3D-Printing @ EEL
What is 3D Printing?
A type of additive manufacturing
- Parts are created layer-by-layer
Can be more efficient and versatile than subtractive manufacturing (e.g. machining)
- But usually at the cost of structural strength or accuracy
Due to the nature of the process, it is often less reliable than other manufacturing techniques
- There are a number of reasons why prints could fail, we will talk about them later
3D-Printing @ EEL
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What is 3D Printing?
A type of additive manufacturing
- Parts are created layer-by-layer
Can be more efficient and versatile than subtractive manufacturing (e.g. machining)
- But usually at the cost of structural strength or accuracy
Due to the nature of the process, it is often less reliable than other manufacturing techniques
- There are a number of reasons why prints could fail, we will talk about them later
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How does it work?
- Take a 3D object
- Split ("slice") the part into many layers of equal thickness
- "Build" the print layer by layer
- Details on the next slide!
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How does it work? - FFF/FDM Printing
"Fused Filament Fabrication" or "Fused Deposition Modeling"
- Uses filament (= "plastic wire") as the material source
- Melt the material, push it through a nozzle and let it cool off
- The nozzle moves along the shape of the layer while the filament is being extruded
- Next layer can be placed on top as soon as the previous layer has solidified enough
- Printers come in two different flavors:
XYZprinters use three axis for correctly positioning the nozzle- Forward/backward, left/right and up/down
- During regular printing, the nozzle never moves back down, because everything below it is already done
Deltaprinters use three arms that can be extended or shortened with regard to the build platform- Very simple operating principle that still covers the X, Y and Z axis
- Works by using parallel rods on each arm to prevent the nozzle from rotating or tilting
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FFF - Advantages & Limitations
Pro
- Can use different materials for a single print
- Only little post-processing necessary
- Can print a wide range of materials
Con
- Overhangs are limited / need support structures
- Nozzle diameter causes tradeoff between speed and accuracy
- Each layer is extruded sequentially
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How does it work? - SLA and Powder-Based Printing
"Stereolithography"
- Uses liquid resin as the material source
- Prints the part upside-down
- Build plate is lowered into a tank filled with resin
- Screen with UV backlight at the bottom of the tank
- Cures the resin between the screen and build plate / finished layers
- Resin is cured (hardened) into solid plastic layer by layer
- Very high accuracy / printing resolution (50μm)
- A whole layer is cured at once
- This means that only the height of the object influences the print time!
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What do we need?
- 3D Object
Slicing Software
3D Printer
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Getting 3D Objects
- Use pre-existing ones
- Create custom ones
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Computer-Aided Design (CAD)
Tools for constructing 3D objects
Either done visually or programmatically
Works by specifying geometric shapes with certain sizes and positions
- Shapes are combined into a single object
- Modifications (rounding, cuts, etc.) can be added at the end
Finished object is rendered and exported
Alternative: 3D scanning existing objects
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Parametric Design
- Define solutions (= objects) as explicitly as possible
- Be able to improve our solution by improving the problem statement
- Fix the measuring error, not the object dimensions
- It’s about re-using information dynamically
- "Variables"
- Example:
- Make sure the wall thickness of an object is consistent by using a parameter instead of typing out the thickness value each time
- Create an object that has the same properties as another one, but with different dimensions/measurements
- Prevents modeling errors and saves time
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Example 1: OpenSCAD
- Programmatic CAD Tool
- Free & Open Source
- Possibilities are nearly endless, as long as you can program it
- Works really well with parametric design principles
- Use and combine variables
- Define allowed values, customize easily
- Create multiple sets of parameters
- Supply parameters as launch arguments
- Easy to integrate with other tools
- You won’t get very far without helper libraries
- Takes too long to build complex shapes without them
- But: Extensibility is one of OpenSCAD’s strengths!
