Week 5: 3D Scanning & Printing

Group Assignment (link): Test the design rules for your 3D printer(s)

Individual Assignment: 1) design, document, and 3D print an object that could not be made subtractively 2) 3D scan an object (and optionally print it)

Design & Print 3D object (which can't be made subtractively)

There were some examples in lab, including an articulated Maple Leaf - which I thought was really cool.

So I designed this beginning with a sketch and extruded the shape:

Then I split the shape in 2 parts and designed the "hinge" to join them:

Here's the final form with one hinge and a cross-sectional view to show how it works and why this design cannot be made subtractively

However, when I went to do a test-print, I saw that it will take several hours, which is not efficient when I really just wanted to test a part.

Redesign: So I went to create a smaller version of the same idea to test. It wasn't so hard to do:

Here's the new sketch and the cross-section:

Printing was successful in 30 minutes. It worked, just the hinge was a bit loose because I had used 1 mm margin on each side

Subsequently I went to reduce the margin to make the hinge tighter. Unfortunately when changing the parameters of the sketches it changed the extrusions

That resulted in a failed print, but then redid it carefully and successfully, resulting in a more secure hinge:

For all of the above prints I used a Creality printer with Cura software.

LEGO, Man

Actually the element I produced reminded me of a LEGO figure..

So I'm inspired to see if I can make a 3D-printed LEGO-ish figure with more moving parts..

I went to Thingiverse for inspiration and ideas, but unfortunately the designs there could be made subtractively also.

So I have to be creative for myself... I designed a figure-head and now have a Bambu printer available...

Here is the Bambu software interface, showing the slicing to see the interior of the print..

Bambu software shows the settings under "Prepare->Global" and also features a camera.

Week's Project:

My final project this week is a half-complete LEGO figure. Just without arms. In any case the objective of the week - namely to design something that cannot (easily) be made subtractively - is achieved. As can be seen in the images below, the design shows how to create moving parts that are also attached.

Learnings from Testing the 3D-Printers

Mainly I learned from my own 3D Printers. Some of the most important tests are bridging and overhang tests. These will determine if one needs to generate support strucutures when preparing the file for printing in the software.

3D Scanner

In the lab is an amazing (and expensive) 3D scanner from Artec. This particular model of scanner is called LEO, and is particularly suitable for larger objects, so our dog would be on the small side. Here is the scanner and the plush dog we will scan:

Shown in this picture is the setup, with the dog in the center of a plain cardboard table. Of course we'll want minimal other objects or items to distract the scanner from the object we'd like to capture.

Now we also need to scan from the side and bottom as well as on top, to get all angles.

Here we can see all area of the dog are showing green, that means it has been scanned.

Except the underside and bottom of the dog. So we turned the dog over to scan the backside, however some difficulties were there, both with the scanner itself to recognize the same object, as well as issue with the dog, namely that the ear fell into a different position when laying on its side.

So we ended up scanning again and just ignoring the bottom, and this is the result.

Processing 3D Scan

Now that we took the 3D scan, we can process the results using the Artec Studio software. There is a mode called autopilot which guides the new user through the process. Anyway, here is what the output looks like initially. It is actually in 2 parts, and has picked up some extra data as seen in black. Ideally we will have just one scan, but we can also work with this data as it is.

Initially we apply a "fast fusion" to generate the 3D model. The model is separate from the texture which is fitted on top of the model.

But if we look at the bottom side of the scan, we see that there are holes from missing data.

To fix this we can manually create bridges, and have some control over the shape of those bridges over the missing area.

Now we have a better model, and can export the mesh into a .stl format

And now if we want we can even 3D print our dear puppy 'Hexi'!

Design files:

Initial test of concept (Fusion)
Armless LEGO figure (Fusion)
Hexi Puppy 3D Scan in .stl