Machining simulation device

Abstract

A machining simulation device according to one aspect of the present disclosure simulates the operation of a machine tool including a tool and a workpiece, the machining simulation device comprising: a speed acquisition unit that acquires speed information indicating the rotation speed of the tool; a tool model acquisition unit that acquires a tool model which corresponds to the speed information acquired by the speed acquisition unit and which can change in shape in accordance with the rotation speed; a simulation execution unit that uses the tool model acquired by the tool model acquisition unit to execute a simulation of the workpiece machining operation by the tool in the machine tool; and an interference check unit that checks for interference of the tool with another object on the basis of the results of the simulation by the simulation execution unit.

Description

Machining simulation device

[0001] The present invention relates to a machining simulation device.

[0002] Before executing a machining program with a machine tool to actually machine a workpiece, a machining simulation device that simulates the operation of the machine tool may be used to check the appropriateness of the machining program, specifically to check for interference between the tool and other objects, such as unintended contact of the tool with the workpiece, etc. Such a machining simulation device uses a three-dimensional tool model of the tool and a three-dimensional model of the workpiece, etc., to simulate the operation of the machine tool and, therefore, the presence or absence of interference (see, for example, Patent Document 1).

[0003] Furthermore, the operation of a machine tool is realized by outputting interpolation pulses generated by a numerical control device to a servo motor, but there is a technology that simulates the machine operation after output of these interpolation pulses to the servo motor before outputting them, predicts in advance whether the tool will interfere with another object, and stops output of the interpolation pulses to the servo motor if interference occurs (see, for example, Patent Document 2).

[0004] Furthermore, there is a technology in which future machine tool operations are calculated by looking ahead at the machining program, i.e., the future position of the tool (advance position) is calculated, and the advance position is used to predict interference between the tool and other objects, and the tool is stopped before it actually reaches that position (see, for example, Patent Document 3).

[0005] International Publication No. 2011 / 125129 Japanese Patent Application Laid-Open No. 9-230918 Japanese Patent Application Laid-Open No. 2019-192103

[0006] Generally, a 3D tool model, such as a tool, has a fixed shape and is defined by data written in a predetermined format, such as an STL file. However, some tools change shape with rotation. Furthermore, for example, a tool with an eccentric shape occupies a larger space when rotating than when not rotating. Therefore, it is necessary to confirm that the tool does not interfere with other objects by defining the model shape of the tool as the sum of the spaces that the tool can occupy at each rotational speed. In other words, conventional machining simulation devices may determine that the tool will interfere even when interference does not occur at the actual rotational speed. Therefore, a machining simulation device that can more accurately confirm tool interference is desired.

[0007] A machining simulation device according to one aspect of the present disclosure is a machining simulation device that simulates the operation of a machine tool including a tool and a workpiece, and includes: a speed acquisition unit that acquires speed information indicating the rotational speed of the tool; a tool model acquisition unit that acquires a tool model that corresponds to the speed information acquired by the speed acquisition unit and whose shape can change depending on the rotational speed; a simulation execution unit that executes a simulation of the machining operation of the workpiece by the tool in the machine tool using the tool model acquired by the tool model acquisition unit; and an interference confirmation unit that confirms interference of the tool with another object based on a result of the simulation by the simulation execution unit.

[0008] Fig. 3 is a block diagram showing the configuration of a machining simulation device according to a first embodiment of the present disclosure. Fig. 4 is a schematic side view showing a tool model of a chip blower tool when it is not rotating. Fig. 5 is a schematic side view showing a tool model of the same chip blower tool as in Fig. 2 when it is rotating at high speed. Fig. 6 is a schematic side view showing a tool model of the same chip blower tool as in Fig. 2, covering from when it is not rotating to when it is rotating at high speed. Fig. 7 is a block diagram showing the configuration of a machining simulation device according to a second embodiment of the present disclosure.

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Fig. 1 is a block diagram showing the configuration of a machining simulation device 1 according to a first embodiment of the present disclosure.

[0010] The machining simulation device 1 simulates the operation of a machine tool including a tool and a workpiece based on a machining program. The machining simulation device 1 includes a program storage unit 10, a tool model storage unit 20, a program analysis unit 30, a speed acquisition unit 40, a tool model acquisition unit 50, a simulation execution unit 60, and an interference confirmation unit 70. The machining simulation device 1 can be realized by causing one or more computer devices having a memory, a processor, an input / output interface, etc. to execute an appropriate processing program. Each component of the machining simulation device 1 is a classification of the function of the machining simulation device 1, and does not necessarily have to be clearly distinguishable in terms of physical configuration and program configuration.

[0011] The program storage unit 10 stores at least a portion of a machining program. In other words, the program storage unit 10 has a working memory space for storing a portion of the machining program necessary for executing a simulation. The machining program may be written in a well-known language such as G-code. The configuration of the program storage unit 10 may be the same as that of a well-known machining simulation device.

