Magdalena Milly Assignments Final Project

05 3D-Scanning and Printing

This week's assignment is to test the design rules for our 3D printers in the group assignment, design and 3D print an object, that could not be easily made subtractively and 3D scan an object.

Group assignment: Design rules for 3D printers

The documentation for our group assignment from the Barcelona node can be found here.

Lessons Learned

3D Scanning our dark sides

Together with @Emily Eickhoff and @Andrea Rubio we decided to test our lab's Revopoint POP 3 scanner and scan ourselves. We simply placed a chair in our lab, so we could more or less move around it and had an ok lighting situation and started off:

Get the scanner running

Start scanning

First we tried to simply move around the scanned person facing the front. While one of us was holding the scanner, another followed her holding the laptop, correcting the scanner's position in order to keep it in the “excellent” section.

3D scan process

On the first tries we used to scan in one level and attempt to do another turn to cover the top and chin/neck part. Which continued to result in Magdalena medusas several times, because we kept loosing the scanning around the top head part and an offset scan started.

scan medusa

We continued to tweak our workflow along the way:

The real game changer was to change the lighting conditions by rotating the stool itself and eventually we had a good result for all the three of us.

After each scan we checked the point clouds on the Revopoint software by finishing the scan. Initially these were very shady but once we found the RGB settings on the bottom we could quickly check the quality. We discarded the first few medusa scans but meshed and saved our final takes as .srl and s .ply files.

scan revopoint

@Daniel Mateos kept his eyes open, when we scanned him, which resulted in the reflection of his eyes being covered in the scan as well.

Lessons Learned

3D printing - Helle's cup

This week was my friend Helle's birthday - since I wanted to use our labs paste printer, I designed a little coffe cup for her. Initially I aimed for an espresso cup, but it turned out to be perfect for a cortado.

Design the cup in Rhino

My initial inspiration for the cup was a mandala, which should represent Helle's danish "trust-the-system" attitude. So the shape plays with convex and concarve shapes as well as alternating round and sharp corners, which could not be achieved by using traditional clay crafting.

design cup rhino

Initially I mixed up my measurements and the cup appeared to be only 4 mm high instead of 40. So my first adjustment was to scale the cup. I had simply used loft to create the shape and offsetthe surface to add thickness

Before starting the print in clay I wanted to test the shape in PLA and familiarize with our lab's printers. Thus I exported the selected surface to an .stl file in Rhino (default export options work fine!) before moving to Cura to slice the file. The file can be found here.

Design the plant pot

I wanted to try out the limits of paste printing in a second iteration and therefore designed a plant pot that had a diameter of 200 mm and a height of 150 mm to test the printer's limits. To test the possible shapes I followed the isocurve tutorial from Advanced 3D-printing with grasshopper, clay and fdm.

rhino clay

The shape is especially particular for clay printing because it could not be easily substractively - it would be extremely hard to form the calculated symmetrical concentric and concarve shapes with a different process than 3D-printing. I tested different roundings and distances to see, when the shape would collapse.

Print with PLA

Slice with Cura

cura add printer

First i had to install Cura and add the lab's printers - I used the Creality Ender-3 Pro, thus added a non-ulitmaker printer. Secondly I changed the nozzle size of the printer to 0.6 mm, which can be done in the machine settings area or in the prepare tab.

cura slicing

I received an instant model error in Cura, because I had not added a top/bottom thickness. Once I had changed this to 2 mm the model was fine. Since I wanted to simulate a clay print, I asked @Julia Leirado Silva, how I could print in a continuous flow. For this special mode Spiralize Outer Contour no extrusion is necessary, but the line width/nozzle size will determine the thickness of the piece.

Once this issue was fixed I had a final sliced model and could preview it's printing time (44 min) and progress. I saved the file to the mini SD card directly from Cura.

Print with the Creality Ender-3 Pro

I entered the SD card in the printer and got the printer ready for the print. First I preheated the PLA by navigating to Temperature/Preheat PLA on the machine's display and secondly heated the nozzle to 215°. Once the temperature was up I simply selected my file under Print and hit print.

3d print ender

After the machine's test my print started going very smoothly and 44 min later I had a little espresso mug in hand. I was really lucky because the bed was levelled and the nozzle did not get clogged, so I basically did not have to troubleshoot.

Lessons Learned

Print with Clay

Printing with clay is a different game on so many levels: it's all about the paste (consistency, material, flowrate,..), which is a fixed and very controlled parameter, when printing with PLA as well as the settings follow a trial and error principle.

Get the paste printer ready

paste printing

Some of our node wanted to print in clay, so @Adai Suri helped us with the preparatory steps and supported us adapting settings during the prints. Special thanks also to @Andrea Rubio for your expertise input and help.

paste process

Printing in clay is ideally a team effort, since there are many steps necessary:

Slice the file with Mamba/Grasshopper

To slice the file for the paste printer you can either use Cura or a Grasshopper Plugin called Mamba. Slicing with Mamba is the lab's recommendation for slicing, because the settings can be configured in a more controlled way. So I downloaded Mamba from food4rhino.com and copied the downloaded folder in Grasshopper/File/Special Folders/Components Folders. After restarting Rhino and Grasshopper the plug-in appears and I could work with the example file.

mamba

First step was to connect the geometry to the file and insert the printers settings: X(235), Y(235), Z(275). Once these are set a blue preview-frame in Rhino will appear. Initially my shape was not able to be sliced, because I had extruded the polysurface. First lesson learned that again you don't need material thickness, since it will be defined by the nozzle size and line height.

slicing

So I had to explode my geometry and delete the unnecessary surfaces. This resulted in some strange printing curves, because I had deleted too many of the tiny surface. After a little back and forth I eventually lofted the initial geometry again. It should be noted here that I had to close Rhino and Grasshopper for several times for the the plugin to recognize the changed geometry. The grasshopper file can be found here.

Print attempts

Our lab's paste printer is a Repetier printer, so I downloaded Repetier Host to be able to control the print. Once downloaded you need to connect the printer by USB and change a few settings under Printer/Printer Settings. Set the port, where the printer is connected and select the Baud Rate of 115200.

repetier host

Before I started to print we had cleaned the extruder to increase flow rate, thus the initial pressure of around 2 bar was too high and a lot of material was pushed. Secondly the clay in the afternoon session turned out to be a little bit more watery, thus the initial setting of the flow rate to 140% in Repetier was too high. Instead on the next session the clay had dried out and with 4 bar and a flowrate of 180 we could not get any paste flowing.

paste failure

I continued tweaking these two parameters on the second attempt and ended up with the following settings working for my final piece on the third attempt:

paste process

Right after the print I measured the print to see it's shrinkage. Initially it was 7 cm high and .. when fully dried.

final outcome

Testing the plant pot and the size and shape turned out to be thrilling. The dimension just fit the printer as well as the isocurve shape almost collapsed, but made it :)

Final Project Clay

Lessons Learned