3D Printer

3D Printers

AHA currently has four 3D printers.

Ender 3 printers -

• Ender 3 - Bert
• Ender 3 - Ernie
• Ender 3 v2 - Oscar

Ender 5 printer

• Ender 5 Plus - Big Bird

All of the printers except Oscar are set up to print via Octoprint. The links to access octoprint are available on each of the printers webpages. The Ender 3 printers all use the same PrusaSlicer config - File:PrusaSlicer config bundle.ini (Current as of 12/16/2023). The Ender 5 uses the profile File:Ender 5.ini. These profiles are installed on the dedicated 3D printing computer, but you may download them and access octoprint from your own computer.

NOTE: most of this information is out of date. I dumped class notes in here for the time being -- they are rough guidelines for how to run the machines, but they are missing a lot of details.

Notes from the 3D printer class:

History:

• Not a new technology -- early 3d printers existed in the '80s.

Types of printing:

• FDM (Fused Deposition Modeling) / FFF (Fused Filament Fabrication) -- "typical" 3d printers
• SLA (stereolithography) / DLP (Digital Light Processing) -- i.e. resin printers
• SLS (Selective Laser Sintering) / SLM (Selective Laser Melting) -- powdered materials melted with a laser. Can be used for metal parts; not consumer-level tech yet.

Software:

• 3D models are saved in STL
• Machines are controlled with GCODE
• Slicers translate STL models into lines of GCODE
• Cura, PrusaSlicer, Slic3r, Simplify3d are a few slicers
• Lots of parameters you can tune or adjust. Most are beyond the scope of this class, or open to experimentation. However, some parameters will frequently be changed to fit your needs, such as brims/skirts/rafts, layer height, shell thickness, infill %, infill type, support materials, bed and nozzle temperatures, and feed rates.

Machine anatomy: go over the major parts

Filament types: go over some common materials

Machine operation:

• Always clean the UNHEATED print bed of old filament bits and dust using a sturdy paper towel or clean, lint-free cloth with 90% isopropyl alcohol on it. Try to avoid touching the bed after you clean it.

• Leveling the bed:
  • You will want to do this before every print.
  • Make sure bed is heated to printing temperature before leveling
  • One printer has a auto-leveling probe (untested), and the other one you will need to use the "paper method". (Demonstrate the paper method using the octoprint bed leveling helper plugin)

• Loading filament:
  • Move print head a fair distance from the bed
  • Remove from the desiccant zipper bag. After removing the spool, always re-seal the bag to keep the desiccant packet as dry as possible.
  • Check the end of the filament when you pull it out of the bag. Make sure it's secured in the side of the spool. If it's not, you will need to try your best to ensure it isn't crossing under another loop to prevent a print failure.
  • Feed filament in from the top, push on the spring lever to allow it to be inserted easily. Continue to push the filament in until the color changes to the new filament's color, or you get a decent flow from the nozzle.

• Printing:
  • Load the model you want, slice it, and send it to the printer
  • Carefully monitor the first layer or two to make sure it has good adhesion
  • First layer nozzle height should be close enough to slightly squish the extruded filament into an "oval" profile. It should not be too far away so as to drop it onto the bed, or so close that it flattens the filament entirely.
  • When the print is finished, wait until the bed has cooled completely before trying to remove it -- it should come off more easily when cool. Try to avoid scraping it off, which can gouge the bed.

• Unloading filament:
  • Always unload and store filament in its desiccant zipper bag when you're done printing for the day. If left out, it will begin to absorb moisture from the air, which will cause it to become unusable over time.
  • Make sure the print head is heated to the working temperature.
  • Push the spring lever in and pull the filament out. If you encounter any resistance, make sure the nozzle is at the right temperature.
  • When unloading the filament, be sure to capture and tuck the loose end securely into the edge of the spool. If you let it flop loose, it's very likely that it will end up crossing under an adjacent loop, which will cause filament feed issues during its next use!

• Finishing up:
  • Always ensure the nozzle heater, bed heater, and print cooling fan is turned off before leaving! The hot-end fan will always remain on.

Questions? Reach out to board@allhandsactive.org, #3dprinting or #Operations on Matrix.

As of 8/24/18:

• Ender 3 - Bert is available to print
• Ender 3 - Ernie is available to print

Older/obsolete information follows, safe to ignore for the most part:

Creating a 3D Model

Lots of software exists to create models. As long as the software can export to STL file format, you can print your model. Check out the following software packages that we recommend.

• Trimble (previously Google) Sketchup Make - [1]
  • Skethcup STL Plugin - [2]
• OpenSCAD - [3]
• Blender - [4]
• Rhino3D - [5]
• OnShape - [6]
• FreeCAD - [7]
• Fusion360 - [8]

3D model database

• Yobi3D - Free 3D model search engine
• Thingiverse - [9]

File Types

STL

The slicing software needs your 3D model as an STL file before it can slice it. Slicing produces a file that has GCODE to describe the tool head movements for each layer. It is important that your STL file only includes one solid water-tight object. Missing faces, open vertices, and improper normal calculations will cause the slicer software to produce errors. You can fix some of these issues in an automated fashion by using NetFabb Basic, Blender (recalculate normals), and MeshLab's repair mode.

How to fix an STL

You've got holes or inverted normals? You can fix this by hand, try Blender or Meshlab. For a quick fix either try netfabb basic on client or NetFabb cloud [10]. These can fix basic problems and possibly produce a better file. You need 1 shell, non-inverted normals, and no holes to get a good print.

The newest versions of Slic3r will automatically try to fix holes and other errors in your stl files. This can work, but make sure that your model hasn't changed dramatically before printing. Take a look at it in the 3d view.

You can also try these awesome pieces of software:

• MeshMixer
• MeshLab
• NetFabb Basic
• blender

GCODE

This is a description of the tool path that is generated by a slicer. The file includes commands which instruct the printer on how to move to produce the final object

S3G/X3G

Replicatorg converts a GCODE file into this reduced and compressed file type. This is equivalent to the GCODE but the smaller and easier to parse file type can be read off an SD card with less work. Use the build to SD card function in Replicatorg to produce this file. It can also be created with Makerbot's software

Jargon

• Layer Height - The size of each layer the printer produces. This is limited at its maximum by the size of the nozzle and at its minimum by the amount of plastic produced and how much stretching occurs.
• Infill - The pattern and amount of plastic put inside the model to support it.
• Shells - The number of solid outer layers the model has
• Raft - A piece of plastic generated to stick to the print bed. This also includes support material for the object
• Filament - The plastic fed into the printer
• Extruder - The part responsible for filament melting and forming it into a continuous profile.
• Slic3r - Produces a GCODE file from an STL file
• Skeinforge - Produces a GCODE file from an STL file, built into Replicatorg
• Replicatorg - Produces a S3G file from GCODE and controls the printer
• OpenSCAD - 3D Solid Modeling software