Frequency Response Studies using Receptance Coupling Approach in High Speed Spindles

2018 ◽  
Vol 100 (2) ◽  
pp. 311-322
Author(s):  
Jakeer Hussain Shaik ◽  
K. Ramakotaiah ◽  
J. Srinivas
Keyword(s):  
Frequency Response ◽  
High Speed ◽  
Receptance Coupling ◽  
Coupling Approach

A Study of Linear Joint and Tool Models in Spindle-Holder-Tool Receptance Coupling

2005 ◽  
Author(s):  
Timothy J. Burns ◽  
Tony L. Schmitz
Keyword(s):  
Frequency Response ◽  
High Speed ◽  
Nonlinear Least Squares ◽  
Analytical Models ◽  
Connection Matrix ◽  
Depth Of Cut ◽  
Combined System ◽  
Receptance Coupling ◽  
Overhang Length ◽  
Exponential Trend

The dynamics of a spindle-holder-tool (SHT) system during high-speed machining is sensitive to changes in tool overhang length. A well-known method for predicting the limiting depth of cut for avoidance of tool chatter requires a good estimate of the tool-point frequency response (FRF) of the combined system, which depends upon the tool length. In earlier work, a combined analytical and experimental method has been discussed, that uses receptance coupling substructure analysis (RCSA) for the rapid prediction of the combined spindle-holder-tool FRF. The basic idea of the method is to combine the measured direct displacement vs. force receptance (i.e., frequency response) at the free end of the spindle-holder (SH) system with calculated expressions for the tool receptances based on analytical models. The tool was modeled as an Euler-Bernoulli (EB) beam, the other three spindle-holder receptances were set equal to zero, and the model for the connection with the tool led to a diagonal matrix. The main conclusion of the earlier work was that there was an exponential trend in the dominant connection parameter, which enabled interpolation between tip receptance data for the longest and shortest tools in the combined SHT system. Thus, a considerable savings in time and effort could be realized for the particular SHT system. A question left open in the earlier work was: how general is this observed exponential trend? Here, to explore this question further, an analytical EB model is used for the SH system, so that all four of its end receptances are available, and the tool is again modeled as a free-free EB beam that is connected to the SH by a specified connection matrix, that includes nonzero off-diagonal terms. This serves as the “exact” solution. The approximate solution is once again formed by setting all but one SH receptance equal to zero, and the connection parameters are determined using nonlinear least squares software. Both diagonal and full connection matrices are investigated. The main result is that, for this system, in the case of a diagonal connecting matrix, there is no apparent trend in the dominant connecting spring stiffness with tool overhang length. However, in the full connecting matrix case, a general constant trend is observed, with some interesting exceptions.

Tool Point Frequency Response Prediction for High-Speed Machining by RCSA

2001 ◽  
Vol 123 (4) ◽  
pp. 700-707 ◽  
Author(s):  
Tony L. Schmitz ◽  
Matthew A. Davies ◽  
Michael D. Kennedy
Keyword(s):  
Frequency Response ◽  
High Speed ◽  
Response Prediction ◽  
High Speed Machining ◽  
Receptance Coupling ◽  
Substructure Analysis ◽  
Receptance Coupling Substructure Analysis ◽  
Shrink Fit ◽  
Chatter Stability Prediction ◽  
Analytic Prediction

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.

scholarly journals Prediction of the Frequency Response Function of a Tool Holder-Tool Assembly Based on Receptance Coupling Method

2018 ◽  
Vol 8 (6) ◽  
pp. 3556-3560
Author(s):  
X. J. Xuan ◽  
Z. H. Haung ◽  
K. D. Wu ◽  
J. P. Hung
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
High Speed ◽  
Milling Process ◽  
Element Analysis ◽  
Tool Holder ◽  
Machine Performance ◽  
Receptance Coupling ◽  
Overhang Length

Regenerative chatter has a fatal influence on machine performance in high-speed milling process. Basically, machine condition without chattering can be selected from the stability lobes diagram, which is estimated from the tool point frequency response function (FRF). However, measurements of the tool point FRF would be a complicated and time-consuming task with less efficiency. Therefore prediction of the tool point FRF is of importance for further calculation of the machining stability. This study employed the receptance coupling analysis method to predict the FRF of a tool holder-tool module, which is normally composed of substructures, tool holder and cutter with different length. In this study, the angular components of FRFs of the substructures required for coupling operation were predicted by finite element analysis, apart from the translational components measured by vibration experiments. Using this method, the effects of the overhang length of the cutter on the dynamic characteristics have been proven and successfully verified by the experimental measurements. The proposed method can be an effective way to accurately predict the dynamic behavior of the spindle tool system with different tool holder-tool modules.

