Education‎ > ‎

3D Printing and Scanning 101

Background

Where do models come from?

Parametric models vs Mesh models

3D SCANNERS

Structure Sensor scanner

  • Plug into Ipad, open “Scanner” App

  • Use settings “Old tracker, “ Low res Color”, “New Mapper” “Low Res Mesh”

  • To scan, keep object in target, revolve around them very slowly, going up and down slowly to capture all internal points

  • Notice: scan has lots of holes

  • Best scanning conditions: bright lights, white backdrop

  • Emits infrared, camera reads infrared, doesnt work outside on a sunny day

  • Post-processing steps:

    • Get rid of excess geometry/background objects

    • You now have a sheet (infinitely thin) - need to solidify

    • Water-tight mesh encapsulates it and makes it solid


NextEngine

  • Software = “Scan Studio HD”

  • Can scan unlimited size (you would need to move it)

  • Use turntable for small items

  • Distance from scanner depends on object; guide on bottom of turntable platform

  • If item has no identifying features put dots or stickers on.

  • Scans take up to 1 hour

  • Settings: quick scan -> snapshot -> 500 = very low; blocky scan; 1000 = higher res

  • Scans affected by ambient vibrations; keep to a minimum

  • How it works:

    • Laser lines pass over surface, camera picks up shape/depth of lasers on face

    • 1 scan results in 1 non-solid, infinitely thin surface

  • More scans = more surfaces

  • “Align”tab - takes multi surface scans and knits them together

  • Use reference points if doing 2 or more scans (ie: overlapping markers on each scan)

  • To solidify model: scan studio (needs several surfaces to solidify

  • For several scans, select the scanner to complete several “brackets”; at least 4-5 to

  • ensure overlapping sections


Watch walkthrough before using to refresh memory.

https://www.youtube.com/watch?v=4UgESNZQ5sA



Other Methods

  • Photogrammetry - gives very high quality scans.  Need good cameras and lighting, as well as a powerful computer to knit back together.

  • Photogrammetry apps


FILE TYPES

  1. .stl = “stereolithography”; gives thin slices that can be printed in layers; only geometry, no colour.  Ideal for Makerbot printers.

  2. .ply = produced by many 3D scanners; may be read by ZPrint (colorjet powder printer), but can be unreliable (

  3. .obj = similar to .stl but have colour (texture) files as well, to give a colour print.  Use with ZPrint

  4. .wrl = produced by NextEngine, works well in ZPrint


3D PRINTERS

Most 3D printers are considered ‘additive’ manufacturing. Layer by layer.



FDM (Fused Deposition Modelling) Plastic Printers

  • Materials:

    • ABS (acrylonitrile butadiene styrene) - Same plastic as Lego; warps/shrinks easily, therefore need to heat build plate or print in hotter area. It has more resilience and flex than PLA. Do not inhale fumes! 210-240 degree for printing. Good for if you wanna drop it, or use in a rough manner.

    • PLA (polylactic acid) - harder than ABS, lower melting point, compostable; doesn’t need heated plate. More friction so can jam easier. 180-200 degree. More brittle than ABS so might break.

    • How to change filament (printer interface: utilities -> change filament)

    • We use 1.75 mm filament, can use up to 3mm


  • Gantry-style printers = on runners, has x,y & z axes

  • Double extruders

  • Very sensitive to temperature and humidity (crack/warp filament)

  • Heated bed ensures ABS doesn’t contract too fast

  • Software: Makerbot desktop (free download)

  • Open model, go through icons/options on side and top of window

  • Set up a sample print





Resources

https://www.thingiverse.com/

http://www.meshmixer.com/

http://designscroggin.com

https://www.youtube.com/watch?v=4UgESNZQ5sA

https://www.sculpteo.com/blog/2017/05/15/fdm-vs-sla-vs-sls-vs-clip-battle-of-the-3d-technologies/

Comments