Processing control device and processing control method of machine tool

Abstract

The present invention relates to a processing control device and a processing control method for a machine tool. The processing control device for a machine tool of the present invention reads a processing program according to each specified reading unit, controls the processing action of a machine tool (10) according to the read processing program, reads the read processing program in sequence, performs processing simulation, and determines the cache state according to the result of the processing simulation. When controlling the processing action, if the cache state is determined to be insufficient, control is performed to stop the processing on a non-processing path in front of the position where the insufficient cache occurs.

Description

Technical Field

[0001] The invention relates to a machining control device and a machining control method for a machine tool. Background Art

[0002] A processing control device that controls a machine tool or the like performs processing according to a processing program. The capacity of the processing program tends to increase with the improvement of the accuracy of the processed object. For example, in the processing program for mold processing, there are many cases where its size exceeds the capacity of the internal storage device (DRAM, etc.) of the CNC. As a method for dealing with such a problem, the following technology is known, that is, the processing control device successively obtains part of the processing program from an external storage device (CF card, SD card, USB device, etc.) and an external computer (server, etc.) that can be connected in a communicative manner, and accumulates (caches) the obtained part of the processing program in the internal storage device. According to this method, the processing control device can realize continuous program operation.

[0003] However, when the processing program is transferred from the external storage device or the external computer to the processing control device, the transfer speed is not constant. Therefore, in the process of the processing control device performing processing control by the processing program acquired from the external storage device one by one, the execution of the data accumulated by the transfer of the processing program in the processing control device is accelerated, thereby generating a transfer waiting state (so-called "cache waiting"). If such a transfer waiting state occurs, the control is temporarily interrupted during processing and the processing quality is deteriorated.

[0004] In order to solve such a situation, Japanese Patent Laid-Open No. 7-239707 discloses a numerical control device having the following remote operation function, that is, accumulating machining program data transferred from a machining program storage device via a communication unit in an operation buffer in a memory, and taking out the machining program data in the operation buffer in sequence according to the program block unit and operating it. In the numerical control device, there are: a setting unit, which sets a retraction avoidance amount and a restart operation program block number as a tool retraction condition, and the tool retraction condition is used to make the tool being cut retreat in the axial direction of the tool installation and then restart the operation when the machining program data in the above-mentioned operation buffer is empty; a tool retraction control unit, which, when the number of remaining program blocks of the machining program data in the operation buffer is 0, after the program block before it becomes 0 ends, makes the tool being cut retreat by an amount corresponding to the retraction avoidance amount, and transfers the machining program data from the machining program storage device, thereby when the number of remaining program blocks of the machining program data in the operation buffer becomes more than the restart operation program block number, the tool is returned from the retracted position by an amount corresponding to the retraction avoidance amount, and the machining is restarted. Thus, for machining program data in the operation buffer, validity / invalidity of the cutting tool retraction when the operation buffer is empty can be set, thereby reducing machining time at a machining position where the cutting tool does not need to be retracted.

[0005] In addition, Japanese Patent Publication No. 2016-31725 discloses a numerical control device, which caches a machining program from an external storage device or an external control device to an internal memory via a connection unit, and an automatic operation execution unit performs automatic operation according to the cached machining program. In the numerical control device, the machining program includes one or more cache points, and the automatic operation execution unit includes: a cache completion confirmation result storage unit, which confirms whether the cached machining program includes the cache point during the caching process of the machining program to the internal memory, and saves the confirmation result; an execution confirmation result storage unit, which confirms whether the executed machining program includes the cache point when the automatic operation execution unit executes the machining program cached in the internal memory, and saves the result; a comparison unit, which compares the cache completion confirmation result storage unit and the execution confirmation result storage unit; and an execution unit, which performs any one of continuing, temporarily stopping, and restarting the automatic operation according to the comparison result. If such a numerical control device is used, even if the data transfer is slow and the internal memory is empty, the machining will not be stopped at a position other than the pre-specified cache point instruction. Therefore, according to this numerical control device, there will be no problem of generation of so-called "tool marks" or vibration on the workpiece.

[0006] In general, in an automatically operated machine tool, if any problem occurs in the control of the machine tool, the control is usually interrupted and the processing of the workpiece is also stopped urgently. At this time, if the workpiece and the tool are in contact and the emergency stop occurs, tool marks will be generated on the workpiece, and the yield of the workpiece as a product will be reduced.

[0007] In order to suppress the reduction of the yield rate during such an emergency stop, for example, in the above-mentioned patent gazettes, it is disclosed that when the automatic control of the processing is temporarily stopped, the numerical control device performs a process of retracting the tool from the workpiece, and after eliminating the problem, returns to the processing point to continue processing. However, if the numerical control device once performs the action of retracting the tool during processing, although the processing position itself can be restored, it is difficult to reproduce (restore) the processing state that is continuously performed on the processing path. Therefore, according to these numerical control devices, as a result, it is inevitable to reduce the processing accuracy of the workpiece whose processing is temporarily stopped.

[0008] In addition, Japanese Patent Publication No. 2016-31725 also records that a non-cutting instruction can be set at a cache point so that no tool marks are generated even if the automatic operation is temporarily stopped. However, in order for the execution unit to perform the temporary stop action of the processing, it is necessary to include the cache point in the program block of the read-in processing program. Therefore, in order to improve the processing accuracy, it is necessary to include the cache point in all the program blocks of the processing program in advance. In this case, there are the following problems, namely, the load when making the processing program is increased, and the versatility of the processing program is reduced. Summary of the invention

[0009] Therefore, a processing control device and a processing control method for a machine tool are required that can cope with a buffer shortage state without setting a special additional point in the processing program and reducing the yield after processing based on automatic processing control of the machine tool.

