AI Models Generate G-Code for a CNC Plasma Cutter

Summary

Glass House Arts describes an experiment in using language models to control a CNC plasma cutter by writing G-code directly, bypassing the usual CAD and CAM workflow. In April 2023, the author asked OpenAI's GPT-4 to create code for a sign. The code loaded successfully, but GPT-4 misunderstood the requested shape, failed to set the initial height at each pierce, and introduced an unexplained 30-second pause; the author reported that nobody was hurt. The page notes that GPT-4 had no vision system and generated text by predicting likely continuations rather than understanding the physical shape. A January 2026 update reports that Claude Opus 4.5 produced a clearly legible sign and was substantially better than the earlier attempt, although its chamfered corners were inverted. In a September 2026 update, Claude Opus 5.5 used Python to write and debug the G-code, included stenciled lettering and lead-ins, and researched specifications for FireControl and the Hypertherm 45XP without example code. The resulting sign still had a material shift caused by the plasma cutter rather than the model, but the page presents the progression as evidence of major practical improvement in model-assisted machine programming.