Nylon is a deservedly popular engineering plastic, prized for its toughness and wear resistance, and you can print it with either SLS or FDM. The two processes produce very different results from the same broad family of material, however, so the right choice for any given job depends on the part itself, the quantity you need and the budget you are working with. Understanding where each one excels saves both money and disappointment.
We run both processes at Global3D, with SLS at our main Perth warehouse through our MJF & SLS printing service and nylon FDM printing available as well, so we can advise on the trade offs honestly without pushing you toward whichever machine happens to be free that week.
Strength and consistency
SLS nylon is close to isotropic, with even strength in every direction and no weak layer bonds waiting to split apart under load. FDM nylon, by contrast, is strong along the layers but distinctly weaker across them, and printing nylon filament well can be genuinely tricky because the material readily absorbs moisture from the air and has a strong tendency to warp as it cools on the bed. Drying nylon filament thoroughly before printing and keeping the bed and chamber warm both help, but the process still demands care and experience to get right.
For demanding functional parts that have to carry real loads or survive impacts in service, SLS usually gives more predictable and dependable performance, which is why it is so often the engineer's choice for end use nylon parts.
Geometry and finish
SLS needs no supports at all and produces an even matte finish all over, so complex shapes, undercuts and internal channels come out clean and ready to use. FDM needs supports for any significant overhang and shows visible layer lines on the surface, though in its favour it handles very large parts comfortably and is extremely cost effective for a single one off component.
If your part is intricate, or you need a batch of several at once, SLS very often wins on both quality and total cost. For a single large, simple bracket where strength in every direction is not critical, FDM may well be the cheaper and more sensible option. FDM also lets you choose from a wide range of filament colours straight off the spool, whereas SLS parts start off white and are coloured later by dyeing.
Cost and quantity
The economics tip on quantity and size. FDM prints one part at a time on a flat bed, so a small batch means a string of separate jobs, whereas SLS nests many parts through the full height of the chamber and prices them together. That nesting is why a tray of twenty small clips is usually far cheaper per part in SLS than in FDM, even though a single large block can be cheaper in FDM.
It is also worth knowing where each process is available, since our Melbourne VIC studio runs FDM only, up to 350 x 350 x 350mm, while all SLS work is handled at the Perth warehouse. We weigh all of this for you on every quote. Knowing which site can make your part early avoids a surprise, so we confirm it as part of the quote.
Choosing between them
The decision really comes down to a handful of practical factors that we weigh up together for every quote, balancing geometry, quantity, strength requirements and budget to land on the best value answer for your specific part.
- Choose SLS for complex shapes, batches and even all round strength.
- Choose FDM for very large single parts on a tight budget.
- SLS gives a consistent matte finish with no support marks to remove.
- FDM nylon can warp and is weaker across the layers.
- Our Melbourne studio prints FDM up to 350 x 350 x 350mm.