Development of Innovative Intelligent Machine Tool Based on CAM-CNC Integration Concept – Adaptive Control Based on Predicted Cutting Force –
Isamu Nishida*,, Ryo Tsuyama*, Keiichi Shirase*, Masahiro Onishi**, and Katsuyuki Koarashi***
1-1 Rokko-dai, Nada-ku, Kobe, Hyogo 657-8501, Japan
**SoftCube Co., Ltd., Osaka, Japan
***Kitamura Machinery Co. Ltd., Toyama, Japan
A new methodology to generate instruction commands for prompt machine control as a replacement for the previously prepared numerical control (NC) programs is developed to realize an innovative intelligent machine tool. This machine tool can eliminate NC program preparation, achieve cutting process control, reduce the production lead time, and realize an autonomous distributed factory. In this study, the innovative intelligent machine tool based on the computer-aided manufacturing-computer NC integrated concept is developed. The special feature of this system is to generate instruction commands in real time for prompt machine control instead of using NC programs. Digital Copy Milling, which is a digitized version of traditional copy milling, is realized by using only the computer-aided design model of the product. In this system, the cutting-force simulation is performed simultaneously with the real-time tool path generation. Then, the tool feed rate can be controlled according to the predicted cutting force. Therefore, both the improvement of the machining efficiency and the avoidance of machining problems can be achieved. The instantaneous cutting force model predicts the cutting force. In this system, the work material is represented by the voxel model, and the uncut chip thickness is calculated discretely from the number of voxels removed. Thus, it is possible to predict the cutting force in the case of non-uniform contact between the tool and the work material. In this study, a machining simulation is conducted to validate the proposed method. The results of the simulation show successful tool feed speed adaptation based on the predicted cutting force. The results also show the effective reduction of the machining time. A case study of a custom-made product for dental prosthetics is examined as a good application of both the proposed adaptive control and the Digital Copy Milling system. Through this method, it is possible to improve the machining efficiency and prevent tool breakage.
-  D. Hamada, K. Nakamoto, T. Ishida, and Y. Takeuchi, “Development of CAPP System for Multi-Tasking Machine Tool,” The Japan Society of Mechanical Engineers, Vol.78, No.791, pp. 2698-2709, 2012.
-  N. Sugimura, “Research trends in process planning,” J. of the Japan Society for Precision Engineering, Vol.72, No.2, pp. 165-170, 2006.
-  A. Ueno and K. Nakamoto, “Proposal of machining features for CAPP system for multi-tasking machine tools,” The Japan Society of Mechanical Engineers, Vol.81, No.825, p. 15-00108, 2015.
-  M. El-Mehalawi and R. A. Miller, “A database system of mechanical components based on geometric and topological similarity. Part I: representation,” Computer-Aided Design, Vol.35, No.1, pp. 83-94, 2003.
-  M. El-Mehalawi and R. A. Miller, “A database system of mechanical components based on geometric and topological similarity. Part II: indexing, retrieval, matching and similarity assessment,” Computer-Aided Design, Vol.35, No.1, pp. 95-105, 2003.
-  I. Nishida, R. Sato, and K. Shirase, “Proposal of Process Planning System for End-Milling Operation Considering Product Design Constraints,” The Institute of Systems, Control and Information Engineering, Vol.30, No.3, pp. 81-86, 2017 (in Japanese).
-  M. M. Hossain, C. Nath, T. M. Tucker, R. W. Vuduc, and T. R. Kurfess, “A Graphics Processor Unit-Accelerated Freeform Surface Offsetting Method for High-Resolution Subtractive Three-Dimensional Printing (Machining),” J. Manufacturing Science Engineering, Vol.140, No.4, 041012, doi: 10.1115/1.4038599, 2018.
-  K. Nakamoto, K. Shirase, H. Wakamatsu, A. Tsumaya, and E. Arai, “Development of Digital Copy Milling System to Realize NC Programless Machining: 3rd Report, Machining Strategy for In-Process Adaptation of Cutting Conditions,” The Japan Society of Mechanical Engineers, Vol.69, No.677, pp. 270-277, 2003.
-  K. Shirase and K. Nakamoto, “Direct Machining Operation Performed by Autonomous NC Machine Tool Controlled by Digital Copy Milling Concept,” The Japan Society of Mechanical Engineers, Vol.74, No.743, pp. 1901-1906, 2008.
-  K. Shirase and K. Nakamoto, “Simulation Technologies for the Development of an Autonomous and Intelligent machine Tool,” Int. J. Automation Technol., Vol.7, No.1, pp. 6-15, 2013.
-  Y. Koren, “Control of Machine Tools,” ASME J. of Manufacturing Science and Engineering, Vol.119, pp. 749-755, 1997.
-  Y. Altintas and W. K. Munasinghe, “A Hierarchical Open-Architecture CNC System for Machine Tools,” CIRP Annals, Vol.43, No.1, pp. 349-354, 1994.
-  M. Mitsuishi, T. Nagao, T. Ohta, and H. Okabe, “A Practical Machining Condition Determination Strategy Using Multi-Axis Force Information,” Annals of CIRP, Vol.45, No.1, pp. 373-376, 1996.
-  M. Mitsuishi, T. Nagao, H. Okabe, and M. Katsuya, “An Open Architecture CNC CAD-CAM Machining System with Data-Base Sharing and Mutual Information Feedback,” Annals of CIRP, Vol.46, No.1, pp. 269-274, 1997.
-  T. Hasegawa, R. Sato, and K. Shirase, “Cutting Force Simulation Referring Workpiece Voxel Model for End-milling Operation and Adaptive Control Based on Predicted Cutting Force,” Japan Society for Precision Engineering, Vol.82, No.5, pp. 467-472, 2016.
-  K. Shirase, T. Kondo, M. Okamoto, H. Wakamatsu, and E. Arai, “Development of Virtual Copy Milling System to Realize NC Programless Machining: Real Time Tool Path Generation for Autonomous NC Machine Tool,” The Japan Society of Mechanical Engineers, Vol.66, No.644, pp. 298-303, 1999.
-  J. Tlusty and P. MacNeil, “Dynamics of Cutting Forces in End Milling,” CIRP Annals, Vol.24, No.1, pp. 21-25, 1975.
-  D. Mongomery and Y. Altintas, “Mechanism of cutting force and surface generation in dynamic milling,” J. of Engineering for Industry, Vol.113, No.2, pp. 160-168, 1991.
-  Y. Altintas and P. Lee, “A General Mechanics and Dynamics Model for Helical End Mills,” CIRP Annals, Vol.45, No.1, pp. 59-64, 1996.
-  K. Shirase and Y. Altintas, “Cutting force and dimensional surface error generation in peripheral milling with variable pitch helical end mills,” Int. J. of Machine Tools and Manufacture, Vol.36, No.5, pp. 567-584, 1996.
-  T. Matsumura, T. Furuki, and E. Usui, “Prediction of Cutting Process with Curved-Edge End Mill (1st Report),” The Japan Society of Mechanical Engineers, Vol.69, No.688, pp. 3396-3402, 2003.
-  T. Miyazaki, “Current Status and Future Perspective of Digital Prosthodontics,” Japan Prosthodontics Society, Vol.4, pp. 123-131, 2012.
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