SLS vs MJF for Nylon PA12: A Practical Comparison.

SLS and MJF both produce nylon parts in a powder bed without attached support structures. For a PA12 project, the useful comparison is the same geometry quoted by qualified suppliers with the same finish, quantity and acceptance criteria. PakMEC prints PA12 in both SLS and MJF, so you can compare the two on your own part.

How the two processes differ

SLS uses a laser to fuse selected powder areas. MJF deposits fusing and detailing agents and applies heat. Both can support complex shapes and batch nesting. Actual mechanical properties are influenced by powder, machine settings, orientation, refresh ratio and post-processing. Formlabs' process comparison describes their shared strengths and differences.

Appearance and finishing

Some SLS PA12 systems produce light parts that can be dyed; MJF PA12 parts are commonly grey before finishing. Appearance varies with material grade and supplier. Ask for a sample in the proposed finish, especially for visible consumer parts. Powder-bed surfaces are typically more textured than a machined face.

Fit, strength and sealing need testing

Do not assume one process always gives stronger or airtight parts. Request a material data sheet for the specified grade and ask how the supplier controls dimensional variation. A pressure or fluid seal should be designed and tested as an assembly, possibly with secondary sealing or machining. Formlabs' nylon guide explains material and application considerations.

Compare total batch cost

Powder-bed nesting may improve machine utilisation, but unit cost is not guaranteed to fall by a fixed percentage at a particular quantity. Obtain quotes at the actual volumes, including depowdering, dyeing, smoothing, inspection, scrap allowance, shipping and any minimum charge. Request the expected lead time and repeatability for later batches.

Frequently asked questions