[0010] The processing control device of the machine tool of the present invention uses a processing program including a processing path and a non-processing path to perform processing control on a workpiece, and the processing control device comprises: a processing program acquisition unit, which reads the processing program according to each specified reading unit; a processing control unit, which controls the processing action of the machine tool based on the processing program read by the processing program acquisition unit; a simulation execution unit, which sequentially reads the processing program read by the processing program acquisition unit and performs processing simulation; a cache state determination unit, which determines the cache state of the processing program acquisition unit based on the result of the processing simulation. In addition, when the cache state determination unit determines that the cache is insufficient, the above-mentioned processing control unit performs control to stop processing on the non-processing path in front of the position where the cache is insufficient.

[0011] The machining control method of a machine tool of the present invention uses a machining program including a machining path and a non-machining path to control the machining of a workpiece, wherein the machining program is read in according to each specified reading unit, and when the machining action of the machine tool is controlled according to the read machining program, the read machining programs are read out in sequence and machining simulation is performed, and based on the result of the machining simulation, the cache status of the machining program is determined, and when the cache status is determined to be insufficient cache, the machining is stopped on the non-machining path in front of the position where the insufficient cache occurs.

[0012] According to the present invention, the following unique effect is achieved, that is, on the basis of automatically controlling the processing of the machine tool, it is possible to cope with the state of insufficient buffer without setting a special additional point in the processing program and reducing the yield rate after processing. This is because the processing control device or method of the machine tool of the present invention determines the buffer state of the processing program based on the results of the processing simulation read in successively, and stops the processing on the non-processing path in front of the position where the insufficient buffer occurs according to the determination result. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The above and other objects and features of the present invention will be apparent from the following description of the embodiments with reference to the accompanying drawings.

[0014] Figure 1 1 is a block diagram showing a representative and exemplary process control device of the present invention and its relationship with peripheral devices.

[0015] Figure 2A and Figure 2B Yes means Figure 1 A plan view showing the relationship between a workpiece and a machining path in a first embodiment of a machining control device and its peripheral equipment.

[0016] Figure 3 This is a flowchart showing an outline of the operation of reading a machining program according to the first embodiment.

[0017] Figure 4 In the first embodiment, Figure 3 The flowchart schematically shows a machining control operation executed in parallel with a machining program reading operation.

[0018] Figure 5 Yes means Figure 4 A flowchart showing an overview of the operation of the normal machining subroutine is shown.

[0019] Figure 6 Yes means Figure 4 The flowchart shown is an overview of the operation of the standby subroutine.

[0020] Figure 7 This is a timing chart showing an example of the machining control method of the machine tool according to the first embodiment.

[0021] Fig. 8A and Figure 8B Yes means Figure 1 A plan view showing the relationship between a workpiece and a machining path in a second embodiment of a machining control device and its peripheral equipment.

[0022] Fig. 9 This is a flowchart showing an overview of the operation of the standby subroutine according to the second embodiment.

[0023] Fig.10 This is a timing chart showing an example of a machining control method for a machine tool according to the second embodiment. DETAILED DESCRIPTION

[0024] Hereinafter, several embodiments of the processing control device and processing control method of a machine tool representative of the present invention and the accompanying drawings will be described. Figure 1 Let me explain.

[0025] Figure 1 1 is a block diagram showing a representative and exemplary process control device of the present invention and its relationship with external devices. Figure 1 As shown, the machining control device 100 for a machine tool comprises: a machining program acquisition unit 110, which reads a machining program including a machining path and a non-machining path in each predetermined reading unit; a machining control unit 120, which controls the machining operation of an object device to be controlled, such as a machine tool 10, according to the machining program read by the machining program acquisition unit 110. The machining control device 100 further comprises: a simulation execution unit 130, which sequentially reads the machining program read by the machining program acquisition unit 110 and performs machining simulation; and a cache state determination unit 140, which determines the cache state of the machining program acquisition unit according to the result of the machining simulation.

[0026] The processing control device 100 is communicatively connected to the machine tool 10 and the external storage device 20 via a wired or wireless communication line or the like. Through this connection structure, the processing control device 100 issues various instructions accompanying processing to the machine tool 10, and receives detection signals from various sensors installed in the machine tool 10. In addition, the processing control device 100 obtains various data, processing programs, etc. used for processing of the machine tool 10 from the external storage device 20, and updates the above data and processing programs as needed.

[0027] The processing program acquisition unit 110 receives the processing programs from the external storage device 20 one by one, and temporarily accumulates the received processing programs in a built-in transfer buffer (not shown). Such accumulation operation is called caching. In addition, the processing program acquisition unit 110 deletes the processing program used for program operation from the transfer buffer in response to a deletion instruction sent from the processing control unit 120.

[0028] The processing control unit 120 sequentially reads the accumulated processing programs from the transfer buffer, and issues processing instructions based on the judgment result of the buffer state judgment unit 140 described later, thereby controlling the machine tool 10. Such a series of actions is called program operation. In addition, the processing control unit 120 transfers data based on the detection signal of the sensor obtained from the machine tool 10 to the buffer state judgment unit 140. In this way, the processing control unit 120 can be configured as a control device, a control unit, or a similar control unit for controlling the machine tool 10.

