(AIM3D: Rostock, Germany) -- 3D pellet-extrusion printers complement conventional processes with an additive manufacturing strategy without molds. AIM3D is now presenting universally applicable extruder developments for third-party suppliers to open up new areas of application for 3D screw extruders. These universal pellet extruders can be used for 3D printing applications (e.g., large-scale printers, process combinations, or robotic systems) as well as for refinement applications such as coating or joining. The universal pellet extruders offer a comprehensive approach to expanding established processes with a 3D production strategy.

Since 2017, AIM3D has focused on 3D pellet printers, which process pellets instead of filaments. The significantly lower material costs for pellets, together with the possibility to also use reclaimed material, form the basis for the high cost-effectiveness of this AM production strategy. Using CEM extruders to integrate into third-party systems can expand the spectrum of 3D printing (so-called universal pellet extruders).

Daniel Selck, CSO of AIM3D, says, “Our approved CEM extruders are characterized by material diversity, robustness, and reproducibility. A special feature when using polymer pellets is the cost savings compared to 3D printing with filaments, but also improved mechanical properties. The transfer of the CEM technology through application-related, separate extruders as universal pellet extruders opens up a variety of new areas of application for third-party suppliers.”

Developing universal pellet extruders for new applications

Thanks to AIM3D’s patents and experience in the field of compact screw extruders for demanding materials such as MIM (metal injection molding), CIM (ceramic injection molding), and high-temperature materials such as ULTEM 9085 and PEEK, third-party suppliers can now use CEM extruders. The options range from purchasing standard extruders from AIM3D, such as the CEM E2 or the CEM E3, to developing application-adapted extruders in the project business. The reasons for using CEM extruders are cost reduction, lightweight construction, bionic designs, and optimizing certain materials.

The CEM extruders CEM E2 and CEM E3 are the “in-house” extruders for the 3D printer series ExAM 255 and ExAM 510 from AIM3D. These 3D screw extruders are characterized by their versatility with metals, ceramics, and plastics (multimaterial 3D printers), as well as by their robustness and high output rate in everyday production.

Performance and build rates of CEM extruders

The build rate of a CEM extruder from AIM3D is currently 150 cm³/h. According to the manufacturer, the aim is to eventually achieve build rates of 300–600 cm³/h. With this, processing volumes of 1,000–4,000 kg per year could be reached. These figures refer to components with a maximum layer thickness of 300 µm, and the use of a 0.5 mm nozzle on the 3D printer. They are comparable to 3D components made using fused deposition modeling (FDM).

Reproducibility is crucial for the construction of a 3D component. For users, this is a key point to ensure consistent component quality, especially in the series production of small and medium-sized batches.

Range of applications and material diversity of CEM extruders

AIM3D’s expertise primarily focuses on high-performance pellets made from polymers such as polyetherimide (PEI), including ULTEM 9085 from Sabic. The cost benefits of using standard pellets compared to 3D printers that process polymers with filaments are enormous. When using ULTEM 9085 with the CEM technology, the homogeneities are comparable to those obtained from injection-molding technology. The low standard deviations achieved during tensile tests according to DIN EN ISO 527-2 Type 1A indicate a high process stability and reproducibility.

These features are achieved thanks to the patented pellet extruder technology, which ensures gentle processing of the material and minimizes the degradation of the polymers in the extruder. The material PEI is also flame-retardant in accordance with UL 94-VO. PEI is therefore suitable for high application temperatures of 180 ºC (217 ºC up to glass transition).

With Sabic ULTEM 9085, 3D pellet printing now reaches component properties that significantly surpass FDM printing. As a result, 100% higher elongation at break is achieved compared to FDM printers. PEI opens up numerous applications for automotive, aerospace, machine industry, rail vehicles, and defense technology along with economical efficiency.

Versatility of universal pellet extruders

By specializing in certain material classes or applications, advantages in terms of discharge rate, extruder weight, and production costs can be achieved when using CEM extruders. Using CEM extruders for special applications or integrating them into the systems of third-party suppliers opens up new areas of application for this proven and robust production strategy.

Examples of 3D printing applications include large-scale 3D printers (additional printing of a smaller material component), process combinations (retrofitting an FDM printer), or robotic systems. The CEM extruders also open up applications outside of 3D printing, such as coating, joining, or application.

Table 1: Depending on the requirement profile, the extruders achieve the following characteristics.

Daniel Selck, CSO of AIM3D.

Range of materials for CEM extruders: MIM (metal injection molding), CIM (ceramic injection molding) and high-temperature polymers