The archive · Product Ideas · Technical decision · 2024–2026
On's LightSpray (2024): one robot arm sprays a laceless shoe upper in three minutes
Robot arms spray On's Cloudboom Strike LS upper in one seamless piece — 170g, no laces, no glue; the technique went mass-market with 30x production in 2026.
On (On Holding AG)
What it had to solve
Performance-shoe uppers were still made the traditional way — fabric cut, sewn and glued around the foot, dozens of parts and labor steps. 3D printing had touched running shoes before (Adidas' Carbon-printed midsoles, Nike's scan-fit uppers), but always in the midsole or fit system, never the structural upper. On set out to design the upper as if manufacturing were being invented from scratch.
How it works
In July 2024, Swiss running brand On unveiled LightSpray: a robot arm that sprays out a stream of foamy plastics and draws an entire shoe upper onto a mold in about three minutes — one seamless, laceless piece that stretches to fit the wearer's foot. The first shoe to use it, the Cloudboom Strike LS, was On's lightest-ever racing shoe at 170 grams (about six ounces), roughly an ounce lighter than comparable super-shoes such as the Nike Vaporfly, and priced at $330.
The trick was a manufacturing argument, not a materials one. Traditional uppers are cut from fabric, then sewn and glued — dozens of parts and steps. LightSpray instead has the robot arm build the upper directly out of 'Double Helion HF' hyper-foam, over 40 percent bio-based plastic, as one solid piece: the material congeals on the mold, then stretches to accommodate the foot. Reviewing the result, Wired called it 'ridiculously light', granted an 8/10, and wrote 'you won't miss laces, that's for sure.'
The strategic bet was to make the factory the moat. After the limited elite drop, On opened an automated LightSpray plant in South Korea in 2026, raised LightSpray production 30-fold, and moved the technique to the mass market with the LightSpray Cloudmonster 3 Hyper — eight parts total, the upper formed in under three minutes, $280, on sale in North America from March 5, 2026 and globally from April 16.
3D printing had reached running shoes before, but not in the structural upper: Adidas' Carbon-printed 4DFWD targeted the midsole, and Nike's patented system used scans for fit tensioning. On's twist was to make the printed part do mechanical work — weight, breathability, propulsion — instead of just covering the foot. Wired, reporting on the scale-up, noted the brand was 'doubling down' on the bet.
Why it lands
- One spraying robot replaces an entire cut-sew-glue supply chain, so the factory itself — not a materials patent — became the barrier competitors must match.
- A seamless sprayed upper kills laces, seams and glue, cutting the shoe to 170 grams and letting the fit stretch to the wearer — properties no stitched upper can claim.
- Because the machine prints any shape, the same process scales across models — from an elite $330 marathon shoe to a $280 mass-market Cloudmonster — magnifying the payoff of the original bet.
- 3D-printing rivals aimed at midsoles and fit systems; On went to the structural upper, a white space where the printed part carries real mechanical load.
What it did
Wired rated the Cloudboom Strike LS 8/10 — 'ridiculously light', with a 'sublime' bounce and 'you won't miss laces, that's for sure'. On then opened an automated LightSpray plant in South Korea and raised production 30-fold in 2026, taking the technique from elite-only drops to a $280 shoe for everyday runners — while 3D-printing rivals (Adidas, Nike) kept their printed parts in midsoles and fit systems.
What you can take
Redesign the process, not just the product: by collapsing the upper factory into one spraying robot, a single machine became the moat — an advantage no design tweak or material patent can copy.
Since then
The Cloudboom Strike LS's 170-gram sprayed upper carried On's claims into elite racing, though Wired flagged the membrane as fragile and the $330 price as steep. The technique then scaled fast: a South Korea automated plant raised LightSpray capacity 30-fold during 2026, and the Cloudmonster 3 Hyper took the technology to everyday runners at $280. On said scaling up LightSpray production globally was a strategic goal 'within the next few years', and reviewers kept debating whether laceless, spray-on shoes will ever fully replace the traditional upper.
Sources
- Review: On Running Cloudboom Strike LS
- On Running Is Finally Ramping Up Production of Its 'Hyper-Foam' Spray-On Shoes
- On Launches Third-Generation Cloudmonster Shoes with 3D Printed Upper for Performance and Propulsion
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