Speed and Feed for Uhmw Green

• #1

I have to mill some white slippery UHMW. 4 flute HSS, brand new. 7/8" diameter and 3/8. Pocket and profile. HURCO bed mill.

What sort of sfm and chip load do you use when cutting this stuff. The calculator I'm using gave me a 1042 sfm with a .023 chipload on the 7/8 mill. This is not the most rigid setup and I want to be sure before I engage the big green button. I don't have time to get more material in.

Thanks

Todd

• #2

Hi T.Jost,
Keep speed low and feed high with lots of coolant rpm 600 and feed of 8" per min, 1 cut

• #3

Hi T.Jost,
Keep speed low and feed high with lots of coolant rpm 600 and feed of 8" per min, 1 cut

X2 Plus use a downcut EM which will reduce the deburr alarmingly.

Oh yea -I know the OP said new, but if the cutter's been used for any metal all bets are off

• #4

we work with alot of UHMW and found out that on a conventional mill using air vs coolant is more effective and you can keep a good speed since you cool the piece/tool with air and you push the chip out faster so i dosent have time to melt down to the piece behind your tool. might give it a try too could save you some cycle time.

• #5

Absolutely new end mills. Pulled them from the box.

I cut it dry with air blast for chip evacuation.

Part just finished up. Profiles look great but the bottom of the pocket is less than perfect. Thankfully I get to press in an aluminum part that will cover all sins.

Thanks for the replies.

• #6

sfm? feedrate?,no science needed here ....three flute high helix...let her rip..set the volume to 11..this and delrin are the few materials you just run as fast as she'll go it untill ya break something,and ya probably wont, then back down a little.....its like butter man....kinda like running balsa wood through a table saw

• #7

I machine LOTS of UHMW. I filled (2) 20 yard dumpsters with chips last year.

For Planing, I use a 6" diameter Valenite shellmill (8) tooth @3700 rpm. 32"/min .1"DOC

For profiling, I use either a 2 flute o-flute router bit or a 4 flute standard endmill (SHARP!!!) 6-8Krpm depending on which VMC 90-120"/min. .5" DOC

I also make (2) 5" Deep x .55" wide slots in the parts I make. For that I use an accupro 1 flute 12mm dia. 6krpm, helical profiling @40"/min .125" DOC/pass

I don't use or need any coolant, or air blast but, on the deep slots I drill a through hole and then connect my shop vac to pull the chips down while milling the slot.

Hope that helps

• #8

Wow those feeds seem like for aluminum.
I mean guys before you were talking about going as fast as possible.

Is this stuff brittle or something? I thought it should machine as regular poliethilen.

For that i used to slot with 3/8" 2 flute carbide endmills .75 DOC and go like 6000RPM and 60ipm
Also no science just figured out on that machine it worked best

• #9

I like sharp colbat 2 to 3 flute cutters......using balls to the wall speeds and feed, dry or air blast, double stuck to a sacrificial sub plate of transparent aluminum...acrylic!

• #10

My speeds n feeds could be faster if I wasn't using a vacuum to hold the material in place.

I profile the part to finished size and do all the operations I can in 1 set-up, Flip it and use 2 dowel pins on the vac plate to locate the part for side 2.

• #11

what is UHMW? isnt there a letter missing at the end?
Ultra High Molecular Weight what? or I am full of chit as usual?
thanks in advance
Gw

• #13

what is UHMW? isnt there a letter missing at the end?
Ultra High Molecular Weight what? or I am full of chit as usual?
thanks in advance
Gw

Polyethylene.
I don't know why it's left out of the acronym.

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Source: https://www.practicalmachinist.com/vb/cnc-machining/leads-feeds-uhmw-247324/

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