Similarly, plastic injection molder Thogus Products Co. Inc. said that it has used 3D printing to make parts out of different kinds of thermoplastics, including acrylonitrile butadiene styrene (ABS) and polycarbonates, as well as from metals. The company added that 3D printing enables it to consolidate multiple parts into one and, in some cases, eliminate assembly steps, cut costs, and save time.
Experts agreed, however, that production volume is still limited when compared to conventional techniques, such as injection molding. Whereas injection molding machines can spit out parts every minute or two, 3D printers can take hours to do a single part. Still, Stratasys pointed to the case of one manufacturer that builds 300 to 400 parts per week for use in aircraft gauges. “We tend to have the most traction in making custom or semi-custom parts, with production volumes of no more than 2,000 to 3,000 parts,” Jon Cobb, executive vice president for Stratasys, told us.
Manufacturers also emphasized that 3D-printed parts don’t emerge from the printers as finished products. Most require pre- and post-processing. Pre-processing includes CAD-level software changes enabling creation of files that can work reliably in 3D printers. Post-processing includes removal or dissolution of plastic supports built into the parts, as well as surface finishing, such as sanding. ”We need to get over the unrealistic expectation that the machine pops out a finished part,” said Dods of GE Energy.
Matt Hlavin, president of Thogus, said that design engineers also need to understand the limitations of the materials involved. “You can’t take a traditional part that was metal, such as a bracket or casting, and print it in plastic and expect it work the same way,” Hlavin told us. “It’s never going to be a one-to-one replacement.”
The most critical skill needed for 3D printing, however, is just good knowledge of manufacturing design, experts agreed. “With 3D printing, you can print virtually any geometry that you can design,” said Cobb of Stratsys. “But you have to have good design skills. And not everyone has that.”