“…The above considerations exemplify a significant progress with respect to the previous ones [7,31], because now the non-linear feedback interactions are additionally included.…”
Section: Cutting Process Dynamicsmentioning
confidence: 93%
“…Based on this model, the cutting forces depend proportionally on the instant thickness of the cutting layer h l (t), as well as on the instant width of the cutting layer b l (t); both differ in time. According to the direction of the action, we separate cutting force component F yl1 acting along nominal cutting velocity v c , cutting force component F yl2 acting along cutting layer thickness, and additionally in contrast to previous approaches [23,31]-cutting force component F yl3 acting along cutting layer width (Fig. 1).…”
The paper presents an original method concerning vibration suppression problem during milling of large-size and geometrically complicated workpieces with the use of novel way of selecting the spindle speed. This consists in repetitive simulations of the cutting process for subsequent values of the spindle speed, until the best vibration state of the workpiece is reached. An appropriate method of obtaining a computational model, called a modal approach, consists in identifying the parameters of the workpiece model created using the Finite Element Method (FEM). Thanks to the results of the identification of the modal subsystem obtained by the Experimental Modal Analysis (EMA) method, it can be stated that the parameters obtained from the experiment and delivered from the computational model have been correctly determined and constitute reliable process data for the simulation tests. The Root Mean Square (RMS) values of time domain displacements are evaluated. The efficiency of the proposed approach is evidenced by chosen technique of mechatronic design, called Experiment Aided Virtual Prototyping (EAVP). The proposed method is verified on the basis of the results of the experimental research of the relevant milling process.
“…The above considerations exemplify a significant progress with respect to the previous ones [7,31], because now the non-linear feedback interactions are additionally included.…”
Section: Cutting Process Dynamicsmentioning
confidence: 93%
“…Based on this model, the cutting forces depend proportionally on the instant thickness of the cutting layer h l (t), as well as on the instant width of the cutting layer b l (t); both differ in time. According to the direction of the action, we separate cutting force component F yl1 acting along nominal cutting velocity v c , cutting force component F yl2 acting along cutting layer thickness, and additionally in contrast to previous approaches [23,31]-cutting force component F yl3 acting along cutting layer width (Fig. 1).…”
The paper presents an original method concerning vibration suppression problem during milling of large-size and geometrically complicated workpieces with the use of novel way of selecting the spindle speed. This consists in repetitive simulations of the cutting process for subsequent values of the spindle speed, until the best vibration state of the workpiece is reached. An appropriate method of obtaining a computational model, called a modal approach, consists in identifying the parameters of the workpiece model created using the Finite Element Method (FEM). Thanks to the results of the identification of the modal subsystem obtained by the Experimental Modal Analysis (EMA) method, it can be stated that the parameters obtained from the experiment and delivered from the computational model have been correctly determined and constitute reliable process data for the simulation tests. The Root Mean Square (RMS) values of time domain displacements are evaluated. The efficiency of the proposed approach is evidenced by chosen technique of mechatronic design, called Experiment Aided Virtual Prototyping (EAVP). The proposed method is verified on the basis of the results of the experimental research of the relevant milling process.
“…l are related to the vector of generalized displacements q of the structural system using the time-dependent constraints equation [ 32 ]: where: T l ( t )—transformation matrix of displacements vector q from the x e 1 , x e 2 , x e 3 coordinates of E-BBs, e = 1, …, 4, to the coordinate system y l 1 , y l 2 , y l 3 of CE no. l [ 32 , 35 , 39 ].…”
The paper presents a thoroughly modified method of solving the problem of vibration suppression when boring large-diameter holes in large-size workpieces. A new approach of adjusting the rotational speed of a boring tool is proposed which concerns the selection of the spindle speed in accordance with the results of the simulation of the cutting process. This streamlined method focuses on phenomenological aspects and involves the identification of a Finite Element Model (FEM) of a rotating boring tool only and validating it with a real object, while dispensing with discrete modelling of a completely rigid workpiece. In addition, vibrations in the boring process in all directions were observed, which implies a geometric nonlinearity of the process model. During the simulation, the values of the Root Mean Square (RMS) of the time plots and the dominant values of the “peaks” in the displacement amplitude spectra were obtained. The effectiveness of the method was demonstrated using a selected mechatronic design technique called Experiment-Aided Virtual Prototyping (E-AVP). It was successfully verified by measuring the roughness of the indicated zone of the workpiece surface. The economic profitability of implementing the method in the production practice of enterprises dealing with mechanical processing is also demonstrated.
“…Kaliński and Galewski [22] suggested an original procedure of the spindle speed optimisation, based on the Liao-Young criterion, in order to reduce vibration level during ball end milling of flexible parts. Another approach to avoid the vibration during machining by adjusting the stiffness of the workpiece holder to the real cutting conditions was presented by Kaliński et al in [23]. The calculation of the optimum stiffness has to be performed before milling, based on the workpiece's modal identification results and the finite element model simulations.…”
Section: Review Of Related Research Workmentioning
The article presents the method for the evaluation of selected manufacturing processes using the analysis of vibration and sound signals. This method is based on the use of sensors installed outside the machining zone, allowing to be used quickly and reliably in real production conditions. The article contains a developed measurement methodology based on the specific location of microphones and vibration transducers mounted on the tested object, in this case on a four-axis CNC ST20Y Haas lathe. A mobile phone was integrated into the measuring system and used to control the measurement process. The results from the analysis of vibration and sound signals recorded during different machining operations are presented. They refer to selected working conditions of a machine tool depending on switching the coolant supply on or off and different machine loads caused by various technological processing as well as the various speed of the positioning movements. The analysis was carried out using selected point measures describing the vibroacoustic signals. The synthesis conducted on the basis of results from the experiments indicates the validity of using vibration and acoustic signals, recorded outside the machining area, to evaluate material removal processes that are diverse in terms of kinematics and processing conditions. It indicates the possibility of using proposed point measures of vibroacoustic signals in the diagnostic aspects of the machine tools to achieve high dimension and shape accuracy and to evaluate the condition of the technological devices in terms of their optimal efficiency. Presented methodology can be used as a supporting tool in the CAD/CAM software for a better selection of appropriate cutting parameters and for a wireless control of manufacturing systems consisting of several machine tools.
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