The same question shows up under two Fuse 1 videos, years apart. “Is SLS with carbon fiber possible?” asked one viewer of 3D Printing Nerd. Another, under Tested’s demo, asked whether carbon fiber even comes in powder form and whether the printer can run it. It does, and SLS carbon fiber behaves differently enough that it’s worth knowing before you quote it.
Can SLS carbon fiber powder run on a Fuse?
Yes, with the right powder and setup. Formlabs sells Nylon 11 CF Powder for the Fuse 1+ 30W, at $999 for 6 kg. It calls it its highest-performance material for that printer, aimed at jigs, fixtures, tooling and metal replacement parts.
Is it stronger in every direction?
No, and that’s the surprise for anyone sold on SLS being isotropic. Formlabs lists ultimate tensile strength of 69 MPa in X, 52 MPa in Y and 38 MPa in Z. Tensile modulus runs from 5,300 MPa in X down to 1,600 MPa in Z. So the part is stiffest along X and weakest across the layers.
Heat is where it clearly wins. Formlabs lists a heat deflection temperature of 178 °C at 1.8 MPa and 188 °C at 0.45 MPa.
What does it change in the workflow?
More than a powder swap. Formlabs says it must print in an inert atmosphere, and its powder comparison lists nitrogen for it. It needs a 300 µm sieve on the Fuse Sift or the depowdering kit instead of the standard 150 µm one. Its minimum refresh rate is listed at 30%.
If you already run Nylon 11 under nitrogen, most of that is in place. If you run Nylon 12 in air, you’ll need a nitrogen supply and a full changeover before your first CF build.
How should you orient CF parts?
Like you would for FDM, which feels odd on a powder machine. Lay the part out so the main bending load runs along the printer’s X axis, and keep critical tension loads out of Z. When you quote it, write the build orientation on the drawing so the next job comes out the same.
Related on the Solvi blog: PA11 vs PA12 on MJF: When Is PA11 Worth Running?; MJF vs SLS Parts: What Should a Bureau Tell Customers?; SLS Material Changeover: Is Switching Powders Worth It?.
Sources: YouTube: Formlabs Fuse 1 First Look (3D Printing Nerd), viewer question; YouTube: Formlabs Fuse 1 demo (Tested), viewer question; Formlabs Nylon 11 CF Powder.