COMPUTER

Abstract

The present invention addresses the problem of providing a computer for a machine tool that can easily be configured without repeated trial-and-error to allow a user to select optimal machining conditions. Provided is a computer for a machine tool machining a workpiece by oscillating a cutting tool and the workpiece relative to each other, wherein by means of a machining program, oscillation conditions and machining conditions including the oscillation conditions are acquired, a machining state is calculated as numerical parameters from the acquired machining conditions and oscillation conditions, and on the basis of the calculated result, the machining state is reflected in a selected block of the machining program, whereby the above problem can be solved

Claims

1. A computer for a machine tool that machines a workpiece while oscillating a cutting tool and the workpiece relative to each other based on a machining program, comprising: a machining condition acquisition unit that acquires a machining condition and an oscillation condition; a machining state calculation unit that calculates a machining state from the machining and oscillation conditions acquired by the machining condition acquisition unit; a display unit that displays the machining and oscillation conditions acquired by the machining condition acquisition unit and the machining state calculated by the machining state calculation unit; and a machining condition reflection unit that reflects the machining and oscillation conditions acquired by the machining condition acquisition unit on the machining program.

2. The computer according to claim 1, wherein the machining state calculation unit has a function of obtaining, after the machining state has been determined, the machining condition from the determined machining state by back calculation and reflecting the machining condition on the machining condition acquisition unit.

3. The computer according to claim 1, further comprising: an input unit that receives the machining and oscillation conditions input by a user; and a machining block selection unit that selects, from the machining program, a block on which the machining and oscillation conditions are reflected by the machining condition reflection unit, wherein the machining condition acquisition unit acquires the machining and oscillation conditions from the input unit or the machining block selection unit.

4. The computer according to claim 3, wherein the block selected by the machining block selection unit is a block selected from the machining program by the user or a block determining the machining and oscillation conditions relating to the block selected by the user.

5. The computer according to claim 1, wherein the machining state calculation unit includes any one or more units selected from a chip shredding determination unit that determines a chip shredding availability; a chip length calculation unit that calculates a length of a chip of the workpiece; a surface roughness calculation unit that calculates a surface roughness of the workpiece; an oscillation frequency calculation unit that calculates an oscillation frequency in relative oscillation of the cutting tool and the workpiece; an oscillation amplitude calculation unit that calculates an oscillation amplitude in relative oscillation of the cutting tool and the workpiece; a maximum speed calculation unit that calculates a maximum speed in relative oscillation of the cutting tool and the workpiece; and a maximum acceleration calculation unit that calculates a maximum acceleration in relative oscillation of the cutting tool and the workpiece.

6. The computer according to claim 5, wherein information including information from which the oscillation frequency is uniquely obtained and information from which the oscillation amplitude is uniquely obtained is transmitted to the chip shredding determination unit of the machining state calculation unit from the machining condition acquisition unit.

7. The computer according to claim 5, wherein information including information from which the oscillation frequency is uniquely obtained and a workpiece diameter is transmitted to the chip length calculation unit of the machining state calculation unit from the machining condition acquisition unit.

8. The computer according to claim 5, wherein information including information from which the oscillation frequency is uniquely obtained, information from which the oscillation amplitude is uniquely obtained, a tool feeding speed, and a blade edge radius R is transmitted to the surface roughness calculation unit of the machining state calculation unit from the machining condition acquisition unit.

9. The computer according to claim 5, wherein information including information from which the oscillation frequency is uniquely obtained is transmitted to the oscillation frequency calculation unit of the machining state calculation unit from the machining condition acquisition unit.

10. The computer according to claim 5, wherein information including information from which the oscillation amplitude is uniquely obtained is transmitted to the oscillation amplitude calculation unit of the machining state calculation unit from the machining condition acquisition unit.

11. The computer according to claim 5, wherein information including information from which the oscillation frequency is uniquely obtained, information from which the oscillation amplitude is uniquely obtained, and a tool feeding speed is transmitted to the maximum speed calculation unit of the machining state calculation unit from the machining condition acquisition unit.

12. The computer according to claim 5, wherein information including information from which the oscillation frequency is uniquely obtained, information from which the oscillation amplitude is uniquely obtained, and a tool feeding speed is transmitted to the maximum acceleration calculation unit of the machining state calculation unit from the machining condition acquisition unit.

13. The computer according to claim 1, wherein information including information from which the oscillation frequency is uniquely obtained and information from which the oscillation amplitude is uniquely obtained is transmitted to the display unit from the machining condition acquisition unit, and oscillation motion is graphically displayed on the display unit.