[0029] As a structural significance of the machining control device 100 of the machine tool of the present invention, it is possible to cite the point that it is provided with a simulation execution unit 130 and a cache state determination unit 140. The simulation execution unit 130 can read the machining program stored in the machining program acquisition unit 110, and perform machining simulation of caching and program operation by a known method. The simulation execution unit 130 can perform the machining simulation successively in parallel with the reading action of the machining program, or can perform the machining simulation each time a machining program block of the machining program is read. For example, the result of the machining simulation performed by the simulation execution unit 130 is transferred to the machining control unit 120 and the cache state determination unit 140 respectively.

[0030] The cache state determination unit 140 compares the capacity of the machining program consumed by the program running at a certain moment and the capacity of the machining program accumulated by the cache according to the result of the machining simulation of the simulation execution unit 130. The cache state determination unit 140 can determine whether a state of insufficient capacity of the accumulated machining program (referred to as cache shortage) has occurred according to the comparison result. In addition, the determination of the cache state includes not only the action of determining whether cache shortage has occurred, but also the action of determining the position where cache shortage has occurred. The position where cache shortage has occurred refers to, for example, a position on a machining path or a non-machining path.

[0031] <First Embodiment>

[0032] Figure 2A 1 is a plan view showing the relationship between a workpiece and a machining path in a first embodiment of a representative and exemplary machining control method for a machine tool of the present invention. Figure 2A As shown, in the first embodiment, a machining program consisting of machining blocks N1 to N8 connecting indication points P1 to P8 is used to control the machining of a workpiece W having a substantially C-shaped cross section. Each machining block N1 to N8 includes a machining path L1 for machining the workpiece W by a tool (not shown) and a non-machining path L2 for moving the tool away from the workpiece W. Figure 2B In, it means Figure 2A Execution time (seconds) of each machining program block N1 to N8 when machining a workpiece W is shown.

[0033] Figure 3 The flowchart schematically shows the operation of reading a machining program according to the first embodiment. The machining program acquisition unit 110 reads the machining program from the processing program acquisition unit 110 at a predetermined clock frequency. Figure 1 The instructions of the processing control unit 120 shown in FIG. Figure 3 The reading action of the machining program is shown.

[0034] In the operation of reading the machining program, first, a part of the machining program is read from the external storage device 20 into the transfer buffer of the machining program acquisition unit 110 in the unit of each clock frequency (step S1). Then, the read part of the machining program is accumulated in the transfer buffer of the machining program acquisition unit 110 (step S2). At this time, if there is already accumulated data in the transfer buffer, the part of the machining program newly read in step S1 is added and accumulated in the transfer buffer.

[0035] Next, the buffer state determination unit 140 determines whether the capacity of the transfer buffer of the machining program acquisition unit 110 has been exceeded by adding data in step S2 (step S3). At this time, if it is determined that the capacity of the transfer buffer has been exceeded, it is assumed that the data of the machining program for subsequent machining is insufficient (for example, a situation such as an abnormality in the physical memory constituting the transfer buffer has occurred), and the machining control device 100 issues a warning indicating "buffer shortage" (step S4), and the reading operation of the machining program acquisition unit 110 is terminated.

[0036] On the other hand, if it is determined in step S3 that the capacity of the transfer buffer is not exceeded, it is determined that the data of the machining program is normally accumulated in the transfer buffer, and the machining program acquisition unit 110, under the control of the machining control unit 120, accumulates the total reading time Tr from the start of reading (step S5). Next, the machining program acquisition unit 110, under the control of the machining control unit 120, determines whether the machining program data read so far has reached the end position of the prescribed unit block, that is, whether the prescribed unit block has been read as the machining program data (step S6).

[0037] In step S6, when it is determined that the reading of the unit program block has not been completed, that is, the data of the processing program read is in the middle of the specified unit program block, the processing program acquisition unit 110 receives the control of the processing control unit 120 and determines whether there is an instruction to delete the processing program data accumulated in the transfer buffer from the processing instruction action described later (step S8). On the other hand, in step S6, when it is determined that the reading of the unit program block has been completed, the processing program acquisition unit 110 counts the program block number Nn indicating the number of the completed unit program block in association with the above-mentioned total reading time Tr (step S7). For example, if the first program block is read, its data is grouped into program block N1.

[0038] Next, if it is determined in step S8 that a delete command for the machining program data has been received, the machining program acquisition unit 110 assumes that machining of a plurality of unit blocks of the program that has been read in the machining command operation described later has been completed, deletes the executed machining program data from the transfer buffer (step S9), and ends the reading operation. On the other hand, if it is determined in step S8 that a delete command has not been received, the machining program acquisition unit 110 ends the reading operation in a state where the machining program data that has been read so far is accumulated in the transfer buffer.

[0039] By executing the above-mentioned operation flow, the data of the machining program corresponding to the total read-in time Tr is accumulated in the transfer buffer of the machining program acquisition unit 110 of the representative and exemplary machining control device 100 of the present invention according to each of the above-mentioned predetermined clock frequencies. At this time, for each predetermined machining program block, the data is grouped and a program block name is added.

[0040] Figure 4 It means Figure 3 Flowchart showing an overview of a machining control operation executed in parallel with the operation of reading a machining program shown in FIG. Figure 3 Similarly, the reading operation of the machining program shown in FIG. 1 is executed by the machining program acquisition unit 110 in synchronization with the reading operation at each predetermined clock frequency according to the instruction from the machining control unit 120. Figure 4 The processing instruction actions shown.

