The Basics of EDM Spark Erosion in Toolroom Capabilities for General Engineering

23 July 2021

Straight to business, spark erosion equipment is not like conventional cutting technology. There’s not a single abrasive disc or cutting blade around. Replacing those forceful, kinetically aggressive tools, an electrically charged electrode discharges a focused point of travelling, material-eroding energy. Eroding thousands of tiny craters per second, the electrode can cut complex outlines into hard metals. Best of all, there’s no contact between the tool and those metals.

Cutting Tool Limitations

Thin-edged saw blades and fine-grain grinding discs are regarded as fundamentally essential machine shop tools. However, they have limitations. A blade will always have trouble laying down a complex geometrical profile. And, should that geometry be required on a hardened metal workpiece, a whole new set of problems seem to appear to vex a project manager. Heat stress, as caused by the blade’s rubbing, alters the microcrystalline structure of the metal. The temperature rises so high, so rapidly, that it deforms the alloy. Again, while not impossible, it’s not easy to apply intricate shapes with conventional cutting tools. No worries, there’s a technology that doesn’t require any contact. Used to create those intricate shaped, the aforementioned frictional hardships become a non-issue.

High-Precision Spark Erosion Technology

With the mechanical, contact-abrasive tool edges gone, that highly charged electrode takes over the job. The metal-to-metal rubbing action is eliminated, replaced by a subtractive cutting process that vaporizes tiny quantities of workpiece alloy. Upon discharging the energy, thousands of these eroded voids form highly focused incision marks. To put it another way, the non-contact electrical charge is highly controllable and capable of applying the finest cuts, which can then travel in any direction, as guided by a system of state-of-the-art motion controlling electronics. All the while, as the intricate shapes are applied, there’s no frictional heat generated, so there are no changes to the metal, no material deformations, and no poorly applied cuts to undermine the process.

Spark erosion work is used to manufacture high-tolerance aeronautics and marine components. Hardened tool metals or softer alloys, it’s all the same, the electrode charge erodes and vaporizes dense or soft metals with equal alacrity. In-process, the workpiece to receive a series of detailed dimensional shapes is sunken into a liquid dielectric, which acts as a circuit insulator and debris flusher. Not that there’s much debris, with the erosion electrode vaporizing 10,000 of those tiny subtractive craters per second. And now, with oil and gas applications, the die-making sector and countless other high-tech applications specifying high-tolerance, dimensionally true parts above all else, spark erosion work has never been in more demand than it is right now.

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