POWER OUTPUT MODULE

Power output module for electrical discharge machining power supply circuit



Power output module for electrical discharge machining power supply circuit

Overview

Included in the power supply is an output module connected to the gap which module uses a power FET. This module has its current output and the current to the gap controlled as a linear function of the control voltage applied to the gate of the FET. A suitable input means for the control voltage, includes manually controlled potentiometers, microprocessors, keyboards and the like.

Electrical Discharge Machining (EDM) is a technology that has been around since the 1950s. It is a proven, mature method for shaping and removing metal.

The Portable EDM System creates holes in metal using an electric arc. The EDM technique is useful where a hard material or uneven surface prevents drilling with a rotary bit (such as in the case of a broken bolt), or where a non-round hole is desired.

Description:

The Portable EDM uses a high-current low-voltage source which is connected between the cutting bit and the work. This voltage is controlled by a switching element. A stepper motor moves the cutting bit close to the work. When the cutting bit and work are very close to each other, an arc occurs. The highly focused electrical arc melts small particles in a precise area or shape in the metal. These small particles of residue are washed away by a continuous flow of cooling fluid.

The most common electrodes are made of carbon, graphite, copper, or brass. The Portable EDM offers precision machining without conventional cutting or drilling.

The Portable EDM is used with a water-soluble lubricant to control the heat and provide an optimal dielectric for the arc. This creates an excellent medium for burning out broken taps and bolts without affecting the surrounding surface area, and most importantly the original threads.

The AGB Portable EDM safely and easily removes broken studs, taps, screws and drills without damaging the threads. Additionally, it can machine any shaped hole in any metal, even hardened steel and carbide.

EDM is used by machine shops in heavy equipment, aircraft, and auto/truck repair, and by R&D and plant maintenance shops.

Introduction

In an apparatus for machining a conductive workpiece by means of electrical discharge across an EDM gap between a tool electrode and the workpiece; a pulser for providing triggeringon-off pulses; a power module including a source of machining power and a power FET having a pair of power conducting electrodes, said power conducting electrodes connected in circuit with said source and said gap; said power FET further having itsgate electrode connected to a point for receiving the triggering output of said pulser; and a variable control voltage source further connected to said point for controlling the current output from said module, said control voltage source comprising avariable voltage input representative of gap power and derived from a first signal representing gap voltage and a second signal representing gap current. (Jaeha 860 2003)

The combination as set forth in claim 1, wherein said pulser comprises a ...