14. A non-transitory computer-readable medium storing a computing program causing a computer to execute computation in a machine tool that machines a workpiece while oscillating a cutting tool and the workpiece relative to each other based on a machining program, the computing program causing the computer to execute a machining condition acquisition step of acquiring a machining condition and an oscillation condition; a machining state calculation step of calculating a machining state from the machining and oscillation conditions acquired in the machining condition acquisition step; a display step of displaying the machining and oscillation conditions acquired in the machining condition acquisition step and the machining state calculated in the machining state calculation step; and a machining condition reflection step of reflecting the machining and oscillation conditions acquired in the machining condition acquisition step on the machining program.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a view for describing oscillation cutting;

[0011] FIG. 2 is a graph of the path of a cutting tool on a surface in oscillation cutting;

[0012] FIG. 3 is a control block diagram of a computer for a machine tool according to the present disclosure;

[0013] FIG. 4 is a diagram showing each calculation unit in a machining state calculation unit of the computer of the present disclosure;

[0014] FIG. 5 is a table showing numerical parameters used in each calculation unit of the machining state calculation unit of the present disclosure;

[0015] FIG. 6 is a view showing a display example of a display unit of the computer of the present disclosure;

[0016] FIG. 7 is a view showing an example where parameters are input on the display unit of the computer of the present disclosure;

[0017] FIG. 8 is a view showing that a parameter to be changed has been selected on the display unit of the computer of the present disclosure;

[0018] FIG. 9 is a view showing a display example after parameters have been changed on the display unit of the computer of the Present disclosure; and

[0019] FIG. 10 is a flowchart of one example of the present disclosure.

PREFERRED MODE FOR CARRYING OUT THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0021] First, oscillation cutting be described. There has been a technique called oscillation cutting. In oscillation cutting, a cutting tool is oscillated in a feeding direction to shred chips caused due to workpiece machining when a workpiece is machined in such a manner that the workpiece is fed in the feeding direction with the cutting tool contacting a workpiece surface while the workpiece is rotating about a main axis, as shown in FIG. 1. By oscillation cutting, an overlap of cutting in previous rotation and cutting in current rotation is formed in every rotation about the main axis, and at such an overlap, air cutting in which the cutting tool does not contact the workpiece is made. By such air cutting, the chips are shredded so that a failure due to, e.g., covering of the cutting tool with the chips can be avoided.

[0022] FIG. 2 shows a graph of the path of the cutting tool on the surface in the above-described oscillation cutting. In this graph, a straight line indicates movement of the point of contact between the cutting tool and the workpiece in a case where the cutting tool is not oscillated, and a corrugated line indicates movement of the point of contact between the cutting tool and the workpiece in a case where the cutting tool is oscillated in the feeding direction. At an overlap of two curved lines, i.e., an overlap of the path of the cutting tool in previous rotation and the path of the cutting tool in current rotation, air cutting is made to shred the chips. From the graph of FIG. 2 obtained in such a manner that an oscillation condition is set/changed, it can be checked whether or not there is an intersection between the previous path and the current path, i.e., the chips are shredded. Conventionally, a trial-and-error process is required for setting the tool path such that the chips are shredded.

[0023] FIG. 3 is a block diagram of a computer for a machine tool according to one embodiment of the present disclosure. As shown in FIG. 3, the computer 1 for the machine tool according to the present disclosure includes an input unit 11, a machining block selection unit 12, a machining condition acquisition unit 20, a machining state calculation unit 30, a machining condition reflection unit 40, and a display unit 50.

[0024] A user can input relevant information for extracting a machining condition and the oscillation condition to the input unit 11, and can select, using the machining block selection unit 12, an intended program block from a machining program for the machine tool. Note that the block selected by the machining block selection unit 12 includes the block selected by the user as described above and a block determining the machining and oscillation conditions relating to the block selected by the user. The information input to the input unit 11 and the information on the program block selected by the machining block selection unit 12 are output to the machining condition acquisition unit 20, and the machining condition acquisition unit 20 receives such information.

[0025] In the machining condition acquisition unit 20, the machining and oscillation conditions are extracted and acquired from the information received from the input unit 11 and the machining block selection unit 12. The machining and oscillation conditions acquired by the machining condition acquisition unit 20 include, for example, information from which an oscillation frequency is uniquely obtained, information from which an oscillation amplitude is uniquely obtained, and information such as a tool feeding speed (mm/min), a workpiece diameter (mm), a blade edge radius R (mm), and a tool clearance angle (). The information from which the oscillation frequency is uniquely obtained includes an oscillation frequency multiplying factor (multiplying number) I indicating an oscillation frequency, per rotation about the main axis, and the information from which the oscillation amplitude is uniquely obtained includes an oscillation amplitude multiplying factor (multiplying number) K indicating the magnitude of oscillation amplitude with respect to a feeding amount per rotation about the main axis. The tool feeding speed is obtained from a rotation number S (1/min) about the main axis and a feeding amount F (mm/rev) per rotation. The information such as the above-described parameters relating to the machining and oscillation conditions extracted and acquired by the machining condition acquisition unit 20 is transmitted to the machining state calculation unit 30, the machining condition reflection unit and the display unit 50.

