Additively manufactured parts have recently been applied to products in aerospace, automobile, and tool industries in terms of design flexibility and material consumption with mechanical strength. Because the surfaces of additively manufactured parts are coarse, milling is conducted as a post-process to achieve fine surfaces within the specified tolerance. However, the microstructures and the mechanical properties of additively manufactured metals differ from those of wrought metals. Therefore, the cutting characteristics should be understood to determine the appropriate cutting parameters. The paper studies the cutting process in peripheral milling of additively manufactured maraging steel in a cutting model. The cutting force, the surface finish, the chip morphology, and the tool wear were evaluated through cutting tests. Although the hardness of the additively manufactured workpiece was higher than that of the wrought workpiece, the maximum cutting forces were approximately the same. An energy-based force model was applied to discuss the cutting force characteristics in terms of the shear area and the shear stress on the shear plane. In milling of additively manufactured workpiece, the shear stress on the shear plane becomes larger than that of the wrought workpiece. However, the shear plane length is short at a large shear angle. Therefore, the cutting force does not significantly increase. The typical change in the cutting force of the additively manufactured workpiece is also compared with that of the wrought workpiece in terms of the cutting model. The chip flow directions, then, are analyzed in the cutting force model. The chips of the additively manufactured workpiece flow more in the radial direction than those of the wrought workpiece.

1. [1] T. E. F. Silva, P. A. R. Rosa, A. R. Reis, and A. M. P. de Jesus, “Machinability of the 18Ni300 Additively Manufactured Maraging Steel Based on Orthogonal Cutting Tests,” J. Machado, F. Soares, J. Trojanowska, and E. Ottaviano (Eds.), “Innovations in Mechanical Engineering,” pp. 1-13, Springer, 2022.
2. [2] S. A. M. Tofail, E. P. Koumoulos, A. Bandyopadhyay, S. Bose, L. O’Donoghue, and C. Charitidis, “Additive Manufacturing: Scientific and Technological Challenges, Market Uptake and Opportunities,” Materials Today, Vol.21, Issue 1, pp. 22-37, 2018.
3. [3] H. Ramazani and A. Kami, “Metal FDM, a New Extrusion-Based Additive Manufacturing Technology for Manufacturing of Metallic Parts: A Review,” Progress in Additive Manufacturing, Vol.7, No.4, pp. 609-626, 2022.
4. [4] M. Yakout, M. A. Elbestawi, and S. C. Veldhuis, “A Review of Metal Additive Manufacturing Technologies,” Solid State Phenomena, Vol.278, pp. 1-14, 2018.
5. [5] L. Zhang, S. Zhang, H. Zhu, Z. Hu, G. Wang, and X. Zeng, “Horizontal Dimensional Accuracy Prediction of Selective Laser Melting,” Materials & Design, Vol.160, pp. 9-20, 2018.
6. [6] J. Song, Q. Tang, Q. Feng, S. Ma, R. Setchi, Y. Liu, Q. Han, X. Fan, and M. Zhang, “Effect of Heat Treatment on Microstructure and Mechanical Behaviours of 18Ni-300 Maraging Steel Manufactured by Selective Laser Melting,” Optics & Laser Technology, Vol.120, 105725, 2019.
7. [7] W. Sha and Z. Guo, “1 – Introduction to Maraging Steels,” W. Sha and Z. Guo, “Maraging Steels: Modelling of Microstructure, Properties and Applications,” pp. 1-16, Woodhead Publishing Ltd., 2009.
8. [8] E. W. Hovig, A. S. Azar, K. Solberg, and K. Sørby, “An Investigation of the Anisotropic Properties of Heat-Treated Maraging Steel Grade 300 Processed by Laser Powder Bed Fusion,” The Int. J. of Advanced Manufacturing Technology, Vol.114, Nos.5-6, pp. 1359-1372, 2021.
