Applying Material Like Toner Promises AM at Speeds Like Injection Molding
The Stratasys-founded company Evolve debuts its STEP technology for production-scale additive processing.
When Evolve Additive Solutions
In the STEP (Selective Thermoplastic Electrophotographic Process) technology, the material layers that are applied like toner are delivered by belt onto a preheated part that is moving
Established 3D printer maker Stratasys developed the technology to its current point, then spun it out into Evolve, a separate company in which Stratasys
The plan is to fully commercialize the technology in 2020, he says. Evolve is announcing STEP this year in part because it is searching for beta testers, and in part because the technology is a solution for (among others) large companies that will need time to recognize that this solution is coming and adapt their plans.
Bradshaw says the capabilities of STEP are more comparable to injection molding than to other additive processes
One other way the process is comparable to molding is this: The process can produce parts missing the layer lines typical of 3D printing. STEP mates heated layers to a heated part, producing fusion that is more complete than in a process such as FDM.
Candidate materials for STEP are the same polymers available for injection molding, the company says. However, delivering the materials as toner requires materials-engineering techniques proprietary to Evolve.
Meanwhile, some of the part-design possibilities are very new. The STEP process has parts passing conveyor-style under the belt applying material, meaning the conveyor could also carry parts—including incomplete parts—to separate processing stations. For example, the unfinished part could pass to assemblers or robots for quick installation of electronics before being sent back into the additive build. The result would be low-cost solid parts with electronics sealed inside.
One other possibility comes right back to the technology’s origins in conventional printing. A laser-jet document printer can apply not just one toner, but several. Similarly, the STEP machine (even in its current alpha form) has multiple print heads. This can allow for multiple colors in the part, but an even richer possibility is the chance for multiple materials. Various different polymers applied at the voxel-by-voxel level could achieve combinations of properties unobtainable in any single material alone. Thus, the technology is potentially a competitor to injection molding in some applications, but this misses the full case for it. At its more powerful extreme, the technology offers a means of realizing parts that were previously unthinkable, then manufacturing them at production scale.
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