Drilling sequence beginning in a pilot hole
NC1070
NC program for a drilling sequence in which the tool is positioned in a pilot hole before actual machining begins. First you define the tools and all required parameters and in the main program. Then a further program is defined in a Cycle 12 This is called at the machining positions using M99 or CYCL CALL. In this program the control calculates the actual drilling sequence and executes it.
The drilling sequence consists of the following steps: first the control positions the tool to the safety clearance that you have defined in the main program. There it switches the spindle on in leftward rotation at the defined rotational speed for the approach. Then is moves the tool into the pilot hole. Now it changes the spindle speed and direction of rotation to the values for drilling and executes a drilling sequence and maybe deburring. When the drilling depth has been reached, the control retracts the tool to the depth of the pilot hole. Then the control switches the spindle back to the speed for approaching and leftward rotation and moves to the safety clearance.