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Author Topic: Constant Velocity problem with 4th axis  (Read 2687 times)

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Constant Velocity problem with 4th axis
« on: March 18, 2010, 08:08:36 PM »
Hi!!! When I use 3 axis everything goes good and not jerk movements and vibrations appear using "Constant Velocity" for angles > 170°. When I use rotary axis and Z axis working at the same time it goes bad, It seems to be working with "exact stop" setting. ¿What is the problem????? I tried to change 4th acceleration settings and nothing got better.

Regards
Tiwanacote
Re: Constant Velocity problem with 4th axis
« Reply #1 on: April 08, 2010, 03:44:10 PM »
Hi, Same problem as I have... Any idees ?

/R
Re: Constant Velocity problem with 4th axis
« Reply #2 on: April 13, 2010, 07:28:04 PM »
I pasted what Mach support answered me
Tiwanacote

----- Original Message -----
From: Maxi Bertotto
To: support@machsupport.com
Sent: Friday, March 19, 2010 9:28 PM
Subject: Question

Mach takes the 4th axis into account for CV mode ?

Thank you!!



Hello Maxi,
 
Yes, it should...  ;-)
 
Thanks,
 
scott
--
Scott Nichols
License Manager
www.machsupport.com

 
Re: Constant Velocity problem with 4th axis
« Reply #3 on: April 13, 2010, 09:55:28 PM »
I believe you may be seeing the effects of a long-standing bug in Mach3.  If you have two axes in-motion, and then transition to a 3-axis move, the acceleration setting of that third axis will be ignored, and it will be expected (more like required) to accelerate at the same rate as X/Y.  This can be easily demonstrated by setting your Z axis accleration to a very low value, as compared to X and Y, then doing a move that transitions to a helical move in X/Y/Z.  The Z axis will lose position at the entry to the 3-axis move.  This is a known problem, and will be fixed someday, but it's not high on the priority list.  This gave me fits when my mill was capable of 3-- IPM on X & Y, but only 50 IPM on Z.  At present, the only work-around is to run in Exact Stop mode.  It would not surprise me a bit if there were a related problem occurring when moving a rotary axis in concert with linear axes.

Regards,
Ray L.
Regards,
Ray L.
Re: Constant Velocity problem with 4th axis
« Reply #4 on: April 14, 2010, 03:32:19 PM »
Thank you for your info Ray!