Electrical discharge machining (EDM) is considered a specialized manufacturing process that is rarely used in the hobby sector because the machines are typically expensive. The EnderSpark project addresses this issue and combines two objectives: an inexpensive option for CNC machining of difficult-to-machine materials such as hardened metals, and a way to reuse older, defective Creality Ender 3 printers. The idea specifically utilizes the existing mechanics of an FDM system as a positioning platform.
For the conversion, the print bed and extruder are removed, leaving a simple motion frame at the core. To increase the necessary accuracy, a 51:1 reduction gear is used between the NEMA 17 motors and drive pulleys. In addition, inexpensive MGN12H linear guides reinforce the X and Y axes so that they can support the weight of a water bath. The mechanical conversion thus aims to achieve greater rigidity and more controllable movements.
The most complex part is the wire feed. It sits on a specially milled aluminum plate. The project uses a RepRap idea: first, a simple frame is created from inexpensive material, and later the machine can cut a thicker and more stable version for an upgrade. A ready-made ruby nozzle is used as the guide nozzle, surrounded by a 3D-printed jacket for water cooling. Electrically, the upper part of the feed and the wire form an electrode, while the lower part is separated and insulated. There, the used wire is pulled down through the nozzle, kept taut, and wound onto a waste spool.
The electronics are largely taken from the Ender, with an additional driver stage. It sends short current pulses from a 48-volt power supply, up to 10 amps, through the wire into the grounded workpiece. This creates the small sparks that remove the material. According to the project, industrial machines operate at higher voltages, but EnderSpark stays at 48 volts for safety reasons, also because it works in water. The water should be deionized, but it absorbs impurities over time and therefore needs to be changed regularly.
The machine is controlled by G-code. A plugin for Fusion 360 converts the tool path into appropriate commands, using a profile for the Wazer water cutter as a template. The project mentions pulse energy control as a possible extension. However, clean control of the horizontal feed rate is considered more difficult with pure G-code. More information about the project can be found on the project page and in this YouTube video:
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