The SLS metal question shows up under almost every polymer SLS video. On SLS4All’s Inova MK2 launch video, one viewer asked flatly: “can it print metal?” Under Tested’s Fuse 1 demo, another was blunter: “so u can’t use metal powder in the sls???? whats the point.” And under a metal printing video, a viewer asked why metal parts need supports at all, since “isn’t the powder itself a support?”
Can a polymer SLS printer do SLS metal parts?
No. Metal parts come from DMLS or SLM machines, not polymer SLS printers. SLS4All answered its viewer directly: the MK2 “is designed for SLS polymer printing and cannot print metal.” Its spec sheet lists a maximum melting point of up to 200 °C and, in so many words, “Metal Powders: Not supported.” Xometry’s comparison says the same about SLS in general: it “can only print plastic parts.”
Formlabs’ SLS guide groups both under powder bed fusion. The plastic machines are what people call SLS, while metal machines are known as DMLS or SLM. Same idea of a laser fusing a powder bed, very different hardware.
What does a metal powder bed machine need instead?
A lot more energy and a controlled atmosphere. EOS’s M 290 datasheet lists a 400 W Yb-fiber laser, a 250 x 250 x 325 mm build volume, max power consumption of 8.5 kW (2.4 kW typical) and a compressed air supply of 7 bar. Xometry notes DMLS chambers fill with inert gas to cut the risk of combustion and oxidation. Compare that with a 200 °C ceiling on a benchtop polymer machine and the gap is obvious.
Layers shrink too. Xometry lists typical layer heights of 100–120 microns for SLS and 30–40 microns for DMLS.
Why does metal need supports when nylon doesn’t?
Xometry’s answer is that “DMLS parts need support during printing” because of the increased mass of metal parts, while SLS parts don’t need support. In nylon SLS the surrounding powder carries the part. In metal, it isn’t enough.
That changes the design job. Overhangs that print freely in PA12 need support planning in metal, and supports mean removal and finishing time that a nylon quote never had.
So what’s the point of polymer SLS?
SLS4All’s reply framed it as functional nylon parts in small batches, with no supports and good isotropy. If a viewer really needs metal, the honest answer is a different machine class or a bureau running one.
If a customer asks you for “SLS metal,” check whether they need metal properties or just a strong, support-free part. If it’s the second, quote PA12 first and send a test part before anyone prices a DMLS run.
Related on the Solvi blog: SLS vs FDM Nylon: When Is Sintering Worth It?; MJF vs SLS Parts: What Should a Bureau Tell Customers?; SLS Print Temperature: Why Nylon Sinters Below 200 °C.
Sources: YouTube: Inova MK2 (SLS4All), viewer question and SLS4All reply; YouTube: Formlabs Fuse 1 SLS 3D Printer Demo (Adam Savage’s Tested), viewer comment; YouTube: It’s Time To Start 3D Printing Metal (SuperfastMatt), viewer questions; SLS4All: Inova MK2 specifications; Xometry: SLS vs DMLS 3D printing; EOS: M 290 system data sheet; Formlabs: Guide to selective laser sintering.