Polymaker has added Rapid Fusion, the UK builder of robotic large-format additive manufacturing (LFAM) systems, to its PolyCore Hardware Partner network. The first result is two validated pellet grades, both PETG with 30 percent glass fiber by weight. The headline material is PolyCore PETG-1113, described in Polymaker's technical data sheet as a cost-effective reinforced grade with good adhesion to gelcoat, aimed at interior decoration and low-temperature tooling. Its sibling, PETG-1013, is the weather-resistant option. VoxelMatters reports that both grades are validated on Rapid Fusion's PE320 pellet extruder, and that the companies have already published a case study: an office table base printed from 20 kg of material in five hours.
Few makers will ever run a robot-arm pellet cell. Still, this kind of material-to-hardware validation decides what large printed parts can be used for, and the datasheets behind it are useful reading for anyone who works with fiber-filled PETG at smaller scales.
What the partnership actually covers
According to VoxelMatters, the partnership took effect at the start of 2026. It covers material validation, technical work, case studies and joint promotion. In practice, the first two PolyCore grades have been validated on Rapid Fusion's PE320 extruder, which is used on the company's Apollo, Zeus and Medusa platforms. Because one extruder spans several machine platforms, a material validated on the PE320 is plausibly easier to adopt across that range, although the report does not say whether each platform was tested separately.
Pellet-fed LFAM depends heavily on this kind of qualification. Unlike filament, which arrives at a fixed diameter and is pushed by a simple drive, pellets have to be melted and metered by a screw. How well that works depends on melt viscosity, fiber content, moisture and the screw's geometry. A pellet that runs cleanly on one extruder can surge, starve or degrade fibers on another. Validation is the vendor's way of telling customers that someone has already done this tuning.
Two grades, two jobs
The two PolyCore grades share a base polymer and the same 30 wt% glass loading. Polymaker positions them for different kinds of work.
PETG-1113 is the economy and tooling grade. Polymaker's February 2025 data sheet (v1.1) lists good cost effectiveness, good gelcoat adhesion, excellent mechanical properties, outstanding printability and dimensional stability. Suggested uses are interior decoration and low-temperature molds such as vacuum-forming molds and construction templates. The thermal numbers explain the "low-temperature" qualifier: a glass transition of 78 °C and a Vicat softening point of 99 °C. The melt flow index is 1.8–3.9 g/10 min at 230 °C under 2.16 kg.
Gelcoat adhesion matters for the tooling market in particular. A printed plug or mold that will be gelcoated and laid up in composites has to bond with that surface layer reliably. VoxelMatters describes the 1113 grade as offering improved gelcoat adhesion, which suggests it is aimed at composite fabricators who want printed tooling instead of machined foam or MDF.
PETG-1013 adds UV stabilization, according to VoxelMatters. Polymaker's wiki describes it as a glass-fiber PETG for big-area additive manufacturing with excellent printability, warping resistance and weather resistance. Its data sheet (v1.1, March 2021) gives a density of 1.39 g/cm³, a Tg of 81 °C, and heat deflection temperatures of 77 °C at 1.8 MPa and 82 °C at 0.45 MPa. For outdoor furniture, signage or architectural pieces that will spend years in sunlight, the UV package is the reason to choose this grade.
The anisotropy problem, in numbers
The PETG-1013 sheet is unusually helpful because it gives mechanical properties for both the in-plane (X-Y) direction and the build (Z) direction. The gap between them is large:
- Bending modulus: 6,094 MPa in X-Y versus 2,701 MPa in Z, so Z keeps about 44 percent of the in-plane stiffness.
- Bending strength: 128.1 MPa versus 46.8 MPa, roughly 37 percent.
- Charpy impact: 21.3 kJ/m² versus 5.2 kJ/m², about a quarter.
Anyone who has snapped a glass- or carbon-filled filament part along a layer line will recognize this pattern. The fibers align with the bead during extrusion, so they reinforce along the toolpath and add little across layer interfaces. At LFAM scale the effect is the same, and the beads are simply much larger. Impact resistance suffers most: the Z direction absorbs roughly a quarter of the energy the in-plane direction does. Anyone designing a large printed part in this material should orient it so that bending and impact loads run along the beads, not across them.
The case study: a table base in an afternoon
The first joint case study is a 700 × 500 × 1,100 mm office table base printed from 20 kg of PETG-1113 in five hours. That works out to an average of about 4 kg of material per hour, including whatever non-printing moves the job required. The part was printed on Rapid Fusion's Cerberus, a hybrid cell housed in a standard high-cube container that combines pellet and filament printing with CNC machining, fitted with the PE320 extruder. It was sliced in AiBuild.
Furniture is a sensible demonstrator. A table base is a large, mostly static structure and an indoor part, which fits the interior-decoration use Polymaker lists for PETG-1113. Including CNC in the same cell also points to the usual LFAM workflow: print near-net-shape, then machine the critical faces.
Rapid Fusion mechatronics engineer Brian Cheng speaks for the company in the announcement. The company has also been in the news this month. TCT Magazine reports that Kingston University has installed a £450,000 Zeus Robotic Cell, which combines 3D printing with integrated CNC milling, at its Roehampton Vale site. Exeter-based CEO Jake Hand called it one of the most advanced LFAM robots in the world, and Rapid Fusion has committed to work placements, potential Knowledge Transfer Partnership opportunities and input into the future curriculum.
What It Means for Makers
For most hobbyists this is news from the far end of the market, but it still has practical value. First, the PETG-1013 datasheet gives a rare set of published Z-direction numbers for 30 percent glass-filled PETG. They are a sober reminder that fiber-filled parts are much weaker across layers. The same principle applies to a desktop GF-PETG bracket, at a smaller scale.
Second, the thermal limits are modest. With Tg values near 78–81 °C and an HDT of 77 °C at 1.8 MPa for PETG-1013, glass fiber makes PETG stiffer but does not turn it into a high-temperature material. Vacuum-forming molds and construction templates are the uses Polymaker itself lists for 1113. Anything that will sit near real heat is not.
Third, for small shops and makerspaces looking at large-format work, partner validation lowers risk. Buying a pellet cell and a material that its builder has already validated and documented in a published case study is very different from qualifying a new pellet yourself.
