CuCrZr vs Pure Copper 3D Printing: CuCrZr or Pure Copper, Which One Should Your Part Be Printed In?

Most buyers arrive with the conductivity table open and a budget in mind, working backwards from numbers. The comparison rarely goes that way round. CuCrZr vs Pure Copper 3D printing is settled by two things a datasheet does not show: how hard the alloy is to build, and what the part has to do at temperature.

Four waisted cylindrical metal samples in different alloy tones standing in a row — Illustrative finish comparison. Not real customer parts; no measurements shown.

We run three copper grades — pure copper (C11000), CuCrZr and GRCop-42 — and the full property set for each is on our copper material page. That page is written to be complete, not comparative. What it cannot do is choose, because choosing is a question about your part and the datasheet only knows about the metal.

The order that works

Build behaviour first, then service temperature, then load, then conductivity. Asked in that order, most copper enquiries land on CuCrZr and never need a second look.

Conductivity goes last because it is the only one of the four where giving some up is usually harmless. A quarter of your conductivity budget is a small price for a build that succeeds.

Why is CuCrZr not simply worse copper?

Because it is a different answer to a different question. CuCrZr is a chromium-zirconium copper, precipitation hardened: it gives up some conductivity for a large gain in strength and high-temperature stability, and it prints far more reliably than pure copper.

The framing of “pure copper, but weaker” causes the wrong choice. Pure copper sits at the limit on three axes at once — conductivity, density at 8.9 g/cm³, and build difficulty. CuCrZr is the engineering answer to a question pure copper cannot answer without cost.

Four upright cylindrical metal samples in different finishes standing in a row — Illustrative material comparison. Not grades we shipped.

How much conductivity do you actually give up?

Pure copper runs at up to ~100 % IACS and roughly 400 W/m·K. CuCrZr sits at about 75–85 % IACS and 320–350 W/m&K, and GRCop-42 between them at 85–90 % IACS and 330–350 W/m·K. For context, that pure-copper thermal figure is roughly 27 times 316L and 57 times titanium.

So the question is not whether the gap exists. It is whether your specification is written as a number or as a temperature, and that single distinction resolves most of it:

Written as a temperature. A cold plate that must hold a surface below a limit, a heat spreader, a busbar cooling under a load. Here, thermal resistance across your geometry dominates, and the difference between 400 and 350 W/m·K changes the design far less than the shape of the internal channel does. CuCrZr is normally enough.
Written as a resistance or a current figure. High-current conductors where the drawing states a maximum resistance, or RF work where skin-depth behaviour sets the loss. Here every percent counts and giving up a quarter of IACS is a real specification change.

If your spec is a temperature, you have room. If it is a number, you are choosing between grades on one axis and should treat it as an engineering decision rather than a purchasing one.

When does pure copper print, and when does it fail?

Pure copper is the hardest thing on our floor to print, and the reason is optical, not metallurgical. 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, it wicks heat away from the melt pool about twenty times faster than steel, which leaves the molten zone small, short-lived and prone to instability.

This is why so much “printed copper” in the world is actually CuCrZr or GRCop rather than pure Cu. The industry answers to the optics are a green or blue laser, which copper absorbs far better, or alloying. On a standard 1064 nm machine, alloying is the available route.

Which means CuCrZr vs Pure Copper 3D printing is not a like-for-like substitution. Moving from pure copper to CuCrZr does not degrade the part; it removes the hardest part of the build. On our SLM metal printing lines, dense copper printing is treated as a specialist capability for this reason, and indium-free copper is the hardest of our metals to fully densify.

The practical consequence is that a pure-copper quote is reviewed by an engineer before it becomes a price, and we quote the density we expect for your geometry and measure a coupon rather than promising a blanket figure.

Flowchart for choosing between pure copper, CuCrZr and GRCop-42 in 3D printing. Step one asks whether the part runs above about 200 degrees Celsius, which rules out pure copper on service temperature. Step two asks whether the part carries sustained load, which also rules out pure copper because it creeps and prints at roughly 210 to 250 MPa against 350 to 450 MPa for CuCrZr and 400 to 500 MPa for GRCop-42. Step three asks whether the specification is written as a temperature or as a resistance or current number, and a number is the only case that sends the part to pure copper at up to about 100 percent IACS. Three grade cards below give the published values for electrical conductivity, thermal conductivity, tensile strength and service behaviour. — The conductivity table is the last step, not the first. Three questions eliminate pure copper before its numbers are ever read.

