Corian is the brand name for a solid surface material created by DuPont. Its primary use is as a countertop surface, though it has many other applications. Coming in a variety of patterns and colors, it is a material that machines really smoothly and can be to be heat formed.
Part of the experiment was to gain insight on how the material reacts to being machined. Considering that it comes in large flat sheets at only half an inch, I wanted to test how much material could be removed and how thin of a part could be milled without the whole sheet warping or breaking.
Step 1: Adaptive Roughing
Adaptive roughing is great for removing large quantities of material as an initial step towards getting to the final geometry. To improve efficiency, a large-diameter bullnose end mill is used and in this case it was a half inch tool.
This first path was not able to reach parts of the design around the edge of the geometry without crashing into stock, so a secondary roughing path was added, this time using a quarter inch end mill.
The secondary path is only added to prevent the smaller tool, the finishing end mill in the proceeding path, from running into stock. To save time and to prevent the tool from roughing the entirety of the pattern, another boundary was sketched to limit the bit to a custom offset boundary around the edge of the geometry.
Step 2: Parallel Finishing
There are multiple finishing options depending on the desired outcome and the shape of your geometry. The larger the round nose End Mill and the smaller the step over, the smoother your finished part will be. Playing with these parameters is also a negotiation with machine time. A 5/8 ball nose end mill was used with an approximate 25% tool diameter step over.
The final finishing path was set to use a 1/8 inch End Mill to machine into the small pockets and crevices of the part. Unfortunately, this path only worked around the edges of the geometry close to where the material was held down by unprocessed stock. As the 1/8 tool machined details near the center of the geometry, the Corian was pulled up as the tool retracted and parts broke off from the pattern.
After consulting with an experienced Autodesk Machinist who suggested an alternative set up, we came to the conclusion that the only method for creating intricate patterns using this final finishing path is to mill the entire geometry in sections. For example if the geometry was divided into vertical strips, each strip would be roughed and finished before moving on to the next strip. This would create a sturdy work holding system around the machining area to run the final finishing path without flexing or breakage.
Step 3: Voila!
After doing the left side of the panel I simply mirrored the operations (minus the 1/8 finishing path) and the sketched boundaries to the other side and reselected the geometry. Corian, as it turns out is a material that just crumbles into ashes as it is being machined, not a single chip stayed intact. Definitely wear a dust mask when cleaning up and make sure the ventilation is on when Machining.