The main body of the electrical discharge machining (EDM) machine includes the bed, column, spindle head, and worktable, primarily used for clamping and adjusting tools and workpieces. The machine body requires sufficient rigidity to prevent deformation during processing, which could alter the discharge gap and hinder machining. During the EDM process, both the tool electrode and the workpiece are immersed in the working fluid. The main function of the working fluid is to compress the spark channel during discharge, allowing the current to concentrate in a small area; after discharge, it must quickly eliminate ionization and restore insulation to prevent arcing. The working fluid also cools the tool and workpiece. To timely remove the erosion products from the electrode gap, the EDM machine is equipped with a working fluid circulation system that uses forced circulation of the working fluid to accomplish this task.

Bed and Column

The bed and column form a fundamental structure that ensures the relative position between the electrode, worktable, and workpiece. Their precision directly affects machining; if the machine's precision is low, machining accuracy is also difficult to guarantee. Therefore, not only should the structure of the bed and column be reasonable and possess high rigidity to withstand the spindle load and the inertial forces from sudden acceleration of moving parts, but they should also minimize deformation caused by temperature changes, eliminate internal stress through aging treatment, and maintain their shape over time.

Worktable

The worktable is primarily used to support and clamp the workpiece. In actual machining, the relative position between the electrode and the workpiece is changed by rotating the longitudinal and transverse lead screws. The upper part of the worktable is also equipped with a working fluid tank to hold the working fluid, allowing the electrode and the workpiece to be submerged in the fluid for cooling and chip removal. The worktable is a component that the operator frequently moves during clamping and alignment, using two handwheels to move the upper and lower sliding plates, changing the longitudinal and transverse positions to achieve the required relative position between the electrode and the workpiece. The types of worktables can be divided into: ordinary worktables and precision worktables.

Spindle Head

The spindle head is a key component of the electrical discharge drilling and forming machine, consisting of three parts: servo feed mechanism, guiding and anti-twist mechanism, and auxiliary mechanism. It controls the discharge gap between the workpiece and the tool electrode. The quality of the spindle head directly affects the machining process indicators, such as productivity, geometric accuracy, and surface roughness. Therefore, in addition to structural differences, the spindle head should also meet the following conditions:

① It should have certain axial and lateral rigidity and precision; ② It should have sufficient feed and return speed; ③ The linearity of spindle motion and anti-twist performance should be good; ④ Sensitivity should be high, with no creeping phenomenon; ⑤ Different machines should have a reasonable capacity to bear the quality of the electrode.