Electrical discharge machining apparatus

An apparatus for electrical discharge machining comprising:

• a housing having a workpiece support area and a rear wall extending upwardly from a rear edge of said workpiece support area;
• workpiece support means secured to said housing within said workpiece support area for holding a workpiece;
• means attached to said housing for performing an electrical discharge machining operation on the workpiece secured to said workpiece support means;
• a tank assembly, said tank assembly including a front wall and two spaced apart side walls, said side walls each having a front edge secured to opposite edges of said front wall, said side walls each having a rear edge adjacent to said housing rear wall when said tank assembly is in a machining position, said workpiece support means being positioned between said side walls;
• means for moving said tank assembly between said machining position and a retracted position;
• means for sealing said tank assembly in said machining position to enable said tank assembly to hold a dielectric fluid;
• a channel attached to said housing for supporting and positioning said sealing means against said tank assembly, said channel extending along said housing rear wall and side walls and front wall of the tank, said sealing means comprising an inflatable bladder which, upon inflation, sealing engages said tank assembly along said front wall, said side walls and along said upwardly extending wall;
• wherein in said machining position said tank assembly encompasses said workpiece secured to said workpiece support means;
• and
• wherein in said retracted position said tank assembly is spaced away from a workpiece secured to said workpiece support means to facilitate access to a workpiece secured to said workpiece support means.