I think a bidirectional jog would be a nice feature. I am thinking of 
doing a crude version of this on my lathe. In jog wheel mode the FRO 
would be tied into the velocity output of an MPG. The faster you turn 
the handle, the faster the code is executed. Stop turning and the 
machine stops. Great for proof testing new code.

One option would be to generate a 'pre-digested' intermediate file. This 
  contains all of the moves after tool compensation, executed code loops 
and any other fancy stuff. It would basically just contain simple linear 
moves, arc moves and triggers for spindle, coolant, I/Os etc. It would 
be easy to design this format so that it can be read in either 
direction. This file is then fed to the TP to generate movement. I 
actually do something similar in SheetCam. The offsets are generated 
then the cut paths are calculated from the offsets, in whatever 
direction is needed.

I think that would be a lot easier than trying to interpret the G-code 
backwards, especially when you take code loops and subroutines into 
account. The only disadvantage is that you would get a delay when you 
load a G-code file as the whole intermediate file (or at least a 
significant portion of it) has to be generated before movement can 
start. For small files the time would be insignificant but it may be an 
issue for multi megabyte 3D contouring code.

Les


> There are several applications for going forward or backward through a 
> move or a series of moves (EDM is one).  There are several difficulties 
> though, especially if you allow all the nifty cutter comp features to be 
> turned on while you're "jogging" through the program.  You have to swap 
> G41 and G42 when you go backwards, as well as G2 and G3.  A complete 
> solution would also need to deal with other machine state, such as 
> spindle and coolant.  There have been many discussions on the topic in 
> the past.  If you have a clear vew of what you need, and ideally a good 
> idea of what other applications might need, please write it up and post 
> it :)
> 

------------------------------------------------------------------------------
Crystal Reports - New Free Runtime and 30 Day Trial
Check out the new simplified licensing option that enables unlimited
royalty-free distribution of the report engine for externally facing 
server and web deployment.
http://p.sf.net/sfu/businessobjects
_______________________________________________
Emc-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/emc-users

Reply via email to