Jan 19, 2018 Simplified 3D Printing in the Library

Over the last few months, we have rolled out several changes to the Marriott Library’s 3D printing program. While we have evaluated many different desktop 3D printers, we have identified the Lulzbot TAZ 6 as our printer of choice as it provides the most feature complete printing platform at a price point that allows us to sustainably scale the operation. This post will identify recent changes and serve as a starting point for future improvements. The aim of our service is to maximize usability for new users, providing access to the broadest possible campus audience. Since our printers are available to all students, faculty, and staff whenever the Library is open, we have done our best to ensure everyone is able to use them and learn about the technology.

Perhaps the most substantive change we have made has been to replace all of our open-use printers with TAZ 6 models. This change is most significant as the learning curve on the TAZ 6 is much lower. Prints can be started using the simple instructions found here: http://www.lib.utah.edu/services/knowledge-commons/3d-printing.php

A second major change is that we now only allow for PLA filament. Swapping out various filament types is a major cause of failure for new users and creates headaches for staff when filaments jam (through a condition known as heat leak or heat creep) or burn (yuck). We have capped the extrusion temperature at 220° Celsius to prevent these issues. We have also capped the heated print bed temperature at 70° Celsius to limit the amount of wear and tear on the build surface. The TAZ 6 is equipped with a polyetherimide (PEI) sheet and we have found that excessive heat on the bed creates bubbles under the sheet, necessitating replacement.

What are the problems we still have to solve for?

• Filament Size: Since users are allowed to bring their own PLA filament, it’s important to remember that diameter matters. 1.75mm filament will not work with the TAZ 6 printer, which only accepts 3mm (or 2.85mm) filament types.
• Filament Materials and Temperatures: Users must select the material they are printing within Cura (this is step 5 in the instructions linked above).
• Slicing Settings: Users should familiarize themselves with terms such as support material, layer height, shell thickness, and infill percentage. These terms can be found in the printed materials located by the 3D printers or online in a 3D printing glossary such as this one: https://www.3dhubs.com/knowledge-base/definitive-3d-printing-glossary

There are still some common types of failure that we are working to resolve:

• Calibration fails: The TAZ 6 cleans the nozzle by wiping it on a felt pad located at the bottom left corner of the print surface (or bed). If that felt pad is caked with excessive material, calibration will likely fail, resulting in an error. Scraping off any hardened plastic from the pad will usually resolve this.
• Print does not stick to bed, or print surface: Usually this can be resolved by increasing the first layer thickness (this is an option in the advanced settings of Cura) or slowing the print down (you can adjust “Feed Rate” by simply turning the knob/dial on the printer while it is running).
• Not enough filament: There is no filament sensor in the TAZ 6. It is possible to swap the filament during the print by pressing the knob/dial and choosing “Change Filament”.
• Bad model geometry: A model with non-manifold geometry can cause issues during slicing. Generally if the model looks good in Cura, it will print fine, but it’s a good idea to check the gcode for inconsistencies (see step 8 in the printing instructions linked above).
• Lack of support material: Overhangs exceeding 60° will likely droop during the print process, so be sure to generate support material accordingly by using the appropriate checkbox in Cura.

Happy Printing! If you have any questions or would like clarification about any of our printing instructions, please reach out to our mailing list: mlib-3dprinting@lists.utah.edu

T.J. Ferrill
Assistant Head of Creative Spaces
thomas.ferrill@utah.edu

View the original article on the Creativity and Innovation Services Blog