Now ill give you it in the way clever people put it lol


Quote Originally Posted by JAZZCNC View Post
In cnc there are 2 coordinate systems, Machine coordinates (MC) and work coordinates (WC).
MC relate to the machines fully movement extents and often defined by having home switch's which set the MC X0,Y0,Z0.
WC is the start point you choose when zeroing on the workpiece and the G-code or part defining the extents.

WC are also related to MC in that they are a known distance from MC X0,Y0,Z0. With home switch's on the machine it makes very easy to get back to accurate WC start point or any other known point on the workpiece by specifiying the offset from MC.

So if you only want to work from one position IE set distance from MC then you need a known start point. This would then become your X0,Y0,Z0 in WC.
This known start position is set by using work offsets which are represented in G-code by G54,G56,G57,G58,G59. The usual default work offset is G54 and most just use this which is basicly set when you manuely zero the WC DRO's.
If you want to define other work offsets then this is done in the control softwares work offsets table section saved under G54,G55 etc, you then basicly program the relavent offset IE:G55 and the machine knows it's distance from MC and goes there using this has it's WC X0,Y0,Z0.

So the process goes like this jog the machine to a point on your bed, in your control software you'll have a workoff set table. This table will have list of coordinates for G54-G59 choose one and save, this save the MC for the position the machines at now.
Now when you program the part at the begining or near the begining of the G-code there will be an entry for setting the machine up safe looking some thing like "
N01 G21 G40 G49 G54 G80 G90 G91.1" This puts the machine in a known safe state. Further down there will possibly be another line with G54 so selecting workoff set G54 and it's WC in the Workoff set table. . . So by now I think you'll have guessed what needs to be done to choose another WC location.? Yep change G54 to G55 etc.!!
Better still is to do this in Cam software, most decent software should let you choose work offsets.

Hope this helps.
Cheers Jazz (copy & paste to notepad)