[0012] The tool model storage unit 20 stores one or more tool models that are models of the three-dimensional shape of a space occupied by a tool. The tool models may be stored as well-known data files such as STL files. At least one of the tool models stored in the tool model storage unit 20 changes shape depending on the rotation speed. Therefore, the tool model storage unit 20 stores the relationship between the rotation speed of the tool (which may be a value of speed information, which will be described later) and the tool model (the shape of the space occupied by the tool).

[0013] The tool model storage unit 20 may define at least a part of the shape of the space occupied by the tool, such as the diameter, length, angle, etc., as a function of the rotational speed of the tool, but it is more convenient to classify the rotational speed of the tool into multiple categories and register one tool model for each category to which the rotational speed belongs.

[0014] The tool model of the tool stored in the tool model storage unit 20 preferably has the shape of a rotating body of the tool when the rotational speed has a value. In other words, when the rotational speed of the tool has a value, the shape of the cross section including the rotation axis of the tool model is preferably constant regardless of the cross section angle. This eliminates the need to consider the rotational angle position of the tool when checking for interference of the tool, thereby reducing the calculation load. On the other hand, when the rotational speed of the tool is zero, the tool model may be a non-rotating body whose cross section shape varies depending on the cross section angle.

[0015] A tool whose occupied space changes shape depending on the rotational speed typically includes a movable part whose posture changes depending on the rotational speed, resulting in a change in actual shape. In this case, the tool model storage unit 20 preferably stores a relationship between the rotational speed and a tool model derived from the posture of the movable part. This allows for a more accurate representation of the shape of the occupied space of the tool, which changes depending on the rotational speed. A specific example of a tool whose actual shape changes depending on the rotational speed is a chip blower tool. A chip blower tool has multiple blower blades attached to a rotating shaft as movable parts so as to be swingable. When the rotational speed is low, the blower blades extend axially to reduce the overall diameter of the tool. When the rotational speed is high, the blower blades deploy by centrifugal force, spreading radially outward. Therefore, the diameter and axial length of the tool model of a chip blower tool change depending on the rotational speed.

[0016] When the tool has a moving part, the tool model may be one of three types: a rotating body shape applied when the rotational speed is sufficiently low (no rotation or low rotation speed) and when the orientation of the moving part is in an initial state; a rotating body shape applied when the rotational speed is sufficiently high and when the orientation of the moving part has changed to a limit state; and a rotating body shape that encompasses all orientations of the moving part and is applied when the orientation of the moving part cannot be identified because the rotational speed is in an intermediate range that does not fall into either of the above two cases and is unclear. In other words, the tool model storage unit 20 may store a tool model of a rotating body shape when the orientation of the moving part is in an initial state, a tool model of a rotating body shape that encompasses all orientations of the moving part, and a tool model of a rotating body shape when the orientation of the moving part has changed to a limit state. For example, FIG. 2 shows a tool model 100 of a chip blower tool when it is not rotating (or when it is rotating at a low speed below a predetermined rotational speed), FIG. 3 shows a tool model 100 of the same chip blower tool when it is rotating at a high speed, and FIG. 4 shows a tool model 100 that encompasses all shapes of the same chip blower tool. The tool model 100 of the chip blower tool has a round rod-shaped shaft portion 101 that models a shaft that is coaxially attached to the main spindle of the machine tool, a disk-shaped holding portion 102 that models a holding portion that swingably holds a plurality of blower blades, and a deforming portion 103 that is a rotor that encompasses the plurality of blower blades and whose shape changes depending on the rotational speed.When the rotational speed range in which the attitude of the movable portion reaches a limit state is small, the tool model storage unit 20 may store two tool models by dividing the rotational speed into two sections: a no-rotation (or low-speed rotation region) and all other rotational speed regions (including when the rotational speed is unknown).

[0017] Furthermore, even if the actual shape of the tool does not change, if a part of the tool is eccentric with respect to the rotation axis, the shape of the tool model can be changed according to the rotation speed. Specifically, when the tool is rotating, interference is determined using a tool model having the shape of a rotating body, and when the tool is not rotating, a tool model that models the shape of the tool in a stationary state that is not a rotating body, i.e., a tool model having a shape that reflects the eccentric part, is used. This makes it possible to more accurately determine tool interference without excessively increasing the calculation load. In this case, the tool model storage unit 20 stores two tool models, one for when the rotation speed is zero and one for when the rotation speed is a value (other than zero).

[0018] The program analysis unit 30 analyzes the machining program and derives command values ​​that specify the position, posture, and rotation speed of the tool for each control cycle according to the machining program. The configuration of the program analysis unit 30 may be the same as that of a known machining simulation device.