9. [9] A. Kirchheim, Y. Katrodiya, L. Zumofen, F. Ehrig, and C. Wick, “Dynamic Conformal Cooling Improves Injection Molding: Hybrid Molds Manufactured by Laser Powder Bed Fusion,” The Int. J. of Advanced Manufacturing Technology, Vol.114, Nos.1-2, pp. 107-116, 2021.
10. [10] A. S. Iquebal, S. El Amri, S. Shrestha, Z. Wang, G. P. Manogharan, and S. Bukkapatnam, “Longitudinal Milling and Fine Abrasive Finishing Operations to Improve Surface Integrity of Metal AM Components,” Procedia Manufacturing, Vol.10, pp. 990-996, 2017.
11. [11] J. C. Heigel, T. Q. Phan, J. C. Fox, and T. H. Gnaupel-Herold, “Experimental Investigation of Residual Stress and its Impact on Machining in Hybrid Additive/Subtractive Manufacturing,” Procedia Manufacturing, Vol.26, pp. 929-940, 2018.
12. [12] M. Santhanakumar, R. Adalarasan, S. Siddharth, and A. Velayudham, “An Investigation on Surface Finish and Flank Wear in Hard Machining of Solution Treated and Aged 18% Ni Maraging Steel,” J. of the Brazilian Society of Mechanical Sciences and Engineering, Vol.39, No.6, pp. 2071-2084, 2017.
13. [13] Y. Yao, H. Zhu, C. Huang, J. Wang, P. Zhang, and P. Yao, “Investigation on Chip Formation and Surface Integrity in Micro End Milling of Maraging Steel,” The Int. J. of Advanced Manufacturing Technology, Vol.102, Nos.5-8, pp. 1973-1984, 2019.
14. [14] Y. Bai, C. Zhao, J. Yang, R. Hong, C. Weng, and H. Wang, “Microstructure and Machinability of Selective Laser Melted High-Strength Maraging Steel with Heat Treatment,” J. of Materials Processing Technology, Vol.288, 116906, 2021.
15. [15] W. Du, Q. Bai, and B. Zhang, “Machining Characteristics of 18Ni-300 Steel in Additive/Subtractive Hybrid Manufacturing,” The Int. J. of Advanced Manufacturing Technology, Vol.95, Nos.5-8, pp. 2509-2519, 2018.
16. [16] A. R. de Oliveira and E. G. Del Conte, “Concurrent Improvement of Surface Roughness and Residual Stress of As-Built and Aged Additively Manufactured Maraging Steel Post-Processed by Milling,” The Int. J. of Advanced Manufacturing Technology, Vol.116, Nos.7-8, pp. 2309-2323, 2021.
17. [17] S. Tamura, T. Matsumura, A. Ezura, and K. Mori, “Anisotropic Cutting Force Characteristics in Milling of Maraging Steel Processed Through Selective Laser Melting,” J. of Manufacturing Science and Engineering, Vol.144, Issue 3, 031012, 2022.
18. [18] J. Hua and R. Shivpuri, “Prediction of Chip Morphology and Segmentation During the Machining of Titanium Alloys,” J. of Materials Processing Technology, Vol.150, Issues 1-2, pp. 124-133, 2004.
19. [19] T. Matsumura and E. Usui, “Predictive Cutting Force Model in Complex-Shaped End Milling Based on Minimum Cutting Energy,” Int. J. of Machine Tools and Manufacture, Vol.50, Issue 5, pp. 458-466, 2010.
20. [20] T. Matsumura, T. Shirakashi, and E. Usui, “Adaptive Cutting Force Prediction in Milling Processes,” Int. J. Automation Technol., Vol.4, No.3, pp. 221-228, 2010.
21. [21] T. Aiso and T. Matsumura, “Effect of Carbon Content on Machinability of Steel in Gear Cutting,” ISIJ Int., Vol.61, No.1, pp. 292-301, doi: 10.2355/isijinternational.ISIJINT-2020-334, 2021.