[0041] In the machining command operation, first, a portion of the machining program accumulated so far is read from the transfer buffer of the machining program acquisition unit 110 to the buffer state determination unit 140 (step S11). Then, the machining control unit 120 determines whether the machine tool is currently performing machining operation (step S12).

[0042] When it is determined in step S12 that a machining operation is currently being performed, the cache state determination unit 140 determines whether a cache shortage of the transfer cache has occurred (step S13). As described above, based on the result of the machining simulation of the simulation execution unit 130, the capacity of the machining program consumed by the program execution at a certain time is compared with the capacity of the machining program accumulated in the cache, thereby determining whether the operation is a cache shortage at this time. In addition, the cache state determination unit 140 can also determine the position (a position on the machining path or a non-machining path) where the cache shortage occurs based on the total read time Tr and the result of the machining simulation.

[0043] If it is determined in step S13 that there is no buffer shortage, it is assumed that a part of the machining program is normally accumulated in the transfer buffer, and the machining control unit 120 executes the normal machining subroutine SP to end the machining instruction operation. On the other hand, if it is determined in step S13 that there is a buffer shortage (or there is a possibility of buffer shortage during machining), in order to avoid machining stopping on the machining path L1, the machining control unit 120 executes the standby subroutine SS to end the machining instruction operation.

[0044] In addition, when it is determined in step S12 that the machining operation is not currently being performed, the cache state determination unit 140 determines whether there is a machining program block including the non-machining path L2 in the part of the machining program read in step S11 (step S14). The determination operation at this time can be performed based on the result of the machining simulation performed by the simulation execution unit 130 on the part of the machining program accumulated in the transfer buffer. In addition, when the machining program contains data for distinguishing the machining path L1 from the non-machining path L2 in advance, the cache state determination unit 140 can also determine whether there is a machining program block based on whether the data is included.

[0045] In step S14, when it is determined that there is no processing program block including the non-processing path L2 in a part of the read processing program, the processing control unit 120 executes the standby subroutine SS to determine whether to maintain the current processing stop state or start processing, and ends the processing instruction action. On the other hand, in step S14, when it is determined that there is a processing program block including the non-processing path L2, the cache state determination unit 140 determines whether there is a buffer shortage of the transfer buffer (step S15). The action of determining whether there is a buffer shortage at this time is the same as the determination action in step S13 described above.

[0046] If it is determined in step S15 that there is no buffer shortage, a part of the machining program is normally accumulated in the transfer buffer, and even if the machining is directly restarted, the machining of the machining program block including the non-machining path L2 where the tool can wait is performed, so it is safe, and the machining control unit 120 executes the normal machining subroutine SP to end the machining command action. On the other hand, if it is determined in step S15 that there is a buffer shortage (or there is a possibility that there is a buffer shortage during machining), the machining control unit 120 executes the standby subroutine SS to make the tool wait (machining stops) on the non-machining path L2 included in the part of the read machining program, and ends the machining command action.

[0047] Figure 5 Yes means Figure 4 The flowchart shown is a schematic diagram of the operation of the normal machining subroutine SP. Figure 5 The usual machining subroutine shown is as follows Figure 4 As shown in the flowchart of the machining instruction action, the action is executed regardless of whether machining is currently being performed. Usually, the machining subroutine is executed on the premise that the simulation execution unit 130 performs machining simulation using the read machining program and the buffer state determination unit 140 determines that there is no buffer shortage.

[0048] That is Figure 5 As shown, the machining control unit 120 issues a machining instruction to the machine tool 10 based on the data of a portion of the machining program that has been read in (step SP1). Next, the machining control unit 120 issues a deletion instruction to the machine tool 10 to delete the machining program for which the instruction to end machining has been issued (step SP2), thereby terminating the subroutine.

[0049] In addition, Figure 5 In the flowchart shown in FIG. 1 , the process control unit 120 directly issues the deletion instruction of step SP2 after the process instruction of step SP1. However, for example, it is also possible to configure such that between step SP1 and step SP2, an additional instruction is added as shown in FIG. Figure 3 The processing control unit 120 issues a deletion instruction only when the processing instruction of the unit block is completed. Thus, the processing instruction and the deletion instruction are performed for each processing block, so the load of the processing control unit 120 accompanying data deletion can be reduced.

[0050] Figure 6 Yes means Figure 4 The flowchart shown is a schematic diagram of the operation of the standby subroutine SS. Figure 6 The standby subroutine shown is as follows Figure 4The standby subroutine is an action that is executed regardless of whether machining is currently being performed, as shown in the flowchart of the machining instruction action. The standby subroutine is an action that is executed when the simulation execution unit 130 performs machining simulation using the read machining program and the cache state determination unit 140 determines that the cache is insufficient, or when the machining program read in during machining stop does not contain a machining program block including the non-machining path L2.

[0051] That is, the processing control device 100, in particular, the processing control unit 120 is as follows Figure 6 As shown, first, it is determined whether the machine tool 10 is currently performing a machining operation (step SS1). In the case where it is determined in step SS1 that a machining operation is currently being performed, it is determined whether the current machining position (tool position) is on the non-machining path L2 (step SS2). At this time, for example, a method of comparing the coordinate value in the position control of the tool with the coordinate value on each machining path obtained by the above-mentioned machining simulation, or a load sensor such as a torque sensor (not shown) for measuring the load of the tool is provided on the tool holding mechanism of the machine tool 10, and a method of detecting the contact between the tool and the workpiece based on the sensor value can be used to perform the determination operation of where the current tool position is located.

