Originally Posted by
JQ_Quint
EdgeFinding..
If it is a corner then a simple method would be to use a touch trigger probe which would beep or light up (these are battyer operated). A cheaper method would be to jog upto edge with say a 6mm dia bar in the tool holder and put a slip (of a known size say 5mm) between the edge and the 6mm bar. Keep jogging until you get a light bite feel. At this point you are exactly 3mm (half of your bar) + 5mm (the slip) away from your edge so you could set your datum to +8mm. repeat for other axis.
Of course a method which i use for real rough ass setting is use a pin and blue tack on the end of a holder. Spin the spindle up "low revs" and touch the end of the pin until it looks central. Move the pin to your corner then set your axis zero points.
Even less accurate can be done with a small drill.
All methods will involve you saving the postions in your datum page (g54 g55 etc positions) and as long as you call these in your program then yes it will repeat on each part.
You shouldn't have to worry about Z repeating on toolchanges.
Hope this helps.
J.
Of course you could just by a mechanical edge finder for $30 or so and they are accurate within a couple of thou.
Warning: DIY CNC may cause extreme hair loss due to you pulling your hair out.