[0026] As shown in FIG. 4, the machining state calculation unit includes a chip shredding determination unit 31, a chip length calculation unit 32, a surface roughness calculation unit 33, an oscillation frequency calculation unit 34, an oscillation amplitude calculation unit 35, a maximum speed calculation unit 36, and a maximum acceleration calculation unit 37.

[0027] The chip shredding determination unit 31 determines the availability of chip shredding from the oscillation frequency multiplying factor I and the oscillation amplitude multiplying factor K. The chip length calculation unit 32 calculates a chip length from the oscillation frequency multiplying factor I and the workpiece diameter. The surface roughness calculation unit 33 calculates a surface roughness from the oscillation frequency multiplying factor I, the oscillation amplitude multiplying factor K, the feeding amount F per rotation, and the blade edge radius P. The oscillation frequency calculation unit 34 calculates the oscillation frequency from the oscillation frequency multiplying factor I and the rotation number S about the main axis. The oscillation amplitude calculation unit 35 calculates the oscillation amplitude from the oscillation amplitude multiplying factor K and the feeding amount F per rotation. The maximum speed calculation unit 36 calculates the maximum speed from the oscillation frequency multiplying factor I, the oscillation amplitude multiplying factor K, the rotation number S about the main axis, and the feeding amount F per rotation. The maximum acceleration calculation unit 37 calculates the maximum acceleration from the oscillation frequency multiplying factor I, the oscillation amplitude multiplying factor K, the rotation number S about the main axis, and the feeding amount F per rotation.

[0028] The chip shredding availability information which is the information calculated/determined by the chip shredding determination unit 31 is transmitted to the machining condition reflection unit 40, and is also transmitted to the display unit 50. Moreover, the numerical data such as the chip length, the surface roughness, the oscillation frequency, the oscillation amplitude, the maximum speed, and the maximum acceleration is transmitted to the display unit 50. In a case where the chip shredding availability information displayed on the display unit 50 indicates unavailable, i.e., the chips are not properly shredded, the user can newly input the relevant information for extracting the machining and oscillation conditions to the input unit 11. The information newly input to the input unit 11 is transmitted to the machining condition acquisition unit, and accordingly, the machining and oscillation conditions are newly acquired. The machining condition reflection unit 40 reflects the machining and oscillation conditions newly acquired by the machining condition acquisition unit 20 on the machining program block selected by the machining block selection unit. Even in a case where the chip shredding availability information displayed on the display unit 50 indicates available, the user may newly input, with reference to each result (the chip length, the maximum speed, etc.) obtained by the machining state calculation unit, the relevant information for extracting the machining and oscillation conditions to the input unit 11, and these conditions may be reflected on the machining program block selected by the machining block selection unit. Alternatively, the oscillation condition where the values obtained by any one or more units selected from the machining state calculation unit 30 are minimized may be obtained by back calculation, and may be reflected on the machining condition acquisition unit 20. The oscillation condition where the values are minimized is calculated from a relational expression among the units selected from the machining state calculation unit 30 and the machining/oscillation condition. In this case, the oscillation condition where chip shredding is determined as available from an expression for determining the availability of chip shredding and the values obtained by the units selected from the machining state calculation unit 30 are the minimum values may be calculated.

[0029] On the display unit 50, each parameter relating to the above-described machining and oscillation conditions acquired by the machining condition acquisition unit 20 and data on the results of the machining state calculated by the machining state calculation unit 30 are displayed. Displaying of the data on the results of the machining state also includes graphic displaying of oscillation motion. Moreover, on the display unit 50, the user can input each parameter relating to the machining and oscillation conditions, and these values are taken as the input to the input unit 11. In addition, the user can specify the block from the machining program displayed on the display unit 50, and such a specified program block is taken as the block selected using the machining block selection unit 12 by the user.

