Vibration Analysis of High-Speed End Milling Operations Applied to Injection Mold Materials

2017 ◽  
Author(s):  
Andris Logins ◽  
Toms Torims ◽  
Pedro Rosado Castellano ◽  
Santiago Gutiérrez ◽  
Rafael Torres
Keyword(s):  
Prediction Model ◽  
Surface Topography ◽  
High Speed ◽  
End Milling ◽  
Dynamical Behavior ◽  
Milling Process ◽  
Injection Mold ◽  
High Speed Milling ◽  
3D Surface Topography ◽  
End Milling Process

High-speed milling has often been applied in injection mold manufacturing processes, where surface roughness is a significant criterion in product quality demands. It is equally applicable to automotive or industrial engineering and to toy manufacturing, where plastic parts with a high-quality surface finish have been processed using the injection molding technique. High-speed milling involves a number of process parameters that may affect the 3D surface topography formation. Literature analysis reveals that dynamical behavior is a significant factor in the end milling process on surface roughness parameters. To improve the accuracy of predicted surface topography models, it is important to include the dynamical behavior of milling factor. This paper describes the surface prediction model of combined end-milling geometrical and dynamical interaction models. The natural frequency of machine assembly and forced vibrations during the cutting process were measured during the flat-end milling process. Unevenly distributed cutting marks were revealed by surface 3D topography images and microscopy images of the machined samples. A mathematical model to predict surface topography was developed, including dynamical behavior and cutting geometries. Machine accuracy also has to be addressed. 3D surface topography parameters from the experimental sample provided the results for the mathematical prediction model. This model offers a software tool for manufacturers to improve the quality of machined part surfaces, taking into account the behavioral properties of their machining equipment. Relevant conclusions about the manufacturing equipment accuracy have been drawn. Vibrations in the milling system affect the cutting process and contribute to the surface topography prediction model. Local cutting tool vibrations do not have any influence on surface parameter mean values.

scholarly journals Effects of machining system parameters and dynamics on quality of high-speed milling

2013 ◽  
Author(s):  
◽  
Khaled A. M. Adem
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
End Milling ◽  
Milling Process ◽  
Depth Of Cut ◽  
Force Model ◽  
Cutting Force Coefficients ◽  
High Speed Milling ◽  
End Milling Process ◽  
Axial Depth

This dissertation outlines research on studying the effects of machining parameters such that cutting speed, feed rate, axial depth of cut, radial depth of cut and helix angle on system dynamic stability and the surface quality of high-speed milling. With the use of structural tool modal parameters, the material cutting force coefficients and the axial depth of cut, the system can avoid the chatter phenomenon of the tool at high cutting speeds. The surface roughness finish in the milling process is determined by the machining parameters and tool structure dynamics. To perform high-speed milling, the chance of tool vibration (chatter phenomenon) which affects the cutting tool, must be minimized or eliminated. In this research, the linear and nonlinear mathematical force models including the effect of the helix angle are presented for an end-milling process. The linear force model includes cutting-edge coefficients. The cutting force coefficients are determined for an end-milling process using two methods, the average force method and the optimization technique method. The second method is developed to identify the cutting force coefficients in the milling process by forming the objective functions using the optimization technique to minimize the error between the experimental and the analytical forces. Moreover, this method produced a good force model that approximates the experimental force results, which compared with the average force method. The stability lobe diagrams are created using the analytical method to determine whether the cut is stable or unstable. In addition, simulations are performed to predict stability of the milling process. By comparing simulated and experimental results, the dynamics and stability of the milling operation can be easily identified before performing any cutting operation. The slot milling experiments show that while the system in the chatter region close to the stability limits and the axial depth of cut increased, the system changes from stable chatter to chaotic chatter. Furthermore, the nature of bifurcation in milling is investigated by performing experiments and simulations. The linear and nonlinear mathematical force models are used for simulating end-milling process. Simulated bifurcation diagrams are generated using both models and compared to experimental results. In addition, the effect of the feed rate on the location of the bifurcation point (start and end of bifurcation) is studied. By comparing simulated and experimental results, the simulation using a nonlinear force model is found more accurate in predicting the dynamics and stability of the milling operation. The applications of Taguchi and response surface methodologies (RSM) are used to minimize the surface roughness in the end milling process. Taguchi’s method for optimum selection of the milling process parameters is applied based on the signal to noise ratio and ANOVA analysis of the surface finish. A second-order model contains quadratic terms that have been created between the cutting parameters and surface roughness using response surface methodology (RSM). Surface roughness of the machined surfaces are measured and used to identify the optimum levels of the milling parameters. Based on Taguchi, ANOVA, and RSM analyses, the end milling process can be optimized to improve surface finish quality and machining productivity.

