3-D printing

For ham radio operators

... and stuff

Topics we could discuss

  • Types of 3-D printers
    • FDM (Fused Deposition Modeling) - most common
    • Resin-based (SLA, DLP, etc; UV-cured)
    • Laser-sintering
  • Comparison of different slicers
  • 3-D modeling
    • Artistic vs Engineering
    • Various types of software
      • OpenSCAD, Fusion360, OnShape, Autocad, Solidworks, Tinkercad, ........
  • Filament
    • Types, brands, temperatures, strength, colors, .....
  • Extruders and types
    • Direct drive vs Bowden
    • Bondtech, gearing, MK8/MK9/MK10/MK11/MK12
    • Thermistor types, heat cartridges, >300°C printing, ...
  • Controllers (RAMPS, RAMBo, Einsy, smoothieboard, .....)
  • Printing with supports
  • Multiple material / color printing
  • Safety
    • Fumes, fans, enclosures, .....

What can you do with a 3-D printer?

Some of the things I've printed

  • Anderson/Powerpole wall plates
  • Cell phone charger stands
  • Apple watch stands
  • Cases for circuit boards
  • Upgrades to my 3d printers
  • Filament spool holders
  • Antenna stacking stand
  • Stack-able quail egg tray
  • Antenna display tube
  • Mobile radio mounting bracket
  • Control head mounting bracket
  • Signal stick parts
  • Raspberry pi cases
  • Marble machine
  • Figurines for my kids
  • Christmas ornaments
  • Pinewood derby car parts
  • Crossfit Jump Rope
  • Leatherman case
  • Screwdriver handle
  • Toy ottoscope
  • Small christmas tree stand

Basic functionality

What is it actually doing?

Hotend

Extruder

Basic extruder types

Cartesian vs Delta

CoreXY is even more fun, but out of today's scope =]

Print bed

Heating and surfaces

Heater options

  • 12V or 24V
    • Lower voltage tends to mean lower power, so lower temperatures and/or slower heat time
  • PCB heated bed
    • Does not require a surface on top (that can be good or bad)
    • Tends to cost less and use less space
    • Some of these have embedded magnets to use with a spring steel sheet
  • Silicone heater pad
    • Requires a flat surface such as glass or aluminum on top

Bed platforms

  • PCB heated bed
    • Few parts, simple to use
    • Heater can sometimes be uneven
    • Have a tendency to warp
  • Glass bed
    • Needs a separate heater -- PCB or heater pad
    • Can use borosilicate glass or even just mirror glass
      • Note that not all glass is completely flat
    • Glass is an insulator, which can be good or bad
  • Aluminum sheet
    • Needs a separate heater -- PCB or heater pad
    • Acts as a "heat spreader" which prevents uneven heating
    • Can be expensive
    • Sometimes can warp

Bed surfaces

  • Bare glass
    • Most plastics won't stick, so people use painter's tape or hairspray on top of it to print with
  • PEI (Polyetherimide)
    • Most plastics stick when it's hot, release when it cools
    • Can be finicky, require care
    • My preferred surface, particularly powder-coated
    • PETG tends to stick *way* too hard
  • BuildTak, others
    • Most other surfaces are similar to BuildTak -- Monoprice printers come with a clone of it. I don't like it, but many find it easier to use because it sticks *really well* (too well for me)
  • Spring steel / magnetic
    • Magnetic sheet with a surface on it for easy removal

Filament

Types? Considerations?

Note that while some types of filament are actually "food safe" the nature of 3d printed objects means that it can be nearly impossible to sterilize them after first use.

