Copper is the best conductor of heat and electricity among the metals we print, and by a wide margin: 8.9 g/cm³, up to 100 % IACS electrical conductivity, and roughly 400 W/m·K thermal. It is also the hardest thing on our floor to print, because it reflects almost all of the laser energy you aim at it. We quote copper jobs only after an engineer has looked at the geometry.
Pure copper is the reference conductor. Nothing else in commercial use matches it: around 100 % IACS electrical conductivity, roughly 400 W/m·K thermal conductivity, and excellent performance at radio frequencies. The reason to print it rather than machine it is geometry. A machined copper heat sink can only have straight fins and drilled holes; a printed one can have conformal channels that follow a curved surface, lattice structures with enormous surface area per unit volume, and integrated manifolds that remove every brazed joint from a cooling loop.
The problem is optical. Copper reflects roughly 95 % of the infrared light a standard 1064 nm fibre laser produces, so very little of the beam energy reaches the powder. On top of that, copper wicks heat away from the melt pool about twenty times faster than steel, so the molten zone is small, short-lived and prone to instability. The industry answer is either a green or blue laser, which copper absorbs far better, or alloying — which is why so much "printed copper" in the world is actually CuCrZr or GRCop rather than pure Cu.
We are straight about this because it changes what we can promise. Pure copper is quotable for geometries that are not pushing the conductivity-to-density ratio to its limit; CuCrZr gives you most of the conductivity with far better mechanical strength and much more forgiving printing behaviour; GRCop-42 is a precipitation-hardened copper developed for rocket engine chambers, where high conductivity and high-temperature strength have to coexist. Every copper enquiry goes to an engineer before it goes to a price, and we will tell you if a different grade serves you better.
The numbers that matter for copper are conductivity numbers, not tensile numbers. Here is what each grade delivers and what it costs you in return.
| Grade | Electrical | Thermal | Tensile | Pick it when |
|---|---|---|---|---|
| Pure copper (C11000) | ~100 % IACS | ~400 W/m·K | ~210–250 MPa | Maximum conductivity is the whole point and the geometry is not extreme |
| CuCrZr | ~75–85 % IACS | ~320–350 W/m·K | ~350–450 MPa | You need strength and heat resistance as well as conductivity — welding electrodes, high-heat flux parts |
| GRCop-42 | ~85–90 % IACS | ~330–350 W/m·K | ~400–500 MPa | High heat flux with high temperature at the same time — combustion chambers, severe thermal cycling |
Three grades, and the choice is nearly always a trade between conductivity and strength. Ask us which one your geometry can actually hold.
The maximum-conductivity route: up to ~100 % IACS, ~400 W/m·K. Soft, and the most demanding of the three to print well, because it reflects almost all of the laser energy. Best for busbars, inductors and heat sinks where conductivity is the only specification.
Chromium-zirconium copper, precipitation hardened. Gives up some conductivity for a large gain in strength and high-temperature stability, and prints far more reliably than pure copper. The general-purpose engineering grade.
A copper-chromium-niobium alloy developed for regeneratively cooled rocket chambers. High conductivity and high strength at temperature at the same time, with good low-cycle fatigue behaviour under severe thermal cycling.
The same grades supplied as powder for your own machines, with batch documentation traceable to the melt. Export eligibility depends on destination and grade — check before you order.
Copper powder is also available in bulk for your own machines — see powder supply. Note that metal powders are export-controlled in most jurisdictions.
Copper is soft and reactive, so finishing is about protecting the surface as much as shaping it.
Supports are cut and dressed by hand. Copper is soft, so dressing is quick but it is easy to gouge — we work the witness faces rather than the functional ones.
A thermal cycle relaxes residual stress. Important on thin, high-aspect copper sections, where the material is soft enough to move under its own residual stress.
Sealing faces, bores, O-ring grooves and threads cut from printed stock. Copper is gummy to machine, so budget for it on anything that has to seal or bear.
Progressive polishing brings up the natural copper colour and lowers roughness on RF surfaces, where skin-depth currents make surface finish an electrical parameter and not a cosmetic one.
Uniform matte finish. On RF parts, note that blasting raises roughness and can measurably change performance.
Bare copper tarnishes. A clear protective coating holds the finish and is essential on any part that is visible in service.
