JP3547618B2 - Computer-readable recording medium storing electric discharge machining apparatus, electric discharge machining method, and program for causing computer to execute electric discharge machining method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is directed to an electric discharge machining apparatus and an electric discharge machining method for performing machining with high accuracy by avoiding electric discharge on a connection path, and a computer-readable recording storing a program for causing a computer to execute the electric discharge machining method. Media related.
[0002]
[Prior art]
Conventionally, instead of transfer processing using a full-form tool, an electric discharge machine that moves a tool electrode having a simple shape such as a cylinder, a cylinder, and a prism in three dimensions by numerical control, and then processes the workpiece into a desired three-dimensional shape. It has been known. In such an electric discharge machining apparatus, there is no need to produce a complex tool electrode having a complicated shape, and therefore, there is an advantage that the mold production cost and the production time can be improved. In addition, since a tool electrode having a simple shape is used, there is an advantage that standardization of the tool electrode is possible, construction of a CAM system is easy, and automation of a machining process can be expected.
[0003]
FIG. 9 is an explanatory diagram showing an example of a machining path and a movement of a tool electrode by a conventional electric discharge machine. A case will be described as an example where a circular pocket portion (island shape) S1 to S4 is formed in a quadrangular pocket (pond shape) I on a workpiece W. The tool electrode is initially at an arbitrary position A on the XY coordinates, and is at an arbitrary position on the Z coordinates (position at a distance a from the upper surface of the workpiece W). First, the tool electrode moves horizontally from the position A on the XY coordinates to the machining start position Rs. Next, a predetermined pulse voltage is applied between the tool electrode and the workpiece W, and the tool electrode is lowered by a distance a. When the tool electrode is lowered, a discharge removal phenomenon occurs between the tool electrode and the workpiece W. The workpiece W is machined into the shape of the tool electrode by the removal action by the liquid interruption continuous discharge.
[0004]
Next, the workpiece W is removed while the tool electrode moves along the rectangular contour according to the machining path K (positions B1 to B5). Subsequently, when the machining for one round of the pond shape I is completed, the tool electrode moves from the outer peripheral machining path K1 (positions B1 to B5) to the innermost machining path K2 (positions C1 to C12). When the machining path interferes with the island shape S, the tool electrode moves along the contour of the island shape S (positions C2 to C3). The tool electrode moves inside the pond shape I according to the machining path K2 (position C3 to position C12), and returns to the original position (position C1) again. Next, the inside of the pond shape is further moved in accordance with the machining path K3 (position D1 to position D3 to position D1).
[0005]
When there is no more unprocessed area in the processing path K3, the processing electrode moves to the unprocessed processing path K4 on the right side in the drawing. In this case, as shown in FIG. 9, the tool electrode linearly moves horizontally over the unprocessed area M according to a connection path R connecting the position D1 to the start position E1 of the processing path K4. Then, the tool electrode starts machining from the position E1 according to the machining path K4 (positions E1 to E2), and processes the entire area within the pond shape.
[0006]
When the tool electrode reaches the processing end point (not shown), the tool electrode moves up by the distance a, moves horizontally, and returns to the initial position A. Thus, the processing of the first layer is completed. Thereafter, the same processing as above is performed a plurality of times, and the removal processing is performed to a desired depth.
[0007]
[Problems to be solved by the invention]
However, in the above-mentioned conventional electric discharge machine, even if the connection path R (from the connection path start point Rs to the connection path end point Re in FIG. 9) is such that the tool electrode moves on the unmachined area M, the tool is not changed. The electrode moves horizontally. For this reason, as shown in FIGS. 10A and 10B, a discharge occurs in the middle of the connection path R and the tool electrode 8 is consumed. Therefore, there is a problem that machining is left behind (step) near the connection path end point Re, and the accuracy of the machined surface is reduced.
