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Rotation radius or diameter? for display
« on: April 25, 2016, 03:40:03 AM »
I am playing around milling out GT2 pulley teeth with a 1.2 mm ball end mill and a rotary table (A axis).
(Mach3 .062, ESS, W7, 1024.set)

Pass 1 digs out the main groove: fine.
Passes 2, 3 & 4 round off the sides of the groove with the side of the cutter, in little steps. For this to work the pulley has to be rotated and the cutter offset sideways a bit. The whole idea works OK (but needs values to 0.01 mm).

BUT
Getting a display which resembles what the job looks like has been difficult.
Obviously the A axis has to be enabled.
Note that the Z=0 point is on the surface of the object being machhined, not on the A axis CL. So the Rotation Radius for the A axis on the Settings page has to be non-zero - that works too.

But what value to put in the DRO? Radius, or Diameter?

Many years ago there was a so-called bug fix which changed the label on the DRO from 'Rotation Diameter' to 'Rotation Radius' in order to get the surface cutting speed working correctly. However I don't care about the surface speed. All I would like is a credible display.
But if I enter the radius the display is pretty awful, and does not look what I am doing (but the machining works).
If I enter the diameter the display looks accurate (wrt the real world) and the machining is fine.

Does anyone know whether the bug fix was only partial: surface speed was fixed but not the display component? That would explain my problem.

Cheers
Roger

Offline dude1

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Re: Rotation radius or diameter? for display
« Reply #1 on: April 25, 2016, 04:13:35 AM »
if you have you set the rotational Radius to the radius, top right of the settings page the led beside A axis on the main page should be yellow and in the toolpath window if you set the axis of rotation correctly it is under config. this should make it look all good.

if you have the wrong axis set it will look bad as well.

if not it might pay to ask art it work fine for me today set like above, like you did

Offline Greolt

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Re: Rotation radius or diameter? for display
« Reply #2 on: April 25, 2016, 05:49:14 AM »
But what value to put in the DRO? Radius, or Diameter?

Many years ago there was a so-called bug fix which changed the label on the DRO from 'Rotation Diameter' to 'Rotation Radius' in order to get the surface cutting speed working correctly. However I don't care about the surface speed.

Yeah it used to be all messed up.  You had to enter radius to get the display right and diameter to get the feedrate compensation correct. (might have been the other way around, I forget)  I'd call that a real bug.

Anyway a number of years ago we got it mostly fixed.

I still think "Rotation Radius" is a poor descriptor for the field, bit it is what it is.

Enter a value equal to the distance the Z axis origin is offset from the centre of rotation and if you have other settings correct then the display will be correct.
Re: Rotation radius or diameter? for display
« Reply #3 on: April 25, 2016, 05:59:29 AM »
Quote
Enter a value equal to the distance the Z axis origin is offset from the centre of rotation and if you have other settings correct then the display will be correct.
I know that's the theory.
On my machine (0.062) I have to enter the Diameter to get the display looking right. Radius does not look right.
And yes, the yellow LEDs light up.

Oh well
Cheers
Roger

Offline dude1

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Re: Rotation radius or diameter? for display
« Reply #4 on: April 25, 2016, 06:09:40 AM »
ok that's a bug I am using .62 as well
Re: Rotation radius or diameter? for display
« Reply #5 on: April 25, 2016, 06:27:28 AM »
Since I don't care about the surface speed thing, and I have turned that off, no worries.

Cheers
Roger

Offline dude1

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Re: Rotation radius or diameter? for display
« Reply #6 on: April 25, 2016, 07:06:34 AM »
I don't even know where that is, I just use radius for feed rate wack up you .XML I might be able to spot something I can compare it to the working one I have

here's mine
Re: Rotation radius or diameter? for display
« Reply #7 on: April 25, 2016, 07:22:08 AM »
Night time here in Oz, and the machine is in the workshop.
Cheers
Roger

Offline dude1

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Re: Rotation radius or diameter? for display
« Reply #8 on: April 25, 2016, 07:48:09 AM »
same here I am only 4 hours away

Offline Greolt

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Re: Rotation radius or diameter? for display
« Reply #9 on: April 25, 2016, 08:27:55 AM »
Using Version R3.043.062 here

Just ran up a test job.  100mm diameter.  Origin at the outer circumference (50mm offset)

Entered 50 in the "Rotation Radius" field.

Toolpath display comes out exactly right.

In the tooplath dialogue box my seting are as per pic