Milling cast urethane

[Sk8MFG]

By chance, has anyone had experience milling cast urethane?
We have a project coming up using Alumilite Performance D80 urethane. Unfortunately, we'll need to mill the part after we pour it.

I'm curious if I'm going to run into issues with cut quality, or goobering up the endmill due to the hint of flexibility the product has.

Any tips or notes would be appreciated.

[steve_g]

A shore D80 urethane is hard… hockey puck hard. I’ve routed hockey pucks as an enclosure for printed circuit boards without issue. I used a 1/8” O flute.
SG

[Brady Watson]

Polyurethane machines fine. Avoid using a big surfacing bit (like you use to flatten your spoilboard) on it at low speeds...keep it moving, or it will gum up. Aside from this, dust collection seems to provide enough airflow to keep things cool.

I've used all O-flute geometries (spiral up/down/straight - single, 2 and 3 flute variants) and 2-flute carbide end mills without an issue; 2D and 3D relief carving, with varying degrees of durometer and material mixes (polyurethane mixed with aggregate etc) - with no problems. Just watch your pass depths so that the chips can get out and the material can be 'grabby' if you are going in deep.

You can check out the tooling recommendations over at PlasticRouting.com (http://www.plasticrouting.com/srchresults.asp?page=Material&material=Polyurethane&company=A.L.+Hyde+Company&color=Off-White) for polyurethane specific tooling. This is a great resource for plastics. Red cast acrylic for example, has a different tool or feed recommendation than say clear or black. This is something that isn't apparent to most when they start cutting plastics.

-B

[Sk8MFG]

I'll be checking out the Plastic Routing site to see what they recommend.


Thanks guys!