[0008]
In addition, if a discharge occurs in the middle of the connection path R, a portion that should be an unprocessed area is removed (processed portion Ma). For this reason, there is a problem that the removal processing is performed twice when the actual processing path passes later, and the processing is performed deeper than in other areas, and the accuracy of the processed surface is reduced. On the other hand, the Z-axis control of the tool electrode 8 is performed, but it is not preferable to move the tool electrode 8 on the connection path R in the Z-axis except for a case where there are a plurality of pond shapes I. This is because discharge occurs when the tool electrode 8 is lowered.
[0009]
In view of the above, the present invention has been made in view of the above, and an electric discharge machining apparatus, an electric discharge machining method, and an electric discharge machining method for performing accurate machining by avoiding an electric discharge on a connection path are provided to a computer. It is an object to obtain a computer-readable recording medium storing a program to be executed.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the electric discharge machining apparatus according to the present invention controls feed of a tool electrode in XY axes based on a machining path and feed control in a Z axis direction for correcting a lengthwise consumption of a tool electrode. By combining and performing three-dimensional control, the desired three-dimensional shape is obtained by applying a pulse-like voltage between the tool electrode and the non-workpiece on the machining path and on the connection path connecting the separated machining paths. In the electric discharge machining apparatus performing the removal machining, on a connection path connecting the separated machining paths, an unprocessed area determination unit that determines an unprocessed area, and when the connection path moves on the unprocessed area, the tool electrode is obtained and an unprocessed area around connecting path generating means for generating a new connection path that avoids the horizontally circulating to unprocessed area without moving the Z-axis direction.
[0011]
When the tool electrode passes over the unprocessed area, an electric discharge is generated, the tool electrode is consumed, and unnecessary removal processing is performed on the workpiece. In addition, it is not preferable to feed the tool electrode in the Z-axis direction on the unprocessed region because electric discharge occurs. Therefore, when there is a connection path that moves on the unprocessed area, a new connection path that avoids the unprocessed area is generated instead of such a connection path, and the tool is generated based on the connection path. The electrodes were controlled by XY. With this configuration, since the tool electrode does not pass over the unprocessed area, it is possible to prevent wear of the electrode and unnecessary removal of the workpiece, thereby improving the precision of the machined surface.
[0012]
The electric discharge machine according to the next invention performs three-dimensional control by feeding control of the tool electrode in the X and Y axes based on the machining path and synthesizing feed control in the Z axis direction for correcting the lengthwise consumption of the tool electrode. An electric discharge machine that removes a desired three-dimensional shape by applying a pulse-like voltage between a tool electrode and a non-workpiece on a machining path and on a connection path that connects distant machining paths. An unprocessed area determining means for determining an unprocessed area on a connection path connecting the separated processing paths, and a pond-shaped portion which has already been processed when the connection path moves on the unprocessed area. And a pond-shaped circling connection path generating means for generating a new connection path such that the tool electrode circulates horizontally without moving in the Z-axis direction .
[0013]
This prevents the tool electrode from moving on the unprocessed area. If there is a connection path on the unprocessed area, a connection path that goes around the already processed pond-shaped portion is generated instead of this connection path. When the XY control of the tool electrode is performed based on the connection path, the tool electrode does not pass over the unprocessed area, so that it is possible to prevent the tool electrode from being consumed and unnecessary removal of the workpiece from being performed. Can be improved.
[0014]
The electric discharge machining apparatus according to the next invention is the electric discharge machining apparatus, further comprising: a plurality of the new connection paths; a connection path path length calculation unit configured to calculate a path length of each of the connection paths; and Connecting path selecting means for selecting a path having a short path length.
[0015]
When a plurality of new connection paths are considered, if the tool electrode is moved based on the connection path having the shortest path length, the processing time can be reduced. For this purpose, the path lengths of a plurality of connected paths are calculated, and the shorter one is selected from the calculated path lengths.
