Introduction to Rapid Prototyping (SLA & FDM)

Rapid prototyping, also known as additive manufacturing, is the third-fastest growing industry in the US by revenue growth (%) in 2020¹. Coming in at 28.8% growth from 2019 to 2020, and only behind online grocery sales and cold medicine manufacturing.

If you’re not familiar with rapid prototyping, well you might want to think again. As far as the novices go, you may think that rapid prototyping is a “one-trick pony”, think again. Try “nine trick pony”, given that there are nine different printing technologies. Hell, 3D printers have produced human organs already, time we start paying attention!

In this installment, I’ll be focusing on two popular and critical technologies in, SLA and FDM rapid prototyping.

SLA 3D Printing (Stereolithography Apparatus)

First, let’s start with SLA 3D printing (stereolithography apparatus), the grandfather, and trailblazer of rapid prototyping. First commercialized in 1988 by 3D Systems which was co-founded by an all-important, Charles Hull². Charles is also the first inventor and patent holder of the SLA 3D printers, dating back to 1983³. SLA prints are created by exposing a photopolymer (photosensitive resin) to a UV laser beam. SLA prints are built by curing together a series of consecutive super thin layers.

Although SLA 3D printing is highly accurate, it is not known for strength, the utmost being an ABS-like (acrylonitrile butadiene styrene) or ceramic-like plastic. Most rapid prototyping vendors offer their own unique wide array of material selections ranging from, clear PP and PC-like (polypropylene & polycarbonate) to opaque, ABS-like, or polyurethane, blacks, grays, and whites. SLA 3D printing is definitely an Engineers’ best friend for evaluating fit and form of accurate and high detail components.

FDM 3D Printing (Fused Deposition Modeling)

Next, FDM 3D printing (fused deposition modeling), was patented in 1989 by Scott & Lisa Crump who later co-founded Stratasys⁴. Since the original patent expiration back in 1998, this rapid prototyping technology has dominated the desktop-size, consumer 3D printer market. FDM prints are created by heating a thermoplastic filament and distributing it through a nozzle system into a series of thin consecutive layers.

Although FDM prints have a stigma against the resolution/quality of the surface finish, they’re known for speed and cost efficiency, while enabling better strength properties with certain materials. Like SLA 3D printing, most rapid prototyping vendors offer a wide array of unique materials to choose from in the FDM world. One material of note, and known for its high strength and heat resistance, ULTEM (polyetherimide). FDM 3D printing has become an Engineering teams’ go-to choice, due to its speed and cost.

Click here for Part 2 of “Introduction to Rapid Prototyping”.