Smart Molding International 1-2026

48 smart_molding interna onal 1/2026 addi ve manufacturing PEEK & ULTEM: The Difference Between “Can Print” and “Prints Reliably” When purchasing a 3D printer for high performance polymers, such as PEEK and ULTEM, there’s a very important dis nc on between “can print” (i.e., can extrude) and “prints reliably”. With a simple $5 80W heater cartridge and $10 RTD PT1000, any manufacturer can claim their 3D printer “can print PEEK and ULTEM”. The fact is, extruding these materials isn’t hard— mi ga ng warping/cracking, slowing crystalliza on, and achieving strong interlayer adhesion a er extrusion is where these materials get their reputa on as “di cult to print”. Polymer Processing Windows & Build Chamber Temperature Every polymer has a unique range of processing temperatures in which it can be reliably extruded and bonded to previous layers without degrading, collapsing, or warping. For commodity polymers, such as PLA and PETG, this processing window is wide, making the materials forgiving and easy to print. Inversely, high performance polymers possess extremely narrow processing windows. Part features, density, size, build volume placement, build volume packing, and convective flows are all factors that can influence regional temperatures enough to result in anisotropy, warping, cracking, and more — this gives high performance polymers their reputation as being difficult to print. For amorphous polymers, a printer’s build chamber should be able to achieve just below the target material’s glass transition temperature (Tg). For semi-crystalline polymers, like PEEK, you need significantly higher chamber temperatures, approaching melting temperature (Tm), to overcome restricted chain mobility and fast crystallization. If a 3Dprinter is unable to achieve these chamber temperatures, high performance polymers become exponentially more difficult to print and a material’s mechanical properties may never be fully realized. Convec ve Flows & Thermal Uniformity High performance polymers are extremely sensitive to thermal inconsistencies and fluctuations throughout the build volume, which can lead to warping, cracking, parts releasing from the build surface, and dimensional accuracy issues. Buyers should assess the thermal design of any prospective printer, looking for convective flows that encourage thermal uniformity across the build volume. Below, we show several convection profiles currently used in the market. As you can see, with some machines you may need to place large and dense parts in hotter regions of the build volume while smaller/thinner parts can be placed in colder areas. In addition, if printing large runs or full build volume parts, you may experience anisotropic properties and variances in dimensionality based on location in the build volume. Prin ng in Colder Build Chambers Yes, printers with sub-par thermals can technically still print some high performance polymers but, before you purchase that $10,000 3D printer with 100C chamber, you should know what to expect — what you can print will be extremely limited, print failures will be frequent, interlayer welding will be poor, parts will have dimensional accuracy issues, and each unique geometry will require cyclical print > tune > reprint cycles. Diminished Part Proper es Simply extruding a high performance polymer does not guarantee a part will possess properties aligned with the polymer’s technical data sheet. Here are some properties that may be impacted by printing in colder build chambers: • Reduced tensile strength and modulus • Lower impact resistance • Increased delamination • Reduced coefficient of friction • Weaker crystalline structure • Reduced heat resistance The maximum chamber temp. for current high temperature 3D printers vs. temperatures required to print certain polymers. ~85% of 3D printers marketed for “high performance polymers” can’t reliably print PEEK, 77% fall short for ULTEM™ 1010, and nearly half can’t reach the required chamber temps to print ULTEM™ 9085. (all pictures: AON3D)