Patent ID: 12246386

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a control device1and program according to an embodiment of the present disclosure will be explained by referencingFIGS.1and2. First, before explaining the control device1and program of the embodiment, a wire electrical discharge machine100controlled by the control device1will be explained.

The wire electrical discharge machine100, for example, is a device which machines a workpiece102by applying a working voltage at the electrode gap between a wire electrode101and workpiece102, as shown inFIG.1. The wire electrical discharge machine100has a movement drive unit103which causes the wire electrode101and workpiece102to relatively move. The movement drive unit103is configured by a plurality of servomotors (not shown) arranged on the respective axes of the wire electrode101and workpiece102, for example. The movement drive unit103machines the workpiece102to a predetermined shape by causing the wire electrode101and workpiece102to relatively move. The movement drive unit103, for example, relatively moves the wire electrode101and workpiece102, by causing an electrically-conductive table104on which the workpiece102is placed, and the wire electrode101to move. It should be noted that, in order to simplify explanation in the following embodiment, an example in which the movement drive unit103moves the wire electrode101relative to the workpiece102will be explained.

Next, measurement of the relative position between the wire electrode101and workpiece102in the wire electrical discharge machine100will be explained. In the wire electrical discharge machine100, upon starting machining of the workpiece102, measurement of the relative position between the wire electrode101and workpiece102is conducted. In the measurement of the relative position, first, a pulse-like detection voltage of a level lower than the working voltage is applied at the electrode gap between the wire electrode101and workpiece102. Then, the wire electrode101and workpiece102are relatively moved in an approaching direction. A change in the detection voltage is detected by the wire electrode101and workpiece102making contact. It is thereby possible to measure the positions of the wire electrode101and workpiece102. Then, the wire electrical discharge machine100can machine the workpiece102to a predetermined shape, with the measured position as a reference position.

Next, the control device1and program according to the first embodiment of the present disclosure will be explained by referencingFIGS.1and2. The control device1is a device which controls the wire electrical discharge machine100. The control device1measures the relative position between the wire electrode101and workpiece102, by detecting contact between the wire electrode101and workpiece102which were made to relatively move. In the present embodiment, the control device1detects twice in the order of a first detection operation and a second detection operation the contact between the wire electrode101and workpiece102. The control device1includes a cycle setting unit11, a voltage application unit12, a movement speed control unit13, and a contact detection unit14, as shown inFIG.1.

The cycle setting unit11, for example, is realized by a CPU operating. The cycle setting unit11sets a pulse cycle of the detection voltage applied at the electrode gap between the wire electrode101and workpiece102. The cycle setting unit11can change the pulse cycle of the detection voltage, based on the pulse frequency inputted from the outside, for example. In the present embodiment, the cycle setting unit11, as shown inFIG.2, sets different pulse cycles, at the first detection operation (act1) and the second detection operation (act3). More specifically, the cycle setting unit11sets the second pulse cycle T2in the second detection operation to be longer than the first pulse cycle T1set in the first detection operation. The cycle setting unit11sets the second pulse cycle T2set in the second detection operation to 1.5 times or more than the first pulse cycle T1set in the first detection operation, for example.

The voltage application unit12, for example, is realized by a CPU controlling a power source12athat applies the detection voltage. The voltage application unit12applies the detection voltage to the electrode gap at the set cycle. The voltage application unit12, for example, applies the detection voltage of the pulse cycle set by the cycle setting unit11at the electrode gap. The voltage application unit12, for example, applies the detection voltage of the first pulse cycle T1in the first detection application to the electrode gap between the wire electrode101and workpiece102, as shown inFIG.2. In addition, the voltage application unit12applies the detection voltage of the second pulse cycle T2in the second detection operation to the electrode gap between the wire electrode101and workpiece102.

The movement speed control unit13, for example, is realized by a CPU operating. The movement speed control unit13controls the relative movement speed by the movement drive unit103. The movement speed control unit13, for example, controls the relative movement speed between the wire electrode101and workpiece102(table104). In addition, the movement speed control unit13can change the relative movement speed based on the relative movement speed inputted from outside, for example. In the present embodiment, the movement speed control unit13controls different relative movement speeds in the first detection operation and the second detection operation. More specifically, the movement speed control unit13controls the second relative movement speed V2in the second detection operation to be slower than the first relative movement speed V1in the first detection operation. In addition, the movement speed control unit13, after execution of the first detection operation, causes the wire electrode101and workpiece102to relatively move (act2inFIG.2), before execution of the second detection operation.

