A low-cost machine for electrochemical machining (ECM) and spark erosion (EDM) that you build yourself.A belt-driven CoreXY moves the head over 300 × 300 × 300 mm; a monolithic 3D-printed PETG flexure driven bythree voice-coil motors salvaged from old hard drives corrects the electrode position in real time, using twooptical sensors that look up at a reference glass.

Simulated performance (time-domain model of the designed machine, p99.7):

• Electrode X / Y error 0.90 / 0.65 µm while the belt stage vibrates ±100 µm
• ECM gap regulation 0.66 µm, EDM gap 1.38 µm
• Firmware checked bit-exact against the simulation

What you get (digital files only)

• 42 print-ready STL (94 pieces, ≈ 2.3 kg PETG, ≈ 109 h), all fit a 180 × 180 × 180 mm bed, already oriented, no supports
• STEP of every part + full-machine assembly STEP + FreeCAD project (assembly, purchased parts, BOM sheets)
• Build guide PDF: bill of materials with prices and 3 build variants (full / ECM-first / ECM-only), print guide,extrusion cut list, step-by-step assembly with pass/fail checks, calibration, safety
• Wiring schematics (6 sheets, SVG/PNG), wire table, STM32 pin map
• Source: STM32G474 C++ firmware + golden test, FPGA gateware (Colorlight 5A-75E), ESP32-S3 safety/sensor hub,the complete parametric CAD + simulation + optimiser in Python (re-generate everything for your own parts)
• Renders and a 360° turntable video

Parts cost: ≈ US$ 510 for the full EDM + ECM machine, ≈ US$ 385 for the ECM-only variant (author's 2026 prices,AliExpress-type parts; frame of 2020/4040 extrusion, MGN12 rails, NEMA 17/23 steppers).

Please note — honest status: this is a complete, simulated and design-rule-checked design. It has not yet beenbuilt and measured; all accuracy figures are simulation results, images and video are renders. The machine usesmains power, up to 96 V DC and chemicals — for experienced makers only. Original design notes and code commentsare in Vietnamese; all build documents are in English. Personal-use license.