Radial land endmills on thin walled plastics

Hey all, first post here

The shop im working for right produces their own products and one of them is a plastic rectangle with a 1.5" x 3" pocket 1" deep and the outer walls of that pocket are .09" thick. They are requiring a 32 or better finish with no chatter. The materials vary from PEEK to Delrin. I've currently gotten it on the 'just barely acceptable' range of 32, with no chatter. But Ive had to come up with odd and time consuming toolpaths to do so. We are currently using run of the mill carbide endmills. I used to work at a shop that used 3 flute SGS endmills with .001" circular land (unrelieved for .001") for aluminum and i was able to get away with crazy deep full DOC wall finishes with it with no chatter. And i was thinking of trying it out on these parts. I was curious if anyone has used something similar and what the results were. Or if any plastics specialized machinists could lead me in the proper direction

Have you tried any of the single flute cutters? In certain situations it can leave pretty clean cuts. I use onsrud 63-700 or 65-000 series on pvc with good results.

Try some plastic specific end mills/routers. Harvey makes some with corner radiuses and Onsrud makes them but with no corner radiuses. Onsrud are about half the price but charge $30 for shipping if they come from Onsrud. These routers work MUCH better than aluminum ground mills on plastic, the only downside is they don't leave a very good finish on the floor of the pocket. If this is a concern then you may want to try Harvey, this isn't a concern for me so I only use Onsrud.

Thanks for the responses. Looks like i will have to look into Both harvey and Onsrud. Floor finish is important but that is dialed in already.

You could buy cobalt EM’s they are nice and sharp and if the part lends itself to it bury it in the vise and conventional cut your way around so that the wall is pushed away from the cutter as opposed to being pulled in

Back in the day I made end mills such as that for steel with back spinning circle grind the diameter to size then back off to .001 or so circle land primary..don't know of any doing so nowadays...actually didn't know anyone doing it back then except for me..Did the same sharpening carbide mill cutters for steel and cast iron.. Made cutting tools for aluminum up sharp with 320 or finer diamond wheel.