This is an elliptical orange/white bowl 3D printed using Onshape and a Makerbox Replicator 2 Dual Extruder. I designed this as a project for the Engineering half of the STEM Skills class of the Governor's School for the Sciences and Engineering at UTK.
Step 1: Step One: Designing the Basic Shape
Using Onshape, we first create an ellipse sketch, then rotate it around the center axis by 180 degrees.
Step 2: Step 2: Detailing the Shape
Wanting a flat base, we create an offset plane about 1.21 inches from the face of the original shape, create a sketch on the offset plane, and use the extrude function to remove all material below that plane, leaving a flat base. Then, we use the shell function to hollow out the inside, leaving the thickness of the shell to be about .1 inches. Next, we use the Fillet tool to smooth out the edges at the mouth of the bowl.
Step 3: Step 3: Layering
In order to create the layered pattern, we first make a copy of our file, then set that to the side for the moment. Back to the original, we create an offset plane .4 mm below the original sketch plane, and create a sketch large enough to encompass the bowl. Additional offset planes will be placed at increments of .8 mm along with more similar sketches. Select all sketches, and use the Extrude function to remove .4 mm from each sketch, with the extrusion facing the base. Repeat the process on the copy, but change the extrusions to face the other direction in order to make room for the layers of the original copy. On the software connected to the printer, align these two files together and set one as orange and one as white. My two files are here: https://cad.onshape.com/documents/5760c613e4b0773e3ab626e5/w/5f06ff18fda9bd0c7ca95b69/e/58cf687a55f34c019dda45f8 and here: https://cad.onshape.com/documents/5760a928e4b053149a435c26/w/1033466e976dabf0b616af97/e/1d2cdf4fd11ffbc41361c5dd
Step 4: Step 4: Printing
The design may take 2-2.5 hours to print. Beware of any technical issues that arise during the printing process.
Step 5: Step 5: the End Product
There were some aesthetic issues such as strings, roughness, and the bottom supports, as were expected from the beginning. Supports were necessary to ensure the base was stable, roughness was attributed to the thin layers, and it the decision to take the suggestion to double the layer height from .4 mm to .8 mm is up to the individual creator. Overall, the bowl displays the layers nicely, and it is possible to cut, break, or sand some of the roughness off of the product.