If you’ve ever worked with 3D printing technologies like PolyJet, DLP, or SLA, then you know how tricky it can be to handle and dispose of the resin materials involved. These UV-cured resins are toxic and environmentally hazardous when they’re still in liquid form. However, once they’ve been printed and cured, they’re perfectly safe to handle and dispose of. To deal with the risks, it’s important to wear basic protective gear like gloves, lab coats, and safety glasses, and ensure that you have good ventilation.

Most of the resin will be used up or cured during the printing process, but any excess that’s left over needs to be dealt with. These uncured photopolymers don’t have a long shelf life, usually less than a year when sealed in a bottle, and only a few weeks when exposed to the printing environment. Even if you check the expiration date on the material from the original equipment manufacturer (OEM), it’s easy to ignore these recommendations and try to keep using the resin beyond its expiration date. However, whether this is safe depends on several factors.

In our experience, there are three simple indicators that show when resin is no longer “printable” and needs to be disposed of: a noticeable change in color, a noticeable change in viscosity, and poor print quality.

excess resin from material changeover

Almost every 3D printing operation ends up with “expired” or partially used material, due to fluctuations in demand, material changeovers, and excess resin from the printing process. In the past, there have been several ways to deal with this waste stream. The first option is to use a hazardous waste disposal service, which involves registering with the EPA, storing the waste in a 55-gallon drum on site, and ultimately disposing of it in a landfill or incinerator. This is costly, so it’s not the best choice for everyone. Another option is to use the “California Lunch Tray” method, which requires a sunny day and pouring the resin in thin layers, but it can be inconsistent, messy, and time-consuming. The third option is to illegally throw the waste resin away, but this is obviously not a good idea.

Thankfully, there’s a better solution available now from Onulis called the WRAP which stands for Waste Resin Axial Printing. This system lets resin printing facilities cure their waste resin safely and efficiently in a single operation. The waste resin is deposited onto a rotating cardboard roll and cured simultaneously using high-powered UV lights. Once the resin is cured and solid, it can be disposed of safely in the standard waste stream.

WRAP system with fully cured waste resin that is safe for disposal

There’s also another version of this system called the Onulis WRAPCure, which can cure SLA and DLP parts at a 405nm wavelength in addition to the waste resin. The rotating transparent tray and mirror system allows for parts to be cured without user interaction, which can be a huge time saver.

WRAPCure with part curing attachment

If you’re interested in learning more about the WRAP systems and how it can help with your additive manufacturing post-processing operations and safely handle your waste resin, please feel free to reach out to your AdvancedTek sales rep or email us at sales@advancedtek.com.

_____

Meet David Kadlec

David is a senior application engineer at AdvancedTek where he is passionate about helping people and organizations with the adoption of additive manufacturing.

Outside of work David enjoys traveling with his wife Kate, snowboarding, and lake life in northern Minnesota.

_____

Have your own question for our 3D printing experts? Submit it below and you may see it used in a future ‘Ask a 3D Printing Expert’ edition!