High-performance Polymers and Composites Printing Technologies – Part I: Robotic Extrusion
by Merve Canalp, Researcher at AMEXCI
As of 2022, there are 16 different additive manufacturing (AM) technologies which employ various types of polymers such as commodity, technical and high-performance thermoplastics in alternating shapes and forms. Thanks to their excellent mechanical properties under high/low temperatures and harsh chemical conditions, high performance polymers and composites are under the spotlight of many end-users. These materials do not only offer promising solutions for replacing metal parts but also provide the benefits of AM processes such as customization, design freedom and many more, as represented in the picture below.
The increasing utilization of both high-performance polymers and composites with such polymer matrix compositions in AM technologies set the pace for industrial adaption. In order to keep up with material and technological developments and optimize the adaption processes for the key industries, we are in close contact with OEMs excelled in printing such functional materials.
Exploring Composite AM Technologies
As Amexci, it is our aim to investigate different properties of such types of materials through research projects while expanding our know-how through building connections with various OEMs. Therefore, following the pre-study “212013-Composite Printing”, four virtual workshops with the participation of high-performance polymers and composites AM companies was held successfully during Q4 2021.
The main material focus was on Composite AM Technologies including Robotic Material Extrusion, Composite Based Additive Manufacturing, Fiber Placement Additive Manufacturing, and Composite Thermoplastic Material Extrusion. Thus, the workshop presenters Ai Build, Impossible Objects & Ricoh, Roboze and 9T Labs, were contacted according to their printing solutions and processes.
With the help of article series, we would like to introduce some of the most prominent AM companies and their technologies which took part in the Composite Workshops 2021. In this first part, we are going to introduce Ai Build and robotic material extrusion.
Robotic Material Extrusion presented by Ai Build
Ai Build, based in the UK, is a software company for Large Format Additive Manufacturing (LFAM), a type of robotic material extrusion technology. They develop solutions for failure reduction via data optimization processes for different types of extrusion systems as well as materials. The optimization is achieved by generating smart and advanced tool-paths, e.g., planar, non-planar, multi-planar, segmented, conformal layers, for broad range of applications.
LFAM or Large Scale Additive Manufacturing (LSAM) offers new ways to produce parts, especially in tooling applications. Compared to the conventional methods to produce metal tools, there are several benefits of employing LSAM to print parts in polymeric materials as indicated in Figure 2 below, such as lower costs, lower amount of waste materials, faster delivery/production time and lower weight of the tools.
One of the downsides of LSAM is the high surface roughness which can be as high as 300 µm (Ra). In most cases, smoother surfaces are preferred for tooling applications, and this can be easily achieved by milling the polymer surface to get rid of printing layers which can result in surface roughness as low as 0,3 µm (Ra). The comparison of a printed and then post-processed (smoothed) tool is given in the picture (Figure 3), as an indication of how the top of the tool looks smoother and shinier after milling. Another downside of producing polymer/composite tools with the use of LSAM compared to conventional metal tool manufacturing is the lower cycles of part in use, i.e., durability. To some extent, this can be optimized by choosing the right material according to the use temperature and pressure.
According to needs of end-users and their applications, LSAM systems can be optimized thanks to their printing system options: Robotic vs. Gantry systems, Filament vs. Pellet extruders with a turnkey or customized solutions.
Large format printing materials can be in two different forms: filaments or pellets. A comparison of these feedstocks is given in the Figure 4, indicating the fact that pellet systems are much more expensive (around x10) than filament extrusion systems, while the feedstock material costs in pellet form are much cheaper compared to the filaments.
In robotic extrusion technologies, a variety of materials from commodity thermoplastics like ABS and Polycarbonate to high-performance polymers such as PEI and PPS as well as composites can be utilized. In tooling applications, the use temperature and pressure play a crucial role in selecting the right material. For prototyping, commodity polymers are preferred over technical and high-performance polymers. Addition of chopped fibers, e.g., carbon fibers, in ABS enhances the mechanical properties and printability of the final parts like boats .
Ai Build closely collaborate with Airtech to produce additively manufactured large tools. Airtech, the developer of Dahltram®, has announced their partnership with Titan Robotics, Ltd. providing materials on all pellet-fed Titan Atlas printers. Dahltram® tooling resins  include different pellets depending on the applications. For instance, modified ABS with carbon fiber pellet (Tservice= 88 degrees Celsius) suits low temperature applications, whereas PEI with carbon fiber pellet (Tservice= 204 degrees Celsius) is used for high temperature tooling applications.
With the help of this virtual workshop, we had the chance to learn more about:
- Business structure, internal/external capabilities and networks, material & technology,
- Case studies and possible application areas through direct interaction.
In the next part of this article series, we will dive deep into CBAM technology developed by Impossible Objects and their service in the UK by Ricoh, summarizing some key takeaway notes from the workshop held in 2021.
 More information on Dahltram tooling resins for AM booklet can be found from here.
About Merve Canalp
Merve Canalp works as a Researcher at AMEXCI and her expertise lies in the field of polymer materials. Her daily tasks include investigating Polymer AM applications and managing corporate R&D projects.
For more information, or if you would like to discuss polymer AM, get in touch with Merve at: email@example.com