In Brief
Printing in three dimensions (3-D printing) constitutes an emergent technology for producing objects made of metals, biologicals and polymers. Already used in several industries, the process holds promise for larger-scale commercialization and, thereby, elevated worker exposures to process hazards. This article examines some of those hazards specifically.
This article frames the present state of 3-D printing and examines the literature about related hazards.
The authors also report original findings from a preliminary hazard assessment of the process and chemicals associated with a commercial-grade photo polymerization 3-D printer. Exposures to organic polymers, particulate matter, the corrosive cleaning agent sodium hydroxide and noise were assessed.
With 3-D printing stories seemingly appearing weekly, one could get the impression that it is a recent technological advance. Indeed, the increase in personal 3-D printers alone reportedly averaged almost 350% per year from 2008 to 2011 (Wohlers Associates, 2013). However, the essential technique, also known as additive manufacturing (AM), has existed for several decades. It is only because of recent advances in CAD/CAM software, in conjunction with important lapsed patents, that the technology has seen such intensive attention and explosive growth (IPO, 2013).
OSH professionals encounter AM in the aerospace, architecture, automotive, medical and dental fabrication, defense, and commercial and consumer product manufacturing industries (Stratasys, 2016). Key areas of interest for newer or emerging development are biomedical applications, electrodes and circuits, but the technology has potential uses in a nearly limitless number of applications. A sampling of these include medical prosthetics (Photo 1), miniature Li-ion micro batteries only 200 μm long (Sun, Wei, Ahn, et al., 2013), embedded inventory control tags and shoes. In an amusing case of life imitating art, NASA has even demonstrated an interest in 3-D printing to create food for astronauts while in flight, much like the food replicators of the Starship Enterprise in the 1966 television show Star Trek (NASA, 2013).
As it is most often seen commercially, 3-D printing, or AM, employs the use of premixed resins sold in proprietary cartridge containers for use in a manufacturer's printer carcass. Two major categories of materials are utilized: inks and supports. Inks are most often plastic monomers thin-layered atop each other to create an object, and support materials are simultaneously layered in and around the inks to provide structure during the build-up (i.e., printing) process. A vendor-supplied makeup for representative types of such inks and supports is shown in Tables 1 and 2 (p. 58), respectively. When exposed to UV light, these organic polymers polymerize, or cure, to a solid, finished state. During the jetting process of the inks and support materials, and/or under the UV polymerization step, hazardous airborne decomposition materials may be produced (CMU).
