Electric heating – Metal heating – Cutting or disintegrating
Patent
1994-10-05
1996-12-31
Evans, Geoffrey S.
Electric heating
Metal heating
Cutting or disintegrating
B23H 102, B23H 718, B23H 720
Patent
active
055890865
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method for controlling electric discharge machining and an apparatus therefor. More particularly, the present invention relates to an electric discharge machining apparatus which generates an electric discharge by applying a voltage across a tool electrode and a workpiece which are opposed to each other through a small gap in a liquid. The gap between the tool electrode and the workpiece is optimized by using a driving means, such as a servomotor, in order to keep the electric discharge constant during a machining operation.
BACKGROUND ART
An electric discharge machining apparatus machines a workpiece into a desired shape by moving tool electrode with respect to a workpiece in accordance with a programmed machining path while material is removed from the workpiece by an electric discharge generated by applying a voltage across the tool electrode and the workpiece. In the machining operation performed by this electric discharge machining apparatus, an electric discharge machining condition must be kept constant. The electric discharge machining condition is provided by the average working voltage between the tool electrode and the workpiece (gap voltage), the time taken from the application of voltage across the tool electrode and the workpiece to the generation of electric discharge, or other factors. For this purpose, the electric discharging gap is adjusted by moving the tool electrode with respect to the workpiece in accordance with a detected electric discharge machining condition.
In the case of a conventional electric discharge machining control apparatus, the electric discharging gap is adjusted by giving a command for the position of retraction of the tool electrode to the position controller (hereinafter referred to as a servomechanism), the position of retraction being determined by the direction and distance of the relative retraction of the tool electrode from the workpiece depending on the detected electric discharge machining condition. Such retracting direction, for example, may be the direction opposite to the direction of the relative movement of the tool electrode with respect to the workpiece at the machining position, or the direction perpendicular to the direction of the relative movement of a wire electrode with respect to the workpiece, that is, the direction normal to the work surface (e.g. in the case of the finishing on a wire electric discharge machine or the machining on a diesinking electric discharge machine). In place of these directions, the direction set in an orthogonal three-axis coordinate system is sometimes provided.
FIG. 6 is a block diagram showing the conventional relative feed control of the tool electrode with respect to the workpiece. In FIG. 6, reference numeral 1 denotes a tool electrode, and 2 denotes a workpiece. A gap condition detector 3 detects the electric discharge condition of the gap between the tool electrode 1 and the workpiece 2 (for example, detects the average working voltage). A command distribution mechanism 4 is composed of a digital differential analyzer (DDA) and the like in a numerical control unit to distribute command values to the positions commanded by a machining program. Numerical characters 5x, 5y, and 5z denote the servomechanisms for X, Y and Z axes, respectively; 6x, 6y and 6z denote servomotors; and 7x, 7y and 7z denote position detectors for detecting the rotational position of each servomotor. A transmission mechanism 8 moves the tool electrode 1 with respect to the workpiece 2 (FIG. 6 shows an example in which the tool electrode is moved by way of three servomotors 6x, 6y and 6z).
The gap condition detector 3 detects the condition between the tool electrode 1 and the workpiece 2, such as the average working voltage, and determines the deviation .di-elect cons. (=Vg-Vs) between the value Vg of the detected condition and the value Vs of the target (preset) condition. Then, the command value distribution mechanism 4 distributes the movement commands (M.sub.cx, M.sub.cy, M.sub.
REFERENCES:
patent: 4564912 (1986-01-01), Schwefel
Odaka Shun'ichi
Sawada Kiyoshi
Evans Geoffrey S.
Fanuc Ltd.
LandOfFree
Method and apparatus for electrical discharge machining with con does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for electrical discharge machining with con, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for electrical discharge machining with con will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1139555