Ana Cabral

Week 5

3D Scanning and Printing

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The assignments

This week there was a group assignment and individual assignments. The group assignment was to test the design rules the printer(s) in or FabLab. The individual assignments were to design and 3D print an object (small, few cm) that could not be made subtractively and 3D scan an object.



Group assignment

We have 2 Ultimaker2 and a Dimension Elite 3d printer in the lab. I have made the group assignment together with Ola Mirecka.

We made a quick search and found a lot of tolerance tests in Thingiverse (link), so we didn’t find it necessary to design our own. We liked particularly this one.

We have downloaded the model, open it in CURA and save it as a .gcode in a SD card for the printer. Our initial idea was to have a really high resolution print, with 0.06mm as layer height, but we had to settle on 0.2mm layer height, due to how long it showed it was going to take. Even so, it took 5 hours with 0.02 layer height. We used PLA.

When the print was done, we verified that 0,2mm worked fine for most of the tests, but the slope and tapered part could have benefited from better resolution.

We ran the same model on the Dimension Elite, both horizontally and vertically, with ABS and solvable support material, layer height 0.177mm (which is actually the highest resolution possible for this printer). It took 20 hours to print.

When the print was done, we had to put it in a chemical bath, heated up to 60 degrees, to dissolve the support material.

When comparing the vertical and horizontal prints from the Dimension Elite, we verified that the printer is more accurate on xy plane than z, take a loot at the pictures below, where we focus on the tapered shape and slopes.

With the help of support material, it shows an incredible result when trying to achieve the infinite thin point on the tapered shape.

When comparing the prints from the Dimension Elite and the Ultimaker2, we verify that the the Dimension performs better in printing thin edges, but the quality of the print, in general, is not impressive. The advantages of working with the Dimension Elite are that:

But there are also a couple of disadvantages...

We have also made a clearance test on the Ultimaker2, using PLA and a layer height of 0.1mm. You can find the model on thingiverse, see here. For these settings, we verified a clearance of 0.1mm, which means when we are designing, we should make an offset in our female joints of 0.05mm, so they are slightly bigger and fit perfectly with the male joints. We get this value by looking at the squared joint… the circular joint printed with some irregularities, probably due to flow of material or retraction settings, see picture below.

In general, we found the tolerance tests time consuming… in the future, we might design our own tests, in order to keep them short, and have a more clear intention on what we are testing, according to the project we are about to design and print.



iSense: 3D Scanning

For 3D Scanning, we have an iSense in FabLab Spinderihallerne. The iSense works with 2 HD cameras (one of which is actually from the iPad it connects to) and an infrared projector. It’s fairly easy to easy. It can scan up to 3x3m objects, but it’s not suitable for objects smaller than 30x30cm.

I had a special guest to do the 3D scan, the Mayor of the city of Vejle. I was impressed how easy and fast it was. One thing I noticed, the scanner had troubles registering his glasses, so we did the scan without glasses.

Afterwards, I connected the iPad to my computer and used iTunes to access the file. I opened the file in CURA, (.obj file), scaled it to an acceptable size (in this case the print took less than 1 hour), saved the .gcode on a SD card and 3D printed it in bronze fill, on an Ultimaker2.

Besides, because the Mayor is retiring, I was asked to make something special for him, that could also show the potential of FabLabs…

So I have used Slicer 360, a plugin for fusion, similar to 123D Make former app. Basically, it slices a 3D model into a specific thickness defined by the user, and makes the files for machining. I have made it in 2mm carton. You can see the video of the whole process here.



3D Printing something that could not be made with a subtractive process…

3D printing and additive processes have the advantage of enabling “hidden” geometries, that are hard to machine unless one starts splitting the model and rotating the material.

I have designed a very simple shape, using fusion 360. It resembles a coral. Because of the internal void and thin wall, it makes it hard for a tool to subtract material, making it more appropriate for 3D printing.

After designing the shape, I have exported it for 3D printing, clicking on the command “make”.

I have 3d printed it in PLA, however, have tried to print other models in different materials, woodFILL and bronzeFILL. In the beginning it was a little frustrating, until I stumbled on really good tutorials, developed by Colorfabb, not only describing the settings, but also proving material profile files. I have downloaded them and import them in CURA. And afterwards, it has been extremely easy to print in different materials. Furthermore, one can inspect/take a closer look at those profiles, and learn from them.

link to woodFILL material profile

link to bronzeFILL material profile