The part programming divided into two segment. Both operations of NC part programming have demonstrate in following figure. The operation are follows as given number from 1 to 18

Figure. 1 Part programming for boundary surface of Sheet

Figure. Part programming for center milling operation

N01	G71	G90	G94
N02	G00	X-20 Y 0
N03	G00	Z20
N04	G01  G42  D20	Z -20   S1000	F200   M03
N05	G01	X0 Y0
N06	G01	X220
N07	G01	X 250 Y -30
N08	G01	X 250 Y -330
N09	G02	X 220 Y -360	R 30
N10	G01	X 30 Y -360
N11	G02	X 0 Y -330	R30
N12	G01	X 0 Y -30
N13	G01	X 30 Y 0
N14	G01	X0 Y0
N15	G00	Z  +20
N16	G00	X 110 Y -75
N17	G01	X 140 Y -75
N18	G02	X 155 Y -90
N19	G01	X 155 Y -270
N20	G02	X 140 Y -255
N21	G01	X 110 Y -255
N22	G02	X 95 Y -270
N23	G01	X 95 Y -90
N24	G02	X 110 Y -75
N25	G00	Z +20
N26	G40
N27	G00	X -20 Y 0
N28	G00	Z 20
N29	M30

In manual NC part programming, it is require to crate NC code for the specific process and operation as well. Whereas the CAD/ CAM part programming is used for multipurpose when it develop for first time, it can feed into other computer device and machine operation also for same operation. It is require to convert into machine language.  The programming post process used to change code which is necessary to read and operate through NC controller for particular machine operation.  The CAD/CAM post processor must be feed into specific code such as G-code and N-code with the X, y and Z co-ordinate system.  The output must be written in individual machine tools.

For numerical part programming, it is not necessary to perform with specific source, it can provide accurate output without specific source. Whereas in CAD/CAM machine operation need automatic selection process for the individual machine operation. Also, the CAD/CAM machine tool system can manage speed and feed at running operation. Path selection for the process also automatic CAD/CAM system and machine tool selection. At the same time, the numerical part programming techniques need manual feed data such as speed and feed for machine operation.

References

(2018). S3.amazonaws.com. Retrieved 9 April 2018, from https://s3.amazonaws.com/academia.edu.documents/35856559/ims_forum_ascona_011008.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&Expires=1523289471&Signature=f1E6gzCVrNby7ZddYOA7OF%2Fjehg%3D&response-content-disposition=inline%3B%20filename%3DSTEP-NC_The_STEP_compliant_NC_Programmin.pdf

Laguionie, R., Rauch, M., & Hascoët, J. (2018). Toolpaths Programming in an Intelligent Step-NC Manufacturing Context. Arxiv.org. Retrieved 9 April 2018, from https://arxiv.org/abs/0905.3079

Li, Y., Fang, T., Cheng, S., & Liao, W. (2018). Research on Feature-Based Rapid Programming for Aircraft NC Parts. Retrieved 9 April 2018, from

Shah, J., Sreevalsan, P., & Mathew, A. (2018). Survey of CAD/feature-based process planning and NC programming techniques. Digital-library.theiet.org. Retrieved 9 April 2018, from https://digital-library.theiet.org/content/journals/10.1049/cae.1991.0004