Bit won't square 2 opposite corners of a rectangle

Bit won't square 2 opposite corners of a rectangle

Postby wdwkr53 » Wed Apr 26, 2017 3:04 pm

I have noticed that when I try to speed up a pocketing or profiling job, the machine consistently rounds the top right and bottom left corners of a rectangle. I have to slow it down to get a "square" cut. But no matter how fast I go, it always comes to the exact corner of the top left & bottom right corners. It doesn't seem to make a difference if I am setting the speed fast in the setup or push it faster with the % button. My speeds vary from 100-150 ipm on.25" endmill. Any thoughts?
User avatar
wdwkr53
 
Posts: 40
Joined: Sun Aug 01, 2010 11:13 pm
Model of CNC Machine: 8020 Extrusion

Re: Bit won't square 2 opposite corners of a rectangle

Postby Mike-S » Wed Apr 26, 2017 3:59 pm

it always comes to the exact corner of the top left & bottom right corners

If it always happens there, you may have something loose in the machine that shows up as the direction changes.
User avatar
Mike-S
Vectric Wizard
 
Posts: 953
Joined: Mon Jun 13, 2011 6:45 am
Location: Hayesville, NC
Model of CNC Machine: Joe's Hybrid 4x4 (but 3x3)

Re: Bit won't square 2 opposite corners of a rectangle

Postby ger21 » Wed Apr 26, 2017 4:20 pm

If your using Mach3, it's your CV mode settings.
Gerry
ger21
Vectric Wizard
 
Posts: 854
Joined: Sun Sep 16, 2007 2:59 pm
Location: Shelby Township, MI, USA

Re: Bit won't square 2 opposite corners of a rectangle

Postby 4DThinker » Wed Apr 26, 2017 8:09 pm

Look up G-Code G64. If you have a G64 with nothing after in either the post processor header or your machine's setup file then your machine will try to keep up feed speed while sacrificing accuracy. If you add a P followed by a fraction the bit will slow down as it needs to keep close to the programmed coordinates (less the fraction). So:
G64 says keep up speed even if it means rounding off corners.
G64P0.001 says stay within .001 of the programmed coordinates.

4D
4DThinker
Vectric Wizard
 
Posts: 978
Joined: Sun Sep 23, 2012 12:14 pm
Model of CNC Machine: CNC Shark Pro

Re: Bit won't square 2 opposite corners of a rectangle

Postby ger21 » Wed Apr 26, 2017 11:26 pm

G64P0.001 says stay within .001 of the programmed coordinates.


This depends on the control that you're using. All controls handle CV modes differently.
Gerry
ger21
Vectric Wizard
 
Posts: 854
Joined: Sun Sep 16, 2007 2:59 pm
Location: Shelby Township, MI, USA


Return to Control Software related questions

Who is online

Users browsing this forum: No registered users and 2 guests