JPS61100324A - Electrical discharge machining device - Google Patents

Abstract

PURPOSE:To enhance the accuracy of machining, by providing electrostrictive members that may be slightly displaced in the direction in which a detecting electrode approaches a machining electrode, at the front end of a position detecting member for detecting the relative position of the machining electrode and a workpiece, so that the contact of the machining electrode is detected to be controlled. CONSTITUTION:A machining electrode 1 is removably attached to a quill 2, and a workpiece 3 is secured to a machining bed 4. A machining tank 5 surrounds the machining bed 4 and the workpiece 3, and machining liquid is reversed therein to such a depth that the workpiece 3 is submerged therein. In this condition an electrical discharge machining is carried out. Position detectors 7, 8 are positioned so that they have a predetermined positional relation with respect to the reference plane of the workpiece 3. The electrode 1 is relatively moved on the center axis between the position detectors 7, 8. The electrode 1 is moved by a motor driven device. The feed control of the electrode 1 is turned into the control by electrostrictive members 74, 84 just before the position where the electrode 1 comes to be contact with detecting electrodes 73, 83, and therefore, the electrostrictive members 74, 84 are applied with a voltage. Therefore, due to elongation of the members 74, 84 the detection and control of approach and contact of the electrode 1 may be carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Art) The present invention relates to electrical discharge machining equipment such as die-sinking electrical discharge machining equipment and wire-cut electrical discharge machining equipment that performs electrical discharge in the gap between a machining electrode and a workpiece facing each other. .

[Prior art]

In electrical discharge machining, it is necessary to be able to easily detect and adjust the relative position between a machining electrode and a workpiece. A conventional positioning jig is equipped with a jig equipped with an electrode that has a predetermined positional relationship with a predetermined reference plane of the workpiece and detects contact, for example, by energizing, when replacing the electrode, etc. In conventional methods, positioning and detection is performed by moving the replaced machining electrode close to and in contact with the detection electrode. If the feed accuracy of movement h<h, it directly affects the accuracy of contact detection, and it was not possible to obtain a higher positioning accuracy of the motor drive device for relative movement.

[Problem solving means]

The present invention was provided in order to improve this positioning accuracy, and the positioning detection tool or the relatively moving drive device is provided with a microscopic drop in the direction in which the detection electrode and the processing electrode at the tip of the positioning detection tool approach each other. It is characterized by providing an electrostrictive material or a magnetostrictive material to be displaced.

〔Example〕

The present invention will be explained below with reference to an embodiment of the drawings.

In FIG. 1, reference numeral 1 denotes a processing electrode, which is detachably attached to the quill 2. Reference numeral 3 denotes a workpiece, which is fixedly mounted on the processing table 4. Reference numeral 5 denotes a machining tank which surrounds the machining table 4 and the workpiece 3, and performs electric discharge machining while supplying and storing machining fluid 6 at a depth that covers the workpiece 3 inside. 7.8
is a position detecting device, and the column 71.81 is magnetically chucked 72
．． 82, and detection electrodes 73, 83 are provided at the tips of the columns protruding above the machining liquid level 6, and the detection electrodes 73
．． Electrostrictive materials 74 and 84 are interposed in 83 to cause a slight displacement.

The position detectors 7 and 8 are for detecting reference positions in the X-axis direction, and are fixed in a predetermined positional relationship with a predetermined reference plane of the workpiece 3 by magnetic chucks 72 and 82, and are used for detection. Electrodes 73 and 83 are provided parallel to the X-axis in the direction of the processing electrode 1. Of course, a similar detection tool is also provided in the orthogonal Y-axis direction.

Although not shown, the processing tank 5 is provided on a moving table that moves in the X-axis and Y-axis directions, and a drive motor controls the positioning of the workpiece 3 by moving it relative to the processing electrode 1 as desired.

The processing electrode 1 is detachably attached to the quill 2, and can be automatically exchanged using an automatic electrode exchanger (not shown) or the like.

