A clean sheet for metal 3D printing

Metal additive manufacturing is now a sector worth nearly US$7 billion globally and growing at double-digit rates. But the technology has a persistent weak spot: its dependence on fine metal powder. The powder is expensive, difficult to handle safely and introduces variability between builds. It also places hard limits on what engineers can actually fabricate. Closed-cell structures — components with fully sealed internal cavities — are effectively off-limits, because powder trapped inside a sealed chamber cannot be extracted after printing.

LAPIS, short for Laser Pulsed Integration of Sheets, is a hybrid metal manufacturing technique developed at NTU’s School of Mechanical and Aerospace Engineering that sidesteps these constraints entirely. Developed by Nanyang Assistant Professor Lai Changquan and his research team, the process combines laser cutting and welding with ultra-thin stainless-steel sheets, stacked and fused layer by layer to form complex metal components. The name is a nod to kueh lapis, a well-known layered cake in Singapore — a fitting reference for a technology whose core insight is that building metal parts from precisely patterned sheets, rather than loose particles, changes what is possible.

Huge gains over existing methods

Parts produced using LAPIS are fully dense and more than 70% stronger than bulk steel, with surface finishes three times smoother than those achieved through conventional metal 3D printing. The layered sheet approach also allows engineers to create complex internal geometries, for example channels and cavities that can improve heat dissipation and fluid flow in heat exchangers, which are particularly valuable in thermal management and energy systems.

One of the most striking findings is what happened when the team tried processing titanium alloy. In powder-based systems, titanium must be handled inside sealed argon gas chambers because fine titanium particles are combustible in open air. Such infrastructure adds cost and complexity. Contrariwise, LAPIS uses solid sheets, so the combustion risk does not arise. The team processed titanium in a standard lab environment — something their powder-based counterparts cannot do without significant safety provisions.

“The initial development of LAPIS was motivated by the desire to fabricate closed-cell lattices,” says Asst Prof Lai. “But we quickly found that using sheets as the precursor material solves a host of other problems: reliability, cost and safety among them. The question shifted from how to make powder work better to whether powder was necessary at all.”

Tested at depth, built for scale

The technology has already been proven in one of the most demanding environments on Earth. In 2025, a steel artwork produced using LAPIS was installed 7,000 metres beneath the sea off Japan — part of the world’s deepest ocean art installation, a collaboration between Singaporean artist Lakshmi Mohanbabu, tech company NuStar Technologies and NTU. The cube, with walls just 4mm thick built from 80 stacked layers of stainless steel, withstood the crushing pressure and corrosive conditions of the deep ocean, showcasing the technology’s remarkable durability.

In 2026, LAPIS was shortlisted as a finalist for the TCT Awards, one of the additive manufacturing industry’s most established international prizes, in the Hardware (Non- Polymer) category — placing it alongside entries from NASA, General Motors and other major industrial players.

Commercialisation is now under way. Asst Prof Lai and his team have incorporated a spin-off, LAPIS Innovations, with support from NTUitive, NTU’s innovation and enterprise company. NTUitive’s proof-of-concept and proof-of-value grants helped bridge what Asst Prof Lai calls the “valley of death” between early-stage research and industry ready deployment. Commercial machines are expected to be available globally before the end of 2026, and the team is in discussions with partners in aerospace, maritime and satellite engineering, sectors where strong, lightweight metal components command a premium.

“We went from making something work well enough to produce a few samples for the next publication,” adds Asst Prof Lai, “to making it repeatable for hundreds of thousands of cycles to meet actual market needs. That is a very different engineering challenge.”

“Forty years ago, we had to send documents to a printing shop. Desktop printers put that capability on every desk. LAPIS is designed to do the same for metal parts — design today, get your part tomorrow, on your own shop floor.”

The LAPIS team with Singaporean artist and architect Lakshmi Mohanbabu (bottom row, third from left). Together they designed and manufactured a stainless-steel cube with walls just 4mm thick but over 70 per cent stronger than bulk steel, which survived the crushing pressures of the deep ocean near the Mariana Trench.

 

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