Stereolithography is turning 30 years old this year, and it's come a long way, baby! Jim Reitz, General Manager for UnionTech Inc. (St. Charles, IL), has spent much of his career in the stereolithography field. UnionTech offers open design 3D printing equipment, allowing users to choose the best and most cost-effective software and materials over a wide range of platforms.
|Image courtesy Somos/DSM and UnionTech.|
Reitz notes that stereolithography (SL) capabilities have advanced significantly over the past 30 years, as new materials and software were developed to increase use applications for 3D-printed parts. Equipment developments have resulted in the broadest range of build envelopes of any 3D-printing technology, while achieving significant increases in build speeds.
In recent years, impressively funded startup companies have emerged that are bringing new capabilities to 3D printing, accompanied by substantial marketing campaigns. Whether a new machine purchase is an initial entry into 3D printing or an expansion of current capabilities, there is a lot of information to sort through.
When considering polymer-based 3D printing, there are basically two foundational types: Light-curable thermosetting photopolymers and melt processable thermoplastics.
“A large part of the performance capabilities of a particular technology is shaped by the material,” Reitz told PlasticsToday. “If you look at thermoplastic print systems, such as sintering or fused filament fabrication, there is a well-established commercial palette of materials to choose from. Equipment innovations over time have significantly advanced access to a wider range of performance well beyond the initially available nylon, ABS and PLA type of materials through advances in processing capabilities of the equipment.”
On the photopolymer side, impressions of early SL materials' aging properties and limited toughness have lingered in some quarters, despite significant advances in stability and mechanical performance. While equipment technology has evolved, many new applications have been developed through material formulation innovations. In 2001, Reitz noted, the industry saw the first optically clear and near-colorless SL materials, which opened new opportunities in fluid flow analysis and functional prototyping.
Composite SL materials came along in 2004, 60 to 65% filled materials that opened up whole new application areas such as rapid tooling and, notably, wind tunnel testing models for Formula 1 and aerospace. “SL patterns have been used to replace wax patterns for the investment casting of metals in low volume or highly detailed parts since the mid-1990s, but formulations advances that improved dimensional stability emerged as early as 2002,” Reitz said.