Abstract:In deep-hole machining process, interrupting chip, chip removal and heat radiation, are key technology problems. The deficiencies of using drilling cycle SINUMIRIK of 840D system to process deep-hole were analyzed. The principle and design idea of regressive deep-hole processing were put forward.A general subroutine for regression deephole processing was developed combining R parameters and CYCLE83 deep-hole drilling cycle instruction. The technology gap of the CYCLE83 cycle was made up. The technical problems of fixed drilling depth were solved,and it has high practical value.