Electrical discharge machining apparatus with exchangeable electrode refeed cartridge

In an electrical discharge machine having an electrode supported on an indexable turret which electrode is transferable to a servo drive head the improvement comprising:

• a refeed cartridge assembly including a frame, means on said frame including magnet means and guide holes, magnetic means and guide pins on the indexable turret for magnetically coupling said frame thereto at said magnet means and guide holes thereon;
• an electrode board on said frame having a plurality of spaced electrode grooves, each of said cartridge assemblies including a combination power receptacle and drive head connected to said board and slidably mounted on said frame for reciprocating said electrode board, and electrode guide on said frame;
• and at least one electrode extending from said board through said electrode guide;
• and plural clamps including at least one clamp on said drive head for moving said electrodes with respect to said electrode guide during electrode refeed and for moving said electrodes toward and away from the workpiece to spark erode a desired opening therein following the refeed operation.

An electrical discharge machine comprising a base frame with a workpiece holding fixture adapted for holding a workpiece;

• frame means including an upright frame member mounted on said base frame;
• a support member slidably mounted on said upright frame member;
• a turret indexably monted on said upright frame member;
• a plurality of spaced electrode refeed cartridge stations mounted on said turret, each of said cartridge stations including magnetic means and guide pins;
• refeed cartridge means including a base frame having means thereon coacting with said magnetic means and guide pins to form a magnetic attraction between the base frame and one of said stations;
• and slide shuttle means relatively moveable with respect to said turret and said workpiece holding fixture including means for engaging said base frame and holding it on said slide shuttle means with a retention force greater than that of said magnetic attraction whereby said refeed cartridge means can be separated from a turret and moved between the turret and a workpiece.

An electrical discharge machine comprising a base frame having secured thereon a workpiece holding fixture adapted to holding a workpiece;

• frame means including an upright frame member mounted on said base frame;
• a support member slidably mounted on said upright frame member;
• a turret indexably mounted on said frame means;
• a plurality of electrode refeed cartridges, interlock means removably mounting each of said cartridges on said turret, each of said cartridges including a frame secured to said turret by said interlock means, drive head means slidably mounted on said frame;
• an electrode guide board cantilevered from said drive head means and freely slidable without friction with respect to said frame for reducing the actuation force through said drive head means;
• at least one electrode slidably supported on said electrode guide board;
• means for moving said support member and turret;
• slide shuttle means relatively moveable with respect to said support member and selectively positioned in a cartridge exchange elevation at the turret and an EDM working location at the workpiece and drive means including an EDM cylinder means fixed on said slide shuttle means for driving at least one electrode into operational relationship with one workpiece to spark erode a desired opening therein.

A refeed cartridge assembly for selectively compensating for electrode wear during a spark erosion process comprising:

• a cartridge frame with an electrode guide on one end thereof, a pair of slide rods on said frame;
• a drive head slidably supported on said slide rods, an electrode magazine board on said drive head having a plurality of longitudinally directed electrode support grooves therein;
• means for fixedly securing said magazine board to said head for movement therewith and for spacing said board from said frame whereby relative movement between said board and said frame is frictionless;
• first electrode clamp means on said electrode guide;
• second electrode clamp means on said drive head;
• said second electrode clamp means engageable in opposite directions and including a neutral position;
• control means operative to release the first clamp means and engage the second clamp means in a first direction during an EDM operation in which said drive head moves said magazine board and electrodes thereon in a first direction with respect to said electrode guide bushing when the drive head is moved in a first direction;
• said control means being operative to release the first electrode clamp means and to condition the second electrode clamp means in neutral when said drive head is moved in a direction opposite to said first direction during a refeed movement wherein electrodes are drawn from said electrode board;
• said control means engaging said first electrode clamp means and engaging second the electrode clamp means in an opposite direction during a reverse refeed movement of said head;
• and means for imposing a controlled spring pressure on said electrode during said refeed movement to advance the electrodes through the electrode guide until a location pressure is imposed thereon at which time the electrodes are slidable against the controlled spring pressure relative to said electrode board.

In an electrical discharge machine having a base with a workpiece holding fixture adapted for holding a workpiece;

• frame means including an upright frame member mounted on said base;
• a support member slidably mounted on said upright frame member, a turret indexably mounted on said frame member;
• a plurality of spaced refeed cartridge stations on said turret the improvement comprising:
• each of said cartridge stations including magnetic means and locator pins;
• refeed cartridge means including a frame having means thereon coacting with said magnetic means and said locator pins to magnetically attract and removably support the frame at one said refeed cartridge stations;
• and slide shuttle means moveable independently of said turret for overcoming the magnetic attraction between said frame and said magnetic means for separating one of said refeed cartridge means from the turret and for moving one of said refeed cartridge means between the turret and the workpiece.

In an electrical discharge machine having a base with a workpiece holding fixture adapted for holding a workpiece;

• frame means including an upright frame member mounted on said base;
• a support member slidably mounted on said upright frame member;
• a turret indexably mounted on said frame means;
• a plurality of spaced electrode refeed cartridge stations mounted on said turret the improvement comprising:
• each of said cartridge stations including magnetic means and locator pins;
• refeed cartridge means including a frame having means thereon coacting with said magnetic means and said locator means to magnetically attract and removably support the frame at one of said stations;
• moveable slide shuttle means operable independently of said turret for overcoming the magnetic attraction between said frame and said magnetic means and for moving one of said refeed cartridge means between the turret and a workpiece;
• said slide shuttle means including an EDM drive cylinder fixed thereto for movement therewith