Home / Services / 3D Printing / Preparing Your 3D print File

Preparing Your 3D Print File

What is 3D printing?
3D printing is the process of building a physical 3D object by laying down one thin layer of plastic at a time. The printer builds the object based on a digital 3D object file (.stl), combined with instructions on how to lay down the layers (.gcode).

video: 3D printing in action 

What material is used?
Polylactic Acid (PLA) is a plastic derived from renewable resources like corn starch or sugar cane. While it is ultimately biodegradable, printed objects should last for many years. It does not create harmful fumes when heated.

Designing a 3D Model

If you are new to 3D modeling and printing Lynda.com has some introductory courses:

  • Learning 3D Printing
  • Design for Additive Manufacturing: FDM

You can access Lynda.com for free through Edmonton Public Library. Sign up for your L-Pass, then access Lynda.com through EPL.ca.

3D Modeling Software:
TinkerCAD - A browser-based application for 3D object design.
SketchUp - The free version is browser-based for technical design of intricate objects.
Blender - A free, open-source, 3D designer for artistic modeling. It’s also available on Steam.
Fusion 360, AutoCAD - Autodesk software for technical design. You can get access to these for free with an education license.

Free 3D Models:
You can also find and download 3D models. Note that just because they have been created and uploaded does not guarantee they are ideal for printing.

Thingiverse.com - Makerbot’s site for user-uploaded 3D designs. Designs uploaded to this site are considered Creative Commons (link to licensing page)
3D Warehouse - User-submitted, 3D objects, created in SketchUp
Instructables - User-submitted from Autodesk community

Preparing your file to print

You will need to submit an .stl file for printing. If there are multiple parts (multiple files), you will need to submit multiple files. If you are printing in dual colour or would like different parts printed in different colours please specify in the "notes" section of the print request form. We have a guide here on how to create a dual colour print.

We use Ultimaker’s slicing software, called Cura, to prepare your objects for printing. You can also use this free software to view your object as it would print on our printers. This will also tell you how long your file will take to print. Note: To give you an idea, printing a 2" x 2" object can take over 2 hrs, more complex prints can take more than 8 hrs. Print time is something to consider when submitting files, prints longer than 24 hrs may have to be printed over weekends depending on the cue. 

MacEwan Library currently has four printers:

  • Ultimaker 2+
    • Single Extruder
    • 223 x 223 x 205 mm Maximum Build Volume
  • Ultimaker 2 Extended+
    • Single Extruder
    • 223 x 223 x 305 mm Maximum Build Volume
  • Ultimaker 3+ (x2)
    • Dual Extruder (two colours, or one colour and support material)
    • 197 x 215 x 200 mm Maximum Build Volume using both extruders

Note: MacEwan University Library supplies Ultimaker or Innofil PLA size 2.85mm. Standard PLA size 1.75mm will not work in our printers. We generally will not print PLA or other filament supplied by users.

Common Problems for Printing 3D Objects

  • Overhangs - The printer cannot print in midair. Objects with overhangs or floating parts will require support that will need to be removed after printing.
  • Build Plate Adhesion - If any parts of the object touching the build plate are too small, they will require additional plate adhesion that will need to be removed. This often requires supports as well.
  • Disjointed Pieces - Some parts of the object are not actually attached. This often happens with artistic pieces built in software like Blender or SketchUp. In these cases, it may not be possible to print the object as-is.
  • Colour - The colour of the printed object depends on the filament used to print it. .STL files do not contain colour information, so it does not matter what colour the object(s) are in the design software you are using.

Note: Objects should not be exposed to heat after printing. While PLA is not harmful if in contact with food, because of microscopic gaps in layers 3D printed objects that can harbour bacteria, printed objects are generally not food safe and definitely not dishwasher safe!