Milling preheatreated 4340

[dan m]

Hi All,

I am milling a square 1.530 X 1.500 deep with 3/32 rad in the corners. And the parts already have a 1.500 hole in them. I usually just deal with the lahte dept but have been given the chance to do this. I feel my cycle time is way to long (apprex. 20 min) and my tool life is not good. we have x6 mill level 2. I am looking for tooling and tool path suggestions. I have tryed many different things and this part shouldn't be that big of a deal in my mind.

 

Thanks in advance

Dan

[Jeremy Herron@DBS Solutions™]

What kind of machine? 3 axis? Max spindle speed? How hard is it?

[dan m]

It's a Hurco vm1 with 7500 rpm. The material is 30 rockwell

[Goldorak]

drill the 4 corners before

rough with a 3/8 endmill using dynamic

finish with an 1/4 endmill

clean the corners with the 3/16

 

you should be able to finish them under 10 min

[dan m]

Goldorak,

I am new to the milling world but been living in the lathe world since 1987. do you have any recomendations on tooling, depth of cut, feeds and speeds?

[Goldorak]

it's hard to tell,

 

what kind of tooling do you use ?

[dan m]

They will let me order what i need for the job. we are making these in lots of 200

[Goldorak]

They will let me order what i need for the job. we are making these in lots of 200

 

 

so get some high quality variable helix end mill

 

you should be able to run them around 450SFM .002 to .005 IPT, in dynamic using a 8-10% step over , you can boost the feed up to .008 to .0010 IPT full length of the flutes (around 3/4 for a 3/8 endmill)

[Jeremy Herron@DBS Solutions™]

Do you have through spindle coolant and or air blast?

 

 

[dan m]

no we just have regular coolant

[Jeremy Herron@DBS Solutions™]

Mitsubishi, guhring, or osg make a carbide drill you can use without through coolant on the drill. +1 to Goldorak's speeds and feeds. I like hanita endmills for this kind of stuff, but any quality endmill would probably. Dynamic contour to rough should do you pretty well.

 

HTH.

[mkd]

"and my tool life is not good"

 

so being a lathe guy, i would presume you are running flood coolant? HT steel, carbide endmilling and flood coolant do not generally get along well due to thermal shock.

air blast would be the only way @450 sfm

[Jeremy Herron@DBS Solutions™]

Loc-line sells a kit with a mag base you can plumb air into and use you external air pump. Works pretty good in a pinch and is a cheap fix.

[dan m]

Thanks for all the replys. I will let you know how it works out

[dan m]

the dynamic toolpaths worked great. thanks for all the advice.

[Goldorak]

the dynamic toolpaths worked great. thanks for all the advice.