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Metodología para la predicción de la estabilidad dinámica en el mecanizado de alta velocidad de suelos delgados

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Author Campa Gómez, Francisco Javier
Published  Universidad del País Vasco, Bilbao, 2009
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Abstract Metodología para la predicción de la estabilidad dinámica en el mecanizado de alta velocidad de suelos delgados.
Metodología para la predicción de la estabilidad dinámica en el mecanizado de alta velocidad de suelos delgados.Tesis doctoral desarrollada en la Universidad del País Vasco por Francisco Javier Campa.
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Scientific publications
2000 and later
Images
 
Distribution of cutting forces on a cutting edge with a lead angle of 90º and 45º
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Stability lobes diagram, spindle speed-chatter frequency diagram and spindle speed-phase diagrama
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Relation between the obtained critical depth of cut and the estimated one in several machine tools
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Tolerance in the estimation of the stability lobes
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Influence of the tool vibration over the real chip thickness.
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Flip and Hopf lobes in the stability diagram of a milling with a tool with 2 cutting edges
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Frequency response functions measured at the tool tip
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Stability lobes in full immersion milling for 4 types of toolholder.
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Milling strategies for industrial marots machining with thin walls
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Materials used in the Boeing 77 of 2003 and in the 787 Dreamliner
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Evolution of the material in the monolithic components machining process
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Machining chatter marks in a thin floor and a thin wall of monolithic parts
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Main parameters in the study of the oblique cutting mechanics
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Diagram of the basic parameters of milling
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Discretization of an end mill cutting edge in differential elements and representation of the cutting forces
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Cutting forces on a differential element of the cutting edge of a bullnose end mill
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Cutting forces in milling on a tool with 9 tooth and corresponding Fourier analysis
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Influence of the radial depth of cut over the harmonic content of the Fourier spectrum in a milling of Aluminum 7075T6
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Influence of the helix angle on the shape of the cutting forces and the harmonic content of the Fourier analysis
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Comparison of the Frequency Response Functions experimentally measured at the tool tip for a milling machine structure, and two end mills with an overhang-diameter relation of 4:1 and 7:1
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Example of the influence of the helix angle on the final geometry of a walll milled with and end mill of 4 teeth and an helix angle of 45º.
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Chip width in a turning operation and in a milling operation with a tool with inserts.
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Simulation in time domain of the stabilizing effect of the nonlinearities that appear during a unstable milling
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Representation of the damping effect.
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Chip thickness variation, the cutting speed, the helix angle and the shearing cutting coefficients in a ball end mill of diameter of 12 mm
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Chatter vibration marks in an Inconel 718 turned part and a milled  L type part of Aluminum 7075.
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Frequency content of the signal of an accelerometer in a unstable milling due to regenerative chatter
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Fourier spectrum, displacement vs. time, synchronized signal with the tooth passing frequency and Pincaré diagram.
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Fourier spectrum, displacement vs. time, synchronized signal and Poincare diagram of a stable milling vibration signal.
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Fourier spectrum, displacement vs. time, synchronized signal and Poincare diagram.
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Vacuum fixtres for the routing and drilling of components for the aerobautical industry.  Active bed-shape fixture based Universal Holding Fixtures from Kostyrka
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Conventional end mill, end mill with variable pitch, and end mill with variable helix angle
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Example of reduction of the vibration severity in and 87% by means of a (SSSV)
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Stability lobes diagram: Influence of the relation 'chatter frequency-tooth passing frequency'
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Influence of the process damping effect on the stability lobes diagram
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1 Degree of freedom model for orthogonal turning.
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Influence of the cutting mode on the stability lobes diagrams
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Influence of the milling mode on the stability diagrams for a system
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Transformation of the FRFs matrix in cartesian coordinates to the loacl axis of the tool, depedent on the feed direction.
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Variation of the stability lobes diagrama shape with the feed direction: Comparison of the lobes from two designs of a universal milling machine
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Left) Polar diagram 'Critical depth of cut-Feed direction. Right) Optimized milling strategy based on the use of the polar diagram.
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Influence of the workpiece material on the stability lobes
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Influence of the number of teeth of a tool in the stability lobes diagram
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Effect of the helix angle on the stability lobes shape.
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Effect of maintaining the stiffness while varying the mass
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Influence of the variation of the stiffness while making the modal mass constant
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Effect of a variable damping on the FRFs and the stability lobes
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Variation of the stability lobes of a universal milling machine inside the workspace
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First modal frequency vs. spindle speed
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Stability diagram calculated with the FRF measured at 0 rpm and at several spindle speeds.
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Jump-to-jump strategy on a thin wall and detail of the difference in height of the tool
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Fourier spectrum of an unstable milling of a thin floor
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Fourier spectrum of an unstable milling
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Surface of a thin wall after an unstable and a stable milling
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Steps on the surface of the thin floor
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Influence of the dynamic displacements in Z direction on the chip thickness.
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Representation of two effects to consider in the study of chatter when milling thin floors: a) Cut of the secondary edge due to the penetration of the edge into the part. b) Interferences between the part and the edges out of the cutting area.
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Stable milling of a part flexible in the tool axis direction: vibration and tooth impacts go in phase and the surface is free of marks.
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Unstable milling due to period doubling chatter
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Unstable milling due to period doubling chatter. Part II
