JPH0468090B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wire electrical discharge machining apparatus equipped with a wire electrode tension control mechanism.

[Conventional technology]

An example of a wire electrical discharge machining apparatus equipped with a conventional wire electrode tension control mechanism is shown in FIG.

That is, upper and lower wire guides 38 and 40 are disposed above and below the workpiece 34,
A feeder 36 is installed above and below each of the wire guides and is connected to a power source 32 together with the workpiece, so that a discharge force is applied to the wire electrode 10 and the workpiece 34, which will be described later, through the feeder. The wire electrodes are slidably supported by upper and lower wire guides, and the idler 1
It is supplied from the supply bobbin 12 via 4a, 14b, 14c and 14d. Tension is applied between the idlers 14a and 14b in the middle by a weight 16 supported by a lever 18 rotatably supported on the axis of the detector 20, and between the supply bobbin and the idler 14a. A wire unwinding section 25 consisting of a capstan and a pinch roller is used to unwind the wire, and after passing through the idler 14b, the wire is wound up by a wire winding and recovery section 28 consisting of a capstan and a pinch roller. The used electrodes are collected into a collection box 30.

In the conventional wire electrical discharge machining apparatus described above, the weight 16 is lifted by the wire electrode 10 while the wire is running, and a tension of half the weight is applied to the electrode. detects the position of the wire, and if it moves above the predetermined position, the wire unwinding part 25
By making the unwinding speed faster than the collecting speed of the wire winding and collecting section 28, the wire is controlled to be returned to the predetermined position, and when the wire moves below the predetermined position, the unwinding speed is changed to the wire collecting speed. By setting the speed slower than the current speed, the control is performed so that the target position is set at a predetermined position. Therefore, the weight always occupies a constant position, and a tension equal to half the weight of the weight is always applied to the wire electrode.

[Problem that the invention seeks to solve]

However, in order to perform high-precision machining with the shortest machining time, it is necessary to change the tension value of the wire electrode during rough machining and finishing machining, and in this case, the operator must manually Since the weights have to be replaced, it not only reduces processing efficiency but also prevents automation of the work.Furthermore, it is necessary to prepare many types of replacement weights depending on the wire electrode diameter and material. There are drawbacks, such as complicating the use of wire electrical discharge machining equipment.

The purpose of this invention is to control and change the tension of a wire electrode to adapt it to a desired machining operation without replacing the tension weight, thereby improving work efficiency and realizing work automation.

[Means for solving problems]

This invention provides a torque generating mechanism that can freely control the torque on the wire electrode on the side of the processing section from the position of the weight of the wire electrode tension control mechanism, and also applies the generated torque of the torque generating mechanism in the running direction and counter-travel direction of the wire electrode. It is generated by generating it in the direction.

[Effect]

Therefore, according to the configuration of the present invention, in order to reduce the tension of the wire electrode, a torque is generated in the running direction of the wire electrode, and in order to increase the electrode tension, a torque is generated in the opposite direction to the running direction of the electrode. The tension in the electrode can be controlled and varied by generating .

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, a torque generating mechanism 53 capable of freely controlling the torque is engaged with and attached to the wire electrode 10 between the idlers 14b and 14c of the wire electrical discharge machining apparatus equipped with the conventional wire electrode tension control mechanism using weights. The torque generating mechanism is constructed by coupling a torque motor 52 to an auxiliary pulley 50 on which the wire electrode is wound one or more times, and the material of the auxiliary pulley is made of a material that has a high coefficient of friction with the wire electrode 10. Select objects so that there is no slippage between them. Therefore, in order to make the tension value of the wire electrode smaller than the tension value of only the weight 16, if the torque motor is operated to generate torque in the same direction as the wire electrode running direction, the auxiliary pulley 50 applies a force to the wire electrode in its running direction, so the tension of the wire electrode in the machining section of the electrical discharge machining device is changed to a tension value obtained by subtracting the force generated by the pulley from half the weight weight. In addition, if the electrode tension value is made larger than that due to the weight alone,
When the torque motor 52 is operated to generate a torque in the opposite direction to the electrode running direction and apply force in the opposite direction, the electrode tension at the processing section becomes a tension value obtained by adding the pulley generated force to half the weight weight. will be changed to. In addition to the torque generating mechanism described in the above embodiments, other torque generating mechanisms such as a pinch roller or a capstan can be used. Furthermore, it is possible to control the generated torque of the torque generating mechanism described above using numerical control commands, and in this case, if the electrode tension values for rough machining and finishing machining are programmed in advance, the torque can be automatically controlled. It is possible to perform high-precision machining work by controlling the tension value of the wire electrode.

〔Effect of the invention〕

As described above, the present invention has an extremely simple structure and operation in which a torque generating mechanism is attached to a wire electrode and the torque generated by this torque generating mechanism is applied in the running direction of the wire electrode and in the opposite direction. This invention has many practical benefits, such as the ability to freely change and control weights, which eliminates the need to change weights depending on the machining purpose, dramatically improving work efficiency, and making it easy to automate high-precision machining. There is something.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram of a wire electrical discharge machining apparatus equipped with a conventional weight-based wire electrode tension control mechanism. DESCRIPTION OF SYMBOLS 10...Wire electrode, 12...Electrode supply bobbin, 16...Weight, 25...Wire unwinding section, 28...Wire winding and recovery section, 34...Workpiece, 50...Auxiliary pulley, 52... ... Torque motor, 53... Torque generation mechanism. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. Wire electrode tension that adds a weight to the wire electrode unwound from the supply bobbin via the wire unwinding section, detects the position of the weight, and controls the tension of the wire electrode to a constant value. In a wire electrical discharge machining device equipped with a control mechanism, a torque generating mechanism whose torque can be freely controlled is attached to the wire electrode closer to the processing section than the position of the weight of the wire electrode tension control mechanism, and the torque generated by the torque generating mechanism is controlled. A wire electrical discharge machining device equipped with a wire electrode tension control mechanism, characterized in that tension is generated in the running direction and in the counter-travel direction of the wire electrode. 2. The wire electrical discharge machining apparatus according to claim 1, wherein the torque generating mechanism is comprised of a torque motor and an auxiliary pulley coupled to a motor shaft of the torque motor. 3. The wire electric discharge machining apparatus according to claim 1, wherein the torque generating mechanism is composed of a pinch roller and a capstan. 4. The wire electric discharge machining apparatus according to claim 1, 2 or 3, wherein the torque generated by the torque generating mechanism is controlled by a numerical control command.