Nickel or gold plating over copper, for wear resistance, solderability, or to stop oxidation on contact surfaces.
Standard on thermal and RF parts to remove trapped powder and residue from internal channels before they go into a cooling loop.
Copper is specified when conductivity is the specification. It is heavy, expensive and difficult, and none of that matters if the part has to move heat or current.
Complex three-dimensional coil geometry that a machined or bent copper tube cannot produce, with integrated cooling in the same part.
Consolidated power distribution with geometry optimised for current density and cooling, replacing a stack of bar, bolts and lamination.
Lattice and pin-fin structures with surface area per unit volume that finned machining cannot approach, plus conformal channels under the actual heat source.
Waveguides, filters, antennas and cavity structures where surface finish and conductivity both set performance. Polished, not blasted.
CuCrZr electrodes with internal cooling channels shaped to the heat, which extends electrode life between dressings.
GRCop-42 regeneratively cooled chambers and nozzles, where conductivity and high-temperature strength have to coexist under severe thermal cycling.
Hairpin windings, rotor bars and busbars with cooling integrated into the conductor itself.
Inserts where the thermal response of copper, not steel, sets the cycle time — usually in a combined mould with a steel surround.
Copper is a conductivity material, not a structural one. Compared on strength it looks poor; compared on heat or current it is in a different class.
| Material | Process | Density | Strength | Heat | Pick it when |
|---|---|---|---|---|---|
| Ti-6Al-4V | SLM | 4.43 g/cm³ | 900–1100 MPa | ~400 °C | Strength per gram, or biocompatibility |
| 316L stainless | SLM | 7.9 g/cm³ | 480–620 MPa | ~400 °C | Corrosion resistance and ductility |
| AlSi10Mg | SLM | 2.67 g/cm³ | 330–400 MPa | ~170 °C | Light, thermally conductive, machinable |
| Copper & Cu alloys | SLM | 8.9 g/cm³ | 210–500 MPa | ~200 °C | Electrical or thermal conductivity is the specification |
| PA12 nylon | SLS | 1.01 g/cm³ | 48–50 MPa | ~120 °C | Tough, complex geometry, no supports |
| Photopolymer resins | SLA | ~1.1–1.2 g/cm³ | 40–70 MPa | ~80 °C | Detail, smoothness, transparency |
The alternative to printed copper is usually a machined copper block with drilled or milled channels, or a brazed assembly. Both are cheaper for simple geometry. Printed copper only earns its price when the cooling channel has to follow a curve, when the surface area has to be extreme, or when the joints in a brazed assembly are the thing you are trying to eliminate.
Two physics problems at once. Copper reflects roughly 95 % of the infrared light from a 1064 nm laser, so very little energy reaches the powder, and it conducts heat away from the melt pool about twenty times faster than steel, so the molten zone is small and short-lived. The industry answer is a green or blue laser, which copper absorbs far better, or alloying. That is why so much printed "copper" is CuCrZr or GRCop rather than pure Cu.
We quote pure copper, but for geometries where the conductivity-to-density ratio is not being pushed to its limit. Where the part is mechanically loaded or runs hot, CuCrZr or GRCop-42 will serve you better and print more reliably. Every copper enquiry goes to an engineer before a price, and we will tell you which grade we would choose and why.
For pure copper we work to roughly 100 % IACS and around 400 W/m·K, but we quote the measured value for your build rather than a blanket figure, because porosity and oxide inclusions reduce conductivity and copper is more sensitive to process behaviour than any other material we run.
For RF work, finish is an electrical parameter, not a cosmetic one. Skin-depth currents concentrate in the outermost microns, so roughness directly raises loss and can detune a cavity. Those parts get polished by default; we do not bead-blast an RF surface.
If the part will be seen, yes — bare copper tarnishes and the colour will drift. A clear lacquer holds the finish. If the part is a contact surface or needs solderability, nickel or gold plating is the usual answer. A hidden internal cooling channel often needs nothing.
Yes, and it is one of the more heavily controlled powders we ship. Metal powders are export-controlled in most jurisdictions and the rules differ by destination, grade and quantity, so run the destination through the eligibility checker first. Note that copper is also on the export-sensitive list for some destinations.
Send us the part and what it has to conduct — the power, the heat flux, the frequency. We will tell you which copper grade your geometry can actually hold, what density we expect, and what it will cost.
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