Essentium
Polymer 3D printed parts have long been bound by preconceptions around their feasibility for end use applications. But after three decades of materials science, hardware improvements, and real world applications to learn from, much of those preconceptions around tricky layer lines, brittleness, and ‘only good for prototyping’, have shifted to mere misconceptions. In fact, in many cases, they’ve proven to be viable alternatives to traditionally manufactured parts – even metals.
"One misconception is that polymers lack the strength and durability for demanding applications,” Nirup Nagabandi, Ph.D., Vice President of Materials and Process Engineering at Essentium said. “However, advancements in high-strength 3D printed polymers have closed this performance gap, allowing plastics to match or exceed the mechanical properties of certain metals.”
Nagabandi offers the example of soft aluminium tooling, which some Essentium customers have replaced with parts made using carbon fibre variants of its high speed sintering powders. One customer was able to manufacture injection moulding inserts using PPS-CF to successfully produce 150 parts, while another, a contract manufacturer, replaced its production aids with parts made with Essentium’s PA-CF which were three times lighter than its aluminium counterparts and about seven times lighter than steel tools.
“Advanced 3D printed polymers like reinforced nylon, PEEK, PEKK, and PPS have mechanical properties that rival certain metals, allowing them to be effective replacements in various applications,” Nagabandi continued. “High-strength 3D printed plastics can offer enhanced corrosion resistance, chemical compatibility, and electrical insulation properties, which can be advantageous in various industries and applications, such as in aerospace and consumer electronics, which are already extending their use of 3D printed polymers beyond prototyping and into full-scale manufacturing.”
Nagabandi also suggests that greater awareness is needed around suitability of polymers in extreme high- and low temperature environments. While some polymers do struggle, materials such as Essentium’s Duratem high-impact, high temperature thermoplastics have been designed for demanding rail, automotive and aerospace applications.
Perhaps directly comparing polymers with metals isn’t entirely fair. Speaking to an anonymous source with over 30 years’ experience in AM polymers, there is an argument to be made for polymers that, while not perfect, are in many instances “good enough” to get the job done. Yet to deepen the adoption of AM in end-use applications, testing and benchmarking against traditional standards is crucial.
“We have to use the same test methods and standards that the plastics industry uses – and test for all environmental factors: heat, light, cold, humidity, water, as well as UV,” they said. “These strict tests are why metal replacement has been so successful in many industries –especially automotive.”
Last year Toyota Racing Development (TRD) established a partnership with Stratasys to expand its use of AM in end-use parts for its TRD-branded vehicles and racing cars – some of which may have traditionally been made in metals.
“There are a few reasons to look at replacing metal parts with high-strength 3D printed plastic (carbon infused),” Nelson Cosgrove, Executive Engineering Director, TRD explained. “One is to reduce mass in an area where the part strength can be managed with the use case. Another reason is when you need to make modifications to the part for additional requirements. Various brackets with clever retention/routing features such as snap fits, tie wrap access, etc."
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The company has brought in a suite of Stratasys Fortus 3D printers and plans to print end-use parts including an FDM Nylon 12CF hood vent for its new production vehicle SAF technology via Stratasys Direct services to manufacture a clamp using sustainable Stratasys High Yield PA11 material.
"Most of the challenges/trade-offs are related to material property demands related to strength and temperature," Cosgrove said. "With most of TRD's applications, we are working in fairly low volumes and the cost trade-offs usually mean we select the 3D printed part when conventional tooling and labour are considered. The ability to add features that can adapt for a higher functioning component is very important for our use cases."
The development of engineering-grade materials specifically formulated of AM is expanding possibilities as manufacturers across automotive, aerospace and consumer goods demand thermal stability, chemical resistance, and dimensional accuracy. Further to that, advancements in multi-material and composite printing have made it possible to combine different materials within a single printed part, creating complex, multi-functional components with tailored properties.
Ilaria Guicciardini, Head of Marketing at Roboze, which specialises in high-performance AM polymers and composites, says for industries such as aerospace and energy, replacing a traditional metal part with high strength 3D printed plastic can be a strategic choice.
“While metal has been traditionally favoured for its strength and durability, advancements in 3D printing technology have led to the development of high performance plastics that can rival some metals in terms of strength and other properties,” Guicciardini said.
Earlier this year, Roboze introduced Carbon PA PRO, a PA 6 reinforced with carbon fibres, which it claims to be its strongest composite material to date, and Carbon PEEK, a PEEK matrix reinforced with carbon fibres. The latter was deployed to manufacture a metal replacement pump impeller for an oil and gas customer, which resulted in an 85% lead time reduction, decreased energy consumption, and 5-6 times lower weight compared to steel.
“These kinds of materials can withstand harsh environmental conditions including corrosion, erosion, and high temperatures,” Guicciardini explained. “The main advantages are the reduced maintenance of the components required thanks to the chemical resistance of the Carbon PEEK, lower mass which translates into safer handling and greater efficiency, dimensional resizing of the valves without necessarily creating special molds and digital warehouse.”
Newcomer Axtra3D made a splash at Formnext 2021 with its Hybrid PhotoSynthesis technology which combines the benefits of three polymer processes: SLA, DLP and LCD. Promoting speed and injection mould-like quality, the company agrees we should't be so quick to judge polymer capabilities.
“There is a misconception that 2-part materials that require post print thermal curing are the only materials that are “good enough” for production," Paul Spoliansky, founding member and Chief Revenue Officer at Axtra3D said. "There’s been a revolution in single part material development by all the large formulators and there are materials quite capable of meeting the demands of some end use applications.”
“There have been major investments made in R&D from some the biggest resin formulators such as Henkel, BASF, 3D Systems, Spectra, Evonik and others,” Spoliansky added. “This has led to much better mechanical performance and long-term stability which is what’s been needed to enable production of end use parts. The rate of innovation has increased substantially, and I believe we’ll continue to see more capable materials being released at a fast pace.”
Roboze
What that may look like, Guicciardini has an idea, and Roboze has recently commenced construction of a new lab for the development of new ‘super materials.’
“Our further step will be the rapid progress in the development of alternative materials to petroleum-based super polymers, favouring the use of bio-based reinforcing fibres and matrices. The challenge lies in researching new materials and technologies that can on the one hand reduce the generation of carbon dioxide (responsible for the greenhouse effect), and on the other hand achieve the properties of the super polymers available today in the replacement of metal parts.”
