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Conductive Thermoplastics for 3D Printing

Ilene Wolff
By Ilene Wolff Contributing Editor, SME Media
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This early-stage 3D-printed drone from Functionalize was made using its conductive, PLA-based F-Electric Filament. Courtesy of Functionalize

As inventive and imaginative as 3D printer technology is, so are the materials that R&D labs have come up with to build parts, including conductive thermoplastics.

Making materials to use in 3D printers can also be lucrative. The materials market is forecast to reach $20 billion by 2027, according to market research and business intelligence company IDTechEx (Cambridge, England).

Conductive thermoplastics are expected to take a bite worth millions of dollars for makers such as 3D Graphene Lab (Calverton, NY) and Functionalize (Seattle, WA) from that $20 billion.

3D Graphene Lab produces low-current, low-voltage conductive thermoplastic filaments with base resins of TPU [1.75mm or 0.07 inches wide] or PLA [1.75mm or 0.07 inches; 3mm or 0.12 inches wide]; the material also comes in pellet form. Graphene Lab also makes a ferro-magnetic PLA filament and an impact filament with HIPS as its base resin [both 1.75mm or 0.07 inches wide].

Graphene Lab’s products offer resistivity of 0.6 ohm/cm (PLA-based filament); 1 ohm/cm (PLA-based pellets); and <1.25 ohm/cm (TPU filament and pellets).

This company provides lots of storage and use information to help you get good results with their products.

In addition to listing 10 physical properties of the material and the reel that holds it, a typical product page on its e-commerce platform, Graphene Supermarket, details recommended print extruder and platform temperatures and feed rates; storage and handling advice; and tips for working with the product.

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3D Graphene Lab Inc. (Calverton, NY) produces low-current, low-voltage conductive thermoplastic filaments with base resins of TPU or PLA. Courtesy of 3D Graphene Lab

Here’s an example of how detailed their tips are, from the page about its G-6 Impact Filament:

“In order to benefit from the high vibration damping performance of our material we recommend to print objects with 100% infill.”

Another company, Functionalize makes a highly conductive filament, F-Electric Filament. It’s a PLA-based material available in diameters of 1.75mm [0.07 inches] and 2.85mm [0.11 inches], with resistivity of 0.75 ohm/cm.

“We found 0.75 ohm/cm to provide a sweet spot of printability, physical properties and conductivity,” said CEO Mike Toutonghi, a longtime entrepreneur and founder of Microsoft’s eHome division. “While we have had internal F-Electric candidates even under 0.5 ohm/cm, they didn’t enable new applications, so we set our spec there and focused on consistent printability and mechanical properties.”

Toutonghi points out that just recently the open-design 3D printer project RepRap (Bath, England), has started electroplating 3D prints using F-Electric.

Another recent development from Functionalize that’s in beta testing is a water soluble, paste acrylic that can be used in place of solder with F-Electric. It’s printable with a paste-capable printer, and has volume resistivity of 0.001 ohm/cm.

To get a perspective on conductive thermoplastics for 3D printing, I asked Jon Harrop, a director and analyst at IDTechEx, and a co-author of its report entitled “3D Printing Materials 2017-2027,” to answer some questions. His answers were lightly edited:

What are the applications for 3D-printed conductive thermoplastics? How important is it to have them available?

They have been used for static and EMI shielding because their conductivity used to be relatively poor. Conductive thermoplastic filaments are now conductive enough for some more electronic and electrical applications such as 3D printed torches (flashlights). However, silver inks and pastes are still much more conductive so dominate the market for conductive 3D printed materials today.

What would it mean for industry to be able to 3D print a battery along with a device? Where would you see applications for this? 

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Functionalize (Seattle, WA) made this 3D-printed circuit using the company’s conductive thermoplastic F-Electric Filament, and no wires or solder. Courtesy of Functionalize

With 3D printed electronics it will be possible to print batteries of any shape and size. Initial applications will be making better use of space in applications like electric vehicles, fitting batteries into odd-shaped gaps. Longer term this is part of what we call “structural electronics” which is the ability to manufacture objects containing integrated electronics and electrics. For example, Voxel8 have already 3D printed a working solenoid and are working on a completely 3D printed electric motor. This will also revolutionize the $80bn PCB industry (see the company NanoDimension, for example).

So far, Graphene 3D Lab has used TPU, PLA and HIPS for its base resins and Functionalize uses PLA. What other base resins would industry be looking for?

ABS is a common thermoplastic (LEGO is made from ABS) and a common 3D printed thermoplastic. TPU is very interesting because it is flexible so you could 3D print flexible conductors or even flexible conductors inside a flexible insulator to make flexible circuits and connections.

3D Graphene Lab also has a ferro-magnetic PLA filament. What would this be used for?

That could be used to 3D print magnets, e.g. as part of a 3D printed electric motor.

The company is somewhat vertically integrated in that it has a partnership with a company that mines carbon. Is this important? 

I don’t think it’s very valuable because carbon is such a widely available commodity material, unless there is something specific (perhaps graphene-related) that they are getting.

This is from the company’s website: “Graphene 3D also holds a new proprietary technology encompassing the preparation and separation of atomic layers of graphene. This technological breakthrough represents a new, energy efficient process to manufacture, sort and classify graphene nanoparticles resulting in the potential for large scale production of high grade graphene at lower costs than exist in today’s marketplace.” Does this sound like marketing hyperbole or does the company truly have something special?

I am not familiar with their technology, but I would not dismiss it as hyperbole. We are forecasting a graphene market of hundreds of millions of dollars in the future.

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