Helical Fusion’s custom coil winder marks stellarator shift to production reality

The completed coil manufacturing machine stands ready at Sugino Machine Limited’s factory in Toyama Prefecture, Japan, poised to wind the high-temperature superconducting coils that will power Helical Fusion’s Helix HARUKA stellarator demonstrator.

(Image courtesy of Helical Fusion)

Helical Fusion has completed a custom winding machine for the high-temperature superconducting coils at the heart of its stellarator reactor programme, marking a concrete shift from laboratory validation to production-ready hardware.

Built with Toyama-based Sugino Machine Limited, a precision manufacturer founded in 1936, the machine winds Helical Fusion’s proprietary HTS cable into the complex spiral shapes that define the helical stellarator configuration. That geometry is central to the concept’s appeal. Stellarators confine plasma without relying on induced plasma currents, which means they avoid the disruption events that make continuous tokamak operation difficult. That inherent stability is the commercial argument Helical Fusion is building its roadmap around.

The collaboration reflects a deliberate division of responsibility. Helical Fusion carries the fusion physics and system architecture; Sugino provides the industrial precision needed to turn a one-off research component into something reproducible at scale.

The machine will now be transported to the assembly site for Helix HARUKA, Helical Fusion’s integrated demonstration device, with on-site work scheduled to begin in 2026. HARUKA is where the company’s two parallel development threads, HTS magnets and an integrated blanket and divertor concept, will be tested together as a complete system.

This follows the October 2025 milestone in which Helical Fusion demonstrated its proprietary HTS cable, designed specifically to be easier to bend and wind to simplify coil manufacturing, and announced the start of HARUKA fabrication. The newly completed winding machine is the direct manufacturing consequence of that work.

Helical Fusion draws on more than 60 years of helical stellarator research accumulated at Japan’s National Institute for Fusion Science. That lineage gives it experimental data and engineering insight specific to the architecture it is commercialising, rather than a clean-sheet design with no operational history.

The company’s commercial case rests on three requirements for a viable fusion power plant: net electricity output, continuous steady-state operation, and maintenance practical enough to sustain a grid asset. Standalone demonstrations of its two core technology pillars are targeted for around 2030, with integrated demonstration via HARUKA and first power generation from Helix KANATA both aimed at the 2030s. Helical Fusion has raised approximately 6 billion yen to reach this point.

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