Assessment of Friction Behavior with Surface Location Error Analysis in Milling Process

2019 ◽  
Vol 823 ◽  
pp. 129-134
Author(s):  
N.A. Rafan ◽  
Siti Nur Madihah Ab Rashid ◽  
Z. Jamaludin

Accurate roundness or circularity measurement is essential to obtain correct functioning of assemblies, making roundness an important quality control parameter in manufacturing industry. Since circular motion while milling a circular work piece leads to quadrant glitches, a phenomenon familiar with existence of highly nonlinear friction behavior, roundness measurement was conducted to investigate this surface location error due to feed rate of the moving work table. This paper presents friction behavior on a milling process circular work piece in line resulted from identified surface error location (SLE).

Author(s):  
Zhongyun Li ◽  
Shanglei Jiang ◽  
Yuwen Sun

Together with machining chatter, surface location error induced by forced vibration may also inhibit productivity and affect workpiece surface quality in milling process. Addressing these issues needs the combined consideration of stability lobes diagram and surface location error predictions. However, mode coupling and process damping are seldom taken into consideration. In this article, an extended dynamic milling model including mode coupling and process damping is first built based on classical 2-degree-of-freedom dynamic model with regeneration. Then, a second-order semi-discretization method is proposed to simultaneously predict the stability lobes diagram and surface location error by solving this extended dynamic model. The rate of convergence of the proposed method is also investigated. Finally, a series of experiments are conducted to verify the veracity of the extended dynamic model. The modal parameters including direct and cross terms are identified by impact experiments. Via experimental verification, the experimental results show a good correlation with the predicted stability lobes diagram and surface location error based on the extended dynamic model. Also, the effects of mode coupling and process damping are revealed. Mode coupling increases the whole stability region; however, process damping plays a vital role in stability improvement mainly at low spindle speeds.


Author(s):  
Tama´s Insperger ◽  
Janez Gradisek ◽  
Martin Kalveram ◽  
Ga´bor Ste´pa´n ◽  
Klaus Weinert ◽  
...  

Two degree of freedom model of milling process is investigated. The governing equation of motion is decomposed into two parts: an ordinary differential equation describing the stable periodic motion of the tool and a delay-differential equation describing chatter. Stability chart is derived by using semi-discretization method for the delay-differential equation corresponding to the chatter motion. The stable periodic motion of the tool and the associated surface location error are obtained by a conventional solution technique of ordinary differential equations. Stability chart and surface location error are determined for milling process. It is shown that at spindle speeds, where high depths of cut are available through stable machining, the surface location error is large. The phase portrait of the tool is also analyzed for different spindle speeds. Theoretical predictions are qualitatively confirmed by experiments.


2004 ◽  
Vol 127 (3) ◽  
pp. 446-453 ◽  
Author(s):  
Brian P. Mann ◽  
Keith A. Young ◽  
Tony L. Schmitz ◽  
David N. Dilley

Optimizing the milling process requires a priori knowledge of many process variables. However, the ability to include both milling stability and accuracy information is limited because current methods do not provide simultaneous milling stability and accuracy predictions. The method described within this paper, called Temporal Finite Element Analysis (TFEA), provides an approach for simultaneous prediction of milling stability and surface location error. This paper details the application of this approach to a multiple mode system in two orthogonal directions. The TFEA method forms an approximate analytical solution by dividing the time in the cut into a finite number of elements. The approximate solution is then matched with the exact solution for free vibration to obtain a discrete linear map. The formulated dynamic map is then used to determine stability, steady-state surface location error, and to reconstruct the time series for a stable cutting process. Solution convergence is evaluated by simply increasing the number of elements and through comparisons with numerical integration. Analytical predictions are compared to several different milling experiments. An interesting period two behavior, which was originally believed to be a flip bifurcation, was observed during experiment. However, evidence is presented to show this behavior can be attributed to runout in the cutter teeth.


2017 ◽  
Vol 8 (2) ◽  
pp. 385-392
Author(s):  
Xianzhen Huang ◽  
Fangjun Jia ◽  
Yimin Zhang ◽  
Jinhua Lian

Abstract. Machining accuracy of a milled surface is influenced by process dynamics. Surface location error (SLE) in milling determines final dimensional accuracy of the finished surface. Therefore, it is critical to predict, control, and minimize SLE. In traditional methods, the effects of uncertain factors are usually ignored during prediction of SLE, and this would tend to generate estimation errors. In order to solve this problem, this paper presents methods for probabilistic analysis of SLE in milling. A dynamic model for milling process is built to determine relationship between SLE and cutting parameters using full-discretization method (FDM). Monte-Carlo simulation (MCS) method and artificial neural network (ANN) based MCS method are proposed for predicting reliability of the milling process. Finally, a numerical example is used to evaluate the accuracy and efficiency of the proposed method.


2009 ◽  
pp. 173-198
Author(s):  
Tony L. Schmitz ◽  
Kevin S. Smith

Author(s):  
Zhiyong Chen ◽  
Hai-Tao Zhang ◽  
Xiaoming Zhang ◽  
Han Ding

Chatter is an undesirable dynamic phenomenon in machining processes, which causes cutting disturbance, overcut, quick tool wear, etc., and thus seriously impairs workpiece quality. To mitigate chatter, traditional methods called passive control focus on optimizing working spindle speeds and depths of cut. But they have inherent disadvantages in gaining highly efficient machining. On the contrary, the research in this paper is along the line of active control. Specifically, an adaptive algorithm is developed based on Fourier series analysis to deal with the so-called regenerative cutting force which causes chatter. As a result, chatter is remarkably mitigated. The performance improvement is illustrated by numerical simulation in terms of both stability lobes diagram (SLD) and surface location error (SLE).


2020 ◽  
Vol 177 ◽  
pp. 105543 ◽  
Author(s):  
Dongqian Wang ◽  
Michael Löser ◽  
Yunhu Luo ◽  
Steffen Ihlenfeldt ◽  
Xibin Wang ◽  
...  

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