Dynamic mill, Inconell 718, speed, feed ,doc

[slyym]

Hopefuly you guys can help me out. I'm cutting a slot 30" long by 2.5" wide by 1" deep in 718 inconel using the dynamic mill toolpath. I'm currently using a Garr 5 flute 45 deg helix xceed coated carbide endmill running at 80 sfm, 7.5 ipm with a .15 step over. It cuts really well but end up having to use 2 endmills to get through 1 slot. I would like to get 1 slot per endmill if possible. Am I close to the right cutting parameters? Do you guys have any other recomendations concerning stepover, feed etc. Thank you.

[robh]

what dia.E.M.?

[slyym]

1"

[Rstewart]

I would definately be attacking this with a 1/2" or 5/8" E.M. I would go with 125 sfm and a .002 cpt with .08 stepover

 

Gotta love those Garr tools, but your wasting too much money by using a 1" tool!

[Leigh @ Kodiak]

I will second the idea of using a 1/2" endmill. I would only go with .04" stepover, 1400 RPM and 30 IPM

[robh]

pretty expensive slot..I'd go with the 1/2 or 5/8 too,reduced stepover..what's your DOC?full?good advice above.

[3R!< W3NG3R]

The smaller tool would also give more clearance in the slot. I rarely buy anything over 1/2" now. The price jump after that is brutal.

[slyym]

I didnt even think about using a smaller endmill. That does make alot of sence though. Right now running 80sfm 7.5 ipm with .15 stepover I get about 20" done and the endmill comes out in good enough shape to be able to be reground. If I take a smaller stepover with faster feed and speed would I get better tool life or would that be reduced?

[Tony35]

quote:

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If I take a smaller stepover with faster feed and speed would I get better tool life or would that be reduced

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plus you can apply chip thinning and get the feedrate faster yet

 

the trick is to get the heat into the chip and use a good coated tool

 

you cutting dry with air blast or coolant?

[Leigh @ Kodiak]

FYI, the feeds and speeds I suggested already had compensation for chip-thinning applied.

[Tony35]

leigh

it looked like you did i just wasnt sure

[slyym]

Can you guys please explane what chip thinning is. Yes I am using coolant, should I be using air blast instead? Thanks for all the help guys.

[Leigh @ Kodiak]

chip thinning explained

 

The article is about axial chip thinning, but the concepts are the same for radial chip thinning.

 

[ 10-31-2009, 09:56 AM: Message edited by: Leigh @ Williams and White Machine ]

[slyym]

Are there any chip thinning calculators?

[Leigh @ Kodiak]

I have one I can send, but Gmail is not co operating today

 

I'm pretty sure Colin has the same one, maybe he will send it your way.