[0052] Here, the operation from step SS1 to step SS2 is equivalent to, for example, Figure 4 In the flowchart of , the process goes from step S12 to step S13 to the standby subroutine SS. In this case, insufficient buffer memory occurs during processing (or there is a possibility that insufficient buffer memory occurs during processing), so there is a possibility that processing stops on the processing path L1. Therefore, when it is determined in step SS2 that the current tool position is not on the non-processing path L2 (i.e., on the processing path L1), the processing control unit 120 immediately issues a forced retreat command for the tool (step SS3) and ends the subroutine. In this way, it is possible to suppress the situation where an unexpected processing stop occurs due to insufficient buffer memory and defects such as tool marks are generated on the workpiece.

[0053] On the other hand, when it is determined in step SS2 that the current tool position is on the non-processing path L2, the processing control unit 120 can determine that the tool is not in contact with the workpiece, and therefore issues an instruction to stop processing at this position (step SS4), and ends the subroutine. Thus, even if a buffer shortage occurs, processing can be safely stopped.

[0054] In addition, when it is determined in step SS1 that the machining operation is not currently being performed, the machining control unit 120 further determines whether the current tool position is located within a machining block including the non-machining path L2 (step SS5). For example, the determination operation at this time can be performed by determining whether the coordinate value in the tool position control is within the range of each machining block obtained by the above-mentioned machining simulation.

[0055] When it is determined in step SS5 that the current tool position is not within the machining program block including the non-machining path L2, the machining control unit 120 recognizes that the tool has stopped at a safe position, issues a machining stop command (step SS4), maintains the machining stop state, and ends the subroutine. This action is equivalent to, for example, Figure 4 In the flowchart of FIG. 1 , the process goes from step S12 to step S14 to the standby subroutine SS.

[0056] On the other hand, when it is determined in step SS5 that the current tool position is in the machining block including the non-machining path L2, the machining control unit 120 further determines whether the current tool position is on the non-machining path L2 (step SS6). The determination operation at this time is the same as that in step SS2.

[0057] Here, when it is determined in step SS6 that the current tool position is on the non-processing path L2, it can be determined that the tool is not in contact with the workpiece, so an instruction to stop processing at this position is issued (step SS4), and the subroutine ends. On the other hand, when it is determined that the current tool position is not on the non-processing path L2, the non-processing path L2 exists in the same processing program block. Therefore, in order to advance the processing to the non-processing path L2, the processing control unit 120 issues a processing continuation instruction based on the data of the processing program that has been read (step SS7), and the subroutine ends.

[0058] Figure 7 is a timing chart showing an example of a machining control method for a machine tool according to the first embodiment. Figure 7 In FIG. 1 , the horizontal axis is set to the elapsed time, and the reading time of the machining program for executing the machining of the machining program blocks N1 to N8 and the actual machining time are shown. In addition, the machining execution time of each machining program block is expressed using Figure 2B In the case shown, the portion of the machining program block that does not include the machining path L2 is underlined. In addition, it is assumed that the reading time (transfer time) of the machining program corresponding to each machining program block is fixed to 1 second.

[0059] like Figure 7 As shown, according to Figure 3According to the flowchart of the reading operation of the machining program shown in FIG. 1 , the total reading time of the machining program acquisition unit 110 reading all the machining programs of the machining program blocks N1 to N8 from the external storage device 20 is 8 seconds. Figures 4 to 6 The flowchart of the machining control operation shown assumes that the machine tool 10 is controlled by the machining control device 100 to continuously execute machining of machining blocks N1 to N8, and the accumulated total machining time is 4.3 seconds.

[0060] When the machining control operation of the present invention starts, the machining program acquisition unit 110 first starts to read the machining program data of the machining program block N1 from the external storage device 20. At this time, according to the machining simulation performed by the simulation execution unit 130, the machining time (execution time) of the machining program blocks N1 and N2 is 1.0 seconds and 0.1 seconds respectively, and the total reading time of the machining program blocks N1 and N2 is 2.0 seconds. Figure 4 In step S13 of the flowchart shown in FIG. 1 , the buffer state determination unit 140 determines that a buffer shortage has occurred, and the process control unit 120 receives the determination result and transfers the operation stage to Figure 6 The standby subroutine SS is shown.

[0061] In the standby subroutine SS, the operation of the path from step SS1 to step SS5 to step SS4 is executed. In this way, when it is determined as a result of the machining simulation that the accumulated data of the transfer buffer is insufficient, the machining control unit 120 performs control to stop the machining on the non-machining path in front of the position where the insufficient buffer occurs. As a result, the machining block N2 is the non-machining path L2, so the actual machining of the machining block N1 is performed during 1.0 to 2.0 seconds after the machining program of the machining block N1 is read, and the tool stops in the machining block N2.

[0062] Next, if the processing control action is transferred to the processing block N3 and later, Figure 2A As shown, almost all of the machining blocks N3 to N5 are constituted by the machining path L1. Therefore, when these machining blocks are to be machined continuously, if a buffer shortage occurs at an intermediate position, the machining operation stops on the machining path L1.

[0063] Therefore, the processing control unit 120 Figure 7 As shown in FIG. 1 , control is performed so that while the tool is in the processing block N2, the processing program acquisition unit 110 waits until the processing programs of N3 to N5 can be accumulated. In this embodiment, the reading of the processing program of the processing block N5 is completed after 5.0 seconds. In contrast, the processing time of the processing blocks N2 to N4 takes 1.1 seconds. Therefore, for example, Figure 4In step S15 of the process, until it is determined that the buffer shortage does not occur (until it is determined that the buffer shortage does not occur even after the processing block N5 is executed), the tool waits for 1.9 seconds in the processing block N2.

