Thread: Just looking for a little advice on milling tool steel

I am going to be milling 2 4 in. X8in. Pockets in a 2in. Steel plate, not sure what type, but its off of a diecast mold.
I am thinking about cutting the outside of the pocket all the way down to bottom leaving some offfall instead of milling it all off, trying to save alot of time. Im not sure how fast i should go. Im using a .625 carbide endmill and was going to cut s650 f7. And take a .01 deep cuts. Any opinions or advice would be greatly appreciated i usually cut aluminum. Thanks

Do you have flood coolant and sufficient horsepower? On my gutless 5 hp spindle with flood coolant I go 3/16" deep at a pass 1500 rpm and F10.0, that is with a carbide 4 fluter.

Originally Posted by ben29

I am going to be milling 2 4 in. X8in. Pockets in a 2in. Steel plate, not sure what type, but its off of a diecast mold.
I am thinking about cutting the outside of the pocket all the way down to bottom leaving some offfall instead of milling it all off, trying to save alot of time. Im not sure how fast i should go. Im using a .625 carbide endmill and was going to cut s650 f7. And take a .01 deep cuts. Any opinions or advice would be greatly appreciated i usually cut aluminum. Thanks

Friendly advise, send it to a mold shop that knows what they are doing.

Hi Ben 29:
Many diecast molds in this corner of the world are made from H13 hardened to 45 Rockwell C or thereabouts.
That's still soft enough to drill with a 5% cobalt HSS drill.
Look up the settings for 17-4 PH stainless at condition H900 if you can't find ones for H13 at 45 RC; that'll get you pretty close.
You shouldn't have any problems unless your mill is pretty rattly.
To estimate the hardness without a proper hardness tester, hit an unimportant corner with a file; at 45 RC you can still file it without having to push all that hard to keep the file from skipping.
If you can't tell which corners are unimportant ones, follow toolmaker96's advice.
Cheers

Marcus
Implant Mechanix – Design & Innovation - home
Vancouver Wire EDM -- Wire EDM Machining

The toolroom is backed up, thats why im getting it im using a 4020 fadal vmc, not sure the horsepower though and a 3 flute carbide. Im sure i can get through it, but it is gonna take all day. thanks.

Originally Posted by ben29

The toolroom is backed up, thats why im getting it im using a 4020 fadal vmc, not sure the horsepower though and a 3 flute carbide. Im sure i can get through it, but it is gonna take all day. thanks.

Without knowing the exact material and it's hardness, you probably will be at it all day +1 more. Do a "file hardness" test and see if you're trying to cut hot-work die parts or just the softer die set. You'd cut one at twice or more the rate of the other.

That said, I think no matter what you'd spend far too much time and trouble trying to slot it out. If it's soft enough, chain drill much of it (carbide insert drill or solid carbide drill) to give the milling cutter relief and a place for chips to fall. Then you can really use a lot more of the end mill to get the job done within this decade. If no drill is available, consider high feed end mills.

Look for a AlTiN-coated end mill. At least you'll get some life out of it.

I saw "tool steel" so I gave feeds and speeds for a common 0-1 or A-2, before hardening. If what your cutting has been hardened, definitely disregard my advice. I thought you were making a mold, not cutting on one.

Originally Posted by ben29

I am going to be milling 2 4 in. X8in. Pockets in a 2in. Steel plate, not sure what type, but its off of a diecast mold.
I am thinking about cutting the outside of the pocket all the way down to bottom leaving some offfall instead of milling it all off, trying to save alot of time. Im not sure how fast i should go. Im using a .625 carbide endmill and was going to cut s650 f7. And take a .01 deep cuts. Any opinions or advice would be greatly appreciated i usually cut aluminum. Thanks

Assuming you are going to use a 5/8 2"Long 4 flute uncoated carbide end millThe parameters you are suggesting are OK.

Well, I finished in about 6 hours of cutting time ended up running at s1250 f13. taking .03 cuts, came out nice, thanks for advice.

Thanks for letting us know how it went.

Originally Posted by ben29

Well, I finished in about 6 hours of cutting time ended up running at s1250 f13. taking .03 cuts, came out nice, thanks for advice.

Why was your doc so small? Probally could have atleast doubled that?

Originally Posted by dstryr

Why was your doc so small? Probally could have atleast doubled that?

Yeah I should have. I was using the full width of cutter so I was worried about it loading up. I did another plate today I only had to
go .400 deep x .875wx5.in.long cuts down each side so I wrote a short program I took .100 deep x .05 in.side cuts till I got my .875 then
modified my tool height .100 each cycle. I used the same s1250 f13 ,cut pretty good.

Was the pocket on a Horiz or Vert mill. Deep pockets are best on a Horiz for chip evacuation. Makes a big difference. Otherwise a lot of high pressure coolant.

Originally Posted by Catfish kid

Was the pocket on a Horiz or Vert mill. Deep pockets are best on a Horiz for chip evacuation. Makes a big difference. Otherwise a lot of high pressure coolant.

Its a vertical, I had to blow out the chips every couple passes when I was about 1.0 in. deep