[0030] FIG. 5 summarizes a relationship among the parameters of the machining and oscillation conditions including the oscillation frequency multiplying factor I, the oscillation amplitude multiplying factor K, the rotation number S about the main axis, the feeding amount F per rotation, the workpiece diameter , and the blade edge radius R, the parameters being used by each of the chip shredding determination unit 31, the chip length calculation unit 32, the surface roughness calculation unit 33, the oscillation frequency calculation unit 34, the oscillation amplitude calculation unit 35, the maximum speed calculation unit 36, and the maximum acceleration calculation unit 37 of the machining state calculation unit 30. Note that in addition to the above-described parameters, the parameters of the machining and oscillation conditions also include information on the clearance angle () and taper angle () of the tool, etc.

[0031] As a method for acquiring each of the above-described parameters, the oscillation frequency multiplying factor I, the oscillation amplitude multiplying factor K, the feeding amount F per rotation, and the rotation number S about the main axis are acquired from modal information. The modal information is unchanged information with a constant value after the user has set the information once as long as the user does not newly set the information again. The blade edge radius R and the clearance angle are acquired from modal tool information (T-number). The workpiece diameter can be acquired from the X-coordinate of the selected. machining program block, and the taper angle can be acquired from the start and end points of the XZ-coordinates of the selected machining program block.

[0032] Next, a specific technique of the embodiment of the present disclosure will be described with reference to a display form on the display unit as shown in FIGS. 6 and 7. FIG. 6 shows a display example of the display unit 50 in the computer 1 for the machine tool, and the machining program is displayed on the left side. In FIG. 6, The user specifies, using the machining block selection unit 12 (FIG. 3), a row (Z10.0 X17.0;) of the machining program with a dot, and a block (a row of G00 Z30.0; to a row of Z10.0 X17.0;) relating to this row is selected accordingly.

[0033] On the right side in FIG. 6, the machining and oscillation conditions for the selected machining program block are displayed. Specifically, on the upper side, a waveform chart showing the path of the cutting tool in the selected machining program block is displayed. In an upper frame on the lower side, the parameters (the oscillation frequency multiplying factor (multiplying number) I, the oscillation amplitude multiplying factor (multiplying number) K, the feeding amount F (mm/rev) per rotation, the rotation number (min.sup.1) about the main axis, the workpiece diameter (mm), the taper angle (), the blade edge radius R (mm), and the clearance angle ()) relating to the machining and oscillation conditions for the selected machining program block are displayed. In a lower frame on the lower side, estimated values (the chip shredding availability, the chip length (mm), the average roughness Ra (mm), the frequency (Hz), the amplitude (mm), the maximum speed (mm/min), and the maximum acceleration (mm/min.sup.2)) of results of machining according to the selected machining program block are displayed. Moreover, for the frequency (Hz), the amplitude (mm), the maximum speed (mm/min), and the maximum acceleration (mm/min.sup.2), the upper limits in machine operation are displayed therebelow.

[0034] FIG. 6 shows that the chip shredding availability is determined as unavailable (cross mark) from I and K and the chip length (mm) and the average roughness Ra (mm) are not displayed. Moreover, it shows that the frequency (Hz)=125.000, the maximum speed (mm/min)=1663.72, and the maximum acceleration (mm/min.sup.2)=1.8505.5 exceed the upper limits (70.000, 1500.00, and 10000.0 in this order) thereof, and therefore, exceed the upper limits in machine operation.

[0035] Next, a method in which the user inputs/sets the machining and oscillation conditions via the input unit 11 (FIG. 3) to reflect these conditions on the machining program will be described with reference to FIG. 7. As shown in a display example of FIG. 7, the user can input the parameters relating to the machining and oscillation conditions as shown in the upper fame on the lower right side. In this example, the oscillation frequency multiplying factor (multiplying number) I is changed to 0.500, the oscillation amplitude multiplying factor (multiplying number) K is changed to 1.50, and these parameter values are inserted into the selected machining program block. In this example, the oscillation frequency multiplying factor (multiplying number) I and the oscillation amplitude multiplying factor (multiplying number) K are changed, and therefore, a command of G8.5 in the selected machining program block is re-edited.

[0036] Machining results calculated alter these parameter values have been reflected on the machining program are shown in the lower frame on the lower right side in FIG. 7. The machining results shown in the lower frame on the lower right side are the frequency (Hz)=41.666, the amplitude (mm)=0.075, the maximum speed (ram/min)=839.049, and the maximum acceleration (mm/min.sup.2)=2570.21, and any of these values is equal to or less than the upper limit. Thus, the chip shredding availability is determined as available (circle mark). In addition, the chip length (mm)=106.814 and the average roughness Ra (mm)=0.319 can also be displayed.

[0037] As seen from FIGS. 6 and 7, the, parameters relating to the machining and oscillation conditions can be easily input in the upper frame on the lower right side on the display unit 50 (FIG. 3), the input parameters are promptly inserted into the selected machining program block and are reflected on the machining program, and the calculation results thereof are promptly displayed in the lower frame on the lower right side. Thus, the user can efficiently change the parameters relating to the machining and oscillation conditions to proper values while predicting the machining results by machining program calculation processing.

