How to Choose the Right Additive Manufacturing Material
Material selection for additive manufacturing is a different problem than it is for machined or molded parts. There is no single "PA12 datasheet" the way there is a single 6061-T6 datasheet — properties shift with printer, process parameters, build orientation, and even the specific lot of powder or resin. Engineers coming from traditional manufacturing often assume a supplier datasheet is the end of the story. In AM, it is closer to the beginning.
That variability is exactly why material selection deserves a structured process rather than a gut call based on "what we used last time." Below is the framework we use internally at AM Navigator — six weighted dimensions that, taken together, cover the vast majority of what actually determines whether a material choice succeeds or fails in production.
1. Thermal performance
Heat deflection temperature (HDT), glass transition temperature (Tg), and continuous-use operating range determine whether a part survives its actual service environment — not just room temperature testing. A bracket destined for an under-hood automotive application faces a completely different thermal reality than the same geometry in a consumer enclosure. Always evaluate HDT at the load condition closest to your application (0.45 MPa vs. 1.8 MPa HDT values can differ by 30–60°C for the same polymer), and treat any datasheet that only reports one HDT figure with healthy skepticism.
2. Mechanical properties
Tensile strength, flexural modulus, elongation at break, and impact resistance — but critically, evaluate these anisotropically. Almost every AM process produces parts with meaningfully different strength along the build axis (Z) versus in-plane (XY). A material that looks excellent on a datasheet tested XY-only can underperform by 40% or more in Z, which matters enormously if your load path runs through the build direction.
If your part sees primarily tensile or bending load, orient the print so that load runs in-plane, not through the layer stack. If you cannot avoid Z-axis loading, budget a larger safety factor or consider a process with better interlayer bonding (e.g., MJF or DMLS over FDM).
3. Process & printer compatibility
A material is only as useful as the fleet of printers that can run it. Compatibility isn't binary — it spans validated machine models, minimum feature size, support requirements, and post-processing infrastructure (a resin that needs a specific wash-and-cure station is a very different commitment than a powder that needs none). Before falling in love with a material's mechanical properties, confirm it runs on hardware you actually have access to, at the throughput your program needs.
4. Maturity
How long has this material been in production use, and at what scale? A material released six months ago might have exceptional properties on paper and almost no field history — which is a real risk for safety-critical or long-lifecycle programs. We cover maturity scoring in more depth in a companion post, but the short version: newer isn't automatically worse, but it changes how much internal validation you should budget before committing.
5. Cost & availability
Raw material cost per kilogram is the easy number to find and the easy number to over-index on. The harder numbers — lead time, minimum order quantities, single-source risk, and regional availability — often matter more for a production program. A material that is 20% cheaper per kilogram but sole-sourced from one supplier with 12-week lead times can cost far more in schedule risk than the cheaper unit price saves.
6. Certifications
If your application touches medical, aerospace, food-contact, or flammability-regulated use cases, certification status isn't a nice-to-have filter — it's a hard gate that should be applied first, before you even look at mechanical properties. We go deeper on how to actually read certification claims in our certifications guide, linked below.
Putting it together
None of these six dimensions matters in isolation — a material that scores perfectly on mechanical properties but fails your certification requirement is not a viable option, full stop, regardless of how good the rest of the sheet looks. That's the reasoning behind weighting: Thermal and Mechanical carry the most weight (25% and 20%) because they're usually the first hard constraint an application hits, Compatibility and Maturity follow at 20% and 15% because they determine whether a good material choice is actually executable, and Cost and Certifications round out the picture at 15% and 5% — smaller weights, but capable of disqualifying a material outright when the application demands it.
“The goal isn't to find the "best" material in the abstract. It's to find the best material for this application, in this quantity, on this timeline, that will pass this specific certification review.”
This is precisely the shortlisting problem AM Navigator is built to compress — describe the application once, and the scoring engine walks all six dimensions against the real datasheet data so you spend your evaluation time on the two or three materials that actually make sense, not the ninety-one that don't.