Does density decide the choice?

No, and this is worth saying because it is a common assumption. Pure copper is 8.9 g/cm³; CuCrZr and GRCop-42 sit within 1–2 % of that. All three are around 3.3 times the density of aluminium and heavier than the steel we print.

Mass is therefore decided by whether you print copper at all, not which copper you print.

What does service temperature rule out?

Pure copper is roughly a 200 °C service material in structural terms. CuCrZr and GRCop-42 hold strength considerably higher, and that is the reason they exist rather than a marginal improvement.

So if the part runs hot, pure copper is out on temperature before conductivity is discussed at all. And if it runs hot and cycles hard, that is the specific case GRCop-42 was developed for: a copper-chromium-niobium alloy for regeneratively cooled rocket chambers, where high conductivity and high-temperature strength have to coexist under severe thermal cycling.

Is pure copper strong enough to carry a load?

Roughly 210–250 MPa as printed, against 350–450 MPa for CuCrZr and 400–500 MPa for GRCop-42. That is a large difference, but the more important point is behavioural: pure copper is not a structural material. It is soft, and it creeps under sustained load, especially at temperature.

So a part that must both conduct and carry load is a contradiction in pure copper: the requirements pull in opposite directions. CuCrZr resolves it by design, which is why welding electrodes and high-heat-flux parts are made from it rather than OFHC copper.

What changes about finishing and surface condition?

Three things, and they are the same three whatever grade you choose:

On RF surfaces, finish is an electrical parameter. Skin-depth currents concentrate in the outermost microns, so roughness raises loss and can detune a cavity. Those parts are polished by default, and we do not bead-blast an RF surface because blasting measurably changes performance.
Dressing is easy to gouge. Copper is soft and gummy, so hand dressing is quick but will cut into a soft face if the process is careless. We work the witness faces rather than the functional ones.
Bare copper tarnishes. A visible part needs a clear lacquer; a contact surface or solder joint wants nickel or gold plating.

Support removal matters here too: copper parts are dressed by hand, and a stress-relief cycle before release is important on thin, high-aspect sections where the material is soft enough to move under its own residual stress.

How do you ask a supplier to compare the three grades?

Four questions, and what each one is really testing.

What to ask	Why it matters	A weak answer sounds like
Is my specification a temperature or a resistance?	It decides whether the conductivity gap is a specification change or a non-event.	“Copper is copper, it all conducts.”
What does this part do above 200 °C?	Pure copper loses structural standing there, and the other two do not.	Repeating the room-temperature tensile figure.
Does the part carry sustained load, and at what temperature?	Pure copper creeps; this eliminates it on mechanics alone.	Quoting tensile strength and stopping there.
Who reviews this before it is priced?	Pure copper geometry is engineer-reviewed, not quoted from a form.	An instant price with no engineering contact.

All four are answerable from a drawing and a paragraph about the application. Our metal powder buyer’s guide covers the same principle one level up: a quote is only meaningful once the specification behind it is written down.

Where this leaves you

CuCrZr vs Pure Copper 3D printing looks like a single-axis trade — conductivity against everything else — and it is not. It is a build question first, a temperature question second, and only then a materials question.

The honest summary. Pure copper is the right answer when conductivity is written as a number, the part runs cool, and the geometry is not pushing the conductivity-to-density ratio to its limit. CuCrZr is the right answer far more often than buyers expect, because it is the general-purpose engineering grade and it builds. GRCop-42 is the answer when high heat flux and high temperature arrive together.

Send the drawing with what the part has to conduct — the power, the heat flux, the frequency — and the service temperature written on it. We will tell you which copper grade your geometry can actually hold, what density we expect for it, and what it will cost. Every copper enquiry goes to an engineer before it goes to a price.

Sources for the figures above: our published copper and copper alloys page (grades, conductivity, thermal conductivity, tensile ranges, density, service temperature, 1064 nm reflectivity) and our SLM metal printing capability page (relative density, build process). Metal powders are export-controlled in many jurisdictions and the rules differ by destination, grade and quantity — verify against the official text for your destination before committing to a bulk order.