The contact detection unit14, for example, is realized by a CPU controlling a sensor14a. The contact detection unit14detects contact between the wire electrode101and workpiece102, based on a change in the applied detection voltage. The contact detection unit14, for example, detects the contact between the wire electrode101and workpiece102, by detecting the disappearance of the peak voltage. In addition, the contact detection unit14measures the positions of the wire electrode101and the position of the workpiece102, by detecting the contact. In the present embodiment, the contact detection unit14, after executing the first detection operation of contact between the wire electrode101and workpiece102at the first relative movement speed V1and first pulse cycle T1, executes the second detection operation of contact between the wire electrode101and workpiece102, at the second relative movement speed V2which is slower than the first relative movement speed V1, and at the second pulse cycle T2which is longer than the first pulse cycle T1.

Next, operation of the control device1according to the present embodiment will be explained usingFIG.2. First, the cycle setting unit11sets the first pulse cycle T1upon executing the first detection operation. Next, the movement speed control unit13sets the first relative movement speed V1.

Then, the voltage application unit12applies the detection voltage set in the first pulse cycle T1to the electrode gap between the wire electrode101and workpiece102. Next, the movement speed control unit13causes the wire electrode101to move (relatively move) in the approaching direction at the first relative movement speed V1, in relation to an end surface S of the workpiece102.

Then, the contact detection unit14detects contact between the wire electrode101and the workpiece102. The contact detection unit14measures the relative position between the wire electrode101and workpiece102. The first detection operation thereby ends. Next, the movement speed control unit13moves (relatively moves) the wire electrode101in a direction distancing from the workpiece102. The movement speed control unit13distances the wire electrode101from the workpiece102at a shorter distance than a relative movement distance of the wire electrode101and workpiece102in the first detection operation, for example.

Next, the cycle setting unit11sets the second pulse cycle T2, upon executing the second detection operation. Then, the movement speed control unit13sets the second relative movement speed V2.

Next, the voltage application unit12applies the detection voltage set in the second pulse cycle T2to the electrode gap between the wire electrode101and workpiece102. Then, the movement speed control unit13causes the wire electrode101to move (relatively move) in the approaching direction at the second relative movement speed V2, to one end surface S of the workpiece102.

Next, the contact detection unit14detects contact between the wire electrode101and workpiece102. The contact detection unit14measures the relative position of the wire electrode101and workpiece102. The second detection operation thereby ends.

Next, a program of the present embodiment will be explained. Each configuration included in the control device1can be respectively realized by hardware, software or a combination of these. Herein, being realized by software indicates the matter of being realized by a computer reading and executing a program.

The program can be stored using various types of non-transitory computer readable media, and supplies to the computer. Non-transitory computer readable medium includes various types of tangible storage media. Examples of non-transitory computer readable media include magnetic recording media (e.g., flexible disk, magnetic tape, hard disk drive), magneto-optical recording media (e.g., magneto-optical disk), CD-ROM (Read Only Memory), CD-R, CD-R/W and semiconductor memory (e.g., mask ROM, PROM (programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory)). In addition, the display program may be supplied to the computer by way of various types of transitory computer readable media. Examples of transitory computer readable media include electrical signals, optical signals and electromagnetic waves. Transitory computer readable media can supply programs to the computer via wired communication paths such as electric wires and optical fiber, or wireless communication paths.

According to the control device1and program of the first embodiment above, the following effects are exerted. (1) In the control device1which controls the wire electrical discharge machine100having a movement drive unit103that causes the wire electrode101and workpiece102to relatively move, the control device1measuring the relative position of the wire electrode101and workpiece102by detecting contact between the wire electrode101and workpiece102which have been relatively moved includes: the cycle setting unit11which sets the pulse cycle of the detection voltage applied to the electrode gap between the wire electrode101and workpiece102; the voltage application unit12which applies the detection voltage to the electrode gap at the set cycle; the movement speed control unit13which controls the relative movement speed by the movement drive unit103; and the contact detection unit14which detects contact between the wire electrode101and workpiece102, based on the change in the applied detection voltage; in which the contact detection unit14executes the second detection operation of contact between the wire electrode101and workpiece102at the second relative movement speed V2which is slower than the first relative movement speed V1, and at the second pulse cycle T2which is longer than the first pulse cycle T1, after executing the first detection operation of contact between the wire electrode101and workpiece102at the first relative movement speed V1and first pulse cycle T1, and the movement speed control unit13causes the wire electrode101and workpiece102to relatively move in a distancing direction after execution of the first detection operation and before execution of the second detection operation.

