Manual or Tutorials to get started using EMC2

I am using EMC2 as my mill controller, but I am having difficulties with a number of the preliminary steps such as Touch Off and Coordination System (G54) to name a few. I am wondering if there is a manual or tutorials that are available to help a newbee over the hurdles. I have tried to read the supplied manual but my lack of knowledge hinders my ability to understand. I have searched the web and did not find much information.

Idle Chipmunk

perhaps explain what step it is your stuck on and no doubt advice will come flooding in
a good book for explaination of gcode etc is ' CNC PROGRAMMING HANDBOOK ' by Peter Smid , i believe it's up to revision 3 at the moment .
search the internet and you'll soon find it .

touch off is the setting of the work zero points which is usualy for argument the corner of x & y axis and the top surface of the work for the z
G54 is the relation of machine zero references and the touch off points or work zero , they of course can be the same if you wish , machine zero is the point at which your machine is homed and ready for use

machine zero is a fixed point , where work zero can be just about anywhere you wish within the cutting envelope and your gcode references to it

wiki.linuxcnc.org/cgi-bin/wiki.pl?CoordinateSystems

Hello,

You might also find some useful information here...
www.sherline.com/CNCinst6.0.htm

Rick G

Thank You

I will see if I can find the book.

Thank You

I will have a look at the Sherline site. I had not done that as my machine is a Taig.

I am a newbie and I have been working on building my new system since 29 Feb. I did not focus on coordinate systems, but yesterday I realized that they were the center of my conceptual problems, so I actually carefully read the wiki page.

Here is the fundamental fact you really need to understand:

The default coordinate system is G54

Repeat:

The default coordinate system is G54

This is hidden in a bunch of clutter in the documentation. In particular, until I edited the wiki this evening, G54 was not distinguished from the other workpiece coordinate systems until quite late in the document.

Basically: G53 is the machine-relative coordinate system, G54 is the workpiece-relative system. If you use a CAD program and then a CAM program to produce G code, the G code will be in the workpiece-relative coordinate system. It is quite practical to always operate in this system and never leave it.

G54 is handled as a special system in several places. Most notably, the "touch off" sets the G54 origin.

OK, then. Why are there other coordinate systems?
G53 is needed to set the actual physical limits for the machine and to identify any special locations, such as the tool change location.
G55 ... G59, and G59.1 ... G59.3 can be used for sub-pieces within the workpiece. I suppose a CAD/CAJM toolchain might use these. Not sure why.
G92 is used to shift the entire set of workpiece systems to a different origin. This is useful if you have several identical workpieces on your machine at the same time.
G43 is used to shift the entire set of workpiece systems up or down to accomodate a longer or shorter tool when you do a tool change.

For a beginner with a simple task and a single workpiece, G55... G59.3 are not used, because there are no sub-pieces. G92 is not used, because there is only one workpiece. G43 IS used, but only if you are using more than one tool on your job. G53 is used to set up physical limits.

Given that I only learned this yesterday, I may not have it all correct.

Thanks for your comments, I downloaded the information from the Sherline site but I have not had time to read it. I will look at the wiki pages, I am sure that they will also help.

Chipmunk, getting closer to making chips.

getting closer to making chips

Well that is what it is all about. The Sherline info may be somewhat dated but the concepts are the same.
After you have gone over the all the info let us know if you found it helpfull.
Good luck,

Rick G

For a single vise I set the G54 offset so that the front of the back jaw is Y0.000 and the left or right side of the material is set to X what ever makes sense for the G code program and Z0.000 to the top of the material with my tool. If you have a tool changer and all the tools are touched off in Z to some common point then all the tools will now be offset properly for the material in the vise.

G55-G59.3 are sometimes refereed to as "fixture offsets" ie if you had 2 vises with stops for the material you would machine one part in G54 and one part in the second vise with the same G code just by using G55... of course you would have to set the G55 coordinate system to the second vise first.

I use G92 on my plasma cutter with every cut to set the XYZ zero point to where I have jogged the torch to.

If you have repeatable tools and by this I mean you can touch off the Z of a tool take it out and put it back and the Z is still the same so this excludes any collet type of tool holder that the collet is in the spindle. When you change tools with Tn M6 you use G43 to load that tools offset.

John

Hi,
I divided my table in areas and work using all of the fixture offsets on LinuxCNC, my question is: is there a way that LinuxCNC (M2) does not restore G54 at the end of each program so I can put a pyvcp button or spinbox that keeps active the fixture offset I want to?
Thanks