Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: rcaffin on April 25, 2016, 03:40:03 AM
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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
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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
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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.
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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
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ok that's a bug I am using .62 as well
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Since I don't care about the surface speed thing, and I have turned that off, no worries.
Cheers
Roger
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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
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Night time here in Oz, and the machine is in the workshop.
Cheers
Roger
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same here I am only 4 hours away
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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
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I think something else is wrong with Rodgers copy of Mach
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How very odd.
My toolpath settings are the same, although the 'Use Radius for Feedrate' settings does no seem to matter for the display. (That figures.) But I can definitely confirm that the display only looks correct if I enter the diameter. I have played around with the X and Z DRO values to put the active point at one of the known positions, and it only matches the display when I use Diameter.
When I use the Radius the display is very obviously wrong. As I increase the value entered from 1/2 to 1 diameter, the display improves to a match. That change continues as I enter progressively larger values, greater than the actual diameter.
Could my version of Mach be faulty? Well, I dunno. It works very well on a semi-production basis the rest of the time, and the A axis works fine in practice. A bug in the code which just changes the way the radius/diameter is used for the display while not affecting anything else is a shade hard to credit.
Could it be an XML value or switch? That is always possible, given how fragile the XML seems to be. I will post a copy of my current XML shortly - it's out in the workshop and that machine does NOT have a network connection. It runs on sneaker-net.
Cheers
Roger
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XML file from machine attached.
There is stuff in there which boggles me slightly - references to folders and files on Art's machine for instance!
Go for it. If you can find a switch which handles this, I would love to know.
Cheers
Roger
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Correction - because the system has timed out so I can't edit a previous posting: the references to Art's machine were in the distributed version of the XML file. Those references have since been displaced by references to my files.
Mind you, the distributed XML also contains an entry for DXFDIR, which my active version does not. Interesting.
Cheers
Roger
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Had a bit of a poke around with your xml.
You had two motor outputs assigned to pin 7. I don't think that was affecting anything.
Loaded my test file. Would not display correctly until I zeroed all the axis DROs. It then displayed correctly.
I have never noticed that behaviour before but it did the same thing with my xml. Probably never noticed it as I would normally reference and zero DROs after startup and before loading file.
So try starting Mach, reference and/or zero all DROs and then load your file.
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Pin 7
Z axis Dir is Pin 7 on Port 1; C axis Dir is Pin 7 on Port 2. No conflict.
I use the C Dir as a universal sync signal when tuning the X, Y and Z servo drivers.
Referencing
I do zero the axes after startup. That is standard of course as the programming assumes a fully zero'ed system.
I have also tested with Ref Home and the same behaviour applies.
Um.
Cheers
Roger
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Z axis Dir is Pin 7 on Port 1; C axis Dir is Pin 7 on Port 2. No conflict.
I use the C Dir as a universal sync signal when tuning the X, Y and Z servo drivers.
OK my bad. :)
xml works here. Then that only leaves a corrupted installation or a poor version.
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Mach3 .062
Not, I suspect, a 'poor' version.
It works very well apart from the display funny. Hardly corrupted, UNLESS there is an unknown funny in the XML. I do not discount that possibility! But my XMl works OK on your machine - with RADIUS?
I wonder - what happens if you enter the Diameter instead?
Cheers
Roger
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Well up to you but I would do a fresh install.
Then I would do a fresh xml. Starting from scratch. Will only take a few minuets if you note all your settings.
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A fresh install. Well, that sometimes works, but right now the machine is functioning perfectly and the display accurately reflects what is being machined. The ROI would be kinda small, wouldn't it?
Cheers
Roger
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It is a fairly trivial matter. Would take me probably five minutes.
As I say the toolpath display comes out perfect here.
Up to you.
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I'll keep it in mind incase it hiccups worse. Right now it is running a 2 hr job, and there are more in the queue.
Cheers and thanks
Roger