This paper presents a new turning system where the guided cut chip during turning is pulled using an external pulling device to attain high-performance cutting. An electro-mechanical pulling device with sensor-less chip tension monitoring function is designed to steadily pull the guided chip and robustly assist the turning operation. The effect of chip tension on the process is modeled and experimentally verified. The developed chip pulling system is utilized to achieve direct real-time control of the cutting process and zero thrust force cutting is demonstrated. Developed system effectively reduces cutting energy for improved tool life and regulates cutting forces for high performance turning.
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High Performance Turning Assisted by Chip-Pulling
Friction is one of the key factors limiting the achievable productivity and efficiency in most machining processes. Typically, adverse effects of friction in machining has been addressed through better tool material design and use of coolants. This paper presents an innovative technique to significantly increase the efficiency of turning processes by alleviating friction forces using an assistive device. As opposed to breaking the cut chip using chip breakers, in the proposed technique, the chip is not broken but pulled using a system to realize a new turning process so-called the “chip-pulling turning”. By pulling the cut chip externally, the friction force acting along tool’s rake face could be reduced and even cancelled. This, in return, increases the shear angle and leads to efficient material removal with significantly lower process forces and energy. An electro-mechanical chip-pulling device is designed that can pull the guided chip continuously during the turning operation. Design of the chip-pulling system, proposed pulling device and its automatic control are presented. The effect of chip-pulling is validated experimentally through various cutting experiments. Furthermore, orthogonal cutting force models are used to model the effect of chip-pulling on the process.
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- Award ID(s):
- 1661926
- NSF-PAR ID:
- 10135048
- Date Published:
- Journal Name:
- American Society for Precision Engineering (ASPE)
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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The rapid wear and premature failure of the cutting tool are prone to happen due to increased forces during machining difficult-to-cut materials such as Inconel 718. The application of alternative toolpath such as trochoidal milling has significantly improved tool life and reduced the overall cycle time of the process. The wear pattern of the tool has a direct impact on the cutting forces, which increases with tool deterioration. The cutting forces in milling are modeled through the mechanistic force model and can be designated through a set of force coefficients, i.e. cutting and edge representing the shearing and ploughing phenomenon of metal removal. It has been established in the literature that tool wear has a considerable effect on the value of edge force coefficients. This paper aims to determine the in-process edge force coefficients for the trochoidal toolpath and correlates them with the corresponding flank wear area. The proposed correlation will further assist in predicting the level of flank wear area based on the force values in trochoidal milling.more » « less
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Budak, Erhan (Ed.)This paper presents a generalized cutting force and regenerative chatter stability prediction for the modulated turning (MT) process. Uncut chip thickness is modeled by considering current tool kinematics and undulated (previously generated) surface topography for any given modulation condition in the feed direction. It is found that chip formation is governed by the undulated surface generated in multiple past spindle rotations. Uncut chip thickness is computed analytically in the form of trigonometric functions, and cutting forces are predicted by making use of orthogonal cutting mechanics. Regenerative chatter stability of the process is also modelled. Analytical semi-discretization-based solution is developed to accurately predict the stability lobe diagrams (SLDs) of the MT process. Predicted stability lobes are validated through numerical time-domain simulations and experimentally via orthogonal (plunge) turning tests. It is found that as compared to conventional single-point continuous turning, regenerative stability of MT exhibits multiple (3) regenerative delay loops and long out-of-cut duration in-between tool engagement stabilizes the process to reach up to 2x higher stable widths/depths as compared to the conventional continuous turning.more » « less
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