[0016]
The electric discharge machining method according to the next invention performs three-dimensional control by synthesizing feed control in the Z-axis direction for controlling the feed of the tool electrode in the X and Y axes based on the machining path and correcting the amount of wear in the length direction of the tool electrode. An electric discharge machining method for removing a desired three-dimensional shape by applying a pulse-like voltage between a tool electrode and a non-workpiece on a machining path and on a connection path connecting distant machining paths. An unprocessed area determining step of determining an unprocessed area on a connection path connecting the separated processing paths, and when the connection path moves through the unprocessed area, the tool electrode moves in the Z-axis direction. And generating a new connection path that avoids the unprocessed area by circling horizontally without performing the process.
[0017]
If there is a connection path that moves on the unprocessed area, the tool electrode generates an electric discharge in the unprocessed area, so a new connection path that avoids the unprocessed area is generated instead of such a connection path. The XY control of the tool electrode is performed based on the connection path. With this configuration, since the tool electrode does not pass over the unprocessed area, it is possible to prevent wear of the electrode and unnecessary removal of the workpiece, thereby improving the precision of the machined surface.
[0018]
The electric discharge machining method according to the next invention performs three-dimensional control by synthesizing feed control in the Z-axis direction for controlling the feed of the tool electrode in the X and Y axes based on the machining path and correcting the amount of wear in the length direction of the tool electrode. An electric discharge machining method for removing a desired three-dimensional shape by applying a pulse-like voltage between a tool electrode and a non-workpiece on a machining path and on a connection path connecting distant machining paths. In the unprocessed area determining step of determining an unprocessed area on a connection path connecting the separated processing paths, and when the connection path moves on the unprocessed area, a pond-shaped portion that has already been processed And a pond-shaped circling connection path generating step of generating a new connection path such that the tool electrode circulates horizontally without moving in the Z-axis direction .
[0019]
By generating a connection path that goes around the already processed pond-shaped portion and moving the tool electrode based on this connection path, the next processing path can be reached while avoiding the unprocessed area. For this reason, wear of the tool electrode and unnecessary removal of the workpiece can be prevented, and machining surface accuracy can be improved.
[0020]
The electric discharge machining method according to the next invention further includes a connection path path length calculation step of calculating the path length of each of the plurality of generated connection paths, and a connection path selection step of selecting a path path having a shorter path length from the plurality of connection paths. , Is included.
[0021]
That is, the path lengths of a plurality of connected paths are calculated, and a shorter one is selected from the calculated path lengths. If the tool electrode is moved based on the selected connection path, the machining time can be reduced.
[0022]
A computer-readable recording medium according to the next invention stores a program for causing a computer to execute the electric discharge machining method.
[0023]
By causing the computer to execute this program, it is possible to prevent the tool electrode from moving on the unprocessed area. Therefore, it is possible to prevent the tool electrode from being consumed and unnecessary removal of the workpiece, thereby improving the machining surface accuracy.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an electric discharge machine, an electric discharge method, and a computer-readable recording medium storing a program for causing a computer to execute the electric discharge method will be described in detail with reference to the drawings. It should be noted that the present invention is not limited by the embodiment.
[0025]
Embodiment 1 FIG.
FIG. 1 is an explanatory diagram showing a configuration of an electric discharge machine 100 according to Embodiment 1 of the present invention. A table saddle 3 controlled by an X-axis servo mechanism 1 and a Y-axis servo mechanism 2, a processing tank 5 installed on the table and holding a workpiece W inside a processing liquid 4 and a column. 7, a head 7 controlled by a Z-axis servo mechanism 6, a tool electrode 8 provided at the tip of the head, a machining power supply 9 for applying a voltage between the tool electrode 8 and the workpiece W, a machining path Path recording unit 10 for recording a path, an unprocessed area avoiding connected path recording unit 11 for recording a connected path for avoiding an unprocessed area, an electric condition recording unit 12 for recording electric conditions, a connected path and an unprocessed area An unprocessed area determination unit 13 that determines whether or not there is interference with an unprocessed area; an avoidance connection path generation unit 14 that generates a connection path that avoids the interference when interference occurs; Based on electrical conditions And a control unit 15 for controlling the driving of the servo mechanism 1,2,6 and machining power supply 9 for each axis.
