scholarly journals An integral algorithm for instantaneous uncut chip thickness measuring in the milling process

2018 ◽  
Vol 13 (3) ◽  
pp. 297-306
Author(s):  
Y. Li ◽  
Z.J. Yang ◽  
C. Chen ◽  
Y.X. Song ◽  
J.J. Zhang ◽  
...  
2018 ◽  
Vol 764 ◽  
pp. 399-407
Author(s):  
Yue Zhang ◽  
Zhi Qiang Yu ◽  
Tai Yong Wang

The instantaneous uncut chip thickness is an important parameter in the study of milling force model. By analyzing the real tooth trajectory in milling process, accurate instantaneous uncut chip thickness can be obtained to solve the complex transcendental equation. Traditional chip thickness models always simplify the tooth trajectory to get approximate solution. A new instantaneous uncut chip thickness model is proposed in this paper. Based on real tooth trajectory of general end milling cutter, a Taylor's series is used to approximate the involved infinitesimal variable in the transcendental equation, which results in an explicit expression for practical application of the uncut chip thickness with higher accuracy compared to the traditional model.


Author(s):  
Nejah Tounsi ◽  
Tahany El-Wardany

Abstract Part I of these two-part papers will investigate the effect of three FEM representations of the milling process on the prediction of chip morphology and residual stresses (RS), when down-milling small uncut chips with thickness in the micrometer range and finite cutting edge radius. They are: i) orthogonal cutting with the mean uncut chip thickness t, obtained by averaging the uncut chip thickness over the cutting length, ii) orthogonal cutting with variable t, which characterizes the down-milling process and which is imposed on a flat surface of the final workpiece, and iii) modelling the true kinematics of the down milling process. The appropriate constitutive model is identified through 2D FEM investigation of the effects of selected constitutive equations and failure models on the prediction of RS and chip morphology in the dry orthogonal machining of Ti6Al4V and comparison to experimental measurements. The chip morphology and RS prediction capability of these representations is assessed using the available set of experimental data. Models featuring variable chip thickness have revealed the transition from continuous chip formation to the rubbing mode and have improved the predictions of residual stresses. The use of sequential cuts is necessary to converge toward experimental data.


Author(s):  
Qiang Guo ◽  
Yan Jiang ◽  
Zhibo Yang ◽  
Fei Yan

As a key factor, the accuracy of the instantaneous undeformed thickness model determines the force-predicting precision and further affects workpiece machining precision in the micro-milling process. The runout with five parameters affects the machining process more significantly compared with macro-milling. Furthermore, modern industry uses cutters with non-uniform pitch and helix angles more and more common for their excellent properties. In this article, an instantaneous undeformed thickness model is presented regarding cutter runout, variable pitch, and helix angles in the micro-milling process. The cutter edge with the cutter runout effect is modeled. Then, the intersecting ellipse between the plane vertical to the spindle axis and the cutter surface which is a cylinder can be gained. Based on this, the points, which are used to remove the material, on the ellipse as well as cutter edges are calculated. The true trochoid trajectory for each cutting point along the tool path is built. Finally, the instantaneous undeformed thickness values are computed using a numerical algorithm. In addition, this article analyzes runout parameters’ effects on the instantaneous undeformed thickness values. After that, helix and pitch angles’ effects on the instantaneous undeformed thickness are studied. Ultimately, the last section verifies the correctness and validity of the instantaneous undeformed thickness model based on the experiment conducted in the literature.


2011 ◽  
Vol 697-698 ◽  
pp. 75-79 ◽  
Author(s):  
Y. Yang ◽  
Min Wan ◽  
Wei Hong Zhang ◽  
Y. Li

Analysis of instantaneous uncut chip thickness (IUCT) in peripheral milling of curved surface with variable curvature is nontrivial due to the combined influences of both process geometry and cutter runout. This paper gives a systematic analysis of IUCT including the effects of changing workpiece geometry and the cutter runout in peripheral milling. The prominent feature of this analysis procedure lies in that the novel equation for computing the IUCT is mathematically derived in detail. Numerical simulations are performed to study the effect of workpiece curvature and cutter runout on IUCT. The proposed model is validated by comparing the measured cutting forces with those predicted based on the IUCT which is obtained using the current approach.


2011 ◽  
Vol 4 (4) ◽  
pp. 1387-1393 ◽  
Author(s):  
Zhenyu Han ◽  
Xiang Zhang ◽  
Yazhou Sun ◽  
Hongya Fu ◽  
Yingchun Liang

Author(s):  
Nejah Tounsi ◽  
Tahany El-Wardany

Abstract In part II of these two-part papers, the effects of four FEM representations of the milling process on the prediction of chip morphology and residual stresses (RS) are investigated. Part II focuses on the milling of conventional uncut chip thickness h with finite cutting edge radius and flank wear, while part I of these two-part papers has reported on the results in the case of milling small uncut chip thickness in the micrometre range with finite cutting edge radius. Two geometric models of the flank-wear land composed of flat and curved wear land are proposed and assessed. The four process representations are: i) orthogonal cutting with flat wear land and with the mean uncut chip thickness h ¯; ii) orthogonal cutting with flat wear land and with variable h, which characterises the down-milling process and which is imposed on a flat surface of the final workpiece; iii) modelling the true kinematics of the down milling process with flat wear land and iv) modelling the true kinematics of the down milling process with curved wear land. They are designated as Cte-h, Var-h, True-h and True-h*. The effectiveness of these representations is assessed when milling Ti6Al4V with a flank-wear land of VB = 200µm.


2011 ◽  
Vol 697-698 ◽  
pp. 71-74 ◽  
Author(s):  
Min Wan ◽  
M.S. Lu ◽  
Wei Hong Zhang ◽  
Y. Yang ◽  
Y. Li

Cutter runout will redistribute the instantaneous uncut chip thickness and the cutting forces in multi-fluted milling process. In this paper, a new procedure is proposed to identify the cutter runout parameters for flat end milling process. By combining least-square method, mathematical derivations and implementation procedures are carried out based on the relative deviation between each cutting edge and the spindle rotation center, measured by a dial gauge. Numerical verifications are conducted to validate the proposed procedures, and the results show that they are efficient and reliable. It is also suggested that to weaken the influence of noise signal, measurements should be conducted at multiple axial positions.


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