A cutting force model based on kinematic analysis in longitudinal and torsional ultrasonic vibration drilling

AbstractThe influence of the grain angle on the cutting force when milling wood is not yet detailed, apart from particular cases (end-grain, parallel to the grain, or in some rare cases 45°-cut). Thus, setting-up wood machining operations with complex paths still relies mainly on the experience of the operators because of the lack of scientific knowledge easily transferable to the industry. The aim of the present work is to propose an empirical model based on specific cutting coefficients for the assessment of cutting force when peripheral milling of wood based on the following input: uncut chip thickness and width, grain angle (angle between the tool velocity vector and the grain direction of the wood), density and tool helix angle. The specific cutting coefficients were determined by peripheral milling with different depths of cut wood disks issued from different wood species on a dynamometric platform to record the forces. Milling a sample into a round shape (a disk) allows to measure the cutting forces toward every grain angle into a sole basic diameter reduction operation. Force signals are then post-processed to carefully clean the natural vibrations of the system without impacting their magnitudes. The experiment is repeated on five species with a large range of densities, machining two disks per species for five depths of cut in up- and down milling conditions for three different tool helix angles. Finally, a simple cutting force model, based on the previously cited parameters, is proposed, and its robustness analysed.

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Physics-Based Predictive Cutting Force Model in Ultrasonic-Vibration-Assisted Grinding for Titanium Drilling

Journal of Manufacturing Science and Engineering ◽

10.1115/1.3159050 ◽

2009 ◽

Vol 131 (4) ◽

Cited By ~ 45

Author(s):

Na Qin ◽

Z. J. Pei ◽

C. Treadwell ◽

D. M. Guo

Keyword(s):

Cutting Force ◽

Ultrasonic Vibration ◽

Removal Rate ◽

Cutting Temperature ◽

Brittle Materials ◽

Force Model ◽

Rotary Ultrasonic Machining ◽

Cutting Force Model ◽

Input Variables ◽

Ultrasonic Vibration Assisted Grinding

Ultrasonic-vibration-assisted grinding (UVAG) or rotary ultrasonic machining has been investigated both experimentally and theoretically. Effects of input variables on output variables in UVAG of brittle materials and titanium (Ti) have been studied experimentally. Models to predict the material removal rate in UVAG of brittle materials have been developed. However, there is no report on models of cutting force in UVAG. This paper presents a physics-based predictive model of cutting force in the UVAG of Ti. Using the model developed, influences of input variables on cutting force are predicted. These predicted influences are compared with those determined experimentally. This model can serve as a useful template and foundation for development of cutting force models in UVAG of other materials (such as ceramics and stainless steels) and models to predict torque, cutting temperature, tool wear, and surface roughness in UVAG.

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