[0026]
Note that the recording device 17 of the computer 16, such as a hard disk or a floppy disk, can be used as the processing path recording unit, the unprocessed area avoidance connection path recording unit, and the electrical condition recording unit. Further, the unprocessed area determination unit 13, the avoidance connection path generation unit 14, and the control unit 15 can be configured by software stored in the recording device 17 and hardware of the computer 16.
[0027]
Next, the operation of the electric discharge machine 100 will be described. FIG. 2 is a flowchart showing the operation of the electric discharge machine 100. In step S201, the unprocessed area determination unit 13 determines whether the connection path interferes with the unprocessed area. Specifically, as shown in FIG. 9, this corresponds to the case where the connection path R passes over the unprocessed area M. Since the connection path R is recorded together with the processing path K in the processing path recording unit 10, interference is determined from the recorded connection path R. If the result of determination is that there is interference, processing proceeds to step S202. If there is no interference, the process proceeds to step S204, and processing is started based on the recorded path.
[0028]
In step S202, the avoidance connection path generation unit 14 generates a new connection path that avoids the unprocessed area. FIG. 3 shows the newly generated connection path Rn. This connection path Rn goes from the movement start position Rs to the movement end position Re by circling the already processed pond shape I without interfering with the island shapes S1 to S4 (positions 31 to 34). In step S203, the connection path Rn is recorded in the unprocessed area avoidance connection path recording unit 11.
[0029]
In step S204, electric discharge machining is started. At the time of machining, a pulse voltage is applied between the tool electrode 8 and the workpiece W. At the time of applying a voltage, an electric condition such as a duty factor recorded in the electric condition recording unit 12 is extracted, and a voltage is applied according to the condition. Further, the control unit 15 controls the servo mechanisms 1, 2, and 6 of each axis based on the machining path K, and relatively moves the tool electrode 8 and the workpiece W.
[0030]
In the newly generated connection path Rn, the tool electrode 8 keeps a constant discharge gap G without moving in the Z-axis direction (see FIG. 4) and orbits the pond-shaped portion horizontally. Therefore, since no discharge occurs in the connection path Rn, unnecessary removal of the workpiece W can be prevented, and the consumption of the tool electrode 8 can be prevented. For this reason, it is difficult to form a step on the processing surface, and the accuracy of the processing surface is improved. The reason why the tool electrode 8 is not moved in the Z-axis direction is that the discharge may fly when the tool electrode 8 is lowered. When the tool electrode 8 reaches the movement end position Re, the control unit 15 controls the Z-axis servo mechanism 6 to perform electrode wear correction.
[0031]
Subsequently, the tool electrode 8 is moved from the movement end position Re to the machining end point (not shown) of the machining path K in accordance with a command from the control unit 15 to perform the removal machining. Specifically, as shown in FIG. 9, the tool electrode 8 is moved from the movement end position Re through the position E2 to the machining end point of the machining path K.
[0032]
Note that, in the above-described embodiment, in order to avoid the interference between the connection path Rn and the unprocessed area M, the path is around the pond shape I, but the avoidance path is not limited to this. For example, as shown in FIG. 5, a connection path Rn ′ that goes around the vicinity of the inside of the island shape S may be generated.
[0033]
Embodiment 2 FIG.
FIG. 6 is an explanatory diagram showing a configuration of an electric discharge machine according to Embodiment 2 of the present invention. This electric discharge machining apparatus 200 is characterized in that a path length calculation unit 18 and a connection path selection unit 19 are provided in the electric discharge machining apparatus 100 of the first embodiment. The other configuration is the same as that of the first embodiment, and the description is omitted. The path length calculation unit 18 calculates the path length of the connection path Rn generated by the avoidance connection path generation unit 14. The connection path selection unit 19 selects a connection path Rn having the shortest path length from the plurality of connection paths Rn. Note that the path length calculation unit 18 and the connection path selection unit 19 can be configured by software stored in the recording device 17 and hardware of the computer 16.
