After My Tech Fun ran JLC3DP’s black resin against its SLS nylon, one viewer asked: “Why is the SLS nylon so less strong than SLA resin?? What is the strongest SLS material now?” It’s a common surprise. In SLS nylon vs resin tests, the answer usually comes down to which property got measured.
SLS nylon vs resin: why can resin win a strength test?
Because a stiff, strong resin can win on peak strength while nylon wins on toughness. Formlabs’ own Form Now table lists SLS Nylon 12 at 50 MPa tensile strength and Tough 2000 resin at 46 MPa, with flexural modulus of 1.8 against 2.2 GPa. So even Formlabs’ “tough” resin is stiffer than its nylon. I don’t know the exact formulation of JLC’s black resin, so I won’t guess its numbers.
Formlabs also compares stiffness directly on its Nylon 12 GF support page. It says Nylon 11 and Nylon 12 have stiffness similar to Tough 1500 and Tough 2000 resins, respectively. Nylon 12 GF sits between Tough 2000 and Rigid 4000.
So where does nylon win?
Elongation and impact. Formlabs lists Nylon 11 at 40% elongation at break and Nylon 12 at 11%. That’s what lets a nylon clip flex and recover, or a housing survive a drop. The same Form Now table also lists SLS Nylon 12 as isotropic, so Z strength matches XY.
What’s the strongest SLS powder Formlabs sells?
For tensile strength, Nylon 11 CF, at 69 MPa in X but 38 MPa in Z. Nylon 12 GF is listed at 38 MPa but with a 113 °C heat deflection temperature at 1.8 MPa, against 87 °C for plain Nylon 12. “Strongest” depends on which direction and temperature you care about.
How should you choose for a real part?
Name the failure you’re designing against before you pick a process. If the part must stay rigid and precise, resin may be the better choice. If it must bend, snap or take a drop, nylon usually wins. When you compare test results, ask for elongation and impact numbers alongside tensile, or you’re only seeing half the picture.
Related on the Solvi blog: MJF vs SLS Parts: What Should a Bureau Tell Customers?; PA11 vs PA12 on MJF: When Is PA11 Worth Running?; MJF Warping: Why Large Flat Parts Warp.
Sources: YouTube: SLA vs SLS (JLC Black Resin vs Nylon), My Tech Fun, viewer question; Formlabs Form Now: Nylon 12 SLS material guide; Formlabs: Using Nylon 12 GF; Formlabs: Using Nylon 11 CF.