In addition, in a program which causes a computer to function as the control device1which controls the wire electrical discharge machine100having a movement drive unit103that causes the wire electrode101and workpiece102to relative move, the control device1measuring the relative position of the wire electrode101and workpiece102by detecting contact between the wire electrode101and workpiece102which have been relatively moved, the program causes the computer to function as: the cycle setting unit11which sets the pulse cycle of the detection voltage applied to the electrode gap between the wire electrode101and workpiece102; the voltage application unit12which applies the detection voltage to the electrode gap at the set cycle; the movement speed control unit13which controls the relative movement speed by the movement drive unit103; and the contact detection unit14which detects contact between the wire electrode101and workpiece102, based on the change in the applied detection voltage; in which the contact detection unit14executes the second detection operation of contact between the wire electrode101and workpiece102at the second relative movement speed V2which is slower than the first relative movement speed V1, and at the second pulse cycle T2which is longer than the first pulse cycle T1, after executing the first detection operation of contact between the wire electrode101and workpiece102at the first relative movement speed V1and first pulse cycle T1, and the movement speed control unit13causes the wire electrode101and workpiece102to relatively move in a distancing direction after execution of the first detection operation and before execution of the second detection operation.

It is thereby possible to preliminarily measure the relative position of the wire electrode101and one end surface S of the workpiece102, at the first pulse cycle T1and first relative movement speed V1in the first detection operation. Then, in the second detection operation, it is possible to suppress the occurrence of craters in the workpiece102, by measuring the relative position of the wire electrode101and one end surface S of the workpiece102at the second pulse cycle T2and second relative movement speed V2. In addition, it is possible to suppress the influence of deflection of the wire electrode101, by using the detection voltage of the second pulse cycle T2. Therefore, by improving the contact detection precision between the wire electrode101and workpiece102, it is possible to improve the measurement precision of the relative position of the wire electrode101and workpiece102.

Although each preferred embodiment of the control device and program of the present disclosure have been explained above, the present disclosure is not to be limited to the aforementioned embodiments, and modifications thereof are possible where appropriate. For example, in the above embodiments, an example using the first and second detection operations is explained; however, it is not limited thereto. For example, measurement may be executed using three or more detection operations. In this case, detection operations executed later are executed with a longer pulse cycle and slower relative movement speed.

In addition, in the above embodiments, an example moving the wire electrode101relative to the workpiece102is explained; however, it is not limited thereto. Both the workpiece102and wire electrode101may be configured to move relatively. It may be a mode in which the workpiece102moves and the wire electrode101does not move.

In addition, in the first detection operation, the first pulse cycle T1and/or first relative movement speed V1may not be constant. In the second detection operation, the second pulse cycle T2and/or second relative movement speed V2may not be constant.

In addition, in the above embodiments, the contact detection unit14is configured to execute the first detection operation and the second detection operation; however, it is not limited thereto. As another embodiment, the contact detection unit14executes the detection operation two or more times, and in any of the detection operations of the second time and later, contact between the wire electrode101and the workpiece is detected more slowly than the relative movement speed of the wire electrode101and workpiece102, and at a pulse cycle longer than the pulse cycle in the detection operations prior to these. By configuring in this way, it is possible to improve the measurement precision of the relative position of the wire electrode101and workpiece102.

In addition, as another embodiment, the contact detection unit14may execute the detection operation a plurality of times by slowing the relative movement of the wire electrode101and workpiece102, and lengthening the pulse cycle, in every detection operation. It is thereby possible to further improve the position detection precision of one end surface S of the workpiece102. In addition, the movement speed control unit13causes the wire electrode101and workpiece102to relatively move in the distancing direction every time during the detection operation. At this time, it may be configured so that the movement speed control unit13shortens the distance by which distancing the wire electrode101and workpiece102every time the number of the detection operation advances. It is thereby possible to suppress an increase in the time required for the overall detection operation, even if the relative movement speed bringing the wire electrode101and workpiece102into contact becomes slower every time the number of the detection operation advances.

EXPLANATION OF REFERENCE NUMERALS

1control device11cycle setting unit12voltage application unit13movement speed control unit14contact detection unit100wire electrical discharge machine101wire electrode102workpiece103movement drive unitT1first pulse cycleT2second pulse cycleV1first relative movement speedV2second relative movement speed