[0064] During the standby in the machining block N2, the machining program acquisition unit 110 reads data up to the middle of the machining block N4 (up to 3.9 seconds), so even if machining from the machining block N2 is restarted after 3.9 seconds, the reading of machining program data up to the machining block N5 is also completed during the machining. As a result, machining of the machining blocks N2 to N5 is performed during 2.9 to 5.8 seconds, and the tool stands by in the machining block N6.

[0065] Similarly, the machining time of machining block N6 is 0.1 seconds, whereas the machining end time up to the machining block N5 is 5.8 seconds later. Therefore, if machining is performed while the machining program acquisition unit 110 reads the machining program for machining block N6, a buffer shortage will occur. Therefore, the machining control unit 120 makes the tool wait in the machining block N6 so that a buffer shortage will not occur during the execution of machining of machining blocks N6 to N8.

[0066] That is, the cumulative machining time of machining blocks N6 to N7 is 1.1 seconds, so the tool only waits in machining block N6 for, for example, 1.1 seconds, so that the machining of machining block N7 is completed 8.0 seconds after the reading of the machining program up to machining block N8 is completed. As a result, when the machining of machining block N7 is completed, the reading of the machining program of machining block N8 is completed, so the machining action (tool movement) of machining block N8 can be immediately executed from 8.0 seconds later, and as a result, the machining control action can be completed in the shortest time from the reading of machining block N8 to the machining, that is, 8.3 seconds.

[0067] As described above, according to the machining control device and machining control method of the machine tool of the first embodiment of the present invention, it is possible to cope with the state of insufficient buffer without setting a special additional point in the machining program and reducing the yield rate after machining on the basis of automatically performing machining control on the machine tool. This is because the cache state of the machining program is judged based on the result of the simulation using the machining program read in successively, and the machining is stopped on the non-machining path in front of the position where insufficient buffer occurs according to the judgment result.

[0068] <Second Embodiment>

[0069] Fig. 8A1 is a plan view showing the relationship between a workpiece and a machining path in a second embodiment of a typical and exemplary machining control method for a machine tool according to the present invention. Fig. 8A As shown in the second embodiment, similarly to the first embodiment, a workpiece W having a substantially C-shaped cross section is processed and controlled according to a processing program consisting of processing blocks N1 to N8 connecting indication points P1 to P8. In addition, each processing block N1 to N8 includes a processing path L1 for processing the workpiece W by a tool (not shown) and a non-processing path L2 for moving the tool away from the workpiece W. Figure 8B In, it is shown Fig. 8A Execution time (seconds) of each machining program block N1 to N8 when machining a workpiece W is shown.

[0070] Furthermore, in the second embodiment, for Figure 1 A block diagram showing a process control device and its relationship with peripheral devices is shown, Figure 3 to Figure 5 The flowchart of the reading action of the machining program and the machining control action shown in the figure, as well as the flowchart of the normal machining subroutine, can adopt the same structure as the first embodiment, so their repeated description is omitted. In addition, in the description of the second embodiment, for the part that can use the same or common structure as the structure described in the first embodiment, the same figure mark is added, and the description is omitted again.

[0071] exist Figure 2A In the first embodiment shown in FIG. 1 , a case is described in which a machining program is composed of machining blocks including a non-machining path L2 at one end or both ends of the machining block, such as machining blocks N1, N3, N5, or N7. Fig. 8A As shown, for example, a machining program is composed of machining blocks such as machining blocks N5 or N7 that include a non-machining path L2 in the middle of a machining path L1. That is, the machining control method of the second embodiment implements machining of a workpiece such that a non-machining area A is included in the middle of a machining block.

[0072] Fig. 9 This is a flowchart showing an overview of the operation of the standby subroutine according to the second embodiment. Fig. 9 The standby subroutine shown is an operation that is executed regardless of whether machining is currently being performed, similarly to the case of the first embodiment. Fig. 9 The standby subroutine shown is an action executed when the simulation execution unit 130 uses the read machining program to perform machining simulation and the cache state determination unit 140 determines that a cache shortage has occurred, or when there is no machining program block including the non-machining path L2 in the machining program read during machining stop.

[0073] That is, Fig. 9 As shown, the processing control device 100, in particular, the processing control unit 120 first determines whether the machine tool 10 is currently performing a processing action (step SS1). When it is determined in step SS1 that the processing action is currently being performed, it is determined whether the tool and the workpiece are in contact at the current processing position (tool position) (step SS2a). At this time, a load sensor (not shown) such as a torque sensor for measuring the load on the tool may be provided on the tool holding mechanism of the machine tool 10, and the contact between the tool and the workpiece may be detected based on the sensor value, so as to perform the determination action of whether the tool and the workpiece are in contact.

[0074] Then, with Figure 6 Similarly, when it is determined in step SS2a that the tool is in contact with the workpiece, the processing control unit 120 immediately issues a forced retreat command for the tool (step SS3) and ends the subroutine. This can prevent unexpected processing stops due to insufficient buffer memory and defects such as tool marks on the workpiece.

[0075] On the other hand, if it is determined in step SS2a that the tool is not in contact with the workpiece, it can be determined that no actual processing is being performed, regardless of the fact that the workpiece is actually being processed. Therefore, the processing control unit 120 issues an instruction to stop processing at this position (step SS4), and ends the subroutine. Thus, it is easy to grasp the position where there is a problem in the processing control action.

