A sign shop has contacted me wanting to know if I can cut some shapes out of Coroplast for them. They will apply vinyl graphics to them, and want to do a trial run of about 50. If they are successful with the idea, then they would need many more.
I have searched the ShopBot forums on this subject, and what I've found is not encouraging. The most recent posts are from about a year ago, and it would seem that the best bits would be either a Belin O-flute, or an Onsrud double spiral O-flute. Brady Watson mentioned a triple spiral, but did not mention the manufacturer. I could not find any information about how long any of these bits would last before the cut degraded to the point of being unacceptable.
I tried a few a test cuts in some material they gave me, using bits that I had on hand. The best cut I got was with a new 1/4" Centurion down cut spiral at 120 in/min and 18,000 RPM. I have included a photo of the cut. The cut is clean on the top and bottom skins, but the feathering of the interior ribs is the problem, as has been noted in previous posts.
I was wondering if anyone has any new information or suggestions. Alternatively, is there another material that would be easier to work with and comparable in price? These are going to be used outside, so they need to be waterproof.