FIG. 2 is a layout diagram of the position detecting tool 7.8, which is positioned in a predetermined positional relationship with the reference surfaces a and b of the workpiece 3 as shown in the figure. The center position p of the position detectors 1 and 8 is determined at a distance of nop in the X-axis direction from the reference plane a, and
, 8 are provided on axes parallel to the reference plane with the point p as the center.

Now, to explain the positioning of the processing electrode 1 in the X-axis direction, the electrode 1 is relatively moved onto the central axis between the position detection tools 7 and 8. The erosion electrode 1 is moved to the right and left in the X-axis direction. Both are moved relative to each other by a numerical control device. Move the processing electrode 1 to the right and detect the detection electrode 7.
Move it 1 until it touches 3. Next, the head is turned to the left and moved until it contacts the detection electrode 83, and the distance traveled at that time is measured using the 1iTf control headpiece.

The processing electrode 1 is moved by a motor drive device, but before it comes into contact with the detection electrode 73.83, the feed control is switched to the electrostrictive material 74.84, and a voltage is applied to the electrostrictive material 74.84. Detection control for approaching and touching is performed as the size increases. The amount of approaching movement by the electrostrictive materials 74 and 84 can be determined by measuring the voltage applied before contact, and the amount of movement proportional to the applied voltage can be accurately measured depending on the characteristics of the electrostrictive materials used. As described above, the dimensional distance traveled by the processing electrode 1 between the detection electrodes 74 and 84 can be accurately detected and measured by the sum of the movement amount measured by the motor drive and the movement amount measured by the electrostrictive material. can.

Therefore, by moving the machining electrode 8i1 to the right by 4 from the position where it contacts the electrode 83, the center of the electrode can be made to coincide with the point p. Further, by moving leftward from point p by Lp, the center of the processing electrode 1 can be made to coincide with the reference plane a.

By feeding back the determination of such dimensions to the numerical control drive system, accurate control and electrical discharge machining can be performed.

In addition, the micro displacement characteristics of electrostrictive material are usually 30μm/400V.
The machining accuracy based on this dimensional measurement made it possible to perform electrical discharge machining to a level of about 0,000 μm.

Note that positioning control can also be performed in the Y1-axis direction by detecting and controlling the workpiece reference surface in the same manner.

(Effects) As described above, the present invention makes it possible to always accurately align the center of the replaced electrode with the reference position when replacing the processing electrode. In particular, we installed an electrostrictive material that moves minutely in the direction in which the detection electrode and processing electrode approach each other at the tip of the positioning detector, and this measures the movement dimension of contact detection, making it easy to reduce the accuracy to 1μ or less. Accordingly, the processing accuracy was able to be approximately 0.005μ. A magnetostrictive material can be used as the minute displacement element, and it can be provided in a drive control device 2Il that relatively moves the processing electrode. In addition, the detection electrode at the tip of the positioning detector uses electricity to detect contact with the machining electrode, but since the detection electrode is always provided so as to protrude above the machining liquid level in the machining tank, there is no possibility of adhering impurities such as machining debris. Therefore, stable and accurate detection control can be performed at all times without disturbing the current-carrying contact.

Is this invention for processing? ! This is particularly effective when electrical discharge machining is automatically performed while replacing electrodes one by one using an automatic electrode changing device.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the implementation operation. 1...... Machining electrode 3... Workpiece 5... Machining tank machine... Machining fluid 7 .8...Position detection tool 73.83...Detection electrode 74.84...
...... Electrostrictive material 3t ノ≦11 21 years 0' - and -13■-

Claims (1)

[Claims] a position detection tool provided with a detection electrode that has a predetermined positional relationship with a predetermined reference surface of a workpiece to be subjected to electric discharge machining, facing the machining electrode, and that contacts and inspects the machining electrode;
In an electrical discharge machining apparatus in which position detection is performed by causing relative movement between the machining electrode and the workpiece by a drive device, the position detection tool or the relative movement drive device includes:
An electric discharge machining apparatus characterized in that an electrostrictive material or a magnetostrictive material is provided for causing a slight displacement in a direction in which a detection electrode at the tip of the position detecting tool and the machining electrode approach each other.