[0076] In addition, when it is determined in step SS1 that the machining operation is not currently being performed, the machining control unit 120 further determines whether the current tool position is located in the machining block including the non-machining path L2 (step SS5). When it is determined in step SS5 that the current tool position is not located in the machining block including the non-machining path L2, similarly to the first embodiment, the machining control unit 120 recognizes that the tool has stopped at a safe position, issues a machining stop command (step SS4), maintains the machining stop state, and ends the subroutine.

[0077] On the other hand, when it is determined in step SS5 that the current tool position is located in the processing program block including the non-processing path L2, the processing control unit 120 further determines whether the tool is in contact with the workpiece (step SS6a). The determination operation at this time is the same as that in step SS2a. Then, when it is determined in step SS6a that the tool is in contact with the workpiece, it can be determined that the current tool position is located on the processing path L1 in the processing program block including the non-processing path L2. Therefore, in order to make the tool move forward to the non-processing path L2, the processing control unit 120 issues a processing continuation instruction based on the data of the processing program that has been read (step SS7), and ends the subroutine.

[0078] On the other hand, if it is determined in step SS6a that the tool is not in contact with the workpiece, the machining control unit 120 issues a command to make the tool move in vain (i.e., move without machining the workpiece) on the non-machining path L2 using the data of the machining program that has been read, in order to make the tool move to the end of the non-machining path L2 (step SS8), and ends the subroutine. Thus, even if the machining path L1 and the non-machining path L2 are mixed in the same machining program block, i.e., the machining path L1 and the non-machining path L2 are mixed, the subroutine ends. Fig. 8A Even in the case of machining such as the non-machining area A shown, the machining control operation can be performed while minimizing the loss of machining time.

[0079] Fig.10 1 is a timing chart showing an example of a machining control method for a machine tool according to the second embodiment. Fig.10 In the same manner as in the first embodiment, the horizontal axis is set to the elapsed time, and the reading time of the machining program for executing the machining of the machining program blocks N1 to N8 and the actual machining time are shown. In addition, the machining execution time of each machining program block is expressed using Figure 2B In the illustrated case, the portion of the machining program block that does not include the machining path L2 is underlined. In addition, it is assumed that the reading time (transfer time) of the machining program corresponding to each machining program block is fixed to 1 second.

[0080] like Fig.10 As shown, according to Figure 3 According to the flowchart of the reading operation of the machining program shown in FIG. 1 , the total reading time of the machining program acquisition unit 110 reading all the machining programs of the machining program blocks N1 to N8 from the external storage device 20 is 8 seconds. Figure 4 , Figure 5 ,as well as Fig. 9 The flowchart of the machining control operation shown assumes that the machine tool 10 is to continuously execute machining of machining blocks N1 to N8 and the accumulated total machining time is 4.0 seconds.

[0081] When the machining control operation of the present invention starts, the machining program acquisition unit 110 first starts to read the machining program data of the machining program block N1 from the external storage device 20. In this embodiment, according to the machining simulation performed by the simulation execution unit 130, the machining time (execution time) of the machining program blocks N1 and N2 is 1.0 second and 0.1 second respectively, and the total reading time of the machining program blocks N1 and N2 is 2.0 seconds. Figure 4 In step S13 of the flowchart shown in FIG. 1 , it is determined that a buffer shortage has occurred, and the process control unit 120 receives the determination result and transfers the operation stage to Fig. 9 The standby subroutine SS is shown.

[0082] In the standby subroutine SS, the operation of the path from step SS1 to step SS5 to step SS4 is executed. In this way, when it is determined as a result of the machining simulation that the accumulated data of the transfer buffer is insufficient, the machining control unit 120 performs control to stop the machining on the non-machining path in front of the position where the insufficient buffer occurs, similarly to the case of the first embodiment.

[0083] As a result, the actual machining of the machining block N1 is performed during 1.0 to 2.0 seconds after the machining program of the machining block N1 is read. At this time, the reading of the machining block N2 is also completed during the machining of the machining block N1, so the movement of the tool corresponding to the machining block N2 is performed during 2.0 to 2.1 seconds. Then, the tool stops at the terminal of the machining block N2.

[0084] Next, if the processing control action is transferred to the processing block N3 and later, Fig. 8A As shown, the entirety of the machining blocks N3 to N4 is composed of the machining path L1, and the machining block N5 includes the non-machining path L2. Therefore, when these machining blocks are to be machined continuously, if the buffer is insufficient during the machining of the machining blocks N3 to N4, the tool will stop machining on the machining path L1.

[0085] Therefore, if Fig.10 As shown in FIG. 1 , the tool is controlled so that while it is in the processing block N2, it waits until the processing program acquisition unit 110 can accumulate the processing programs of N3 to N5. That is, after 5.0 seconds, the reading of the processing program of the processing block N5 is completed. On the other hand, the processing time of the processing blocks N3 to N4 takes 1.0 second. Therefore, for example, Figure 4 In step S15 of the process, until it is determined that the buffer shortage does not occur (until it is determined that the buffer shortage does not occur after the processing block N5 is executed), the tool waits for 1.9 seconds at the terminal of the processing block N2.

[0086] During the standby at the end of the machining block N2, the machining program acquisition unit 110 reads data up to the end of the machining block N4 (up to 4.0 seconds). Therefore, when machining from the machining block N3 is restarted after 4.0 seconds, the reading of machining program data up to the machining block N5 is also completed during the machining. As a result, machining of the machining blocks N3 to N5 is performed during 4.0 to 5.0 seconds.

