Plunge Rate and percent feed per tooth

[GreggT]

Gents;

 

How do I calculate plunge rate? I've been told as a rule of thumbe to use 75% of Feedrate, but an not sure this is a good value?

 

Also what does the % of matl. feed per tooth field do for me? What is it a percentage of, since I don't seem to have a feed per tooth field?

 

TIA

[?Mark]

Plunge rate is taken from tool parameters page.

Feed-Plunge-Retract rates.

What are you trying to acomplish Gregg?

 

Regards, Mark

[GreggT]

How do you calculate plunge rate for a given tool? I am just wondering where you get an initial value for this field. I am at the Define Tool>Parameters tab filling things out.

 

The second part of my question is what exactly do the "% of matl.cutting speed/feed per tooth" fields actually control and where do they get there initial values and why would I use them vs. just changing the feedrate and rpm?

 

Thanks for the reply Mark.

[?Mark]

quote:

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How do you calculate plunge rate for a given tool? I am just wondering where you get an initial value for this field

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Initial value comes from Tool parameters tab.

 

Plunge rate will depend on mill used, material, cutting conditions and so on....

 

quote:

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"% of matl.cutting speed/feed per tooth"

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This comes from job setup, feed calculation: material or from tool.

Never used it, to many variables to have it set ahead of time...

Hope it hepls

Regards, Mark

[mcpgmr]

In the job setup. Pick a material and double click it. You will see where all this stuff gets used. I slowed the base SFM and feed per rev down by 25% and this is what I use as a starting point for new programs. I then saved that material to a new library so I could call it back up for the next program that has similar cutting conditions. Seems like the default values are too fast for HSS cutters. You can do the same with your tools from the library. I've got a seperate library for 2, 3 and 4 flutes. This way I don't have to mess around with them each time I start a new job. Hope this helps. Works for me.

[Storkman]

Plunge rate can vary depending on what your doing. If you use an entry/exit vector it will use your plunge rate as a feedrate. I usually create a entry entity, so I can use a plunge rate of 100 to 200 ipm. This gives my operator more control with his feedrate override when dry running. Some of our machines won't dry run in rapid. I'm going back a long ways, but in version 6.12 you could set a feedrate on entry/exit lines. I miss that.

[?Mark]

quote:

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in version 6.12 you could set a feedrate on entry/exit lines

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Ver.9. has override feed rate in lead in/out.

Is it what you have in mind?

 

Regards, Mark

[GreggT]

Thanks Mark, Paul, and Storkman.

 

Boy there are a lot of ways to control stuff in MC. Set-Comp-Override........ I think I'm going to need a class just on setting up tool and material libraries.

 

Thanks again

[Storkman]

quote:

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Ver.9. has override feed rate in lead in/out.

Is it what you have in mind?

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Sorry Mark, I misspoke. I meant the direction in surface toolpaths. Not the lead in/out.

[Fred @ Slate Industries]

most of the time when I am surfacing

I keep the Feedrate and the plunge rate the same.

The machine cuts smoother then if it had to

keep adjusting its feedrates all over the place.