There are several energy-consuming steps in thermoplastic 3D printing. One is the conversion of the commonly used material, acrylonitrile butadiene styrene (ABS), into a polymer. Another is the re-melting of the ABS in a compounder to include additives like carbon fiber. The ABS, now in pellet or chopped form, is melted a third time for deposition during the print process. In addition, the printing table is typically heated during the thermoplastic printing process to prevent the parts from cooling too fast.
Thermosets, by contrast, require heat to make the original polymer, but beyond that the only added energy is what’s required to pump and mix the PRD 1520 as it’s processed through the RAM equipment.
The Electric Power Research Institute (EPRI) found that the thermoset additive manufacturing process is about 500% more energy efficient than the thermoplastic process, Hershey says.
The ability to control the exothermic reaction in the RAM process provides opportunities to vary the characteristics of a part.
“With thermoplastics, once you lay the bead down that’s the hottest it’s going to be. It starts to cool so you can’t print through it,” says Kastura. “That’s not true with thermosets. You can literally cross through that previously laid bead on the same plane, so you can have different geometries, different print patterns.”
In addition, the RAM machine can be equipped with a robotic claw that can insert objects into a part as its being printed. “The claw could grab pipes for heating or cooling channels and drop them precisely into your print because it’s all part of the machine code,” says Kastura.
The claw could also precisely install different types of sensors inside a tool as it’s being manufactured. Those sensors could relay data to help predict the part’s end of life or to validate a tool’s effectiveness during the process by providing metrics at certain times. Embedded sensors could be used to monitor temperature within a tool to ensure that it’s at the proper temperature while it’s being used.
One other unique feature of RAM is its patent-pending removable printing table, which will enable a shop to index the table rather than the part, then easily move the printed part to its next location, such as milling or routing. Then, by inserting another table, the shop can continue to make the best use of its high-demand AM equipment.
Testing It Out
Thermoset additive manufacturing is attracting attention from government and commercial customers, including the military, automotive/transportation, wind/aerospace, tub and shower manufacturers and job shops. “Many of them have looked at thermoplastics 3D printing, and they know some of the limitations. There’s a strong case that can be made that thermosets can solve a lot of those issues,” says Kastura.