speeds and feeds

[rodzilla]

I have some questions about sppeds and feeds relating to depth of cut. In calculating S&F how does DOC come into play I have been playing around with S&F in Mach3 it asks for Material, Cutter type, Chips per tooth then you hit calculate and it comes up with a spindle rpm and IPM but it doesn't say anything about DOC. It also doesn't let you choose Cobalt as a choice for bits. My question is how do you determine the DOC with the IPM and RPM that they give you?

[PYROMANIAC]

I'm only new to this CNC thing. in my workshop we have the older machinest that beleive that deep slow cuts remove matterial faster. but we also have the younger machinest that think shallow fast cuts are quicker and improve tool life. so i was at a bit of a loss until i found this, feedsspredsheet.xls i hope it helps you

[Geof]

...... My question is how do you determine the DOC with the IPM and RPM that they give you?

Once you have the speed (RPM) and feed (IPM) based on your material and tool then you find out what depth of cut you have the power for. If you have a large commercial scale VMC you might be able to drive a cutter with a depth of cut equal to the cutter diameter. If you are restricted to 1 or 2 horsepower you may need to limit your depth of cut to only 10% of the cutter diameter. It also depends on the width of engagement of the cutter, are you cutting full width or only 20% of the cutter width. And do you have no coolant, mist coolant or flood coolant. All these come into play and you need to do some experimenting.

[rgengstrom]

I am new to this forum but am experienced int CNC steel cutting. I have found that DOC is mostly a factor of Tool Geometry. I have used carbide insert tools, touted as very strong hogging tools that would choke a 1" dia. cutter at a .100 DOC - however, at a .030 DOC, the sam cutter would efficiently cut 4150 steel at 30 in/min. I have found that cutting speeds and feeds are most effectively discovered by experiment. The charts available for speeds and feeds are only a good experimental starting point. Sorry that I couldn't offer a more concrete answer to your query, but the fact is: tool geometry greatly influences DOC. The available charts ARE reasonable estimates based upon cutter material vs. cut material.


rgengstrom,

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