[0034]
Next, the operation of the electric discharge machine 200 will be described. FIG. 7 is a flowchart showing the operation of the electric discharge machine. In step S701, the unprocessed area determination unit 13 determines whether or not the connection path R interferes with the unprocessed area M (see FIG. 9). If the result of the determination is that there is interference, processing proceeds to step S702. If there is no interference, the process proceeds to step S706, and processing is started based on the recorded path.
[0035]
In step S702, the avoidance connection path generation unit 14 generates a plurality of new connection paths Rn that avoid the unprocessed area M. FIG. 8 shows a newly generated connection path Rn. The connection path Ra extends from the movement start position Rs to the movement end position Re via the positions 81 to 84. On the other hand, the connection path Rb reaches the movement end position Re from the movement start position Rs via the positions 81, 85, 86, and 84. Each connection path Rn orbits the already processed pond shape I without interfering with the island shapes S1 to S4.
[0036]
In step S703, the path length calculation unit 18 calculates the path lengths of the connection paths Ra and Rb. In step S704, the connection path selection unit 19 selects the connection path Rn with the shortest machining path. Since the connection path Rb is shorter than the connection path Ra and the connection path Rb, the connection path Rb is selected.
[0037]
In step S705, the selected connected path Rb is recorded in the unprocessed area avoiding connected path recording unit 11. In step S706, electric discharge machining is started based on the machining path K including the connection path Rb. In this way, if the shortest connection path Rb is selected, the processing time can be reduced.
[0038]
【The invention's effect】
As described above, according to the electric discharge machining apparatus and the electric discharge machining method of the present invention, when there is a connection path that moves on the unprocessed area, the unprocessed area is replaced with such a connection path. A new connection path to be avoided is generated, and the XY control of the tool electrode is performed based on the connection path. For this reason, it is possible to prevent consumption of the electrode and unnecessary removal of the workpiece, and to improve the machining surface accuracy.
[0039]
In the electric discharge machining apparatus and the electric discharge machining method according to the next invention, when there is a connection path on the unprocessed area, a connection path that goes around the already processed pond-shaped portion is generated instead of the connection path, and the connection is performed. The XY control of the tool electrode is performed based on the path. For this reason, since the tool electrode does not pass over the unprocessed area, it is possible to prevent wear of the tool electrode and unnecessary removal of the workpiece, thereby improving the machining surface accuracy.
[0040]
In the electric discharge machining apparatus and the electric discharge machining method according to the next invention, the path lengths of a plurality of connection paths are calculated, and a shorter one is selected from the calculated path lengths. For this reason, the processing time can be reduced.
[0041]
In a computer-readable recording medium according to the next invention, a program for causing a computer to execute the electric discharge machining method is stored. For this reason, by causing the computer to execute the program, it is possible to prevent wear of the tool electrode and unnecessary removal of the workpiece, thereby improving the machining surface accuracy.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a configuration of an electric discharge machining apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a flowchart showing an operation of the electric discharge machine shown in FIG.
FIG. 3 is an explanatory diagram showing a newly generated connection path.
FIG. 4 is an explanatory diagram showing a relationship between a tool electrode and a workpiece.
FIG. 5 is an explanatory diagram showing another example of the connection path.
FIG. 6 is an explanatory diagram showing a configuration of an electric discharge machine according to a second embodiment of the present invention.
FIG. 7 is a flowchart showing the operation of the electric discharge machine shown in FIG.
FIG. 8 is an explanatory diagram showing a newly generated connection path.
FIG. 9 is an explanatory view showing an example of a machining path and a movement of a tool electrode by a conventional electric discharge machine.
FIG. 10 is an explanatory diagram showing a relationship between a tool electrode and a workpiece.
