hi there, im new and this may be in the wrong place, so just move it admins if it is and sorry for the troubles. on to the problem

i am engraving some stuff into a piece of aluminum, its a street sign, i cut squares out of a stop sign and am engraving on the non painted side. i am using a 1/16 inch carbide end mill. when i start the engraving it just melts the aluminum instead of actually cutting the aluminum away. i have tried changing the feed speed and spindle speeds up and down and the problem hsant been fixed. two questions: what can i do to make it actualy cut away the aluminum and is it bad for the bit if i melt the engraving all the way through? thanks