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3D Printing and Scanning 101

3D SCANNING AND PRINTING 101


INTRO

- names, projects?

- 1st hour = 3D scanners:

1. Sense scanner:

- consumer grade, ~$400

- same technology as Xbox Kinect

- easy, low-res scans

- ~5 min scan

2. Next Engine scanner:

- ~$4000

- laser scanner

- sub-mm resolution

- ~1 hour scan

- 2nd hour = 3D printers

1. Plastic FDM Makerbot Clones

2.  Z650 Colorjet Powder printer



3D SCANNERS

1. Sense scanner:

- Plug in to computer; open software

- 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


2. NextEngine:

- software = “Scan Studio HD”

- in theory, can scan unlimited size (you’d need to move it)

- use turntable for small items

- distance from scanner depends on object; guide on bottom of turntable platform

- 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

    Step by step instructions: http://clas.uiowa.edu/ees/sites/clas.uiowa.edu.ees/files/Next-Engine-3D-Scanner-Instructions.pdf


3. Structure scanner: coming soon!  Ideal for interiors.


4. 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.


1. 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 i 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


2. (Powder Bed and Binding) Colorjet powder printer:

- Materials:

-gypsum-based powder

-infiltrate with cyanoacrylate (UV sensitive, yellows over time), paraffin wax, or epsom salt solution (whites only)

- parts of printer (show build bed, carriage, print head, glue cartridges, vacuum, depowder chamber)

- Bed fills with powder and the powder gets glued by the binder (water, glue and ink)

- 0.089 - 0.1 mm layer thickness or resolution

- Minimum 0.2 mm detail

- Software:

- ZPrint: open model, can scale,move, etc

- “ZEdit Pro” can fix model if necessary, add texture, etc

- File -> 3D print (see estimated volume) - make as hollow as possible to keep cost down

- print 1 batch per week

- Align in the X or Y axis for strongest orientation esp if the part is small and thin

- Part placement: smallest dimension on Z axis

- Create fixtures for overhanging parts (Edit > Make Fixture)

- View > Collision Detection  and Slice View (2D icon) before print

- Check build settings (File > 3D Print Setup)


RATES

1. FDM: member = $0.25/g (if you bring your own filament)

drop-in = $0.50/g (if you do it yourself)

full service = $0.75/g

2. Powder: member = $0.50/g

full service = $0.75/g


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