- Objects become (very) slow to render with increasing complexity
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Example 2: Fusion 360
- Graphical CAD Tool
- Paid and Cloud-Based
- Very powerful, very easy to use
- Even complex shapes are easy to design
- Renders very quickly
- Useful timeline of modeling steps
- Even allows rewinding to a previous step
- Much more maintainable for complex designs
- Additional CAD features (rendering, animating, manufacturing, simulating)
- Multiple parameter sets only possible through an add-on
- Saved to a separate file and inconvenient to switch
Shoutout to Marco! :D
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Slicing Software (Slicers)
- Ultimaker Curahttps://ultimaker.com/software/ultimaker-cura
- Easy to use
- Powerful, but convoluted
- Open Source
- Very straight-forward
- Powerful, better algorithms than Cura
- Open Source
Chituboxhttps://www.chitubox.com/- SLA-Slicer
- Not as many features (not necessary)
- Commercial
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Popular Printers (FFF only)
- Prusa MK3(S+)
- Easy to set up, easy to use
- Tried & Tested
Creality Ender 3- Cheap
- Prints well after some tweaks
- Ultimaker S5
- Made for low maintenance
- Dual Extruder
Voron 2.4- Open Source
- Moddable & very performant
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Printing!
- Ideally: insert USB drive, select file, start the print
- Make sure the printer is ready before beginning!
- Is the build plate empty?
- Use spatula (below printer) to remove any residue
- Is there enough filament installed?
- You can ask someone to change it for you, or try it yourself!
- Is the build plate empty?
- Careful: printer has a heated bed!
- Can reach up to 130°C, depending on material / print settings
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Printing Workflow
- Prepare the 3D Object
- Slice the object
- Print it!
Demo time! 🥳
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Use Cases
- Replace broken parts
- Create custom cases or front shields
- Test drafts before ordering machined parts
- Print trinkets and decorations
- /r/CookingWith3dPrinters
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Deployed Prints @ EEL
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Basic Parameters
FFF/FDA only
- Layer Height
- Controls surface quality, strength and print time
- "Resolution" of the print
- Wall/Top/Bottom Thickness
- Increases strength of hollow prints
- Infill Density
- Controls how much material is put inside of "hollow" prints
- Truly hollow prints can simply be squished together
- Different infill patterns for different applications
- Build Plate Adhesion (Brim/Skirt)
- Primes the nozzle (making sure filament starts to extrude right away)
- Brims and Rafts can help tall prints stick to the build plate
- If a print comes loose while printing failed print
- Support
- You can’t print in mid-air
- Support structures add extra material to brace ("support") layers above
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Common Problems
FFF/FDA only
- 3D printing mainly constrained by thermodynamics
- Governs print speed, print quality
- Introduces some peculiar effects
- Overhangs & Bridging
- Solution: cooling & support structures (slicer setting)
- Warping
- Filament contracts while cooling down
- Can deform the print or cause it to fail
- To counter: heated bed + enclosure
- Printing multiple objects at once
- For each additional object, the "layer time" increases
- Material has more time to cool in-between layers
- If a print fails Spaghetti 🍝
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Filaments
(Tough) PLAeasy to print versatile
ABSdurable needs an even temperature
Nylonhigh toughness resistant to wear
TPU (95A) / TPC / TPEflexible chemically resistant hard to print
CPEhigh chemical resistance
PPhigh fatigue resistance low friction coefficient
PCgood thermal resistance high strength
PVAwater-soluble messy to printSupport
Breakawaybrittle doesn't bond well with other materialsSupport
...and many more
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Advanced Troubleshooting
Failed prints not always as easy to diagnose as this:
(Axis came loose)
- Elephant's foot
Initial Layer Line Width
- Ugly Overhangs
Print Cooling, Tree Support and printing multiple objects at once
- Dual Extrusion Problems
Prime/Wipe Tower and Retraction - Underextrusion
Material Flow and Printing TemperatureAlso: check filament feeders for grinding!
- Scratches
Z-Hop or Combing Mode
- Ugly Seam
Z-Seam Alignment
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Conclusion
3D Printing isn’t hard!
It just gets harder the more you deviate from "normal" prints
You can print a ton of things & there are many applications
Different printers for different tasks
- Fast, durable, rough: FFF/FDM
- High-precision & batches of small prints: SLA
3D Printing can solve many problems you might have
- Especially good for custom solutions
- Just ask me if you need help!
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Thanks for your attention!
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