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4 axis Job Display problem
« on: November 19, 2012, 01:31:19 PM »
Friday I was doing some engraving on a 4 axis mill, with the rotary head oriented along the x axis.Been doing this for a couple of years now. No problem. I noticed that the Job Display was actually showing the engraving in the right orientation, ie around the part. This was the first time it had done this! Usually it just shows some jumbled lines in x and y. I loaded another program Saturday and it went back to the jumbled lines. How do I turn this feature on so that I see the toolpath rotated around the part?
thanks
i_r_

Offline Hood

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Re: 4 axis Job Display problem
« Reply #1 on: November 19, 2012, 01:52:04 PM »
Only thing I can think of is on Toolpath  from Config menu, there is an option to enable A rotations.
Hood
Re: 4 axis Job Display problem
« Reply #2 on: November 19, 2012, 07:35:30 PM »
That isn't it.It seems to show the "A" axis moves as a going around the part, but the "x" axis is compressed to about .1". Like I said, I've been engraving on this machine for a couple of years and it always looked the same. Then for one session it looked perfect. I've hunted for G code change but it all matches. Could it be something in my graphics card?
thanks
i_r_

Offline BR549

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Re: 4 axis Job Display problem
« Reply #3 on: November 19, 2012, 08:20:57 PM »
HOW about the radius setting for the 4th ?

Post an example file and I can test for a solution.

Just a thought, (;-) TP
Re: 4 axis Job Display problem
« Reply #4 on: November 20, 2012, 08:41:45 AM »
Here is one of my files.
Thanks for the help!
i_r_

Offline Greolt

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Re: 4 axis Job Display problem
« Reply #5 on: November 21, 2012, 05:00:08 AM »
Hard to know what you are expecting but here is a screen shot of it loaded into Mach.  With the settings as shown in pic.

2D screen shots are always hard to post a meaningful picture of.  You really need to be able to twiddle the 3D view to get a idead of what you are looking at.

Looks to me that you have the Z axis origin at the centre of rotation.  If this is correct then "Rotation Radius" setting should be zero.  (should be called origin offset)

Another thing is the "R" is backwards.  Most likely explanation is that you have the rotary axis not turning in the conventional direction.  Otherwise Mach would display it correctly.  (Mach follows conventional axis direction)


EDIT:  Upon re-reading your original post, my guess is that you have an incorrect value in "Rotation Radius" and that is why you are seeing a compressed toolpath view.
« Last Edit: November 21, 2012, 05:04:46 AM by Greolt »

Offline Vogavt

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Re: 4 axis Job Display problem
« Reply #6 on: November 21, 2012, 08:37:53 AM »
Another thing is the "R" is backwards.  Most likely explanation is that you have the rotary axis not turning in the conventional direction.  Otherwise Mach would display it correctly.  (Mach follows conventional axis direction)

I can confirm the "R" is backwards on my machine as well.

Offline Greolt

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Re: 4 axis Job Display problem
« Reply #7 on: November 21, 2012, 06:49:01 PM »
There are basically three things that must be done to get a rotary axis toolpath to display correctly in the toolpath view.

1.  Designate the rotary axis as "A"   No matter if technically the rotary is B or C,  it must be called A.  Mach will only display A axis correctly.

2.  Set the axis of rotation in "Toolpath Configuration"  and check  "A Rotations Enable"

3.  Have the correct value in  "Rotation Radius" on the settings page.

If you are, for example engraving, on the outer diameter of a  4" cylinder and the Z axis origin is on that outer circumference, then the correct value would be 2.  Z axis origin is offset 2"

If you are doing the same but the Z axis origin is at the centre of rotation, then the correct value would be zero.  The value is whatever the Z axis origin is offset from centre of rotation.


In your previous jobs, which never displayed correctly, I guess you had the Z axis origin at the outer diameter but neglected to enter the offset value. This would compress the displayed toolpath.

On this one occasion that the display looked correct, most likely you set the Z axis origin at centre of rotation.
Re: 4 axis Job Display problem
« Reply #8 on: November 24, 2012, 11:39:51 AM »
Sorry for the late reply, I've been out of town for the holidays. I'll print off the replies and go play on the machine today. Center of rotation has always been z axis origin. Rotational axis is .745". Changed it from zero to get the machine to feed properly on x axis moves, per another post.
thanks
i_r_
Re: 4 axis Job Display problem
« Reply #9 on: November 24, 2012, 12:06:49 PM »
The R isn't backwards. Your displays are correct. You are looking at the back side of the R, thru the cylinder. It must be in my computer graphics because I have the same settings as Greolt has. Mine is not producing the x axis moves on the display. I'll load Mach on this computer and see what happens.
thanks
i_r_