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max feed rate?
« on: December 12, 2006, 06:28:34 PM »
well Ive just put my kit together for my cnc mill and ive got my first software question.
ive set the steps per inch to 20,000 just like the directions for my servo's sais. but when I do. I can only turn the max velocity up to 75 ipm. when I should be able to do about 120. I thought it was a problem with the kernel speed but I turned it up to 45000 Hz and still can only turn the velocity up to 75ipm.
any thoughts?

Hood

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Re: max feed rate?
« Reply #1 on: December 12, 2006, 07:30:59 PM »
Hve you confirmed it is actually doing 45Khz, should be on the diagnostics screen, but as I dont use a standard screenset it might have changed.
Also without knowing your ballscrew pitch and if you have reduction I cant say what max you should expect to get.
Hood

Offline Chip

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Re: max feed rate?
« Reply #2 on: December 12, 2006, 07:34:38 PM »
Hi, guynamedbathgate

Have you increased / Adjusted the Velocity and Acceleration settings under, Config., Motor Tuning, with 20000 steps you probably need to.

Hope this Helps, Chip

Offline ger21

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Re: max feed rate?
« Reply #3 on: December 12, 2006, 08:36:04 PM »
You have to restart Mach3 after changing the kernel speed for it to take effect. You also need a licensed copy for the higher kernel speeds.
Gerry

2010 Screenset
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JointCAM Dovetail and Box Joint software
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Re: max feed rate?
« Reply #4 on: December 13, 2006, 06:19:07 PM »
yeah I figured out that i need to restart the program after changing the speed. but now my axis are going nuts with interfearence from the higher kernel speed. is there a way to reduce this. because Id hate to have to run my machine at a slower speed.
my motor wires are all in close proximity to the cntroller and my computor. should they be further apart or what.
thanks

Hood

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Re: max feed rate?
« Reply #5 on: December 13, 2006, 06:31:43 PM »
My wiring all runs pretty close to each other but all my signal and motor wires are shielded and the power wires have ferrites.
Hood
Re: max feed rate?
« Reply #6 on: December 13, 2006, 06:36:52 PM »
shielded how and what are ferites

Hood

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Re: max feed rate?
« Reply #7 on: December 13, 2006, 06:43:52 PM »
Shielded wires have either a braid or a foil that surrounds the actual wires, one end of the braid is connected to ground in the control cabinet. Ferrites are these ring like things that wires are sometimes looped through, you may have seen them inside your computer case, the front  LED and Switch wires often have one.
Hood

Hood

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Re: max feed rate?
« Reply #8 on: December 13, 2006, 06:47:03 PM »
If you look at the pic below you will see the ferrites on the power wires to my Geckos (yellow things, can be any colour though) Also you will see the braid on my motor wires through the clear top layer.
Hood

Edit
Actually I dont have them on the power wires  :-[ its the motor wires I have the ferrites on.

« Last Edit: December 13, 2006, 06:52:51 PM by Hood »
Re: max feed rate?
« Reply #9 on: December 13, 2006, 07:27:13 PM »
hmmm. it apears that my encoder wires have the foil shielding. so i should ground them to the enclosure? what about at the encoder end. do i do anything there? my motor wires themselves do not apear to have any shielding. will ferites help if i put them on even without shielding or should I pursue some other solution.
thanks