What is 3D Printing?

In essence, 3D printing works by creating many hundreds or thousands of relatively thin individual layers, one on top of another and stuck together. 

Depending on the type of printing, those layers might be made out of a melted plastic (like PLA or ABS), or an ultraviolet light reactive photopolymer (like resin). At the current cutting edge of 3D printing, there’s also a means to use lasers to selectively fuse shapes out of finely ground powder – but that’s far more advanced than my print shop can handle! [Maybe someday…]

While 3D printing is seeing use in fields as diverse as medical sciences and home building, my 3D printers get used to make prototypes, costume accessories, prop weapons and armor, wargaming terrain and high quality resin gaming miniatures. In these applications, each of those layers I mentioned above are typically between 0.01 mm and 0.2mm each – depending on the project and the use, an object might have a hundred layers per vertical millimeter! 

Materials and their properties:

In general, there are many different materials used in 3D printing – everything from concrete (for houses!) to human cells (for 3D printing skin and other organs!). 

The prints I produce, though, are either in PLA (PolyLactic Acid) or in photopolymer resin.

PLA is a compound made primarily from plant starches (typically corn). PLA is safe for regular use and handling, and can even be made into medical implants. This material is printed using a roll of filament several hundred meters long, which feeds into a machine where it is simultaneously heated to its melting point and extruded onto a print bed by a moving nozzle. Layers are built up individually, and are typically between 0.08 and 0.2 mm in height. PLA has a softening temperature of 50 degrees C and otherwise behaves like most other plastics.  

Photopolymer resin is UV reactive, meaning that it hardens when exposed to UV light. This material is printed by pouring several hundred milliliters of liquid resin into a holding tank that is positioned above a UV light. The resin printer can selectively direct or block UV light, and create shapes by hardening the resin. The hardened layers stick to the build plate of the printer, or to the previously hardened layer, and as the print progresses, it lifts up and out of the vat of resin. An entire layer is cured by the UV light at the same time, and each later can vary in height between 0.01mm and 0.05mm; between 100 and 20 layers per vertical millimeter of the print! 

Health Cautions

Occasionally, you may want to sand something that has been printed. Both PLA and resin produce very fine dust when dry sanded – for this reason, it is strongly recommended that you wet sand and wear a well-fitted respirator. Neither cured resin or PLA are toxic in-and-of themselves, but breathing in the dust from either material is a bad time. Don’t have a bad time.  

In liquid form, resin is a sensitizer (meaning a person can become allergic to it over repeated exposures) and must be treated with care. Liquid resin can cause skin irritation and/or severe eye irritation. Once cured, however, the resin can be safely handled. 

All items printed in resin will be cured fully prior to being sold.

Resin can be negatively impacted by over-curing, often cracking. Until it is painted, a resin print should not be exposed to additional UV light (kept out of direct sunlight, for example). Once painted with no exposed sections, a resin print is shelf stable like plastics. 

Additional information on the material properties can be found in the MDSS for each manufacturer (provided upon request) and/or located via your favorite search engine.