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Mach Discussion => General Mach Discussion => Topic started by: i_r_machinist on November 19, 2012, 01:31:19 PM

Title: 4 axis Job Display problem
Post by: i_r_machinist 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_
Title: Re: 4 axis Job Display problem
Post by: Hood 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
Title: Re: 4 axis Job Display problem
Post by: i_r_machinist 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_
Title: Re: 4 axis Job Display problem
Post by: BR549 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
Title: Re: 4 axis Job Display problem
Post by: i_r_machinist on November 20, 2012, 08:41:45 AM
Here is one of my files.
Thanks for the help!
i_r_
Title: Re: 4 axis Job Display problem
Post by: Greolt 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.
Title: Re: 4 axis Job Display problem
Post by: Vogavt 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.
Title: Re: 4 axis Job Display problem
Post by: Greolt 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.
Title: Re: 4 axis Job Display problem
Post by: i_r_machinist 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_
Title: Re: 4 axis Job Display problem
Post by: i_r_machinist 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_
Title: Re: 4 axis Job Display problem
Post by: i_r_machinist on November 24, 2012, 12:51:09 PM
Can't get mach3 loaded on this computer. Dell laptop with a windows 7 64 bit os. Says it can't find the enable40.dll. How do I make this happen? Or can I make this happen? I've searched the forum.
Thanks
i_r_
Title: Re: 4 axis Job Display problem
Post by: Greolt on November 24, 2012, 03:18:27 PM
Had another look to make doubly sure, the R is backwards.
Title: Re: 4 axis Job Display problem
Post by: BobsShop on November 24, 2012, 05:08:02 PM
Difficult to determine your problem without being there.  But I think you have at least two settings wrong.  I do some circular engraving on ring faces that I have cut.  Attached (apologize if the screen shots don't help) are three different versions of a ring with a skull, crossed- guns, and the script "Bad Company," I engraved.  The two critical settings are to Enable the A Axis (in ports and pins) and the correct diameter set in the "Settings" key.

The 1 Inch version shows the ring correctly.  The od of the ring was 2 inches.   The "A"  Rotation Diameter in the Settings screen was set to 1.00

The 2 inch version skews the ring slightly and makes the X Axis appear smaller.  No changes were made to the code, but the "A" Rotation diameter in the Settings screen was set to 2. 

The 5 inch version skews the ring completely with the X Axis shrinking greatly.  No changes were made to the code, but the "A" Rotation diameter in the Settings screen was set to 5.

The fourth pic was made without the A Axis (in Ports and Pins) being enabled.  A totally wasted version.

I maintain two profiles in the Mach3 Loader.  1 is set for 3 Axis only.  The other is set for 4 Axis.  This saves me the trouble of remember what I have to set each time I switch from one project to the other.
 
Title: Re: 4 axis Job Display problem
Post by: Greolt on November 24, 2012, 07:19:22 PM

The 1 Inch version shows the ring correctly.  The od of the ring was 2 inches.   The "A"  Rotation Diameter in the Settings screen was set to 1.00

If the DROs on the settings page are labelled "Rotation Diameter" then you are using an old Mach version.   

There was substantial problems with Feedrate Compensation and display of 4th axis toolpaths.  These were addressed three years ago. 

See this entry from the changelog;

Dec 23/2009
Release 3.042.033
-- Fix for - scale and IJK arc commands
-- Spindle speed register expanded for computers over 3GHz (they where reading - speed)
-- Rotational feed correction fixed for moves with Z axis !=0
-- Rotational Dia feed changed to Radius rather then Dia


If this is the case I recommend updating Mach.    The fixes will be good for your 4th axis work if nothing else.
Title: Re: 4 axis Job Display problem
Post by: BobsShop on November 24, 2012, 11:24:34 PM
Just pulled mach up.  Says this is version 3.043.066.  Checked Settings and it still shows Rotation Diameters

Bob
Title: Re: 4 axis Job Display problem
Post by: Hood on November 25, 2012, 03:13:18 AM
You may have a custom named screenset and thus the changes made to the standard Mach screenset are not used on the one you have loaded.
Hood
Title: Re: 4 axis Job Display problem
Post by: BobsShop on November 25, 2012, 05:20:56 PM
Thanks.  Did not realize that my screenset was not up-to-date.  Fortunately, the old screenset did not appear to affect anything I had cut before.  Have made the changes to both my office and shop Mach3.

Bob@BobsShop
Title: Re: 4 axis Job Display problem
Post by: i_r_machinist on November 27, 2012, 06:34:50 PM
If I download a new version of mach3, am I going to have to go back and set all the parameters back up?
thanks
i_r_
Title: Re: 4 axis Job Display problem
Post by: Hood on November 27, 2012, 07:03:02 PM
No you wont lose them, or shouldnt unless something goes wrong in the install. Your settings are stored in a file with the name of your profile and a xml file extension so make a copy of that and save it in a safe location. If anything should go wrong you just have to copy that file back. Likewise if your computer ever dies and you have a copy of that xml its just a case of placing it in the Mach folder on your new computer and all your settings will be transferred.
Hood