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Author Topic: ramping speed on turns  (Read 2860 times)

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ramping speed on turns
« on: August 30, 2013, 08:57:40 AM »
Hi.  I am not sure what has changed, but when I rand Mach3 over the years it always slowed down for radius turns.  It is now overshooting the turns.   Slowing down the feed rate helps some, but it is still an issue and slowing down the machine on straight shots make the job take longer.   I have a custom built CNC router and it seems to have started being an issue after I did maintenance and lined everything up, but I could have sworn the machine used to slow down for turns before.  I could not find settings to this.   Should I be dealing with the motor tuning and change the acceleration and deceleration? or is there a specific knob for radius % speed? 

Thanks,
Charlie

Offline Hood

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Re: ramping speed on turns
« Reply #1 on: August 30, 2013, 10:23:55 AM »
Axis speed is controlled via your feeds in your G Code so if it slowed previously your code must have had slower feeds for the rads.
Hood
Re: ramping speed on turns
« Reply #2 on: August 30, 2013, 11:28:24 AM »
Ok. That makes sense.  I got tired of fighting with LazyCam (you get what you pay for...) and started using SheetCAM, which is much easier and does not have nearly as many issues with the imports etc. I will have to chase that setting down for feed rate for a radius.

Thanks,
Charlie
Re: ramping speed on turns
« Reply #3 on: August 30, 2013, 12:27:19 PM »
There is no seperate feedrate for a radius in SheetCAM. There is one feedrate for each operation, and that feedrate is applied regardless of the type of move.  You should easily see this if you look at the G-code.  If you are over-shooting on turns, it sounds much more like you have a VERY low acceleration setting for one or more axes in Mach3 motor tuning, and it can't change direction fast enough to make the turn where it should be.

Regards,
Ray L.
Regards,
Ray L.

Offline BR549

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Re: ramping speed on turns
« Reply #4 on: August 30, 2013, 09:41:05 PM »
Ray the latest version allows you to set the corner speed based on parameters of the corner.

Just a thought   (;-) TP
Re: ramping speed on turns
« Reply #5 on: August 30, 2013, 09:43:12 PM »
Ray the latest version allows you to set the corner speed based on parameters of the corner.

Just a thought   (;-) TP

Terry,

Where?  I don't see anything like that....
Regards,
Ray L.

Offline BR549

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Re: ramping speed on turns
« Reply #6 on: August 30, 2013, 09:59:35 PM »
Ray you have always been able to set corner speeds in arcs based on the POST variables.

The new Path Rules are even MORE flexable as you can look at any spot in the contour and ajust things based on rules.

(;-) TP