[0019] The speed acquisition unit 40 acquires speed information indicating the rotational speed of the tool. The tool rotational speed is obtained by analyzing the machining program in the program analysis unit 30 or analyzing the state of the machine tool in the simulation execution unit 60. Specifically, the speed information is preferably at least one of a spindle speed command value (a value output according to the machining program) and a spindle speed estimate value (an estimated value of the spindle rotational speed estimated from the current value of the spindle motor in a simulation, an estimated value of the spindle rotational speed estimated from the gear ratio, or an estimated value of the spindle rotational speed during acceleration / deceleration estimated from the acceleration / deceleration of the spindle). By using speed information that indicates the tool rotational speed relatively accurately, the presence or absence of interference can be accurately confirmed using a tool model that accurately reflects the tool state. Note that the rotational speed of the tool may differ from the spindle rotational speed, for example, when the tool is driven by the spindle via a gear. Furthermore, the drive current frequency of the spindle motor may also be used as the speed information.

[0020] The tool model acquisition unit 50 acquires a tool model corresponding to the speed information acquired by the speed acquisition unit 40 from the tool model storage unit 20. The tool model acquisition unit 50 may be configured to transmit the speed information or the rotational speed of the tool converted from the speed information to the tool model storage unit 20 and acquire a data file of the corresponding tool model from the tool model storage unit 20. The tool model acquisition unit 50 may also be configured to identify a tool to be used based on a tool number described in a machining program and acquire a tool model corresponding to the rotational speed of the identified tool. The tool model acquisition unit 50 may also be configured to generate or modify a tool model based on the information acquired from the tool model storage unit 20.

[0021] The simulation executing unit 60 executes a simulation of the machining operation of the workpiece by the tool in the machine tool using the tool model acquired by the tool model acquiring unit 50. Specifically, the simulation executing unit 60 places the tool model acquired by the tool model acquiring unit 50 and a model of the workpiece, etc. in a virtual space, and moves the tool model within the virtual space based on the machining program. The configuration of the simulation executing unit 60 may be similar to that of a known machining simulation device, except that a tool model whose shape changes depending on the rotation speed is used.

[0022] The interference checking unit 70 checks whether or not the tool interferes with another object, i.e., whether or not an unintended overlap occurs between the tool model and a model of another object such as a workpiece, based on the results of the simulation performed by the simulation executing unit 60. Typically, the interference checking unit 70 determines that the tool will interfere with another object when the tool model and a model of the workpiece overlap spatially while the tool model is being moved from one machining point to the next, or when the tool model and a model of an object other than the workpiece overlap spatially. If it is determined that the tool will interfere with another object, the interference checking unit 70 may be configured to notify the user of this and prompt the user to modify the machining program. The configuration of the interference checking unit 70 may be similar to that of known machining simulation devices.

[0023] The machining simulation device 1 having the above configuration checks for interference of the tool with another object by changing the shape of the tool model in accordance with the rotational speed of the tool. Therefore, interference between the tool and another object can be checked using a tool model that represents the shape of the minimum necessary occupying space in accordance with the rotational speed of the tool, and therefore, it is possible to prevent erroneous detection of interference when no interference actually occurs.

[0024] Next, a second embodiment of the present disclosure will be described. Fig. 5 is a block diagram showing the configuration of a machining simulation device 2 according to a fifty-second embodiment of the present disclosure. In the description of the machining simulation device 2 of this embodiment, the same components as those in the machining simulation device 1 of Fig. 1 are designated by the same reference numerals, and redundant description may be omitted.

[0025] The machining simulation device 2 uses information generated by a numerical control device to simulate the operation of a machine tool including a tool and a workpiece. The machining simulation device 2 can be configured to predict interference between a tool and another object in advance by simulating future command values ​​calculated in advance by looking ahead to a machining program in the machine tool's control device before the machine tool executes them. Alternatively, the machining simulation device 2 can be configured to predict interference between a tool and another object in advance by simulating machine operation when interpolation pulses are output to a motor in a numerical control device that performs interpolation processing for motor operation before outputting the interpolation pulses to the motor.

[0026] This allows the machining simulation device 2 to stop the machine tool before the tool actually interferes with another object. The machining simulation device 2 includes a tool model storage unit 20, an operation information acquisition unit 80, a speed acquisition unit 40, a tool model acquisition unit 50, a simulation execution unit 60, and an interference confirmation unit 70. Like the machining simulation device 1 in Fig. 1, the machining simulation device 2 is realized by causing one or more computer devices to execute appropriate processing programs, and its components are classified according to the functions of the machining simulation device 2.

[0027] The operation information acquisition unit 80 acquires various types of operation information indicating the state of the machine tool. Specifically, the operation information acquisition unit 80 acquires, as operation information, information necessary to identify the operation state of the machine tool in a simulation of the operation of the machine tool from the machine tool, such as information on the tools used by the machine tool, interpolation pulses, position information on each axis, and the rotational speed of the spindle measured by a device such as an encoder. The operation information acquisition unit 80 may convert the information acquired from the machine tool into operation information to be used in the simulation as necessary.

