1- Fixed Cycles on the Mill - Overview
|Fixed cycles on a CNC mill are primarily used for hole machining. Types of hole machining include center drilling, counter sinking, drilling, reaming, counter boring, boring, right hand tapping, and left hand tapping.
A hole can be as simple as a 1/4 inch diameter hole drilled through the part. Other holes could be more complicated by being: a blind hole, a low tolerance hole, or stepped hole.
The following example shows the usefulness of canned cycles. If you were to drill the four holes in the plate shown on the right, here is how you would have to program without fixed cycles:
Assume Z-1 will drill through.
Now the same program with a G81 canned cycle
Notice that the 13 line program has been replaced with a much simpler 6 line program and that every new hole needs only one line of code.