At 12:15 PM 7/18/2007, you wrote: >Andre' Blanchard wrote: > > > > The X,Y U,V wire EDM's I run have a set of what they call Z constants. > > Z1 is the distance from the machine table to the point at which the X,Y > > size is held true. > > Z2 is the distance from the table to the point at which the feed rate is > > held true. > > Z3 is the distance from the table to the upper wire guide. > > Z4 is the distance from the table down to the lower guide. > > > > Using this info the control can calculate the displacement of the U,V > > slides from the X,Y to get the taper angle and the part size programmed in > > the G code. >Since these are all constant, there's no need to burden EMC with >that. You could put these values into the CAM software to >calculate the correct XY UV to make the desired part. > >I suppose you could re-do the kinematics so it solves all this >in EMC, but I'm not sure that is necessary or desirable. > >Jon
They are constant until you do some maintenance (could be just cleaning the guides) on the machine then you have to find new constants, opening that loop up back to some CAM software is going to introduce more potential errors. Feed rates in wire EDMs are really just starting points for the control, you almost always run in adaptive mode where it tries to go as fast as possible. As such the Z2 constant ends up being the point for which the actual feed rate is displayed to the operator. Reposting and transfer to the CNC machine is slower then having family part macro subs in the control and letting the user simply change some sizes and run the next part. The reason for doing things like this in the control is to keep the spindle turning as much as possible. Break a tool, put in a new one edit the comp offsets and hit the green button. Teaching the average CNC operator how to efficiently run a CAM package is not easy. The chances of them making an error posting a new program are greater then if all they have to do is change an offset. Taken to the extreme you can do everything in the CAM software and simplify EMC to just G0 G1, no need for G2,3 because the CAM can do it all with G1s, no need for tool offsets or cutter comp because the CAM software can do it, likewise for G81, 82, 83, etc. canned cycles. Just telling how it works in controls that are found in machine tools around the world. Yes there are shops that depend on CAM software for everything but they tend to not be running 3 min. or less finish op cycle times on pre-blanked parts with 1 to 5 parts per order, with the operator doing 50 to 100 orders per day. __________ Andre' B. Clear Lake, Wi. ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
