UHMW Speeds & Feeds

First time using UHMW. Needless to say less than stellar results.
Either it's not very machine able or my feeds & speed & feeds are way off.
Using a 1/2" 2 flute carbide FEM.
Suggestions appreciated.

John

John,

Spindle at max RPM, LOTs of coolant, and haul a$$. I typically cut at anywhere between 50-100 IPM, depending on depth. For a clean cut, get straight-flute endmills, or just use carbide router bits. Also, leave enough for a generous finish cut (0.025-0.050") as you can't take off just a little very effectively. If going deep, do a final spring pass for best dimension.

Regards,
Ray L.

Ray

Appreciate the info. Will try again tomorrow.

John

I use the same endmills I use for aluminum, 3 flute carbide. Make sure your end mill is razor sharp, UHMW doesn't like a dull cutter. Like Ray said max RPM, I don't have flood coolant so I start 20-40 IMP and an air blast.

Gents

A quick update. Tried a new HSS coated cutter (very sharp), 50 IPM & flood coolant. HUGE difference.

Only remaining issues:

1. Finish on chamfer sucks. (6000 rpm, 50 IPM). See attached photo.
2. Defining chamfer in Bob Cad not terribly intuitive.

Thanks for the advice


John

John,

That surface finish is still pretty awful - should be MUCH better. You will do a lot better with a straight-flute tool.

Regards,
Ray L.

Ray

Will check it out

Thanks

John

I use Delrin in my products. I like it better tan nylon and UHMW. It cuts really well on the lathe.

Delrin is great for some things, but it's a very different material from UHMW, and UHMW is a fraction of the cost. UHMW is really great stuff for many applications. I use it both as part of the structure, and for bearing surfaces, in my PDBs and ATC. It's softer, but also "slicker" than Delrin, making for very smooth, quiet operation. Delrin certainly machines better, and you can achieve a better surface with tighter tolerance, but UHMW also machines well using the right tools. I use Delrin for the "lift" leadscrew on the ATC, where UHMW would be too soft (though the production parts will be Turcite, which is considerably lower friction than Delrin).

Regards,
Ray L.