Electric heating – Metal heating – Cutting or disintegrating
Patent
1987-09-21
1989-02-21
Envall, Jr., Roy N.
Electric heating
Metal heating
Cutting or disintegrating
219 69M, B23H 706, B23H 704
Patent
active
048067202
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a method for wire electrode type electrical discharge machining and equipment employable for wire electrode type electrical discharge machining. More specifically, this invention relates to an improvement applicable to a method for wire electrode type electrical discharge machining in which the angle between the direction in which a wire electrode extends and the direction along the surface of a workpiece varies (hereinafter referred to as taper machining), for the purpose of improving the machining accuracy thereof and for improving equipment employable for wire electrode type electrical discharge machining, for enabling the above mentioned improved method to be performed therewith.
DESCRIPTION OF THE RELATED ART
Wire electrode type electrical discharge machining, which is performed by employing an equipment for wire electrode type electrical discharge machining, is classified into two categories. The first category is ordinary machining, in which the angle of a wire electrode is 90.degree. from workpiece that is, the wire electrode is maintained perpendicular to the direction in which a workpiece is being moved. The second category is the so-called taper machining. In taper machining, the angle between the wire electrode and the direction perpendicular to the direction of motion for a workpiece (the angle by which a wire electrode is inclined or the taper angle) is not zero degrees, or the angle is intentionally varied. In other words, the angle of the wire electrode from the direction of motion for the workpiece is not 90.degree..
Referring to FIG. 1, taper machining can be conducted by relatively moving upper and lower electrode guides 2U, 2L from side, to side as illustrated in FIG. 1. The angle .theta. from perpendicular for a wire electrode 1 is thereby controlled. In FIG. 1, the upper electrode guide 2U (as shown by dotted lines in the drawing) is moved, giving the angle .theta. from perpendicular for the wire electrode 1. If this taper angle could be a direct sharp angle, then a taper machining could readily be realized by a servomechanism. Since a wire electrode 1 is elastic, however, the wire electrode 1 does not extend in a straight line between the upper and lower electrode guides 2U, 2L but in a gradually curved line. In other words, the wire electrode 1 does not actually extend as shown by a chain line 25 shown in FIG. 1, but in a solid line 26.
Since taper machining is conducted exclusively by relatively moving the upper and lower electrode guides 2U, 2L from side to side as illustrated in FIG. 1, it is essential to remove any error caused by the aforementioned curvature of the wire electrode 1 between the upper and lower electrode guides 2U, 2L. To remove the error, the reference supporting points of the upper and lower electrode guides 2U, 2L (the last points of contact between the electrode guides 2U, 2L and the wire electrode 1) must be corrected from an end point 21 to a point 22 (the cross point at which a current direction in which the wire electrode 1 actually extends crosses a perpendicular line 27 along which the wire electrode 1 extends in the case where the upper and lower wire guides 2U, 2L are superposed to each other as shown by a dashed dotted line for the upper electrode guide 2U and the line 27 in FIG. 1). This correction is called a positional correction of the supporting points of a machining electrode.
The amount of correction .delta. by which the wire electrode guide supporting points are shifted is a constant, provided the elastisity of the wire electrode is a constant.
However, when the angle or direction in which a wire electrode proceeds along a workpiece during a machining process is changed to make a turn during a taper machining process (or when a X-Y axis control system changes the direction of a table on which the workpiece is mounted at a corner during a taper machining process), the machining current must be decreased. Otherwise, the pressure caused by an electric spark discharge causes the radius of curva
REFERENCES:
patent: 4383159 (1983-05-01), Inoue
patent: 4675491 (1987-06-01), Marendaz
patent: 4703146 (1987-10-01), Kinoshita
Envall Jr. Roy N.
Evans Geoffrey S.
Fanuc Ltd.
LandOfFree
Method and apparatus for wire-cut electrical discharge machining 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 wire-cut electrical discharge machining, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for wire-cut electrical discharge machining will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1523647