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1

General Mach Discussion / Cutter Compensation and Arcs: Confused by tool path from G02 when G42 is used

« on: March 31, 2013, 12:57:07 AM »

Hi,
   I'm learning to write Gcode by hand.  I have a project where I want to cut 7 full circle arcs out, and I thought using G42 to account for the cutter diameter would be pretty straight forward.  My code does show in the tool path the nice purple lines for the circles, but then it also shows a white spiral line which when I run the program seems to be the true cutter motion.  So I'm totally confused why it won't just follow out the purple arc lines.  Where is the spiral coming from?? 

   Here is my program.  Note that I've tried both settings for IJ being relative or absolute.  Doesn't change the behavior at all.  Let me know if you need me to include a screen shot of the sprials.  I've also tried putting G42 on the same line as G02.  Didn't help either.  When I did that, the arc actually didn't cut out at ALL!  It would plunge to start the cut, and then just raise again and move to the next hole location.  I did learn that the spiral depends on where I put the G42 line in sequence of the other lines. 

Code: [Select]

% 6 LEDS and reset button
G40
G01 F20 S5000
M03
G21
(-----hole1------)
G00 Z5.0
G00 X25.0
G00 X25.0 Y19.0
G42 P3.175
G01 Z-5.0 F80
G02 X25.0 Y19.0 I25.0 J15.0
G40
(-----hole2------)
G00 Z5.0
G42 P3.175
G00 X40.0 Y34.0
G01 Z-5.0 F80
G02 X40.0 Y34.0 I40.0 J30.0
G40
(-----hole3------)
G00 Z5.0
G00 X55.0 Y49.0
G01 Z-5.0 F80
G02 X55.0 Y49.0 I55.0 J45.0
G40
(-----hole4------)
G00 Z5.0
G00 X70.0 Y49.0
G01 Z-5.0 F80
G02 X70.0 Y49.0 I70.0 J45.0
G40
(-----hole2------)
G00 Z5.0
G00 X85.0 Y34.0
G01 Z-5.0 F80
G02 X85.0 Y34.0 I85.0 J30.0
G40
(-----hole1------)
G00 Z5.0
G00 X100.0 Y19.0
G01 Z-5.0 F80
G02 X100.0 Y19.0 I100.0 J15.0
G40
(-----reset hole------)
G00 Z5.0
G00 X62.5 Y21.625
G01 Z-5.0 F80
G02 X62.5 Y21.625 I62.5 J15.0
G40
G00 Z5.0
G00 X0.0 Y0.0


2

General Mach Discussion / How do I install CAM post processors

« on: January 04, 2013, 01:13:28 AM »

Hi,
   So I'm very new to milling.  I milled my first pocket ever with the wizard tonight into some wood.     I'm wondering about how to move eventually to using CAD/CAM.  I found this page:

http://www.machsupport.com/posts.php

   And would like to try out the bobCAD demo.  But I don't see what to do with the Bobcad_post.zip.  I looked at the mach3 install pdf and the manual pdf.  I don't see any info on it but maybe I just missed it?

   Also, side question, how do I purchase (and install) the "Mach3 Addons for Mill"  I don't see any link in the artsoft website.

3

General Mach Discussion / Jogging in the Zed goes the wrong direction for a tiny amount

« on: January 03, 2013, 12:00:12 AM »

Hi,
   So I have a sherline 3 axis metric mill and their CNC driver box with 4 outputs (I'm not using the "A" output).  I grabbed the xml for the setup from the xml ftp site Mach3 has.  The X and Y motors run quite smooth both in 50% and 100% (shift key) jogging.  I can change directions without issue.  But on the Zed axis, I page down and it goes down every time, but if I try to go up after going down previously, the only way to get it to really go up is to do a quick tap of the page up key a few times.  Then it will go up on subsequent presses of the page up key.  Very strange. 

   So to debug it, I've tried a few things but they all seem intermittent.  I unplugged Z motor from the Z output and instead connected the Z motor to the the "A" output of the cnc driver box.  I updated the pins in the pin config of course, and then Z was working.  Seemed perfect so I figured my Z output of the box or PC port was bad.  But then it started doing it again.  So I tried swapping the X and Z and similar story.   

   What is very odd is the behavior when it fails.  I just can't switch from jogging Zed down to then jogging it up without the difficulty.  It goes down even when I try to go up until I tap quickly the up jog key on the keyboard a few times.  It's like its remembering that I'm going down.  Note that switching  from jogging up (after I finally get it working) to jogging down always works the very first try.

    I will try to reverse the zed direction now to see if then I have the opposite issue. 

   I looked and I don't think I have any "backlash" turned on.  But I'm quite new to mach3 so I could be wrong there? 

   So do I have a bad motor, a bad cnc box, a bad parallel port, or just a bad mach3 setup?  ANY HELP APPRECIATED! 

Justin

4

General Mach Discussion / Is there a way to Auto Zoom to the work area?

« on: January 02, 2013, 12:40:30 AM »

Hi, I'm new, and I was watching the videos on homing.  I liked how the "display mode" toggle button was showing the whole table, and then auto zooming to the road runner gcode area.  Is there a way other than scroll wheeling all the way in to see just the tool path of the work area.  I.e.  auto zoom to the work area?  Right now even in ALT-4 tool path screen, if I toggle the display mode button, it just shows the table outline or not. 

Thanks!
Justin