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Author Topic: Can I make spindle speed dependant on feed rate?  (Read 2587 times)

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Offline ASC

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Can I make spindle speed dependant on feed rate?
« on: August 25, 2010, 11:04:06 AM »
Hey guys, work is progressing on the dispensing machine and we're now at that crucial stage of tuning the living hell out of it!

I ended up using 2 seperate .xml files for the system, one to use the high speed spindle for milling, and a second to use the stepper driven dispenser as a spindle itself.

What I'm trying to do now is synchronize the speed of the dispenser to the feedrate or blended feedrate of the rest of the machine in order to get a constant flow rate.  I'm brainstorming a few ways to do this, any advice or criticism welcome, I just need some feedback!

1) Can I make my S-value in the spindle speed control set by a function of the blended feedrate?  For example, Blended Feed rate / 1000 = S value...  Is this possible with a VB script or a brain?

2) Can I use a constant S-value and override the spindle with a function of the blended feedrate, or is there any other way to scale the spindle speed in small increments on the fly?

Again, any thoughts and criticism welcome, just seeing what you guys think.  Cheers!



Mr. Creosote

Offline simpson36

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Re: Can I make spindle speed dependant on feed rate?
« Reply #1 on: August 28, 2010, 06:43:52 AM »
It may be more typical to have the feedrate follow the spindle speed.

Feedrate, although it is often expressed in IPM, should actually be calculated by feed per tooth of the cutting tool. G95 (I think) sets the system to consider the commanded 'feedrate' as being travel per revolution. If you use this, then you can vary the spindle speed and the feedrate will follow in order to maintain a constant travel per rev.  This is very convenient for small machines that typically experience chatter. Often a very small change in speed with reduce or eliminate chatter, so it is useful to be able to change the speed/feed  'on-the-fly'.

Offline ger21

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Re: Can I make spindle speed dependant on feed rate?
« Reply #2 on: August 28, 2010, 09:18:48 AM »
I seem to recall reading that G95 only worked in Turn? But I could be mistaken.
Gerry

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Offline simpson36

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Re: Can I make spindle speed dependant on feed rate?
« Reply #3 on: August 28, 2010, 12:38:25 PM »
It has been working for me in Mach mill for a long time. An example feedrate for me is F0.004