Start with the use environment
The single most important factor in material selection is where the part will live and what it will experience. Indoor, low-heat, protected environments open the door to PLA. Outdoor exposure changes the calculation significantly — PLA will degrade. Load-bearing structural use demands attention to which direction forces are applied and what failure mode is acceptable.
Before choosing a material, answer these questions: indoors or outdoors, what temperature range, UV exposure, any mechanical load, whether flex is needed or undesirable, and what happens if the part fails.
PLA / PLA+ — the prototype default
PLA is the right starting point for prototypes, fit checks, display parts, and anything that lives in a controlled indoor environment. It prints cleanly, holds detail well, and is the most forgiving material for first runs.
The limit is heat. PLA begins to soften at around 60°C. Leave a PLA part in a hot car or near a heat source and it will deform. If heat is a factor at all, move to PETG or ASA.
PETG / PCTG — the functional default
PETG is the right choice for most functional parts that need to do more than sit on a shelf. Better impact resistance than PLA, better heat tolerance, and reasonable performance in moderate outdoor conditions make it the general-purpose workhorse for practical parts.
PCTG is a copolymer variant with slightly improved mechanical properties and better optical clarity. Both are strong choices for replacement parts, housings, mechanical components, and anything that will see regular handling.
TPU — when the part needs to move
If the part needs to compress, flex, absorb impact, or seal against a surface, TPU is the answer. Hardness varies by filament grade — softer grades behave more like rubber, harder grades approach a flexible plastic. Grips, bumpers, pads, sleeves, gaskets, and protective covers are all natural TPU applications.
TPU is not a substitute for rigid structural parts. If the part needs to hold a precise shape under load, rigid materials are the right call.
ASA — the outdoor choice
ASA was specifically developed to resist UV degradation and color fading outdoors. If a part is going outside — on equipment, on a vehicle, mounted to a building, used in agriculture or marine environments — ASA should be the first material considered after PLA and PETG have been ruled out for UV reasons.
ASA has good heat tolerance and reasonable impact resistance. The trade-off is that cosmetic surface finish is not as clean as PETG, and it prints best in an enclosure to avoid warping.
When to ask about extended materials
If the use case requires ABS for machinability, nylon for fatigue resistance, or a composite fill for stiffness — mention it in the quote request. Extended materials are available for production runs that justify the setup. The quote will reflect material availability, any additional setup cost, and whether the extended material is the right fit for the specific part requirements.