Messages

41

G-Code, CAD, and CAM discussions / Re: 4 th Axis problem

« on: March 21, 2014, 10:53:29 PM »

............... changed my ports and pins for the "C" axis to the "A"  and changed it in the general config but it wouldn't jog from the screen buttons.

  Does this mean  I will have to do a screen MOD which I haven't done before. Is there any way to switch it in the .XML file?

Are you using the standard screen for Mach3?

If so the jog buttons on the fly out screen (press tab), operate X Y Z and A. 

If this is not the case on yours, then someone must have edited it for the 4+ and 4- to jog C axis rather than A.

It is a trivial matter to change the behaviour of these buttons with a screen editor.  I recommend MachScreen.

On the other hand if you meant that the keyboard hot keys are what you are using, then these can be altered with menu "System Hotkeys"

Greolt

42

G-Code, CAD, and CAM discussions / Re: 4 th Axis problem

« on: March 17, 2014, 11:12:47 PM »

I am not sure whether or not the "rotary axis feedrate compensation" feature works on C axis.

I do know that only A axis rotations are able to be represented in the toolpath view.  Not B or C.

Suggest you try designating the rotary as A axis and see if that makes a difference.

43

General Mach Discussion / Re: 4th Axis on 3040 CNC

« on: February 24, 2014, 05:25:57 PM »

I can click the 'A+' Button and it will rotate Counterclockwise and when I click the 'A-' button it also rotates counterclockwise.

I assume that the X axis is disconnected and the A axis connected in its place.  Is this correct?

If so, then pressing the X+ button should move the A in one direction,  and X- button should move A in the other direction.  Does this happen?

Mach3 will not know that you have replaced X with A unless you tell it so by changing settings.  Are you changing "ports and pins" settings etc?  Or using another profile for rotary use which may be set up differently?

Greolt

44

G-Code, CAD, and CAM discussions / Re: 4 axis feedrate coordination

« on: January 25, 2014, 03:48:30 PM »

 Mach will ignore everything else and calculate the correct 4th axis federate for a move using G93 (provided you have the bandwidth - rotary axis pulse rates can get very high in a hurry).  

I have never used G93, my CAM does not support it.

However I assume Mach will still honour the maximum velocity as set in motor tuning. (normal rapid speed)  If so, then why will pulse rates go beyond normal levels ?

Greolt

45

G-Code, CAD, and CAM discussions / Re: 4 axis feedrate coordination

« on: January 22, 2014, 04:59:32 AM »

I intended to run your code on my machine to see long it took.

However a quick calculation of F800 at 25mm dia. works out at approx 3700 degrees/min of the rotary axis.  

My rotary max's out at 3000 degrees/min.  So it would not give a proper comparison of time taken.


I assume that finishing toolpath is done with a ballnose cutter.   Why not run "along axis" rather than "across axis" ?  Much less demanding of rotary axis feedrate.

Greolt

46

G-Code, CAD, and CAM discussions / Re: 4 axis feedrate coordination

« on: January 21, 2014, 05:05:36 PM »

I increased the velocity for A axis to 18000 which is the highest value i can enter at 35k kernel speed, and total time was 10:20 - not a big difference. Then i increased the acceleration to 4725 (maximum value) and now total time dropped to 7:14. I guess i would have to increase the kernel speed in order to set higher values for velocity and acceleration?

Are talking about actual cutting time or estimated?

Most CAM programs that I have seen have an time estimation feature but also have a scaling factor that needs to be set to get that estimation somewhere near actual.  Machine acceleration and other factors are unknowns.

47

G-Code, CAD, and CAM discussions / Re: 4 axis feedrate coordination

« on: January 21, 2014, 04:39:05 PM »

Here`s some sample code made using RhinoCam, feedrate is 800mm/min.
4 axis sample code.gc -  150 KB

You will need to upload your code directly to the forum.

That download site wants me to open an exe file disguised as your code file.  No way.

Greot

48

G-Code, CAD, and CAM discussions / Re: 4 axis feedrate coordination

« on: January 20, 2014, 01:44:07 AM »

There is a bug in Mach that turns the whole "rotary axis feedrate compensation" off, if the "Rotation Radius" DRO has a value of zero.

The work around for this is, when the correct value is zero (Z origin at centre of rotation) then enter a very small value. EG, 0.001

I am sure I remember Brian sending me a version where this bug was fixed, but it never seemed to make it into general release.


This may or may not be the issue you are having.  

Remember that the maximum velocity of the rotary axis, as set in motor tuning, is never exceeded even if the feedrate compensation system wants it to.

Post some example code and I will try it out here.

Greolt

49

General Mach Discussion / Re: Offset for Laser Pointer?

« on: December 30, 2013, 12:57:08 AM »

I don't want to mess much with the screen editor, because I don't know what I am doing.

I think that is the best way to learn.  Make a copy of the screen set and MESS WITH IT. 

You can't hurt anything.

Greolt

50

General Mach Discussion / Re: Offset for Laser Pointer?

« on: December 28, 2013, 03:46:21 PM »

Make an onscreen button and have it run code like this,

Code "G91 G0 X -32.5 Y -56.5" ' put the relevant offset amounts here
While IsMoving ()
Wend
Code "G90" 'set things back to absolute
Msg = "Zero X and Y DROs?" 'question for message box
Style = 4 + 32 + 0
Title = "Laser Zero"
Response = MsgBox(Msg, Style, Title)
If Response = 6 Then 'if reponse is yes then zero the DROs
SetOEMDRO (800,0)
SetOEMDRO (801,0)
End If

Change it to this if wanting to automatically zero X and Y,

Code "G91 G0 X -32.5 Y -56.5" ' put the relevant offset amounts here
While IsMoving ()
Wend
Code "G90" 'set things back to absolute
SetOEMDRO (800,0)
SetOEMDRO (801,0)