On Thu, Aug 19, 2010 at 10:48:37AM -0500, Viesturs L??cis wrote: > Ok, but then how comes I do not receive this error, when cutting a > rectangular hole in material, which is defined by 4 G01 moves (and G41 > or G42 is active) - there is sharp 90 degree corner and round tool - > so the corner cannot be completely reached. But somehow EMC solves the > task.
You are right - EMC does have handling for concave corners. When two moves come together to form a concave corner, EMC calculates where the tool is tangent to both original moves and puts the offset corner there. The error happens when the tool can't be tangent to both moves forming the corner because it doesn't fit. > I am sorry, but I do not really understand, why it is ok for corner, > where it is turn by 90 degrees, but error is produced, if the corner > is sharper than 90 degrees. Are there some limitations on how the path > of the tool is offset, when G41/G42 is activated? Inside a 90 degree corner is a good simple example: if both moves making the 90 degree corner are longer than the tool radius, the tool fits in there. The disconnect here is you are thinking of a corner as "where I think a corner should be on my part, even if there are several little moves in the gcode that the tool can't get in there to touch without gouging the part" but EMC thinks of a corner as the point where *two* adjacent moves come together. EMC handles a corner concavity of *two* adjacent moves. EMC does not handle throwing away a whole series of unwanted moves to make a new corner out of non-adjacent moves. > > This makes G41/G42 move the path only a tiny amount as if there was > > a tiny tool. ?Offsetting a tiny amount makes it much less likely > > that you will have unreachable moves. > > Sorry, but I do not see the difference, I still have to include the > compensation in the code by CAM programm. I like the ability that I > can quickly adjust the code by hand rather than doing it in CAM > application or releasing clamps and repositioning the material on the > table and then clamping it down again. > I can still edit it manually, but having the compensation already > included in the code creates more room for my mistake, so that is why > I had this question. > Ok, seems like I will have to live with that. I think you did not understand what I meant - I wish I could be more clear. If the CAM does compensation for the nominal tool size, you can move the path a little bit by using a small positive or negative diameter in your tool table. This will work better. > Chris, did manage to check the second code sample I provided? Is EMC > showing error there? No, I haven't done that. I'd rather explain the error to you so you can debug the particulars once you understand it. Chris ------------------------------------------------------------------------------ This SF.net email is sponsored by Make an app they can't live without Enter the BlackBerry Developer Challenge http://p.sf.net/sfu/RIM-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users