hi, i have a 3 axis cnc milling and engraving machine. i need to know if it is possible to engrave on sfere or wavy surface?? is it true i need 4 axis cnc to do that?


(my cnc machine: http://www.cnc-router-routers.com/html/prices_about_cnc_router_engrav.HTM )

It depends how much the surface is angled from the tip of the engraver. Too much angle (from 90 degrees that is) you will get another pattern and at last the tip will "slip off".
Give it a try, make a test run on something! :)

Regards,
Sven

the more the angles the greater the error

unless all the waves are along one axis you would need a 5 axis mill

if it has shallow waves a ball end mill may work

It depends on the tolerance you need. You can easaly mounth a manual forth axis(low cost around 350 eur) used on the manual mills for making gear, sprocets than all you got to do is to make couple CNC programs for a smaller angle where undercating is not ocuring and manualy rotate the axis between the programs. I usuly engrave cilinders for marking and stamping that way.

It depends on the tolerance you need. You can easaly mounth a manual forth axis(low cost around 350 eur) used on the manual mills for making gear, sprocets than all you got to do is to make couple CNC programs for a smaller angle where undercating is not ocuring and manualy rotate the axis between the programs. I usuly engrave cilinders for marking and stamping that way.

So simple, why didn't I think of that...
Great idea Karamitrov, sometimes the solution is too close to be seen. :)

It has worked for me job after job i work on HAAS TM1 and every job was perfectly finished.