Mechanical and technological aspects of micro ball end milling with various tool inclinations

Abstract This paper is focused on the evaluation of mechanical and technological aspects of the micro ball end milling of hardened TOOLOX 44 steel. The experiment includes the measurement of acceleration of vibrations during the micro milling tests with variable feed per tooth and tool's axis inclination angle values. The next step involves the analysis of dynamics, based on the determination of measured signals’ statistical measures and Fast Fourier Transform (FFT). This stage includes also the prediction of micro ball end milling forces on the basis of mechanistic model considering run out, variable edge forces, and kinematics of low radial immersion milling with tool axis inclination. Subsequently, the optimization of the micro ball end milling process is conducted. This procedure is carried out by the minimization of process responses with the application of a method based on the minimization of total desirability function. In the last stage, the obtained optimal values of tool's axis inclination angle and feed per tooth are validated during the micro milling tests involving the measurements of machined surface roughness. Research reveals that micro ball end milling with the optimally selected tool's axis slope along the toolpath and feed per tooth affects the minimization of milling vibrations and improvement in surface finish.

[1]  Svetan Ratchev,et al.  Chatter modelling in micro-milling by considering process nonlinearities , 2012 .

[2]  O. Burak Ozdoganlar,et al.  A three-dimensional model for the dynamics of micro-endmills including bending, torsional and axial vibrations , 2011 .

[3]  Szymon Wojciechowski,et al.  The estimation of cutting forces and specific force coefficients during finishing ball end milling of inclined surfaces , 2015 .

[4]  Kornel Ehmann,et al.  The Mechanics of Machining at the Microscale: Assessment of the Current State of the Science , 2004 .

[5]  Simon Barrans,et al.  Optimisation of machining parameters during ball end milling of hardened steel with various surface inclinations , 2017 .

[6]  Adriano Fagali de Souza,et al.  Size effect and minimum chip thickness in micromilling , 2015 .

[7]  Erhan Budak,et al.  Modeling and Measurement of Micro End Mill Dynamics using Inverse Stability Approach , 2016 .

[8]  Martin B.G. Jun,et al.  Investigation of the Dynamics of Microend Milling—Part I: Model Development , 2006 .

[9]  Grzegorz Krolczyk,et al.  Investigation on the edge forces in ball end milling of inclined surfaces , 2016 .

[10]  R. DeVor,et al.  Microstructure-Level Force Prediction Model for Micro-Milling of Multi-Phase Materials , 2001, Manufacturing Engineering.

[11]  Sangkee Min,et al.  Recent Advances in Mechanical Micromachining , 2006 .

[12]  Wanlu Duan,et al.  Effect of tool Inclination Angle on the Elastic Deformation of Thin-walled Parts in Multi-axis Ball-end Milling , 2016 .

[13]  J. Paulo Davim,et al.  Optimization of Surface Roughness in Micromilling , 2010 .

[14]  Yusuf Altintas,et al.  Prediction of ball-end milling forces from orthogonal cutting data , 1996 .

[15]  Hilde Pérez,et al.  Estimation of cutting forces in micromilling through the determination of specific cutting pressures , 2007 .

[16]  Martin B.G. Jun,et al.  Modeling of dynamic micro-milling cutting forces , 2009 .

[17]  P. Rodríguez,et al.  A new model for the prediction of cutting forces in micro-end-milling operations , 2013 .

[18]  Szymon Wojciechowski,et al.  Cutting Forces and Vibrations During Ball End Milling of Inclined Surfaces , 2014 .

[19]  Simon S. Park,et al.  Investigation of micro-cutting operations , 2006 .

[20]  Simon Barrans,et al.  Precision surface characterization for finish cylindrical milling with dynamic tool displacements model , 2016 .

[21]  Juan Carlos Campos Rubio,et al.  Determination of the critical undeformed chip thickness in micromilling by means of the acoustic emission signal , 2016 .

[22]  Bartosz Powałka,et al.  Workpiece Grain Size Influence on the Vibration in Micro-milling , 2014 .

[23]  H. Weule,et al.  Micro-Cutting of Steel to Meet New Requirements in Miniaturization , 2001 .

[24]  Huaizhong Li,et al.  Development of a hybrid cutting force model for micromilling of brass , 2016 .

[25]  Giuliano Bissacco,et al.  Micromilling of hardened tool steel for mould making applications , 2005 .

[26]  Borys Storch,et al.  Distribution of unit forces on the tool edge rounding in the case of finishing turning , 2012 .

[27]  Jun Zhao,et al.  Investigation on ball end milling of P20 die steel with cutter orientation , 2012 .

[28]  Young-bong Bang,et al.  5-axis micro milling machine for machining micro parts , 2005 .

[29]  Martin B.G. Jun,et al.  Investigation of the Dynamics of Microend Milling—Part II: Model Validation and Interpretation , 2006 .

[30]  Wanshan Wang,et al.  Cutting forces in micro-end-milling processes , 2016 .

[31]  Takahisa Masuzawa,et al.  State of the Art of Micromachining , 2000 .

[32]  Grzegorz Krolczyk,et al.  Modeling of cutter displacements during ball end milling of inclined surfaces , 2015 .

[33]  Tony L. Schmitz,et al.  Case study: A comparison of error sources in high-speed milling , 2008 .