Embedded Files
Program: TinkerCAD
Discipline: Fabrication, Computer-Aided Design (CAD), 3D Modelling
Course: TGJ3M, TGJ4O
Background
Background
The first 3D printing technologies started to appear in the late 1980s but did not become financially feasible for consumers until very recently. It may seem simple, but the technology that 3D printers utilize is quite advanced and requires high precision microcontrollers and moving parts that are less prone to failure.
The application of 3D printing is quite simple however. 3D objects can be cut up into very thin almost-2D objects and layered one on top of another and sealed together to achieve a full 3D object.
A digital 3D object is generally stored as an .STL (standard tessellation language) or .OBJ (object) file on a computer. These files only describe the surface geometry of the object, without any colour, texture, lighting or other attributes. (Note: most 3D printers can’t print more than 1 colour at a time). These .STL or .OBJ files need to processed in a special piece of software called a Slicer which creates very thin 3D slices and outputs the step-by-step instructions that the 3D printer will follow.
The instructions the 3D printer needs is called G-Code. This code literally tells the motors in the printer when to turn on and for how long (see translated example on the right).
The process and materials to achieve this cheaply, quickly and easily have only really become available over the last couple of years.
There are dozens of types of 3D printers, but there are generally 2 consumer used types, filament-based printers and resin-based printers. They each utilize different chemical properties of substances to create 3D dimensional objects by printing 2D layers one at a time.
Filament Extrusion Printers
Filament Extrusion Printers
Utilizes solid printing materials, generally made available as “filament” or long continuous threads that are stored on spools. These materials (e.g. plastic PLA) are generally brought to their melting point through a heated nozzle and “extruded” out on to a print bed, where it cools down. The nozzle moves about the X and Y axis, printing in 2D dimensions until the 3D dimensional layer is complete. The bed will either move down in the Z axis or the nozzle will be moved up in the Z axis to start the next layer.
Resin Polymerization Printers
Resin Polymerization Printers
Utilizes liquid printing materials, commonly known as “resin”. The resin starts in a liquid state at room temperature and the bottom of the print bed usually starts submerged in this liquid. A special light source is projected using moveable mirrors so that it can be projected in the X and Y axis. This light causes the liquid material to solidify through process of chemical reaction. It cannot be reliquefied using this method. The bed rises out of the liquid one Z axis layer at a time, the resulting print is upside down when finished.
3D printers, while pose no inherent risk on their own, are still dangerous pieces of machinery if handled incorrectly. Take a moment to familiarize yourself with the parts and terminology of the printer you'll be using.
You'll also want to familiarize yourself with the different kinds of filament and hand tools you may need to use.
Getting Started
Getting Started
3D modelling software is the foundation for 3D printing. It enables users to transform their ideas into digital models that can be refined, modified, and prepared for printing. It acts as a virtual workshop where users can unleash their creativity and turn their imagination into reality.
There are plenty of software solutions for 3D modelling, but the best place to start as a new learner, and for someone working to create models that will be used for 3D printing is: AutoDesk's TinkerCAD.
Rather than having the user create custom geometries and polyhedra, TinkerCAD provides a wide range of pre-designed shapes and tools that allow users to build their models. Users can drag and drop shapes, resize them, and manipulate them to create customized objects. TinkerCAD also enables users to combine multiple shapes using “boolean” logic to create composite polyhedra for more complex designs.
Complete the first 10 tutorials in the Learn TinkerCAD module to get the basics of how to use the application.
Once you get a hang of the software, consider what you'd like to model. You will need to make considerations for the printer you'll be using. For now, try to focus on designs that:
Don't require fine amounts of detail (i.e. faces, text)
Use blocky shapes instead of curvy/round shapes
Make a good amount of contact with the ground
Do not have many parts that "float" or need to bridge gaps (i.e. think how the letter "H" has a bridge across two pillars, the bridge will be difficult to print without supports since there is nothing beneath it to support it)
Once your 3D model is completed, it can be exported in a format that is compatible with 3D printers, such as .STL or .OBJ. These file formats store the information about the object's shape, size, and structure, allowing the 3D printer to understand how to recreate the model in the physical world.
Exporting Your Model
Exporting Your Model
As mentioned earlier, a slicer is a special kind of program that can take 3D models in the form of .STL or .OBJ files and convert them into instructions for a 3D printer to execute (known as G-Code or .gx files).
Recall that most consumer grade 3D printers can only create 3D models one layer at a time and must do so by heating printing materials to a high temperature. There are a lot of limitations that come with these restrictions. For example, it’s not possible to add material to a location that does not have an already solidified layer nearby (e.g. in mid-air), so a special kind of support structure needs to be printed and removed once the print has completed. These are known as supports and generally don’t use much material. Printers can generally apply filament so long as the overhang (amount making contact with a previous layer) does not exceed 60 degrees.
Since the extruded filament of the 3D printer can never get thicker than a few tenths of a millimeter, finished prints would not be very strong and likely break under their own weight if they were printed hollow. Thus, a slicer program can generate infill which is a pattern of filament that is printed in the interior of the print, increasing the total strength of the final print. The downside is that infill significantly increases the amount of material used and time spent printing. Generally, 10 to 15% of the interior space should be occupied by infill. Triangles and hexagons are the most efficient patterns to use for infill.
Depending on the type of material and the temperature in the room, some prints can experience shrinkage from the original dimensions as a result. If the first layer of the print does not adequately adhere to the base plate of the printer, you may also end up with a print that is warped in one axis (usually up towards the extruder as new layers cool and compress together). Common solutions for this involve the use of a heated bed to keep the first layer warm enough to stick to the bed. In the event that a heated bed cannot be used, making the build plate stickier by applying a thin layer of glue stick or hairspray can help with first layer adhesion. A slicer program can also add a brim (pictured right) or a raft (pictured left), which add a few fill layers below the model that act as “printed build plates” to add points of adhesion and structure to the final build.
Success Criteria
Success Criteria
Boolean
Boolean
Design uses an appropriate number of polyhedra, uses holes and groupings to create new shapes.
Cohesion
Cohesion
Design is cohesive (e.g. no seams, consistent poly count throughout), offers some level of complexity
Functionality
Functionality
Design is functional (for a use), attractive, or interesting and demonstrates proficiency in design thinking.
Process
Process
Design has appropriate overhang, bridging, contact with bed, and support, is sliced with an appropriate infill percentage and pattern and with the correct printer nozzle and bed temperature settings
File Submission
File Submission
- First Name - Print.st
- First Name - Print.gcode
Student Exemplars
Student Exemplars
Come see the physical versions in class!
Come see the physical versions in class!
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