[0028] The speed acquisition unit 40 acquires speed information indicating the rotational speed of the tool (actual spindle speed) from the analysis results of the state of the machine tool in the operation information acquired by the operation information acquisition unit 80.

[0029] The tool model acquisition unit 50 acquires from the tool model storage unit 20 a tool model corresponding to the tool used by the machine tool acquired by the operation information acquisition unit 80 and the speed information acquired by the speed acquisition unit 40.

[0030] The simulation execution unit 60 places the tool model and the model of the workpiece, etc. acquired by the tool model acquisition unit 50 in a virtual space, and moves the tool model and the model of the workpiece, etc. within the virtual space at a speed corresponding to the speed of each axis acquired by the operation information acquisition unit 80.

[0031] The interference checking unit 70 checks whether or not the tool will interfere with another object based on the results of the simulation by the simulation executing unit 60. If it is determined that the tool will interfere with another object, the interference checking unit 70 can stop the machine tool before the tool actually interferes with the other object by sending an emergency stop signal to the machine tool.

[0032] The following supplementary note is further disclosed regarding the above embodiment and modified examples. (Supplementary Note 1) A machining simulation device (1) is a machining simulation device (1) that simulates the operation of a machine tool including a tool and a workpiece, and includes: a speed acquisition (40) that acquires speed information indicating the rotational speed of the tool by analyzing a machining program or the state of the machine tool; a tool model acquisition unit (50) that acquires a tool model that corresponds to the speed information acquired by the speed acquisition unit (40) and whose shape can change depending on the rotational speed; a simulation execution unit (60) that executes a simulation of the machining operation of the workpiece by the tool in the machine tool using the tool model acquired by the tool model acquisition unit (50); and an interference confirmation unit (70) that confirms interference of the tool with another object based on the result of the simulation by the simulation execution unit (60).

[0033] (Supplementary Note 2) The machining simulation device (1) of Supplementary Note 1 or 2 may further include a tool model storage unit (20) that stores the relationship between the rotation speed of the tool and the tool model.

[0034] (Supplementary Note 3) In the machining simulation device (1) of Supplementary Note 3, the tool may include a movable part whose posture changes depending on the rotation speed, and the tool model storage unit (20) may store a relationship between the speed information and a tool model derived from the posture of the movable part.

[0035] (Supplementary Note 4) In the machining simulation device (1) of any one of Supplementary Note 1 to Supplementary Note 3, the tool model may have a shape of a rotating body of the tool when the rotation speed has a value.

[0036] Although the present disclosure has been described in detail above, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible to these embodiments without departing from the gist of the present disclosure or the gist of the present disclosure derived from the content of the claims and their equivalents.

[0037] The machining simulation device according to the present disclosure may not include a tool model storage unit, and may acquire a tool model corresponding to tool speed information from an external device. That is, the tool model storage unit may be provided in the external device. Furthermore, the machining simulation device according to the present disclosure may be configured integrally with a numerical control device or the like that controls the machine tool. That is, the machining simulation device according to the present disclosure may be realized as one function of the control device of the machine tool.

[0038] REFERENCE SIGNS LIST 1 Machining simulation device 10 Program storage unit 20 Tool model storage unit 30 Program analysis unit 40 Speed ​​acquisition unit 50 Tool model acquisition unit 60 Simulation execution unit 70 Interference confirmation unit 80 Operation information acquisition unit

Claims

1. A machining simulation device that simulates the operation of a machine tool, including tools and workpieces, A speed acquisition unit that acquires speed information indicating the rotational speed of the tool, A tool model acquisition unit acquires a tool model whose shape can change according to the rotational speed, corresponding to the speed information acquired by the speed acquisition unit, A simulation execution unit that uses the tool model acquired by the tool model acquisition unit to perform a simulation of the machining operation of the workpiece by the tool in the machine tool, An interference confirmation unit confirms interference between the tool and other objects based on the results of the simulation performed by the simulation execution unit, A machining simulation device equipped with the following features.

2. The machining simulation apparatus according to claim 1, wherein the speed information is at least one of the spindle speed command value, the actual spindle speed, and the estimated spindle speed.

3. The machining simulation apparatus according to claim 1 or 2, further comprising a tool model storage unit that stores the relationship between the rotational speed of the tool and the tool model.

4. The tool includes a movable part that changes its orientation according to the rotational speed, The machining simulation apparatus according to claim 3, wherein the tool model storage unit stores the relationship between the speed information and the tool model derived from the posture of the movable part.

5. The machining simulation apparatus according to claim 1 or 2, wherein the tool model has the shape of the rotating body of the tool when the rotational speed is a value.