PA12 nylon is the material most MJF parts are made from, and there is a very good reason it dominates the process. It strikes a rare balance of strength, flexibility, chemical resistance and dimensional stability, which together make it suitable for almost everything from small clips to large enclosures. Few printed materials cover such a wide range of work so dependably, and fewer still do it without fuss.
Understanding what PA12 does well, and where it has its limits, helps you design parts that genuinely last in service rather than failing after a few weeks. We print PA12 every single day as part of our MJF & SLS printing service, so we have seen exactly how it performs across many applications and environments.
Strength with a little give
PA12 is tough without being brittle, which is a combination that not many plastics manage. It can flex under load and then return to its original shape, and that property is exactly what allows snap fits, living hinges and clips to work reliably without cracking. At the same time it carries real structural load, so brackets, mounts and housings hold up well in daily use.
Because MJF parts are near isotropic, that strength is reliable in every direction, which is something many other printed plastics simply cannot promise. You do not have to orient the part carefully to avoid a weak axis, which makes designing with PA12 far more forgiving and the finished part more predictable under real loads.
Resistance and stability
PA12 resists many oils, greases, fuels and common solvents, which makes it a sound choice for automotive, industrial and workshop parts that live in messy environments. It also holds its shape across a useful temperature range and does not warp easily once it has been printed and cooled properly, so parts stay true over time.
It does absorb a small amount of moisture over time, which is worth bearing in mind for parts that need very tight long term tolerances or that sit in wet conditions. For the vast majority of applications, though, it is extremely stable and behaves predictably year after year, which is exactly what functional parts demand.
How PA12 compares to other grades
Against standard FDM plastics, PA12 generally offers better all round toughness and far more consistent strength between axes, which is why it suits parts that take knocks from any direction. Against resin parts from SLA printing, it trades some fine surface detail for much greater durability and resistance to cracking.
If you need a stiffer part than standard nylon gives, a glass filled PA12 raises rigidity and heat resistance for demanding brackets and mounts. The trade off is a little less flexibility, so it pays to match the grade to whether the part needs to bend or stay rigid in service. As a rough rule, choose standard PA12 for clips and hinges that must flex repeatedly, and the glass filled grade for load bearing mounts that should barely move under pressure, since matching the grade to the duty avoids both cracking and unwanted bending later on.
Common uses for PA12
The combination of toughness, fine detail and chemical resistance means PA12 turns up across a huge range of work, from consumer products to heavy industry. It is genuinely a do everything material for functional printing, which is why it has become the default for so many jobs that need to survive real use.
- Housings, enclosures and covers for electronics.
- Brackets, mounts and structural clips that carry load.
- Jigs, fixtures and manufacturing aids for the shop floor.
- Ducting, manifolds and fluid handling components.
Designing with PA12
If you want stiffer parts than standard nylon provides, a glass filled version is available, and we cover that in its own article. For most jobs, though, standard PA12 is exactly the right starting point. Send your design through and get a quote and we will confirm the best grade for the way your part actually works.