3D Printing FDM (Fused Deposition Modelling)
v0.4 by Ger Walsh - Nov 2023
General
Video credits to Ultimaker.
Steps:
Design your own models:
To print, you need a 3D object in a file. These files may be: .STL, or .OBJ, or .AMF.
- TinkerCAD (In-Browser)
- onShape (In-Browser)
- Blender
- Fusion360
- Rhino3D
- SketchUp (In-Browser)
- SolidWorks
- Z-brush, or SculptGL
Note: Sketchup can be used for free in the browser and is a good software for a beginner to start with. Sketchup Tutorials are available here. The only requirement for a 3D software is that it can produce a .STL file, so if you know another, it
* Slicing software will also be required, and is covered on the subsequent, relevant pages.
Download a 3D object:
There are many 3D files online, ready to download and print. The file type you need for printing is an .STL file.
Some interesting, specific-purpose, repositories:
3D Scanning
- Stereoscopy
- Photogrammetry
- LiDaR
Then...
Fixing your .STL file
An .STL file needs to be a single, solid object.
If it has gaps between its faces, it may not print properly. Netfabb, Meshmixer are tools that can automatically fix some issues. In SketchUp, you can install a plugin called "SolidInspector2" to fix models. Or the "_ShowEdges" command in Rhino is a very good way to highlight issues.
Familiarise yourself with the Boolean or Union or Join commands in the program you are using. Using these can help keep models solid as you are working on them.
Slicing
Slicing software takes your 3D model, slices it and creates a file (.gcode) that the printer can read. It is simple to use, and the specific settings needed for our printers can be got from us when you call in.
- PrusaSlicer (Free, tutorial)
- Ultimaker Cura (Free, tutorial)
- Simplify3D ($149 USD)
Materials And Properties
The name FDM, Fused Deposition Modelling, refers to fused layers of extruded plastic. There are many suitable plastics and bio-plastics. Almost all FDM printers use filament, i.e., rolls of long plastic strands. They are commonly available in 1.75 and 2.85mm, and some of the common types are PLA (Polylactic Acid), PET/PET-G, ABS, PS, TPU, and mixed filaments that contain a kind of aggregate, in small particles that passes through the machine, e.g., metal filings, fine sawdust or filler made of coffee grounds, glass dust.
We keep a good supply of PLA plastic. We can order more material as required, though we also welcome people bringing their own material in to use on our machines. New materials are being developed regularly including metal composites. Examples are on display in Fab Lab Limerick.
The properties of FDM printing stem from material properties, extrusion process.
Layers - layer height, can be up to half of your nozzel diameter, determines most-directly the time taken to complete your print.
Infill - given as a '%', influences the time taken to print and the strength of the final part. You can define the pattern of infill to be generated also.
Also, Wall Thickness, Speed/Accel settings, temperatures for bed and nozzle, supports to be generated and lots, lots, lots more.
Test your printer with a Benchy (Benchmark Test), an XYZ cube or a Torture Test to see how well it is tuned.
Printing
Bed Preparation
The first layer of printing is very important. If this layer does not adhere to the bed properly, your print is likely to fail. PLA is easiest to print. Use Isopropyl Alcohol (Isopropynol, IPA) and a tissue to wipe down the bed. Give the bed a light spray with Hairspray if required. With other plastics such as ABS you will need additional adhesives to bond to the bed.
On the Prusa printers, you can go to Tune > Live Adjust Z-Height to make fine adjustments (0.00x mm) as the printer is starting.
The Wasp Printers require Pritt Stick, or glue stick to provide additional adhesion to the bed. Ensure that the print area gets an even coating, and consider brims and rafts as other techniques to improve the bed adhesion of your print.
Changing Materials
On the Prusa Mini's, go to Filament > Unload and follow the screen prompts. You will have to select the correct material in order for the machine to heat up and release the previous material.
The printer may take a minute or two to reach the required temperature.
When loading material, use a cutters, to taper the tip of the material to make it easier to load. Feed to the ETFE guide tube, and press Continue, while pushing the material in slightly. The material will hopefully start to pull into the machine, will be forwarded to the hot end. The printer will continue to push the material, purging the last of the previous material. Select No on screen to purge a little bit more, if you think it might need to get a bit more out.
If the material isn't coming through at this point, the machine may be clogged. Try these steps again, and ask for help if it doesn't work the second time.