit displays the judgment result. The control unit controls operation based on the input judgment result as follows: if there is no error, operation continues, and if there is an error, operation is stopped.

[0050] Various modifications are possible to the embodiments of the present disclosure. In the above description, the tool data is the length of the tool. The tool data is not limited to the length of the tool. Even if the tool data is the diameter of the tool, a correction amount for the length of the tool, or a correction amount for the diameter of the tool, an error in the tool data can be determined in the same manner as described above.

[0051] In the above description, the deviation degree is calculated based on two pieces of tool data. However, the degree of peeling may be calculated based on three or more pieces of tool data. When calculating the deviation degree based on three pieces of tool data, the deviation degree may be, for example, the degree of variation of the other two pieces of tool data relative to the median value. For example, if the three pieces of tool data are D1, D2, and D3 in descending order of value, the deviation degree can be (D3-D1) / D2. This deviation degree may be compared with a predetermined threshold value to determine whether the tool data D1, D2, and D3 are incorrect.

[0052] The present disclosure is not limited to the above-described embodiments, examples, and modifications, and includes modifications and improvements within the scope of achieving the object of the present disclosure.

[0053] The following supplementary notes are further provided with respect to the above embodiment. (Supplementary Note 1) A numerical control device (1) for controlling a machine tool (50) equipped with two or more spindles, comprising: a tool data error determination unit (10) for calculating a degree of deviation between tool data for the two or more spindles, the tool data including any one of the length of a tool attached to the spindle, the diameter of the tool, a correction amount for the tool length, and a correction amount for the tool diameter, determining an error in the tool data based on the degree of deviation and a threshold value, and outputting the determination result; and further comprising at least one of: a notification unit (12) for receiving the determination result from the tool data error determination unit (10) and outputting the determination result externally; and a control unit (14) for receiving the determination result from the tool data error determination unit and stopping or continuing operation of the machine tool based on the determination result. (Supplementary Note 2) In the above numerical control device (1), the tool data and the threshold value are set by a machining program or external input, or are set in advance on the numerical control device (1). (Supplementary Note 3) In the above-mentioned numerical control device (1), the deviation is calculated based on the difference between the tool data included in one block, and the tool data error determination unit (10) determines that there is no error when the absolute value of the difference is smaller than the threshold value according to the tool data. (Supplementary Note 4) In the above-mentioned numerical control device (1), the deviation is calculated based on the ratio of one piece of tool data included in one block divided by the other piece of tool data that is the largest among the tool data, and the tool data error determination unit (10) determines that there is no error when the ratio is larger than the threshold value according to the tool data. (Supplementary Note 5) In the above-mentioned numerical control device (1), the deviation is calculated based on the ratio of one piece of tool data included in one block divided by the other piece of tool data that is the smallest among the tool data, and the tool data error determination unit (10) determines that there is no error when the ratio is smaller than the threshold value according to the tool data.(Supplementary Note 6) In the above-mentioned numerical control device (1), the tool data error determination unit (10) calculates and compares the degree of deviation of the tool data for each combination of any two axes of two or more spindles. (Supplementary Note 7) In the above-mentioned numerical control device (1), the notification unit (12) outputs the determination result by displaying the determination result. (Supplementary Note 8) In the above-mentioned numerical control device (1), the notification unit (12) highlights the display related to the tool data determined to be erroneous when displaying the determination result. (Supplementary Note 9) The above-mentioned machine tool control method includes the steps of: calculating the degree of deviation between the tool data for two or more spindles of a machine tool equipped with two or more spindles, for tool data including any one of the length of a tool attached to the spindles, the diameter of the tool, a correction amount for the tool length, and a correction amount for the tool diameter; and determining an error in the tool data based on the degree of deviation and a threshold value; and outputting the determination result or stopping or continuing operation based on the determination result.

[0054] REFERENCE SIGNS LIST 1 Numerical control device 10 Tool data error determination unit 12 Notification unit 14 Control unit 50 Machine tool 100 Machining system

Claims

1. A numerical control device for controlling a machine tool equipped with two or more spindles, comprising: a tool data error determination unit that calculates a degree of deviation between tool data for the two or more spindles for tool data including one of the length of a tool attached to the spindle, the diameter of the tool, the amount of correction for the tool length, and the amount of correction for the tool diameter, determines whether there is an error in the tool data based on the degree of deviation and a threshold, and outputs the determination result; and further comprising at least one of: a notification unit that receives the determination result from the tool data error determination unit and outputs the determination result to the outside; and a control unit that receives the determination result from the tool data error determination unit and stops or continues operation of the machine tool based on the determination result.

2. The numerical control device according to claim 1, wherein the tool data and the threshold value are set by a machining program or external input, or are set in advance on the numerical control device.

3. A numerical control device as described in claim 1, wherein the deviation is calculated based on the difference between the tool data contained in one block, and the tool data error determination unit determines that there is no error when the absolute value of the difference is smaller than the threshold value depending on the tool data.

4. A numerical control device as described in claim 1, wherein the deviation is calculated as a ratio when one piece of tool data contained in one block is divided by the other piece of tool data that is the largest among the tool data, and the tool data error determination unit determines that there is no error if the ratio is greater than the threshold value depending on the tool data.

5. A numerical control device as described in claim 1, wherein the deviation is calculated as a ratio when one piece of tool data contained in one block is divided by the other piece of tool data that is the smallest among the tool data, and the tool data error determination unit determines that there is no error if the ratio is smaller than the threshold value depending on the tool data.

6. The numerical control device according to claim 1, wherein the tool data error determination unit calculates and compares the degree of deviation of the tool data for each combination of any two axes of two or more spindles.

7. The numerical control device according to claim 1, wherein the notification unit outputs the determination result by displaying the determination result.

8. The numerical control device according to claim 7, wherein the notification unit, when displaying the judgment result, highlights the display relating to the tool data judged to be incorrect.

9. A method for controlling a machine tool, comprising: a step of calculating the degree of deviation between tool data for two or more spindles of a machine tool equipped with two or more spindles, the tool data including any one of the length of a tool attached to the spindles, the diameter of the tool, the amount of correction for the tool length, and the amount of correction for the tool diameter; and a step of determining whether there is an error in the tool data based on the degree of deviation and a threshold value; and outputting the determination result, or stopping or continuing operation based on the determination result.

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