Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: dreamstar156 on April 04, 2010, 04:56:15 PM

Title: how to "set" rapid feedrate G0 in MACH3
Post by: dreamstar156 on April 04, 2010, 04:56:15 PM
Hello,
I have made a homemade 3-axis CNC mill and have been testing with Mach3 with good results.
I am wondering if the rapid feedrate can be set or adjusted in any way in Mach3?
The reason I am asking is because since I calibrated my axiis with the axis calibration function within Mach3, my feedrate went WAY WAY down to an unacceptable level. If I bring the feedrate back up with "motor tuning" then my calibration is WAY off... meaning if I ask the X axis to travel 1", it will do 7". So at this point, it's either I have my axis well calibrated but deal with an impossibly slow rapid or I have good rapid with axiis that are WAY off... Any thoughts?
Thank you in advance
Title: Re: how to "set" rapid feedrate G0 in MACH3
Post by: RICH on April 04, 2010, 05:09:18 PM
You need to tune all the motors ie; set the velocity and acceleration in motor tuning so it's correct for YOUR system. Then when you calibrate the axes all should be fine. You have what you have. The max travel / ipm on a rapid depends on a number of  things.

RICH
Title: Re: how to "set" rapid feedrate G0 in MACH3
Post by: dreamstar156 on April 04, 2010, 06:18:55 PM
Thank you Rich,
So you are saying once you tune your axiis with "motor tuning" and then again with axiis calibration, the rapid is set and you are not able to adjust it after that?
Title: Re: how to "set" rapid feedrate G0 in MACH3
Post by: RICH on April 04, 2010, 06:46:39 PM
Are you using steppers?
You can go in and change the motor tuning anytime you want.
The steps per unit should be calculated and that is what you use, but, you can also use the calibration feature in Mill to do it.
I would think that if the steppers were skipping that you would keep getting different movements and not be able to resolve the movements with the calibration feature. That would be a sign to you that the velocity / accel are not appropriate.
RICH
Title: Re: how to "set" rapid feedrate G0 in MACH3
Post by: dreamstar156 on April 04, 2010, 06:53:47 PM
Yes I am using steppers and they do not seem to skip when properly tuned...
you are talking about motor tuning and axis calibration.... aren't they the same? If i use axis calibration and tune the motor this way, I can no longer tune them manually otherwise I will mess up the calibration , right?
Title: Re: how to "set" rapid feedrate G0 in MACH3
Post by: RICH on April 04, 2010, 06:58:35 PM
Axis calibration is confirming your steps per unit are correct and nothing more. It is using the velocity and accel values you entered in motor tuning.
If the steps per unit are correct there is no need to ever change them. You can refine your velocity and accel  after that.
  RICH
Title: Re: how to "set" rapid feedrate G0 in MACH3
Post by: elpablito on April 04, 2010, 08:39:12 PM
Maybe you can override motor speeds setting this parameters in a macro. Never tested it.

"VelocitiesX" = X MaxVel from motor tuning page (SetParam as units/second. Mach will multiply X60 for display in motor tuning as units/minute.)
"VelocitiesY"= Y MaxVel from motor tuning page (SetParam as units/second. Mach will multiply X60 for display in motor tuning as units/minute.)
"VelocitiesZ" = Z MaxVel from motor tuning page (SetParam as units/second. Mach will multiply X60 for display in motor tuning as units/minute.)
Title: Re: how to "set" rapid feedrate G0 in MACH3
Post by: dreamstar156 on April 04, 2010, 11:35:59 PM
Thank you Rich