Receptance Coupling Study of Tool-Length Dependent Dynamic Absorber Effect

2004 ◽  
Author(s):  
Timothy J. Burns ◽  
Tony L. Schmitz
Keyword(s):  
Frequency Response ◽  
High Speed ◽  
Removal Rate ◽  
Stability Lobe ◽  
Receptance Coupling ◽  
Rapid Prediction ◽  
Substructure Analysis ◽  
Dynamic Absorber ◽  
Receptance Coupling Substructure Analysis ◽  
Free Material

The chatter-free material removal rate during high-speed machining of aluminum using long, slender endmills is limited by the cutting system dynamics, which changes with the tool length. Traditional stability-lobe diagrams that predict the maximum allowable chip width for a given spindle speed are determined using the tool point frequency response function. A brief review is given of a combined analytical and experimental method that uses receptance coupling substructure analysis (RCSA) for the rapid prediction of the tool-point frequency response as the tool length is varied. The basic idea of the method is to combine the measured direct displacement vs. force receptance (i.e., frequency response) at the free end of the spindle-holder system with analytical expressions for the tool receptances. The method is then used to provide an explanation for the dynamic absorber effect that has been observed in the context of tool-length tuning.

Intercellular communication between ciliated cells in culture

1988 ◽  
Vol 254 (1) ◽  
pp. C63-C74 ◽  
Author(s):  
M. J. Sanderson ◽  
I. Chow ◽  
E. R. Dirksen
Keyword(s):  
Frequency Response ◽  
Mechanical Stimulation ◽  
Intercellular Communication ◽  
High Speed ◽  
Beat Frequency ◽  
Computer Assisted ◽  
Image Analysis System ◽  
Ciliated Cells ◽  
Short Delay ◽  
Similar Frequency

Cultured mammalian ciliated cells from the respiratory tract respond to mechanical stimulation of their cell surface by displaying a rapid transient increase in beat frequency. Surrounding adjacent and more distal neighboring ciliated cells display a similar frequency response after a short delay that is proportional to their distance from the stimulated cell. To characterize the progression of this communicated response we developed an automated computer-assisted image-analysis system to examine high-speed films of responding cells. Transmission of the frequency response between cells occurs at 0.63 cells/s at 25 degrees C and 1.54 cells/s at 37 degrees C. We have also confirmed that gap junctions exist between cells in both epithelial explants and outgrowths and that adjacent or nonadjacent ciliated, as well as nonciliated, cells are electrically coupled. We postulate that mechanical stimulation and intercellular communication provide a mechanism to regulate beat frequency between ciliated cells in order to facilitate efficient ciliary function and mucus transport.

scholarly journals Modeling of Position-, Tool- and Workpiece-Dependent Milling Machine Dynamics

2016 ◽  
Vol 2 (1) ◽  
Author(s):  
Christian Brecher ◽  
Marcel Fey ◽  
Matthias Daniels
Keyword(s):  
Machine Tool ◽  
High Speed ◽  
Dynamic Properties ◽  
Major Effect ◽  
Modeling Framework ◽  
Milling Tool ◽  
Milling Machines ◽  
Engagement Process ◽  
Coupling Approach ◽  
Interpolation Strategy

AbstractDepending on the machine design, milling machines can show a significant variation of their dynamic properties with respect to the axes configurations, in particular at high speed spindle rotations and high feedrates. Moreover, the workpiece and the milling tool are critical parts of the machine tool and can have a major effect on the dynamic properties. Certain combinations of milling tool,workpiece, tool engagement, process parameters and axes configurations can come along with undesired forced or self-excited vibrations. So far, planning of milling processes usually does not account for these unwanted vibrations. The focus of this paper is to present a modeling framework, which accounts for the abovementioned influences via simulation. The dynamic properties of various workpieces and tools as well as the dynamic properties for many different axes configurations are stored in databases. Based on these databases, the dynamics of any given machine tool configuration can be simulated efficiently based on a substructure coupling approach and an interpolation strategy.

Simultaneous Time-Frequency Control of Multi-Dimensional Micro-Milling Instability

2012 ◽  
Author(s):  
Meng-Kun Liu ◽  
Eric B. Halfmann ◽  
C. Steve Suh
Keyword(s):  
Frequency Response ◽  
High Speed ◽  
Frequency Control ◽  
External Perturbation ◽  
Micro Milling ◽  
Time Frequency ◽  
System A ◽  
Control Concept ◽  
The Time Domain ◽  
Tool Damage

A novel control concept is presented for the online control of a high-speed micro-milling model system in the time and frequency domains concurrently. Micro-milling response at high-speed is highly sensitive to machining condition and external perturbation, easily deteriorating from bifurcation to chaos. When losing stability, milling time response is no longer periodic and the frequency response becomes broadband, rendering aberrational tool chatter and probable tool damage. The controller effectively mitigates the nonlinear vibration of the tool in the time domain and at the same time confines the frequency response from expanding and becoming chaotically broadband. The simultaneous time-frequency control is achieved through manipulating wavelet coefficients, thus not limited by the increasing bandwidth of the chaotic system — a fundamental restraint that deprives contemporary controller designs of validity and effectiveness. The feedforward feature of the control concept prevents errors from re-entering the control loop and inadvertently perturbing the sensitive micro-milling system. Because neither closed-form nor linearization is required, the innate, genuine features of the micro-milling response are faithfully retained.

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