ABS

  • Very strong
  • Reasonable heat tolerance
  • Smelly and toxic (never food safe)
  • Warps while it cools, requires heated bed
  • Generally cheap

PLA

  • Generally considered to be the easiest to print with
  • Warps in the dishwasher
    • There are higher temp versions
  • Generally cheap
  • PLA is the most commonly used material

PETG

  • Stronger than PLA
  • Higher heat tolerance than PLA
  • Can be food safe (depending on additives)
  • More heat tolerant than PLA
  • Has a tendency to string
  • Has a tendency to stick hard to the bed

PC (Polycarbonate)

  • Prints at a higher temperature
  • Requires a hot heated bed, hotter than ABS
  • Stronger than ABS
  • Very few colors available

"Special" filaments available

  • Filaments with abrasives require hardened nozzles
    • Glow in the dark, carbon-fiber-infused, etc
  • Water-soluble filaments for supports
  • HIPS filament dissolves in limonene
  • Color change
  • Wood or metal-infused
  • Conductive (none are any good)
  • Nylon
    • Very strong but also very hard to print (humidity)
  • Flexible filaments (TPU)
    • Nearly impossible to print with bowden-style printers
  • High temperature plastics (PEKK, PEEK, PEI, etc)
    • Require modifications to your printer and an enclosure to print

Software

Using your printer

Octoprint

  • Remotely watch your printer
  • Remotely control your printer
  • Remotely stop your printer
  • Automatic time lapse videos
  • Many plugins
  • Works with multiple material options
  • Runs great on a raspberry pi

3D model design

  • Fusion360 - windows, mac
    • Made by autodesk, free for small companies (< $100K revenue) and students
    • ~$500 / yr otherwise
  • Tinkercad - web-based
    • Surprisingly useful but very primitive
  • OpenSCAD - open source, windows/mac/linux
    • Code your models -- this is how I designed the signal stick glue caps
  • OnShape - Free and works on linux. I don't have any experience with this
  • Blender - Open source and free, all platforms. Better for artistic renderings

Slicers

  • Slic3r - Open source, more technical options
  • Cura - Open source, better interface
  • PrusaSlicer - Based on slic3r, adds a lot of features which Slic3r lacks and improves the interface
    • This is the one that I use for all printers these days
  • Simplify3D - $150, has a lot of customization features missing from the others. I used to recommend this one, but PrusaSlicer has added most of the things that were missing and just seems to do a better job for me these days

A slicer takes the 3-D model (usually a STL file) and converts it to the instructions (usually GCODE) which tell the printer how to print it.

Supports

Popular 3-D Printers

(the ones I've used)

Prusa i3 MK3S

https://www.prusa3d.com

  • "Gold Standard" for open source FDM printers
  • Most other FDM printers are modified "clones" of the i3 line
  • Relatively easy to use (as 3-D printers go)
  • If you build it from the kit (strongly recommended) then you know how to fix it
  • Build volume 210x210x250
  • *lots* of modifications which can be made easily
  • Open source including software

MP Mini Delta

https://tinyurl.com/buympmini

  • Cheap ($160 but have seen refurb for $80)
  • Delta style, not Cartesian - no moving bed
  • Heated bed only goes to 60°C, best for printing PLA (doesn't print many filament types without mods)
  • Decent starter printer
  • Custom / closed source controller and firmware, hard to modify electronics
  • Build volume 110mm (round) by 120mm tall

Monoprice Maker Select Plus

https://tinyurl.com/mpselectplus

  • Cheap-ish ($329)
  • 24V, so heated bed is hot enough to print ABS, etc
  • Works okay, but just less reliable and not as good quality as the Prusa
  • Custom RAMPS clone controller; closed source. Open source firmware available
  • No auto bed leveling built in (can be added but requires modifications)
  • Build volume 200x200x180

Ender 3

(just google it)

  • Cheap (< $200)
  • One of the cheapest options for its size
  • Generally needs some upgrades before it does everything you'd want
  • Uses a "bowden" style feed instead of direct drive
  • Build volume: 220 x 220 x 250

CR-10s

(just google it)

  • Cheap for its size (< $500)
  • Only runs 12V, so bed heats up slowly
  • Cheap hotend, may need to be upgraded to print some plastics
  • Uses a "bowden" style feed instead of direct drive
  • Large Build volume: 300 x 300 x 400
  • Cheap electronics
  • Large beds are a pain to level, harder to print on
  • Bed is held on by binder clips

3-D printing

By Richard Bateman

3-D printing

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