Essentium, which develops 3D printers, has teamed up with chemicals specialists the Lehvoss Group to develop materials for extrusion-based additive manufacturing processes that are able to meet the standards required for specific industry applications.
This has led to a new line from Essentium of PEEK and High-Temperature Nylon (HTN) materials using Luvocom 3F compounds. These materials are said to offer easy printability and non-warping properties, as well as heat and chemical resistance and high mechanical strengths, enabling end-parts that can withstand the rigours of the factory floor. Essentium claims that these materials are suitable for applications such as mechanical engineering, medical technology and parts subject to high stresses for the engine compartment and drive train in the automotive sector.
In the past, Essentium has actively developed its own materials including adding high quality, multi-layer structures into the filaments to create a no-compromise electrostatic discharge (ESD)-safe material for 3D printing that eliminates sloughing conductive particles onto electronic assemblies during manufacturing.
Brandon Sweeney, head of R&D for Materials and Co-founder of Essentium, explains: “Essentium spent a lot of time evaluating materials that are 3D printable but not designed specifically for 3D printed applications and not well suited for a materials extrusion process. The materials need to be tuned so that they can be processed at speed while being strong enough to withstand impact loading, fatigue, or cyclic loading and protect electrostatic-sensitive devices.” He adds: “With Lehvoss, we have reversed the materials development cycle starting with idea that the material must be 3D-printable and certified to meet the standards required in the most demanding manufacturing environments.”
Sweeney says that there are two things that distinguish these materials from others: “The first is the polymer resin itself which has been compounded and formulated specifically for the additive manufacturing process. The materials we’ve launched with Lehvoss so far are semi-crystalline thermoplastic which generally have increased chemical, wear, creep, and temperature resistance compared to their amorphous counterparts. The problem with semi-crystalline thermoplastics is that they generally shrink a great deal as they cool and crystallize, which typically leads to large stress build-up in parts, warping and poor dimensional tolerances, and in many cases poor layer bonding. Working with Lehvoss has been revolutionary for us because they formulated these compounds to specifically address these issues, each material has been tailored for a slow controlled crystallization profile to help eliminate stress build-up in parts as they print, and we’ve observed dramatic improvements in interlayer bonding with Lehvoss materials.”
He continues: “The other thing that distinguishes Essentium filaments made with Lehvoss compounds is Essentium’s patented multilayer extrusion technology that allows us to provide functional material properties like ESD-safe materials and highly loaded fibre-filled compounds. One example is Essentium HTN-CF25 where we worked with Lehvoss to filamentise their 25% carbon fibre-reinforced high temperature nylon by coating it with a tough casing of the base resin. We basically made filament sausage! This takes a material that is normally unable to be extruded into filament because it’s too brittle to wind, and makes it tough enough to convert to filament. We love this material because it has incredible strength and stiffness, but is very easy to print, with a beautiful surface finish and is low wear on the drive and feeding sections of a 3D printer.”
Sweeney acknowledges that Lehvoss is also working with other 3D printer vendors to tune its materials for their 3D printers but says that if 3D printing is to become a serious contender as an industrial process for end-use products, then an open market focused on developing new materials with better and faster machines is the only way those manufacturers will be able to develop new applications and new business opportunities. He adds: “We are working with our partners including Lehvoss to advance an open ecosystem approach to give customers greater control of their innovation, more choice in materials, and industrial-scale production at ground-breaking economics.”
He points out that Essentium’s HSE 3D Printing Platform can use materials from other suppliers, saying: “Until now, the industrial AM market has been dominated by closed systems where customers are locked into vendors’ hardware, processes and materials. As the technology obstacles around economics, scale, strength and speed of production fall away, the number of manufacturers using 3D printing for full-scale production has doubled compared to last year and manufacturers are now demanding open ecosystems to overcome system inflexibility and use the materials of their choice. In order to be competitive, large production manufacturers require open materials for differentiation, cost and scale, and Essentium’s goal is to provide just that.”
Sweeney concluded: “While there are many compounding companies that optimize materials for 3D printing, few can rival Lehvoss’ manufacturing knowledge and their approach for designing compounds specifically for extrusion-based 3D printing processes. With Lehvoss we have a true partner who shares our passion in applying material science innovation to accelerate industrial-scale additive manufacturing. We have already seen strong demand for our PEEK and HTN materials and look forward to developing new materials that give manufacturers the trust and confidence to shift from prototyping to full-scale production using 3D printing.”