Dynamics Modeling of Clamping System Considering Characteristics of the Clamping Contact Surface

Author(s):  
Yanmin Zhao ◽  
Jianfu Zhang ◽  
Pingfa Feng ◽  
Yuan Ma

The dynamic characteristics of the clamping system, which is composed of workpiece and chuck, have important effects on the stability of turning process. However, in current researches on cutting stability, the influence of the characteristics of clamping contact surface on the clamping system was rarely considered. In order to improve the prediction accuracy of stable cutting limits in turning process, the role of clamping contact surface in deciding the dynamics of the clamping system was analyzed in this paper. Then, the dynamics model of clamping system was established considering the characteristics of clamping contact surface between workpiece and chuck. The dynamics parameters of the clamping system were obtained with receptance coupling substructure analysis method. The frequency response function of clamping system at different cutting position was presented, which is a foundation for analyzing the cutting stability.

Author(s):  
Rong Yan ◽  
Xiaowei Tang ◽  
Fangyu Peng ◽  
Yuting Li ◽  
Hua Li

The stability lobe diagrams predicted using the tool frequency response function (FRF) at the idle state usually have discrepancies compared with the actual stability cutting boundary. These discrepancies can be attributed to the effect of spindle rotating on the tool FRFs which are difficult to measure at the rotating state. This paper proposes a new tool FRF identification method without using noncontact sensor for the rotating state of the spindle. In this method, the FRFs with impact applied on smooth rotating tool and vibration response tested on spindle head are measured for two tools of different lengths clamped in spindle–holder assembly. Based on those FRFs, an inverse receptance coupling substructure analysis (RCSA) algorithm is developed to identify the FRFs of spindle–holder–partial tool assembly. A finite-element modeling (FEM) simulation is performed to verify the validity of inverse RCSA algorithm. The tool point FRFs at the spindle rotating state are obtained by coupling the FRFs of the spindle–holder–partial tool and the other partial tool. The effects of spindle rotational speed on tool point FRFs are investigated. The cutting experiment demonstrates that this method can accurately identify the tool point FRFs and predict cutting stability region under spindle rotating state.


2005 ◽  
Vol 127 (4) ◽  
pp. 781-790 ◽  
Author(s):  
Tony L. Schmitz ◽  
G. Scott Duncan

In this paper we present the second generation receptance coupling substructure analysis (RCSA) method, which is used to predict the tool point response for high-speed machining applications. This method divides the spindle-holder-tool assembly into three substructures: the spindle-holder base; the extended holder; and the tool. The tool and extended holder receptances are modeled, while the spindle-holder base subassembly receptances are measured using a “standard” test holder and finite difference calculations. To predict the tool point dynamics, RCSA is used to couple the three substructures. Experimental validation is provided.


2021 ◽  
Vol 11 (18) ◽  
pp. 8527
Author(s):  
Ji-wook Kim ◽  
Jae-wook Lee ◽  
Kun-woo Kim ◽  
Ji-heon Kang ◽  
Min-seok Yang ◽  
...  

One of the factors that influence the dynamic characteristics of machining systems is the cutting tool. Cutting tools are very diverse, and receptance coupling substructure analysis (RCSA) is essential for analyzing the dynamic characteristics of each tool. For RCSA, a full receptance matrix of the equipment and tools is essential. In this study, rotational degree-of-freedom receptance was estimated and analyzed using translational receptance. Displacement/moment receptance was analyzed according to the distance of the response point using the first-and second-order finite difference methods. The rotation/moment receptance was estimated according to the distance of the response point. Rotation/moment receptance was analyzed using Schmitz’s method and compensation strategies. The limitations of these strategies were analyzed, and the rotation/moment receptance for the beam under free-free boundary conditions was predicted using the second compensation strategy.


Author(s):  
M. M. Rezaei ◽  
M. R. Movahhedy ◽  
M. T. Ahmadian ◽  
H. Moradi

Receptance coupling substructure analysis (RCSA) is extensively used to determine the dynamic response of milling tool at its tip for the purpose of prediction of machining stability. A major challenge in using this approach is the proper modelling of the joint between the substructures and determination of its parameters. In this paper, an inverse RCSA is developed for experimental extraction of tool-holder frequency response function (FRF) including joint parameters. The accuracy and efficiency of this method is evaluated through an analytical investigation. It is shown that the extracted holder FRF can provide a highly accurate prediction of the tool tip FRF. The developed method is used in prediction of tool tip FRF with different values of the tool overhang. The proposed approach is validated through experimental validation.


