Tasks Work on final project Sth not subtractable Group Assignment 3D Scanning

W5 - 3D scanning and printing

Computer controlled cutting

Tasks

  • Group assignment:
    • ✔ Test the design rules for your 3D printer(s)
  • Individual assignment:
    • In Process: Design and 3D print an object (small, few cm3, limited by printer time) that could not be made substantively
    • X 3D scan an object (and optionally print it)

Design sth subtractable

Left: Fusion See through view to inside; Right: hero shot

This piece is not subtractable bc it is impossible to get these holes into the cube at the same location every time. It is also not possible to keep them there fixed because there is no connection to the outside.

You'll find the download files in the cloud to keep this page in minimal size.

3D design puzzRob pieces

For more information and pictures please visit the final project page.

sketchCornerV4
Sketch on paper corners V4

Download link files:

These could also be made substantively but are necessary for the final project.

Design ideas:

  • Easy electronics mounting by adding pieces step-by-step
  • Designed around the RFID module
  • Make them as small as possible from above to fit more of them on a table/ floor
  • If changes in size are required, only half a set of corners has to be printed. Thus, saving recourses and time as well as reducing the environmental impact.

Product description:

  • There are 2 types of corners: Inner (longer side towards the middle) and Outer (longer side away from the robot).
  • Each corner consists of 3 linearly independent fingers.
  • One finger is longer. It is meant as the height and goes parallel to the longer side of the RFID module.

Assembly of robot:

  1. Print 4 corners of each type (Inner and Outer). Get the other required components.
  2. Start screwing the lower half of the robot. An Inner goes next to an Outer and so on.
  3. Program,attach, and electronics to the base. More detailed information tba.
  4. Finish attaching the upper half of the puzzRob including the button. Above each Outer goes another Outer. Same for the Inner.
  5. Charge if necessary.
  6. All set, enjoy :)

Group Assignment

Link to group assignment in lab

Theory:

  • To print sth. the 3D-file needs to be in either a .stl or .step format
  • Infills: Measure (in %) of how much filament is used inside the print. There are different structures, for example: honeycombs (very stable), cubic (fast-print, stressful).
  • Placement and orientation determines the angles that can support higher or lower stress. Turn accordingly.
  • Brin: Extend first layer. Adds stability. Use when adhesion problems or slim first layer.
  • Draft: Brim but all over the shadow ground area of object.
  • Layer height: height that the tip of the printer nozzle goes up after finishing on each layer. High layer height makes it faster but the result is less fine. 0.2mm is standard.
  • Standard filament: PLA, PETG, TPU (if it has to bend, requires special settings).
  • Once the slicing is completed, a gcode will be created. Copy it onto a USB, insert in printer, make sure the right filament is inserted, go!
  • The print might stick to heat bed. usually heat bed is attached magnetically. Therefore, it can be removed, bent carefully and the piece should snap off.

Test results:

Using 0.4mm nozzle, 0.2mm layer height, structural preset, Official Prusa recommended programs otherwise.

Files:

Hero Shots:

Top left: What color symbolizes which filament on which printer. Top right: overhang test (none are really good). Bottom left: testing the tightness of the tolerances. Bottom right: test to determine minimum thickness.
More exact measurements from group assignment website.

Findings:

The test were done with the Prusa XL and MK4. Results from these test highly fluctuate when tested on other printers.

  • The differences are about 0.2mm.
  • The bigger the object, the bigger the differences. Prusa XL PETG was off
  • Steep printing without support: 30deg recommended, up to 50deg precise, 60deg with tolerances.
  • Bridges without support: 25mm (maximum test length) works splendidly.
  • Surface finish looks goo on every angle.
  • Min. limit on wall thickness: 0.34mm to 0.37 depending on printer and filament.
  • Try to avoid 90deg overhang in any length.
  • Tolerance: Min. 0.3mm if it should move. 0.2mm for semi strong connections. 0.1mm if the connection should be tight.

Comparison slicing software:

I wanted to know which software (and printer family) is the best from the ones I have access to: Orca (Flashforge), Prusa (Prusa), or Cura (Ultimaker)

ultiCornerSTLs orcaCornersStl prusaCornersSTL
In terms of speed,. Prusa is by far fastest. Afterwards is Orca and lastly Cura.

I tested with the same model and same parameters (as much as I could). Cura refused to print in the formation shown in the other 2 examples. It was also the only one that could not deal with the closeness of the parts. Orca also threw a warning but allowed exporting the gcode nonetheless.

3D Scanning

Tba. The plan is to:

  1. Scan my Squirtle Can. Compare the result with the .stl file from Thingyverse
  2. Repair the lab googles. Someone came into the lab and asked us to do it so why not.

brokenLabGlasses
Broken lab glasses