Predictive Model of Surface Roughness in High-Speed End Milling Process by Factorial Design of Experiments

2007 ◽  
Vol 339 ◽  
pp. 189-194
Author(s):  
Su Yu Wang ◽  
Xing Ai ◽  
Jun Zhao
Keyword(s):  
Surface Roughness ◽  
Design Of Experiments ◽  
Factorial Design ◽  
High Speed ◽  
End Milling ◽  
Milling Process ◽  
Regression Coefficients ◽  
Milling Parameters ◽  
Factorial Design Of Experiments ◽  
End Milling Process

Predictive models are presented for the surface roughness in high-speed end milling of 0.45%C steel and P20 die-mould steel based on statistical test and multiple-regression analysis. The data for establishing model is derived from experiments conducted on a high-speed machining centre by factorial design of experiments. The significances of the regression equation and regression coefficients are tested in this paper. The effects of milling parameters on surface roughness are investigated by analyzing the experimental curves.

Simulation of End Milling for Weak-Rigidity Structural Parts of Aluminium Alloy in Aviation

2011 ◽  
Vol 201-203 ◽  
pp. 332-336
Author(s):  
Chun Lin Fu ◽  
Cong Kang Wang ◽  
Tie Gang Li ◽  
Wan Shan Wang
Keyword(s):  
High Speed ◽  
End Milling ◽  
Element Model ◽  
Milling Process ◽  
Milling Force ◽  
Drilling Tool ◽  
Structural Parts ◽  
Aluminum Alloy 7075 ◽  
End Milling Process ◽  
Lower Material

To resolve the problem of the parts deformation because of the milling force, a finite element model (FEM) of end milling process simulation in milling force field was established. On the base of FEM, we simulate the high-speed end milling type structure of aluminum alloy 7075 parts. We successfully predict the end milling force, obtain the effect between the upper and lower material to the milling force, and Mises stress and the tool length beyond the part.The simulation results show that the lower material can increase the milling force to upper, and upper material can decrease milling force to lower layer.The drilling tool length beyond the part is about 0.5 mm .

Experimental Study on Ball-End Milling of C/C Composite

2013 ◽  
Vol 650 ◽  
pp. 139-144
Author(s):  
Chen Wei Shan ◽  
Ying Zhao ◽  
Dong Peng Cui
Keyword(s):  
Prediction Model ◽  
High Speed ◽  
End Milling ◽  
Orthogonal Experiment ◽  
Carbon Matrix ◽  
Milling Process ◽  
Cutting Depth ◽  
Milling Force ◽  
Ball End Milling ◽  
Milling Forces

Along with the development of high speed machining technology, the ball end milling cutter’s application is more and more widely. An influence of four control parameters, namely feed, cutting depth, spindle speed and cutting width, on cutting forces is investigated. This paper focuses on experimental research of milling process of carbon fiber reinforced carbon matrix composite (C/C composite). The milling force prediction model for milling of composite using the carbide ball-end tools is built by orthogonal experiment. The experiment results show that : the reliability of the this prediction model is quite high, and the effect of milling speed on milling force is not very obvious, but the milling force increases with the increment of feed per tooth, milling depth and milling width. Using this information, a new prediction model for the milling forces is proposed that can be used for C/C composite milling.

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