[tbenst]

The high thermal conductivity of copper makes it difficult to maintain needed temperatures during SLM. Also, copper is prone to oxidation at high temperatures, further complicating (thermal based) laser melting 3D printing techniques. It’s more typical to print copper alloys than pure copper.

[FrostKiwi]

Those are solved issues.

> oxidation at high temperatures

SLM machines typically use an Argon gas chamber. DED machines use an Argon gas shield.

> It’s more typical to print copper alloys than pure copper.

In the context of modern SLM, it depends on your definition of "pure" and "alloy". During the process, a bit of resin to is mixed into the powder and heat treated in a final step to get to 99.9% pure copper.

edit: Just fixed up my knowledge. Indeed alloys are typically used (99% copper with things like Chrome added on depending on use-case), tough the pure copper can be used with higher laser power.

[ju-st]

Printing pure copper (99.9%) is possible since years with SLM process using lasers with an appropriate wavelength