OT-Hard milling without coating.-help

[Lars Christensen]

Hi guy's

 

I made one of these

 

And is now standing with 3 blocks of D2 back from heat-treat. I need to mill a path .02 deep 1.2" wide and 4" long. I do not have any TIALN coated endmills, I have regular endmills 4 flute and 3 flute in the sizes 3/16-1/4-3/8-1/2. I have a VF3 Haas with 15.000 rpm.

 

Can one of you guy's be kind enough to give me a hint in the right direction??

I am thinking 15.000 rpm with a chip load around .0005 with a 1/4 4 flute endmill.??

Coolant/No collant?

 

I would verly apreciate any help.

 

Thanks

Lars

 

[ 04-16-2004, 05:32 PM: Message edited by: Lars ]

[Harryman]

Hi,I'm Tom from MN USA

Try 3/8 or 1/2 four flute 45 sfm .0005/tooth at full depth. Use air blast, all you got.

Put in a fresh end mill to finish the sides to size.

[Lars Christensen]

Hi Tom/Harry,

 

So what you are telling me is if I take a 1/2 4 flute endmill going 344 rpm at 0.68 inch per min. at .020 depth. I know you know more about milling than I do, but WOW that seems slow to me.

 

Thanks

Lars

[Harryman]

Harry back.

 

Tom is the new other old dude here. I invited him to take a shot at your question.

 

I'd give his numbers a try. But hard milling isn't my bag, that's why I gave Tom a shot.

 

Hardmill might chime in with a different answer.

[Lars Christensen]

Harry,

I wasent sure if your split personalit name was Tom. Mine has numbers Lars1 and Lars2. Friends and famely says Lars2 is

 

I will give it a shot unless hardmill or someone else gives something better( I dont know if there is anything better) I just know that at one point I got recomended running full rpm and steps of .001 with air blowing as crazy, but I was using TIALN coated endmills.

I am not to concernd with finish and size.

 

Say thanks to Tom from me.

 

Thanks

Lars

[Harryman]

Not a split personality.

 

Thought I'd introduce Tom to the forum.

 

Hope all goes well.

 

Signed: Non-Tom

[crazy^millman]

No what he said sounds like a good starting place. The no coolant was an excellent choice in this case the coolant to the carbide would have cuase to much thermal shock and just killed the endmill and the part. I also agree wit hthe use a new endmill to finish the sides and bottom. I have anothet little trick get a CBN grinding wheel and keep it in your box for just such occasions. You could have ground this in about 3 or 4 passes and been done. Again same thing with Hardmilling alot of air and slow feedrate olny difference is 15,000 rpms. I woould think about 5 to qo ipm would have worked perfect if you had the tool. Duragrind sells them give them a try.

 

 

Welcoem to the Forum Tom hope we see more of you and you are always welcome back any time. How are thing going over the Harry. I am off again this weekend and going to Vegas Wedensday to saturday got alot of Family flying in there so we are makign the drive to see them. Hope you are not working this weekend.

[Marty A]

Lars

 

if size and finish is'nt a concern

use the 1/2 carbide end mill and take

full cut of .02. run rpm around 1500/2000

for a start and feed around 25 ipm. it's

pretty easy cutting hardened steel once

you get used to it.hope this helps

 

marty

[Lars Christensen]

Hi guy's

 

Thanks for the response.

Tom your feed and speeds worked great, that thing just cut nice like it was butter.

 

So is it me who is confusing HSM with hardmilling, since I want full throtle and small steps with like 10 % step over, or is it because I did not have a TIALN coated cutter?

 

I apreciate all the help, there will be a colded one with your guys name on it, if you stop by the house.

 

Thanks

Lars