Theoretically they can be - but not all programming packages have this feature. Some that do call it a "power up" distance which is the distance that you believe flushing will be stabilized from the edge of the stock. At that point the nc code would insert a new epack number (much higher power) and a much faster feedrate. If your NC package doesn't include this feature, putting in an extra point at the right location with manual editing can be a little daunting, especially if you are in 4 axis mode and you are entering the workpiece tangentially in an arc motion. Obviously, in a production part you are very likey to take the time to put all of it in the code.
However, doing it on the fly is very easy. You have great visual clues at the machine for the flushing condition (upper and lower flowmeters). When both flows drop off, indicating most of the water pressure is now going around the wire through the thickness of the stock (instead of squirting down the edge of the part), you pop in the high power epack and faster feedrate. If you do this too soon, the wire overheats and breaks. Then you remove all the covers, raise the head and rethread the wire and try again.  |