[0087] Next, the processing of the processing block N5 starts. At this time, it can be seen that the processing block N5 includes a non-processing path L2 in the middle, so even if a buffer shortage occurs in the middle of the processing according to the results of the processing simulation, the tool can wait on the non-processing path L2. Therefore, the processing of the processing block N5 continues after 5.0 seconds from the end of the processing of the processing block N4.

[0088] On the other hand, the reading of the machining programs of the machining program blocks N6 to N8 is performed simultaneously and in parallel. In the present embodiment, the machining time of the machining program block N6 is 0.2 seconds. On the other hand, it is assumed that the end time of machining to the terminal of the machining program block N5 is 5.6 seconds later. Therefore, if the machining of the machining program block N5 is completed during the reading of the machining program for the machining program block N6, a buffer shortage occurs in the machining program block N6 which is a non-machining path. Therefore, the tool is made to wait in the non-machining path L2 of the machining program block N5 so that a buffer shortage does not occur during the execution of the machining of the machining program blocks N6 to N8.

[0089] That is, until the middle of the machining program block N5, Figure 4 In the flowchart of the machining control action shown in FIG. 1 , machining of the normal machining subroutine SP is performed, but thereafter, insufficient buffer memory occurs and the process is transferred to the standby subroutine SS. Fig. 9 In the standby subroutine SS shown, the process is transferred from step SS1 to step SS5, and the tool is moved to the terminal of the non-processing path L2 of the processing block N5 and waits. At this time, in the standby subroutine SS, it is determined whether the tool is in contact with the workpiece, so that the tool can be surely made to wait in the non-processing path L2 where there is no contact between the tool and the workpiece.

[0090] Then, the cumulative machining time of machining blocks N6 to N7 is 1.0 seconds, so the machining control unit 120, for example, makes the tool standby on the non-machining path L2 of machining block N5 for 1.4 seconds, and when it is determined that the buffer shortage is eliminated, the machining is restarted from the remaining part of machining block N5, so that the machining of machining block N7 is completed just 8.0 seconds after the reading of the machining program up to machining block N8 is completed. As a result, when the machining of machining block N7 is completed, the reading of the machining program of machining block N8 is completed, so the machining action (movement of the tool) of machining block N8 can be immediately executed from 8.0 seconds later, and as a result, the machining control action can be completed in the shortest time from the reading of machining block N8 to the machining, that is, 8.3 seconds.

[0091] As described above, according to the machining control device and machining control method of the machine tool of the second embodiment of the present invention, it is possible to suppress the occurrence of tool marks on the workpiece, and to cope with the state of insufficient buffer without reducing the yield rate after machining. This is because the machining control device and machining control method of the machine tool of the second embodiment can detect whether the tool is in contact with the workpiece, and configure the standby position of the tool on a non-machining path where there is no contact between the tool and the workpiece.

[0092] The present invention is not limited to the above-described embodiment, and can be modified appropriately without departing from the gist of the invention. The present invention can modify any structural element of the embodiment or omit any structural element of the embodiment within the scope of the invention.

Claims

1. A machining control device for a machine tool, the machining control device using a machining program including a machining path and a non-machining path to perform machining control on a workpiece, characterized in that: The processing control device has: a processing program acquisition unit that reads the processing program in each predetermined reading unit; a machining control unit that controls a machining operation of the machine tool according to the machining program read by the machining program acquisition unit; a simulation execution unit that sequentially reads the machining program read by the machining program acquisition unit and performs machining simulation; a cache state determination unit that determines the cache state of the machining program acquisition unit based on the result of the machining simulation, When the buffer state determination unit determines that the buffer is insufficient, the processing control unit performs control to stop processing on a non-processing path in front of a position where the buffer is insufficient.

2. The processing control device according to claim 1, characterized in that: Once the buffer state determination unit determines that the buffer is insufficient, the process control unit continues to stop the process control until it determines that the insufficient state is resolved.

3. The processing control device according to claim 2, characterized in that: The processing control unit further performs control to move the tool position to the rear end of the non-processing path while the buffer state determination unit determines that the buffer is insufficient.

4. The processing control device according to any one of claims 1 to 3, characterized in that: The processing control unit controls the resumption of processing when the buffer state determination unit determines that the processing program acquisition unit has accumulated the processing program through the processing path next to the current non-processing path during processing stop and to the next non-processing path.

5. A machining control method for a machine tool, the machining control method using a machining program including a machining path and a non-machining path to perform machining control on a workpiece, characterized in that: The above-mentioned machining program is read in according to each specified reading unit. When the machining action of the above-mentioned machine tool is controlled according to the read-in machining program, the read-in machining program is read out in sequence to perform machining simulation, and based on the result of the above-mentioned machining simulation, the cache status of the above-mentioned machining program is judged. When the above-mentioned cache status is judged as insufficient cache, the machining is stopped on a non-machining path in front of the position where the above-mentioned cache shortage occurs.

6. The processing control method according to claim 5, characterized in that: Once the buffer state is determined to be insufficient, processing is stopped until it is determined that the insufficiency has been resolved.

7. The processing control method according to claim 6, characterized in that: While the buffer state is determined to be insufficient, the tool position is moved to the rear end of the non-machining path.

8. The processing control method according to any one of claims 5 to 7, characterized in that: When it is determined as the buffer state that the machining program is accumulated through the next machining path of the current non-machining path during machining stop and further to the next non-machining path, machining is restarted.

Images