2013 ◽  
Vol 345 ◽  
pp. 539-542
Author(s):  
Li Jun Zhai ◽  
Xiao Lei Song ◽  
Li Gang Cai

Stiffness identification of toolholder-spindle joint is a basic work for machine tool dynamic research. In this paper, an identification method based on receptance coupling substructure analysis is described. Once the frequency response functions of the toolholder, the spindle and the toolholder-spindle assembly are obtained, the analytical stiffness could be calculated. The method is verified efficiency through dynamic response experiment. Identified stiffness results under different drawbar forces are also discussed.


2011 ◽  
Vol 223 ◽  
pp. 622-631 ◽  
Author(s):  
Iker Mancisidor ◽  
Mikel Zatarain ◽  
Jokin Munoa ◽  
Zoltan Dombovari

In many applications, chatter free machining is limited by the flexibility of the tool. Estimation of that capacity requires to obtain the dynamic transfer function at the tool tip. Experimental calculation of that Frequency Response Function (FRF) is a time consuming process, because it must be done using an impact test for any combination of tool, toolholder and machine. The bibliography proposes the Receptance Coupling Substructure Analysis (RCSA) to reduce the number of experimental test. A new approach consisting of calculating the fixed boundary dynamic behaviour of the tool is proposed in the paper. This way the number of modes that have to be considered is low, just one or two for each bending plane, and it supposes an important improvement in the application of the RCSA to the calculation of stability diagrams. The predictions of this new method have been verified experimentally.


2001 ◽  
Vol 123 (4) ◽  
pp. 700-707 ◽  
Author(s):  
Tony L. Schmitz ◽  
Matthew A. Davies ◽  
Michael D. Kennedy

The implementation of high-speed machining for the manufacture of discrete parts requires accurate knowledge of the system dynamics. We describe the application of receptance coupling substructure analysis (RCSA) to the analytic prediction of the tool point dynamic response by combining frequency response measurements of individual components through appropriate connections. Experimental verification of the receptance coupling method for various tool geometries (e.g., diameter and length) and holders (HSK 63A collet and shrink fit) is given. Several experimental results are presented to demonstrate the practical applicability of the proposed method for chatter stability prediction in milling.


Author(s):  
Lu Xiaohong ◽  
Jia Zhenyuan ◽  
Zhang Haixing ◽  
Liu Shengqian ◽  
Feng Yixuan ◽  
...  

One of the challenges in micromilling processing is chatter, an unstable phenomenon which has a larger impact on the microdomain compared to macro one. The minimization of tool chatter is the key to good surface quality in the micromilling process, which is also related to the milling tool and the milling structure system dynamics. Frequency response function (FRF) at micromilling tool point describes dynamic behavior of the whole micromilling machine-spindle-tool system. In this paper, based on receptance coupling substructure analysis (RCSA) and the consideration of rotational degree-of-freedom, tool point frequency response function of micromilling dynamic system is obtained by combining two functions calculated from beam theory and obtained by hammer testing. And frequency response functions solved by Timoshenko's and Euler's beam theories are compared. Finally, the frequency response function is identified as the modal parameters, and the modal parameters are transformed into equivalent structural parameters of the physical system. The research work considers the difference of theoretical modeling between the micromilling and end-milling tool and provides a base for the dynamic study of the micromilling system.


2014 ◽  
Vol 1006-1007 ◽  
pp. 398-402
Author(s):  
Kun Long Wen ◽  
Hou Jun Qi

Tool point frequency response function (FRF) is the key parameters to predict the milling stability in high-speed milling. Receptance coupling substructure analysis (RCSA) is described to predict the tool point FRF. The major difficulties in RCSA are the identification of joint connection parameters and the obtaining of FRFs of substructure. This paper separation of the milling system into three substructures: the machine-spindle-holder taper, the extended holder-tool shank, and the tool extended portion. Develop the connection model compose of linear and rotational springs and dampers. Determine the substructure FRF by measurement and Euler-Bernoulli beam model. Tool point FRF is obtained by coupling the substructure FRFs through the connection model by RCSA.


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