Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Vmax on February 03, 2006, 01:25:09 PM

Title: Angular axis A
Post by: Vmax on February 03, 2006, 01:25:09 PM
When using an angular axis such as A and it being a rotary table shouldn't the A DRO count up to 360 and reset to 0 as it rotates thru 360 degrees. My setup just keeps on counting up or down. Have I missed something on setup?????? I have the axis set to angular.    Terry
Title: Re: Angular axis A
Post by: nicad on February 03, 2006, 02:22:26 PM
That sounds right.. mine also keeps going. Most of the time I want to know how many times I have revolved anyhow.. rolling from 359 -> 0 would loose that information.

now, the way Mach treats degrees as a unit does not seem right (feedrates, acceleration, etc..). but I can live with it for now (Grex.. muahaha!) :)
Title: Re: Angular axis A
Post by: Keith on February 03, 2006, 02:56:34 PM
You will see that circumstantially when you apply your A-axis that the continuation of the increment makes sense and is desirable.For instance if you are 'incrementally' doing a negative a-axis combined with a positive a-axis move,you will certainly be keeping track of where you are and where you've been within the 360 numbers.Otherwise,you'd be traversing some distance in some other axis rather than just rotating the axis in one place and as with the example of say milling a cone,you would calculate how many turns you need as you went in some axis to cut a proper end and cusp of the cone,prior to cutting and included this in your code which could be accomplished with three moves of three axis at once.This number would be greater than 360 and where the continuing display of your degrees past 360 is a desirable knowledge because it is what you would come up with in your calcualtion for the height and cusp versus rotational turns.-Keith
Title: Re: Angular axis A
Post by: Vmax on February 03, 2006, 04:15:35 PM
I see your point for doing cones or other lathe type work on a mill but in the real world there is only 360 deg in a circle and then you are back to 0. Keeping track of the number of turns is irrelavent to the need to know where you are in that circle at any given moment without have to keep track of total degrees rotated divided by 360. I do a lot of cam lobe work and I may make many rotations of a lobe in a machine process. Keeping track of total degrees is not feasible. I guess there is a need for both setups. Kinda like having absolute and incremental measurements, Knowing the absolute coordinate is vital but not very handy at times.  Terry
Title: Re: Angular axis A
Post by: Brian Barker on February 04, 2006, 05:05:26 AM
On the Fanuc mills you can change this in the parameters. But in the end it is that you see because the Mill KNOWS how many times it has turned.... The problem that most people have is that you are working in deg/min NOT inch/min! SO GREAT care must be taken when programing a 4th axis job. Inverse time is a bout the best because you just tell it how long of a time to make the cut (min / inch)

How is that clear as mud?
Title: Re: Angular axis A
Post by: Vmax on February 04, 2006, 10:16:31 AM
Brian are you refering to the divisions of an angle in Deg,min,sec. Yep that is the way it is suppose to be. I guess it is the "old school" way of doing it. It would be nice if Mach had the 360 deg option. I can deal with the .001 of a degree but the 10,000 degrees of rotation doesn't work for me.  (:~)= Terry
Title: Re: Angular axis A
Post by: Brian Barker on February 05, 2006, 07:14:09 AM
Nope :) The rate is in Deg per Min ... This is something that takes most some time to get there head around it.
Title: Re: Angular axis A
Post by: Vmax on February 05, 2006, 09:49:05 PM
OK the RATE.  gotcha yes the rate would be deg/min. Polar think Polar!!!  (:~)= Terry
Title: Re: Angular axis A
Post by: Vmax on February 06, 2006, 11:26:36 AM
ART, is there any way to make Mach only count 360deg per rev on a Polar axis and not totalize the count on multiple rotations???  Thanks Terry
Title: Re: Angular axis A
Post by: Keith on February 06, 2006, 12:31:16 PM
How about a liberal sprinkling of G92 A0 after a turn?-Keith
Title: Re: Angular axis A
Post by: Vmax on February 06, 2006, 12:52:00 PM
Keith , that is one way to do it. But I need to be able to see it on the DRO when doing a part setup. As it is now if I am in the 350 deg side and need to go to the 5 deg side, to maintain the DRO I have to rotate all the way back around to 5 when I could have easily rotated 15 deg and been there. It all goes back to having the computor work for me instead of me having to do it's job plus mine.  (:~)= Terry
Title: Re: Angular axis A
Post by: nicad on February 13, 2006, 04:39:07 PM
I would not trust G92.. I have had it ignored once too many times at random in code that works most of the time.

Acceleration rates are being calcualted based on a unit/sec^2 scale.. It causes problems when simultaneous angular and linear axis moves are made. Mach needs to calculate acceleration in STEPS/sec^2, like I other control software does. take units out of it...
The way it is now, you woud have to have ~115" diameter object in your A-axis (pi*115 = ~360) for "units" to be the same...

But alas, I will make another thread about this and see if I can get Art to change it.... after asking many time before.. :)
Title: Re: Angular axis A
Post by: Prepro on April 05, 2006, 09:05:22 PM
nicad

I've been trying to solve the addition of a 4th axis using mach2.  I'm having a problem trying to figure out what mach want's to see as g code.  I'm using mastercam, and need to fix up my post.
Title: Re: Angular axis A
Post by: Tarak on April 15, 2006, 09:32:26 PM
I also think it would be handy to have a rotary axis display up to 360.00 degrees then return to 0.00 degrees once you are on the second turn.
Title: Re: Angular axis A
Post by: Brian Barker on April 15, 2006, 09:33:35 PM
That is in Mach3 under state. :)
Title: Re: Angular axis A
Post by: Tarak on April 15, 2006, 10:50:55 PM
God I'm an idiot, I didn't even see that, Thanks Barker806