Topics

1

G-Code, CAD, and CAM discussions / G52 Rapid Positioning Problem

« on: May 24, 2008, 04:51:56 PM »

Hello,  I've got a problem that maybe someone can shed some light on.  Sometimes after issuing a G52 offset for X and Y, if I don't immediately issue a X or Y command, the next rapid position acts as if it were in Incrimental and not Absolute positioning mode.  I'm in Absolute.

If you plug the following code into Mach3 then you'll see that it rapid positions way to the right, and then back before entering the subroutine the first time.  However, if you remove the line in the subroutine "G00 Z.125 % Remove this line" then it acts fine.  I always like to have that safe z positioning in there, just in case I forgot somewhere else.  This has been a problem for a while, if anyone knows a fix for it then please let me know.  Perhaps I need to change some settings.

Thanks,
   Stewart

G90
G52 x0 y0

% Contour Outside
F10
G00 X6.75 Y-.020
G00 Z-.125
G01 X7 Y0
G03 X7.5 Y.5 R.5
G01 Y4
G03 X7 Y4.5 R.5
G01 X6.75 Y4.520
G00 Z.125

%Countersink holes

G52 X7 Y.75
M98 P100

G52 X7 Y1.75
M98 P100

G52 X7 Y2.75
M98 P100

G52 X7 Y3.75
M98 P100

G52 X0 Y0

M02  % end program


O100 % SUBROUTINE bore hole .630 diameter, .375" deep
  G00 Z.125 % Remove this line
  G00 X0 Y0
  G00 Z-.125
  F3 G01 Z-.25
  F6
  G02 X.057 Y0 R.0285
  G02 X.057 Y0 I0 J0
  G02 X0 Y0 R.0285
  F3 G01 Z-.375
  F6
  G02 X.065 Y0 R.0325
  G02 X.065 Y0 I0 J0
  G02 X0 Y0 R.0325
  G00 Z.125
M99

M0

2

General Mach Discussion / gcode to mill half ball with cnc mill

« on: December 09, 2007, 03:52:30 PM »

Hello,  I'd like to make half a ball on my mill, and am trying to figure out the best way.  I don't have any good cam software.

I'd like to just create an arc on the XZ plane and then rotate the coordinates of the XY plane incrimentally by a degree for every cut.  that way I coud just copy the same few lines of code over and over and that would work.  Unfortunately Mach3 wont use  the rotated coordinates in any plane but the XY so that doesn't work.

Any ideas?  Are there any "wizards" out there that do this?  I know a lathe would be ideal for this, but I don't have one with CNC or a large enough ball turner.  Before I've mounted a rotary table on my lathe bed to hold my bit, but I'd like to avoid doing that again and there should be a way to make the cnc mill work anyway.

Thanks!
   Stewart

3

General Mach Discussion / G19 and G68 at same time

« on: April 10, 2007, 11:28:55 PM »

Hello, i've got a circle and need to carve out some notches, but I'd like to feather the edges with vertical arcs in the YZ azis (selecting G19).  To make the Gcode easy, i've created one set of commands and just copy them using a different coordinate rotation (G68) for each cut.

Unfortunately, it seems that Axis rotation can only occur when in the G17 (XY plane) mode.  Does anyone know of a workaround that might do the same thing?  Will concurrent G19 and G68 be available in a future release?

Thanks,
   Stewart

4

General Mach Discussion / backlash compensation going haywire

« on: April 09, 2007, 03:01:35 PM »

Hello, I just upgraded to the latest Mach3 version (2.0.061) which fixed some problems cutting circles in the ZX plane, but now my backlash compensation is all screwy. It acts like the backlash is set to an inch when it is actually set to .001".  I've turned on and off the backlash with different values, and restarted each time, none of it helps, except keeping it off.

Has anyone else experienced this?

Thanks,
   Stewart

5

General Mach Discussion / 1st question... Re: New people welcome !!

« on: February 25, 2007, 12:43:08 PM »

Hi, my name is Stewart and I just finished converting a Rong-Fu mill to CNC with parts from Homeshopcnc.com pmdx.com and a computer running Mach3!  It seems to be running great, but this is my first venture into CNC milling so I have some pretty big knowledge gaps.  I'm a filmmaker in Dallas, TX, but have been a hobbyist machinist for many years and have a pretty good shop in the back yard.  I'm hopefully going to use the CNC to build camera parts and accessores that I've been designing.

I look forward to participating on this forum.  Thanks for the forum, and such great and affordable software....

So my first newbee question, what is the convention for the direction of the axis?  When the Z plunges down, should that be a positive or negative move?  Same with the table, when the Y comes towards you, positive or negative?  When the X moves to the right, is that move positive or negative?  I put in what I thought made sense, but found some of the wizards behaved oppositely of my intuition.  Then, in Mach3, is there a software way to reverse the motor direction (I've looked but cant find it), or just switch the wires on my stepper motors?

Thanks!

Stewart