US 4,430,544 AGranted

EDM Machine tool with compounded electrode-reciprocation and servo-feed drivers

AssigneeInoue-Japax Research Incorporated

InventorKiyoshi Inoue

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Abstract

An improved EDM machine tool is disclosed in which an electrode reciprocating assembly is mechanically coupled between a movable (e.g. tool) electrode and a machine-head spindle which is axially driven by a motor in response to servo-feed signals. The assembly includes a rotary member driven by a separate motor to reciprocating rotate through a limited angle of rotation and link means for converting a reciprocatory rotary movement of the rotary member into a corresponding rectilinear reciprocal movement of the movable electrode in the servo-feed direction or a direction perpendicular thereto. The stroke and period of electrode reciprocation are determined by the angle and rate of rotation of the rotary member, respectively. The servo-feed operation, especially advance-feed movement therein is interrupted while the reciprocating assembly is in operation. The reciprocating operation is preferably conducted in synchronism with the dielectric flushing operation.

Claims20

Dependent claims

In an EDM machine tool for machining a workpiece electrode wherein a tool electrode and the workpiece electrode one of which is movable are spacedly juxtaposed with one another to define a machining gap therebetween in the presence of a liquid machining medium and a succession of electrical discharges are effected between the tool electrode and the workpiece electrode across the machining gap to electroerosively remove material from the workpiece electrode, the combination of:

a machine-head spindle for supporting said movable electrode;
first motor means drivingly coupled with said machine-head spindle and responsive to electrical conditions in said machining gap for axially displacing said spindle to move said movable electrode towards and away from the other electrode so as to maintain said machining gap in size substantially constant;
and
an electrode reciprocating assembly mechanically coupled between said machine-head spindle and said movable electrode and including a rotary member, second motor means operable independently of said first motor means and drivingly coupled with said rotary member for reciprocatingly angularly displacing said rotary member through only a limited angle .theta. of rotation where 0.degree.<.theta..ltoreq.180.degree. and link means coupled between said rotary member and said movable electrode for converting the reciprocatory angular displacement of said rotary member into a corresponding rectilinear reciprocatory movement of said movable electrode;
and
reciprocation stroke setting means associated with said second motor means for determining said limited angle .theta. of reciprocatory angular displacement of said rotary member so as to set the stroke of rectilinear reciprocatory movement of said movable electrode at a desired value.

3 more elements

In an EDM method wherein a tool electrode and a workpiece electrode, one of which is movable, are spacedly juxtaposed with one another to define a machining gap therebetween in the presence of a liquid machining medium and a succession of electrical discharges are effected between the tool electrode and the workpiece electrode across the machining gap to electroerosively remove material from the workpiece electrode, the improvement which comprises:

(a) supporting said movable electrode with a machine-head spindle;
(b) sensing electrical conditions in said machining gap for operating first motor means drivingly coupled with said machine-head spindle to move said movable electrode towards and away from the other electrode so as to maintain said machining gap substantially constant in size by axially displacing said spindle;
(c) mechanically coupled between said machine-head spindle and said movable electrode an electrode reciprocating assembly comprising a rotary member, second motor means drivingly coupled with said rotary member and rotation-to-rectilinear motion converting link means coupled between said rotary member and said movable electrode;
(d) independently of the movement of said movable electrode by said first motor means in step (b), reciprocating with said assembly said movable electrode towards and away from said other electrode with a predetermined stroke of reciprocation by operating said second motor means to reciprocatingly rotate said rotary member through a predetermined angle of rotation .theta. where 0.degree.<.theta..ltoreq.180.degree. and to cause said link means to convert the reciprocatory rotary movement of said rotary member into a rectilinear reciprocatory movement of said movable electrode;
and
(e) determining said limited angle .theta. of reciprocatory rotary movement of said rotary member to set the stroke of rectilinear reciprocatory movement of said movable electrode at a desired value.

3 more elements

Dependencies are inferred from the claim text.