[0038] Next, a method in which the oscillation condition where the values obtained by any one or more units selected from the machining state calculation unit 30 are minimized is obtained by back calculation and is reflected on the machining condition acquisition unit 20 as described above will be described with reference to FIGS. 8 and 9. FIG. 8 shows a state in which the machining and oscillation conditions are input and the value obtained by each unit of the machining state calculation unit is derived. In this state, any of the frequency, the amplitude, the maximum speed, and the maximum acceleration which are the machining results is equal to or less than the upper limit, and therefore, the chip shredding availability is determined as available (circle mark).

[0039] In a case where the oscillation condition where the values obtained by any one or more units are minimized is obtained by back calculation and is reflected on the machining condition acquisition unit 20, any one or more units are selected from the machining state calculation unit. In this case, the maximum acceleration is selected, and a cursor is placed thereover. Then, a minimum value setting button is clicked, and accordingly, the oscillation condition where the maximum acceleration is minimized is set within a chip shredding available range as shown in FIG. 9. That is, the values of K, I, the frequency, the amplitude, and the maximum speed are changed accompanied by a change in the maximum acceleration. Since the oscillation condition is changed, each machining state value is also updated, and the values of the chip length and the average roughness Ra are updated.

[0040] Next, an example of use of the computer for the machine tool according to the present disclosure will be described with reference to a flowchart of FIG. 8. First, the machining condition acquisition unit acquires the machining and oscillation conditions from the machining block selection unit (Step 1). This step is performed in such a manner that the user selects one block from the machining program and selects a row from which results are obtained.

[0041] Next, each parameter relating to the machining and oscillation conditions is extracted from the selected block, and is transmitted to the machining state calculation unit. That is, the machining state calculation unit calculates, from the acquired machining and oscillation conditions, state results at the time of such acquisition (Step 2). These results are used subsequently in Step 3.

[0042] In Step 3, it is determined, from the state results calculated in Step 2, whether or not the machining and oscillation conditions acquired by the machining condition acquisition unit are proper (Step 3). In a case where the answer of Step 3 is YES, i.e., it is determined that the machining and oscillation conditions are proper, the processing proceeds to Step 5. In a case where the answer of Step 3 is NO, i.e., it is determined that the machining and oscillation conditions are not proper, the processing returns to Step 2 through Step 4.

[0043] In Step 4, the machining condition acquisition unit acquires the machining and oscillation conditions from the input unit. This step is performed in such a manner that the user inputs numerical values to input fields for the parameters relating to the machining and oscillation conditions on the display unit. Then, the processing proceeds to Step 2, and the machining state calculation unit calculates, from the acquired machining and oscillation conditions, state results at the time of such acquisition again, and these calculation results are used subsequently in Step 3. Until the answer is determined as YES in Step 3, i.e., until it is determined that the machining and oscillation conditions are proper, a loop of Steps 2, 3, and 4 is repeated.

[0044] In Step 5, the acquired machining and oscillation. conditions are inserted into the machining program, and the machining program is re-edited (Step 5). Accordingly, the machining condition reflection unit reflects the acquired machining and oscillation conditions on the machining program (Step 6). That is, by this step, the user can obtain a determination result, which indicates whether or not the machining and oscillation conditions are proper, once again, and this flow ends.

[0045] As described above, the computer for the machine tool according to the present disclosure has the following significant features and advantageous effects: the parameters relating to the machining and oscillation conditions can be easily input; and the machining program, the parameters relating to the machining and oscillation conditions, and the machining results (state) are displayed on one screen, and therefore, the user can easily select and set the optimal machining and oscillation conditions without repeating the trial-and-error process.

[0046] Implementation of the present invention has been described above with reference to the embodiment, but the present invention is not limited to this embodiment. Needless to say, the present invention can be implemented in various aspects without departing from the gist of the present invention.

EXPLANATION OF REFERENCE NUMERALS

[0047] 1 Computer

11 Input Unit

12 Machining Block Selection Unit

20 Machining Condition Acquisition Unit

30 Machining State Calculation Unit

31 Chip Shredding Determination Unit

32 Chip Length Calculation Unit

33 Surface Roughness Calculation Unit

34 Oscillation Frequency Calculation Unit

35 Oscillation Amplitude Calculation Unit

36 Maximum Speed Calculation Unit

37 Maximum Acceleration Calculation Unit

40 Machining Condition Reflection Unit

50 Display Unit