[Explanation of symbols]
Reference Signs List 100 EDM machine, 1 X-axis servo mechanism, 2 Y-axis servo mechanism, 3 table saddle, 4 machining fluid, 5 machining tank, 6 Z-axis servo mechanism, 7 head, 8 tool electrode, 9 machining power supply, 10 machining Path recording unit, 11 unprocessed area avoidance connection path recording unit, 12 electrical condition recording unit, 13 unprocessed area determination unit, 14 avoidance connection path generation unit, 15 control unit, 16 computer, 17 recording device, W workpiece, K processing path, Rn connection path.

Claims (7)

The tool electrode on the basis of the machining path performs synthesizing and three-dimensional control of the Z-axis direction of feed control for correcting the longitudinal wear rate of the tool electrode which controls the feed in the XY-axis direction, working pass on, and spaced machining In a discharge machining apparatus for removing a desired three-dimensional shape by applying a pulsed voltage between a tool electrode and a non-workpiece on a connection path connecting the paths ,
An unprocessed area determining means for determining an unprocessed area on a connection path connecting the separated processing paths;
When the connection path moves on the unprocessed area , the unprocessed area avoiding connection generates a new connection path such that the tool electrode circulates horizontally without moving in the Z-axis direction to avoid the unprocessed area. Path generation means;
An electric discharge machining device comprising: The tool electrode on the basis of the machining path performs synthesizing and three-dimensional control of the Z-axis direction of feed control for correcting the longitudinal wear rate of the tool electrode which controls the feed in the XY-axis direction, working pass on, and spaced machining In a discharge machining apparatus for removing a desired three-dimensional shape by applying a pulsed voltage between a tool electrode and a non-workpiece on a connection path connecting the paths ,
An unprocessed area determining means for determining an unprocessed area on a connection path connecting the separated processing paths;
When the connection path moves on the unprocessed area, a pond-shaped circling for generating a new connection path such that the tool electrode horizontally circulates the already-processed pond-shaped portion without moving in the Z-axis direction. Connecting path generating means;
An electric discharge machining device comprising: A connection path length calculation unit configured to generate a plurality of the new connection paths and calculate a path length of each connection path;
Connecting path selecting means for selecting a short path length from the plurality of connecting paths,
The electric discharge machining device according to claim 1 or 2, further comprising: The tool electrode on the basis of the machining path performs synthesizing and three-dimensional control of the Z-axis direction of feed control for correcting the longitudinal wear rate of the tool electrode which controls the feed in the XY-axis direction, working pass on, and spaced machining In a discharge machining method for removing a desired three-dimensional shape by applying a pulsed voltage between a tool electrode and a non-workpiece on a connection path connecting the paths ,
An unprocessed area determining step of determining an unprocessed area on a connection path connecting the separated processing paths;
When the connection path moves in the unprocessed area , the unprocessed area avoiding connection path generates a new connection path such that the tool electrode orbits horizontally without moving in the Z-axis direction to avoid the unprocessed area. Generating step;
An electrical discharge machining method comprising: The tool electrode on the basis of the machining path performs synthesizing and three-dimensional control of the Z-axis direction of feed control for correcting the longitudinal wear rate of the tool electrode which controls the feed in the XY-axis direction, working pass on, and spaced machining In a discharge machining method for removing a desired three-dimensional shape by applying a pulsed voltage between a tool electrode and a non-workpiece on a connection path connecting the paths ,
An unprocessed area determining step of determining an unprocessed area on a connection path connecting the separated processing paths;
When the connection path moves on the unprocessed area, a pond-shaped circling for generating a new connection path such that the tool electrode horizontally circulates the already-processed pond-shaped portion without moving in the Z-axis direction. A connection path generation step;
An electrical discharge machining method comprising: A connection path length calculation step of calculating a path length of each of the plurality of generated connection paths;
A connection path selection step of selecting a path having a short path length from the plurality of connection paths,
The electric discharge machining method according to claim 4, further comprising: A computer-readable recording medium storing a program for causing a computer to execute the electric discharge machining method according to any one of claims 4 to 6.

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