Does anyone here have experience in milling PEEK?
I wonder how doable that is on these very cheap desktop CNCs.

@gigabecquerel PEEK is a joy to machine. I did it on a Roland MDX-40A which was not cheap but is absolute dogshit when it comes to rigidity.

@owiecc Oh that's great to hear, thanks!

pinging @x44203 , maybe?

@gigabecquerel previous colleague has, from memory the biggest gotchas are that it can have massive residual stresses and heat build up can be an issue.

@PatrickHerd Oh that's good to know!
Looks like those can be tempered out, but only if one knows they're there in the first place ;-)

Thanks to my great impulse control I bought a small, very cheap desktop CNC (TwoTrees 3018S) and verified the g-code in POM. Tomorrow I'll cut down my rod of PEEK and run it through that. The end goal is a thermal isolator, but mechanically rigid holder for my HPGe at 77 k-ish. At least in POM it's pretty damn rigid, and I'm qute happy with it!

And yes, linear rails and a new spindle for the mill are already ordered and shipped 😉

@gigabecquerel hell yea, milling the night away :3

(And I think PEEK is mostly okay, as long as it's neither glass fibre filled, nor has high required tolerances)

@gigabecquerel Are you happy so far with that machine? How much did you spend on the extras you just ordered? Totally looking for a tiny home CNC (wood, plastics, FR4+copper, I guess).

@maehw I'm pretty happy with it!
For the price you really can't expect much, but then again the price is pretty low. It will definitely be enough for PCB milling, and as you can see it does POM just fine, as well :D

I spent a total of~150€ on extras like linear rails, an entire new Z axis and a new spindle. But these aren't here yet, and I'm enjoying the stock experience.

@la That's great to hear!
My peek is virgin, and the tolerances I need aren't critical at all. Out of curiosity, what's limiting the tolerance in your experience?
Assuming a rigid machine, ofc.

@gigabecquerel I think it's the parts warping. But I have never actually done it myself.

It machines really nice on the lathe, and I'm hoping that property transfers to the mill, too.

@gigabecquerel PEEK, which I know only as "that stuff I can't 3d print at home"

@jmorris Stuff I can't 3D print at home but would really love to use more

I happened upon this (one meter long!) rod for way too cheap, and now I have the perfect excuse to do something with it 😁

The mill audibly struggled more with the harder plastic and the surface isn't as pretty, but the part is definitely usable!

Can't wait for the linear rails so it doesn't chatter itself apart when cutting plastics.

@gigabecquerel
Oh very nice