A New Method for Identifying the Cutter Runout Parameters in Flat End Milling Process

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.

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.


Author(s):  
Xuewei Zhang ◽  
Tianbiao Yu ◽  
Wanshan Wang

An accurate prediction of cutting forces in the micro end milling, which is affected by many factors, is the basis for increasing the machining productivity and selecting optimal cutting parameters. This paper develops a dynamic cutting force model in the micro end milling taking into account tool vibrations and run-out. The influence of tool run-out is integrated with the trochoidal trajectory of tooth and the size effect of cutting edge radius into the static undeformed chip thickness. Meanwhile, the real-time tool vibrations are obtained from differential motion equations with the measured modal parameters, in which the process damping effect is superposed as feedback on the undeformed chip thickness. The proposed dynamic cutting force model has been experimentally validated in the micro end milling process of the Al6061 workpiece. The tool run-out parameters and cutting forces coefficients can be identified on the basis of the measured cutting forces. Compared with the traditional model without tool vibrations and run-out, the predicted and measured cutting forces in the micro end milling process show closer agreement when considering tool vibrations and run-out.


2003 ◽  
Vol 17 (08n09) ◽  
pp. 1401-1407
Author(s):  
Young Moon Lee ◽  
Seung Han Yang ◽  
Seung Il Chang

In intermittent cutting processes, characterized by the use of rotating tools, the undeformed chip thickness varies periodically according to the phase change of tool. Although many studies have already concentrated on intermittent cutting processes, there has been no previous analysis of the shear and friction processes. In the current study, an up-end milling process is transformed into an equivalent oblique cutting process. The varying undeformed chip thicknesses and cutting forces in the up-end milling process are thus replaced with the equivalent average ones. As a result, the shear process in shear plane and the chip-tool friction process of intermittent cutting are analyzed using the equivalent oblique cutting model. The validity of the proposed analysis was verified based on two sets of cutting tests i.e. up-end milling and equivalent oblique cutting tests.


2000 ◽  
Vol 123 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Hsi-Yung Feng ◽  
Ning Su

This paper presents an improved mechanistic cutting force model for the ball-end milling process. The objective is to accurately model the cutting forces for nonhorizontal and cross-feed cutter movements in 3D finishing ball-end milling. Main features of the model include: (1) a robust cut geometry identification method to establish the complicated engaged area on the cutter; (2) a generalized algorithm to determine the undeformed chip thickness for each engaged cutting edge element; and (3) a comprehensive empirical chip-force relationship to characterize nonhorizontal cutting mechanics. Experimental results have shown that the present model gives excellent predictions of cutting forces in 3D ball-end milling.


2010 ◽  
Vol 102-104 ◽  
pp. 506-510 ◽  
Author(s):  
Ying Chun Liang ◽  
Kai Yang ◽  
Qing Shun Bai ◽  
W.Q. Chen

In this paper, the effect of minimum chip thickness on cutting temperature in micro-end- milling of aluminum alloy Al2024-T6 using a tungsten-carbide cutter are investigated and analyzed. The three-dimensional coupled thermal-mechanical finite element model is adopted to determine the effects of varying depth of cut on cutting temperature considering size effects. The simulation results show that the cutting temperature in micro-end-milling is lower than those occurring in conventional milling processes. When the depth of cut is approximately 40% of the cutting edge radius, there is no chip formation. The maximum temperature occurs at the contact region between micro cutting edge and workpiece, which shows an obvious size effect. The experimental verification of the simulation model is carried out on a micro-end-milling process of aluminum alloy 2024-T6 with a high precision infrared camera. The influence of various cutting depths on cutting temperature has been verified in experiments. The experimental measurements results are in a good agreement with the simulation results.


1998 ◽  
Vol 120 (4) ◽  
pp. 684-692 ◽  
Author(s):  
Y. Altıntas¸ ◽  
P. Lee

Mechanics and dynamics of cutting with helical ball end mills are presented. The helical ball end mill attached to the spindle is modelled by orthogonal structural modes in the feed and normal directions at the tool tip. For a given cutter geometry, the cutting coefficients are transformed from an orthogonal cutting data base using an oblique cutting model. The three dimensional swept surface by the cutter is digitized using the true trochoidal kinematics of ball end milling process in time domain. The dynamically regenerated chip thickness, which consists of rigid body motion of the tooth and structural displacements, is evaluated at discrete time intervals by comparing the present and previous tooth marks left on the finish surface. The process is simulated in time domain by considering the instantaneous regenerative chip load, local cutting force coefficients, structural transfer functions and the geometry of ball end milling process. The proposed model predicts cutting forces, surface finish and chatter stability lobes, and is verified experimentally under both static and dynamic cutting conditions.


Machines ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 27 ◽  
Author(s):  
Constantine David ◽  
Dimitrios Sagris ◽  
Evlampia Stergianni ◽  
Christos Tsiafis ◽  
Ioannis Tsiafis

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