{"id":71138,"date":"2026-08-06T00:01:33","date_gmt":"2026-08-05T22:01:33","guid":{"rendered":"https:\/\/www.3dnatives.com\/en\/?p=71138"},"modified":"2026-08-05T22:36:49","modified_gmt":"2026-08-05T20:36:49","slug":"3dstartup-kupros-filament-cu29","status":"publish","type":"post","link":"https:\/\/www.3dnatives.com\/en\/3dstartup-kupros-filament-cu29\/","title":{"rendered":"#3DStartup: Kupros’ Cu29: A Conductive Copper Filament for FDM Electronics an Expert Said Would “Never Be 3D Printed”"},"content":{"rendered":"

When Ian Ramsdell, founder of Kupros<\/strong>, started asking electronics specialists about 3D printing solid copper, he faced plenty of skepticism. One expert, in Ramsdell\u2019s recollection, insisted it could not be done and never would be: \u201cCopper can\u2019t be 3D printed, it\u2019ll never be 3D printed.\u201d<\/em> What that expert did not know was that Ramsdell was already working from a confirmed laboratory experiment, one the US military had run and validated years earlier.<\/span><\/p>\n

That distance between \u201cimpossible\u201d and \u201calready proven in a lab\u201d is the founding story of Kupros and its flagship product, Cu29: a fully metallic, conductive filament engineered to print on standard fused deposition modeling<\/a><\/strong> (FDM) machines<\/strong>, the desktop hardware already sitting in most workshops. The ambition reaches past printed circuits. Because the conductor is extruded alongside structural plastic in the same build, Cu29 is aimed at integrated sensors, embedded signal routing, and conformal antennas and conductive paths that follow a part\u2019s geometry rather than sitting on a flat board. In aerospace and defense, where Kupros sees its strongest early demand, the pitch is concrete: fewer wiring harnesses, connectors and interconnects, structural-health sensing built into load-bearing parts, and faster iteration as electrical and mechanical design evolve together. <\/span>\u201cJust because somebody has been told that something is impossible, doesn\u2019t mean it can\u2019t be done,\u201d <\/span><\/i>Ramsdell said.<\/span><\/p>\n

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Cu29 can be used to develop embedded electronics.<\/p><\/div>\n

NASA, Northrop and <\/span>Boeing Pre-Ordered Cu29 B<\/span>efore It Existed<\/span><\/h2>\n

The market committed before the material was finished. Accepted as an Army xTech finalist at the 2022 DMC conference in Tampa, Ramsdell left with prepaid orders from NASA, Northrop and Boeing.<\/strong> More pre-sales followed, from KBR, US Army DEVCOM and several universities. Buyers put money down while the material science was still in development. \u201cThey were willing to prepay me for first access to the material as soon as it came off production,\u201d<\/em> he says. It is an unusual level of confidence for a pre-revenue materials startup.<\/span><\/p>\n

The Navy-Lab Origin<\/h2>\n

The underlying technology came out of a US Navy lab, credited by Ramsdell to scientist Carson Holmes, then a technician working on additive electronics systems from Optomec, Nano Dimension and nScript. Those seven-figure machines relied on silver inkjet chemistry with real limits: \u201cAs a result of the porosity in the traces, they\u2019re sometimes restricted to only low voltage and low amperage usage,\u201d<\/em> Ramsdell explained. Holmes\u2019 proposal for a better route was named top paper of 2017 under the Office of Naval Research Design Innovation Award, then sat unused until Ramsdell licensed it in 2021 through a US Department of Defense startup studio.<\/span><\/p>\n

That route is why he pursued a material others had dismissed: rather than gamble on unproven science, he took on technology a national lab had already de-risked. The failure he set out to beat was long-standing, not niche. \u201cOne very, very large electronics manufacturer told us that they were trying to manufacture material similar to this since the 1990s and they\u2019ve been unsuccessful.\u201d<\/em><\/span><\/p>\n

Why Copper Is Hard to 3D Print<\/h2>\n

The difficulty is intrinsic to the metal. \u201cCopper<\/a> is highly reflective and it transfers heat in a very efficient manner and then it oxidizes at the slightest temperature change,\u201d<\/em> Ramsdell says, a combination that has frustrated copper printing across process families for decades. Solving it, he argues, opened a door well beyond conductive traces. The team can now dope the material for properties such as radiation shielding and anti-tamper structures, \u201cso people can\u2019t x-ray components to reverse engineer.\u201d<\/em><\/span><\/p>\n

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Conductive filament printing allows users to build embedded signal routing, integrated sensors, conformal conductive paths, embedded antennas, and more.<\/p><\/div>\n

Built for Hardware You Already Own<\/h2>\n

The commercial case rests on access. Additive electronics has historically meant six- and seven-figure machines. Cu29 is built to drop into equipment already on the bench: Ramsdell has run it on sub-$300 desktop printers and on a Bambu Lab A1 Mini with its automated material system, and is qualifying the Prusa XL as a recommended platform. It needs no printer modifications beyond a steel hotend,<\/strong> and Kupros claims that a printed conductor is functional straight off the bed, with no sintering, plating, curing or chemical cleanup,<\/strong> a pointed contrast with silver inkjet\u2019s maintenance overhead.<\/span><\/p>\n

Notably, Cu29 is not meant to build bulk metal parts the way PLA builds plastic ones. Ramsdell says the team has printed only \u201cfive or six layer heights\u201d in the Z axis, mainly to test self-adhesion, and is \u201cnot trying to build in the third dimension currently.\u201d<\/em> Rather, the focus is on embedded electronics.<\/strong> The filament functions as a conductor laid into and onto polymer structures, which is why the workflow is multi-material: structural plastic and Cu29 printed together, often on a dual-extruder or IDEX machine, so the electrical path is embedded as the part is built. \u201cInstead of putting traditional components directly on the PCB, you\u2019re gonna actually put them directly at that point of need.\u201d<\/em><\/span><\/p>\n

The Performance Claims<\/h2>\n

Kupros\u2019 performance figures, which Ramsdell is careful to label preliminary, are the headline. In early high-voltage testing the company pushed 12,500 volts through the material without destroying it, then kept raising the current. \u201cWe kept blowing up power supplies and couldn\u2019t get enough current to actually do destructive testing,\u201d<\/em> he said. A supercapacitor bank later drove what he estimates at well over 600 amps through a short sample, still without failure. Against silver inkjet, the only comparable additive material, Ramsdell claims Cu29 is 48,000% more conductive. Those numbers are company-stated and await independent verification, but the positioning is clear: a single material for both high- and low-power applications, which the incumbent chemistry cannot serve.<\/strong> Kupros also took the TCT Materials Award at RAPID this year.<\/span><\/p>\n