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Unstable milling due to period doubling chatter
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Unstable milling due to period doubling chatter
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Unstable milling due to period doubling chatter
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Projection of the displacements in x,y and z over the chip thickness
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Direction of the forces on the cutting edge of an insert and a bull nose end mill.
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Stability lobes diagram and chatter frequencies diagram for 1 and 3 harmonics
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Stability lobes and frequency-velocity for 5 and 15 harmonics
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Computational time as a function of the number of harmonics
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Stability lobes diagram for 0, 1 and 5 harmonics.
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Chatter frequencies diagram for 0,1,3,5 and 15 armonics
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Comparison of methods to obtain stability diagrams: Chebyshev, single-frequency and multi-frequency.
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Comparison of computational times between some solutions.
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Aproximation of [Altintas, 2001] for circular inserts.
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Linearization of the cutting edge lead angle for each axial depth of cut
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Parameters used in the averaging of the lead angle and the cutting coefficients
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Variation of the section of the chip as a function of the dynamic chip thickness
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Variation of the averaged cutting edge lead angle
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Variation of the cutting edge lead angle averaged
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Left) Experimental device and modal parameters. Right) Stability diagram and experimental results
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Mean roughness, surface and Fourier spectrum of the tests performed. Part I
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Mean roughness, surface and Fourier spectrum of the tests performed. Part II
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Second experimental device and corresponding modal parameters
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Results of the comparison of averaging methods: Method 3, method 2 and method 1
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Influence  on the stability diagram of an error of 10% on the cutting coefficients, the relative damping and the stiffness
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Solution of the averaging method 3 when the mode is in axial direction or in radial direction
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Algorithm for the obtention of a tridimensional lobes diagram. Part I
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Algorithm for the obtention of a tridimensional lobes diagram
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Stability diagram and stable spindle speeds
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Contour stability diagram and colorbar
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Angular acceleration of two spindles with and without position encoder: Faemat (red) and Kessler (blue)
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Critical depth of cut- Bulk of material diagram.
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Critical depth of cut-Dynamic stiffness diagram for several radial depths of cut.
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Detail of the aluminum plate and the testprobe.
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3 axis machining center Kondia HS 1000.
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Dominant modes of the testprobe and FRFs
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Stability diagrams of the milling of the testpart
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Experimental results: stable, unstable and slightly unstable
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Accelerometer signal and Fourier spectrums in points 1, 3 and 5
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Accelerometer signal and Fourier spectrums in points 1, 3 and 5
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Ampliation of the stability diagrama at a depth of cut of 4 mm.
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Accelerometer signal in the milling of the testpart
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Surface after an unstable milling.
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Geometry and dimensions of the testpart 'Aerosfin'.
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Milling strategy tested in the thin floor cutting.
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Dynamometric plate Kistler© 9255B and amplifier Kistler© 5017B
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Measurement of the FRF of the floor
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Surface roughness measurement and section made to the testpart.
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Left) Evolution of the first modal frequencies in the 8 steps.Right) Mesh of the part
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a) Detail of the nodes used for the comparison. b) Gzz in pints 1,2,3. c) Gyy in points 1,2,3. d) Gzz in pints 4,5,6. e) Gyy in points 4,5,6.
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Left) Lobes obhtained from the Gzz in points 1-3 and from points 4-6. Right) Comparisonm of the lobes calculated from Gzz in points 1 and 4 and the ones calculated considering Gxx, Gyy and the crossed FRFs in 1 and 4.
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Distribution of the relative dampings calculated by modal fitting.
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Evolution of the modulus of the FRFs (m/N) durinf the milling of the testpart
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Comparison between the FRFs calculated by MEF (red) and the experimentally obtained ones (blue).
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Stability diagrams: From experimantal FRFs (blue) and calculated from FRFs estimated by FEM (red).
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Final surface of the milled testpat with a initial bulk of material of 5 mm at 24.000 rpm: Mean roughness Ra in microns and detail of the marks.
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Final surface of the testpart with a bulk of material of 5 mm and machined varying the spindle speed: mean roughness Ra and detail of the marks.
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Left) Evolution of the experimental FRF. Right) Stability diagram for the machining with a bulk of material of 6 mm.
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Final surface of the test milled woth a bluk of material of 6 mm at 24000 rpm: mean roughness Ra in microns and detail of the marks.
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Final surface of the test with a bulk of material of 6 mm and milled varying the spindle speed: mean roughness Ra and detail of the marks.
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Mean roughness Ra measured in each test part with the maximum deviation with respect to that value
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Influence of an error ef 10% in the relative damping, the stiffness and the cutting coefficients
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Critical depth of cut-Bulk of material diagram in the step P4 of the Aerosfin test part.
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Final surface of the part machined with a bulk of material of 8 mm at 24000 rpm: mean roughness Ra in microns and detail of the marks.
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Final surface of the part milled with a bulk of material of 9 mm at 24000 rpm.
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Final surface of the test part in the step 4 with a bulk of material of 5 mm, 6 mm, 8 mm and 9 mm.
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Critical depth of cut-Dynamic stiffness diagram
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Linked items
Images: Final surface of the part milled with a bulk of material of 9 mm at 24000 rpm.
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DMG-Lib FaviconDMG-Lib https://www.dmg-lib.org/dmglib/handler?docum=13367009
Europeana FaviconEuropeana  http://www.europeana.eu/portal/record/2020801/dmglib_handler_docum_13367009.html
Data provider
UBCUniv. Basque C.  http://www.ehu.es/compmech/welcome/Home.html
Administrative information
Time of publication 2009

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