3D Printing Material News: BigRep Releases Flexible Filament, Army Researchers Using Recycled Plastic as 3D Printing Feedstock

In order to 3D print high-quality parts, you need high-quality materials with which to make them. Berlin-based technology startup BigRep develops and manufactures some of the largest 3D printers in the world, but has been focused lately on the materials side of things. The company recently announced a materials partnership with BASF, and this week released the global FFF 3D printing industry’s first flexible 3D printing material with engineering-grade properties: TPU-based PRO FLEX filament.

The company’s latest innovation can be used by customers and manufacturers for a multitude of applications, though it does advise that users should have some experience in handling the sometimes challenging extrusion of flexible materials.

The durable PRO FLEX filament was expertly developed and tested to work on the standard 1 mm extruder of the company’s largest industrial 3D printer, the BigRep ONE. The company analyzed the behavior of elastomers in its 3D printers’ extruders, and adapted the material evaluation procedure until it had developed the final thermoplastic elastomer material.

PRO FLEX is a Shore 98 A on the Shore Hardness scale, and has low temperature impact resistance, along with excellent damping behavior, high temperature resistance, and other dynamic properties.

“Printing elastomers is clearly one of the biggest challenges in the FFF AM industry, so we are proud to have found an industrial-grade solution,” said BigRep’s CTO Moshe Aknin. “In terms of applications with PRO FLEX, we see high potential for 3D printing in fields like footwear, custom vibration dampers, and seals, due to its high chemical resistance.”

Aknin is excited about how many different manufacturing parts and applications PRO FLEX will make possible – in the sporting goods industry, the filament could help in prototyping ski tips and ends, skateboard wheels, and sporting shoe shells. PRO FLEX could also be used to prototype parts like door handles, cable sheathing, and gear knobs for the automotive industry.

PRO FLEX is available for purchase on the BigRep website – a 2 kg, 2.85 mm spool of black material will cost €98.90 plus VAT, if applicable. The company will provide all PRO FLEX customers with a guidance document, and customer service technicians are also available when necessary, thanks to the BigRep 360° service.

Continuing on in FFF 3D printing material news today, the US Department of Defense (DoD) is exploring 3D printing feedstock made from plastic containers that have been left on the battlefield.

Army Research Laboratory (ARL) researchers are working to develop an FFF filament by taking recycled polyethylene terephthalate (PET), with no chemical additives or modifications, from discarded bottles and plastics. Recycled polymers contain all sorts of fillers, dyes, and additives, which could make them less effective as 3D printing feedstock, but the DoD reports that plastics, such as packaging and water bottles, are some of the most common waste found on battlefields.

Large volumes of plastic waste are generated by both US and coalition forces, so it would be a great help in terms of logistics if the waste could somehow be reused as 3D printing material to manufacture on-demand parts on the front. Not only would disposal costs go down, but the burden of transporting parts to forward bases would also be reduced.

According to tests, the recycled PET is a viable 3D printing feedstock – as long as it’s cleaned and dried, 3D printed parts made with the material have mechanical properties comparable to parts from commercial filaments.

The new material was tested on small parts, as well as larger long-lead military parts, like radio brackets; mechanical testing, like three-point bending experiments and uniaxial tensile, took place in the laboratory. Most FFF polymers have bulk strengths between 30 and 100 MPa, and the recycled PET fell right in the middle, with an average strength of 70 MPa. The tensile strength of the 3D printed recycled PET was similar to commercial filaments. Additionally, the recycled plastics underwent thermal stability tests and chemical analysis.

The researchers made a custom text fixture to test a 3D printed radio bracket. The tests showed that brackets made using recycled PET failed at a load similar to that of brackets 3D printed with commercial ABS filament, which means that it’s strong enough to replace commercial 3D printing filament for a range of plastic parts.

All units have large stockpiles of spare parts in case of emergency, but this increases cost, as well as risk to warfighters during transportation. In addition, it’s not easy to predict lifecycle and failure for the parts. The Army says that this new research will enable US forces to 3D print replacement parts on demand, which will increase equipment readiness and allow for the manufacturing of mission-specific devices in the field.

Right now, the ARL research team is building a mobile recycling facility, which will be located inside a 20′ ISO container not dissimilar to the X-Fab 3D printing facility. The facility will include all the necessary tools and equipment soldiers will need in the field to make 3D printing filament from plastic waste. The researchers are also investigating the use of filaments from other recycled plastics as potential 3D printing feedstocks.

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