If you’re looking for custom-fit prosthetic legs or replacement parts for your Hoover vacuum cleaner that’s been out of production since 1960, your best bet may be to just make the item from scratch. Additive manufacturing, or 3D printing, is being increasingly used to create cost-effective models and real parts for machines and end-use products.

While you may still be struggling to wrap your head around 3D printing, 3D Systems’s co-founder Chuck Hull has been experimenting with the concept since the Reagan Administration. Hull invented stereolithography, or three-dimensional layering, back in 1983 and stuck a patent on designs for a 3D printer three years later.

Rock Hill, SC,-based 3D Systems designs and sells printers and associated materials and services for both home and commercial use. In mid-2012 it doubled its R&D expenditures and improved marketing to expand its products and boost sales. Those efforts seem to be paying off. Second quarter revenues increased 45%, with sales in all categories improving. --S.G.