Abstract: Taking orifice chamfering as the research object,in understanding the macro-program processing method of FANUC 0i system,proposes a method of write orifice chamfering NC macro program.Based on orifice chamfering tool and tool path analysis,on the basis of using the macro-program directive of FANUC 0i system extension,developed orifice chamfering machine cycle instructions.Practice shows that the method can satisfy on the NC milling machine processing orifice chamfering production requirements.This instruction to achieve the desired results at the same time,simplify the algorithm and the programming process,it has been verified by the actual effect is good.

Key words: the macro-program, orifice chamfering, cycle instruction