US 4,430,180 A · Apparatus for and method of electroerosively drilling a thin hole in a workpiece

Abstract

An apparatus for and method of electroerosively drilling a thin hole, e.g. of 1 mm diameter, of a high depth-to-diameter ratio, e.g. 5 or more, in a workpiece with a tubular electrode of corresponding high slenderness. The system utilizes a novel liquid-delivery mechanism which comprises a cylindrical reservoir communicating through an outlet opening thereof with the internal bore of the tubular electrode and hence with the machining gap and a plunger member for operative reception in the reservoir to be movable therein. Prior to a drilling operation, the reservoir is charged via a check valve with a given amount of the machining liquid from a source thereof. During the drilling operation, a motor advances the plunger member to move it within the chamber at a controlled rate. The charged machining liquid in the reservoir chamber is thus pressurized by the plunger member and discharged from and delivered through the internal bore of the tubular electrode into the machining gap at a regulated rate of flow.

Claims16

Dependent claims

An apparatus for electroerosively drilling a thin hole of a high depth-to-diameter ratio in a workpiece with a tubular electrode of corresponding high slenderness, comprising

power-supply means for passing an electroerosive machining current between said tubular electrode and said workpiece across a machining gap flooded with a machining liquid delivered from the internal bore of the tubular electrode open to the machining gap;
electrode feed means for relatively advancing said tubular electrode axially into said workpiece to progressively form said hole in the workpiece;
and
liquid-delivery means comprising:
a reservoir chamber communicating through an outlet opening thereof with said internal bore of the tubular electrode;
means for charging said chamber with a predetermined amount of said machining liquid from a source thereof;
a plunger member for operative reception in said reservoir chamber to be slidably movable therein longitudinally;
and
displacement means for relatively advancing said reservoir chamber and said plunger member received therein at a controlled rate of relative displacement to pressurize said charged machining liquid in the chamber with the plunger member, such as to cause said liquid to be progressively discharged out of the chamber and to be delivered through said internal bore at a regulated rate of flow to said machining gap.

6 more elements

A method of electroerosively drilling a thin hole of a high depth-to-diameter ratio in a workpiece with a tubular electrode of corresponding high slenderness, comprising the steps of:

passing an electroerosive machining current between said tubular electrode and said workpiece across a machining gap flooded with a machining liquid delivered from the internal bore of the tubular electrode open to the machining gap;
relatively advancing said tubular electrode axially into said workpiece to progressively form said hole in the workpiece;
and
delivering said machining liquid into said machining gap by:
providing a reservoir chamber communicating through an outlet opening thereof with said internal bore of the tubular electrode and a plunger member for operative reception in said chamber to be slidably movable therein longitudinally:
charging said chamber with a quantity of said machining liquid from a source thereof;
and
relatively advancing said chamber and said plunger member received therein at a controlled rate of relative displacement to pressurize said charged machining liquid in the chamber with the plunger member, thereby causing said liquid to be progressively discharged out of the chamber and to be delivered through said internal bore at a regulated rate of flow to said machining gap.

5 more elements

Dependencies are inferred from the claim text.

Apparatus for and method of electroerosively drilling a thin hole in a workpiece

Life of this patent

Apparatus for and method of electroerosively drilling a thin hole in a workpiece

Life of this patent

Abstract

Claims16