Optimization of machining conditions for multi-tool milling operations

2000 ◽  
Vol 38 (15) ◽  
pp. 3537-3552 ◽  
Author(s):  
M. C. Cakir ◽  
A. Gurarda
Keyword(s):  
Machining Conditions ◽  
Milling Operations

Chatter in Gear Hobbing

1970 ◽  
Vol 185 (1) ◽  
pp. 767-782 ◽  
Author(s):  
R. G. Hannam ◽  
C. Andrew
Keyword(s):  
Relative Motion ◽  
Feed Rate ◽  
Dynamic Stiffness ◽  
Vibration Characteristics ◽  
Depth Of Cut ◽  
Machining Conditions ◽  
Milling Operations ◽  
Gear Hobbing ◽  
The Mean ◽  
Work Table

This paper describes an investigation into the characteristics of chatter in gear hobbing. The likelihood of chatter occurring was shown to increase with feed-rate, depth of cut and gear diameter; it was also shown to be critically dependent on the material being cut. Chatter was found to be of the regenerative type, occurring in bands of speed in a manner similar to its occurrence in milling operations. On a given machine and for a given gear material, the factor deciding whether chatter would arise was shown to be the magnitude of the mean total chip-width being cut by the flanks of the hob teeth. This magnitude was computed for various machining conditions from a knowledge of the hob and gear geometries, the feed-rate and the depth of cut. The machine's design was considered in terms of the vibration characteristics at the hob-blank interface; the dynamic stiffness of relative motion tangential to the gear blank was shown to be critical. Special techniques were used to derive the associated torsional characteristics of the work-table system experimentally.

Effects of Ion Beam Milling on Surface Topography

1973 ◽  
Vol 31 ◽  
pp. 84-85
Author(s):  
P.G. Pawar ◽  
P. Duhamel ◽  
G.W. Monk
Keyword(s):  
Surface Topography ◽  
Ion Beam ◽  
Solid Material ◽  
Beam Current ◽  
Atomic Mass ◽  
Micro Milling ◽  
Ion Milling ◽  
Controlled Atmospheres ◽  
Milling Operations ◽  
Sufficient Energy

A beam of ions of mass greater than a few atomic mass units and with sufficient energy can remove atoms from the surface of a solid material at a useful rate. A system used to achieve this purpose under controlled atmospheres is called an ion miliing machine. An ion milling apparatus presently available as IMMI-III with a IMMIAC was used in this investigation. Unless otherwise stated, all the micro milling operations were done with Ar+ at 6kv using a beam current of 100 μA for each of the two guns, with a specimen tilt of 15° from the horizontal plane.It is fairly well established that ion bombardment of the surface of homogeneous materials can produce surface topography which resembles geological erosional features.

Effect of machining conditions on shear angle in turning of A286 iron based nickel super alloy

2021 ◽  
Author(s):  
M. Venkata Ramana ◽  
G. Krishna Mohana Rao ◽  
G Prasanth ◽  
Bidya Sagar ◽  
P. Ravi Kumar ◽  
...  
Keyword(s):  
Shear Angle ◽  
Machining Conditions ◽  
Iron Based ◽  
Super Alloy

scholarly journals Optimum Selection of Variable Pitch for Chatter Suppression in Face Milling Operations

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 112 ◽  
Author(s):  
Alex Iglesias ◽  
Zoltan Dombovari ◽  
German Gonzalez ◽  
Jokin Munoa ◽  
Gabor Stepan
Keyword(s):  
Removal Rate ◽  
Face Milling ◽  
Heavy Duty ◽  
Variable Pitch ◽  
Thin Walls ◽  
Chatter Suppression ◽  
Milling Operations ◽  
Optimum Selection ◽  
Cutting Capacity ◽  
Selection Of

Cutting capacity can be seriously limited in heavy duty face milling processes due to self-excited structural vibrations. Special geometry tools and, specifically, variable pitch milling tools have been extensively used in aeronautic applications with the purpose of removing these detrimental chatter vibrations, where high frequency chatter related to slender tools or thin walls limits productivity. However, the application of this technique in heavy duty face milling operations has not been thoroughly explored. In this paper, a method for the definition of the optimum angles between inserts is presented, based on the optimum pitch angle and the stabilizability diagrams. These diagrams are obtained through the brute force (BF) iterative method, which basically consists of an iterative maximization of the stability by using the semidiscretization method. From the observed results, hints for the selection of the optimum pitch pattern and the optimum values of the angles between inserts are presented. A practical application is implemented and the cutting performance when using an optimized variable pitch tool is assessed. It is concluded that with an optimum selection of the pitch, the material removal rate can be improved up to three times. Finally, the existence of two more different stability lobe families related to the saddle-node and flip type stability losses is demonstrated.

A Success Story: Utilizing Different Variables in Design and Execution of Coiled Tubing Extended Reach Milling Operations

2020 ◽  
Author(s):  
Kaveh Yekta ◽  
Benjamin Stang ◽  
Scott Hilling ◽  
Chris Schwartz ◽  
Bettina Cheung ◽  
...  
Keyword(s):  
Success Story ◽  
Coiled Tubing ◽  
Milling Operations

Predicting the High Speed Cutting Process of Titanium Alloy by Finite Element Method

2011 ◽  
Author(s):  
Xiangqin Zhang ◽  
Xueping Zhang ◽  
A. K. Srivastava
Keyword(s):  
Finite Element ◽  
Cutting Forces ◽  
High Speed ◽  
Cutting Temperature ◽  
Chip Morphology ◽  
Cutting Process ◽  
Fe Model ◽  
Dry Cutting ◽  
Friction Coefficients ◽  
Machining Conditions

To predict the cutting forces and cutting temperatures accurately in high speed dry cutting Ti-6Al-4V alloy, a Finite Element (FE) model is established based on ABAQUS. The tool-chip-work friction coefficients are calculated analytically using the measured cutting forces and chip morphology parameter obtained by conducting the orthogonal (2-D) machining tests. It reveals that the friction coefficients between tool-work are 3∼7 times larger than that between tool-chip, and the friction coefficients of tool-chip-work vary with feed rates. The analysis provides a better reference for the tool-work-chip friction coefficients than that given by literature empirically regardless of machining conditions. The FE model is capable of effectively simulating the high speed dry cutting process of Ti-6Al-4V alloy based on the modified Johnson-Cook model and tool-work-chip friction coefficients obtained analytically. The FE model is further validated in terms of predicted forces and the chip morphology. The predicted cutting force, thrust force and resultant force by the FE model agree well with the experimentally measured forces. The errors in terms of the predicted average value of chip pitch and the distance between chip valley and chip peak are smaller. The FE model further predicts the cutting temperature and residual stresses during high speed dry cutting of Ti-6Al-4V alloy. The maximum tool temperatures exist along the round tool edge, and the residual stress profiles along the machined surface are hook-shaped regardless of machining conditions.

Stability of Milling Operations With Asymmetric Cutter Dynamics in Rotating Coordinates

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Alptunc Comak ◽  
Orkun Ozsahin ◽  
Yusuf Altintas
Keyword(s):  
Time Domain ◽  
Machine Tools ◽  
High Speed ◽  
End Mill ◽  
Spindle Shaft ◽  
Milling Operations ◽  
Stability Model ◽  
Principal Directions ◽  
The Stability ◽  
Rotating Coordinates

High-speed machine tools have parts with both stationary and rotating dynamics. While spindle housing, column, and table have stationary dynamics, rotating parts may have both symmetric (i.e., spindle shaft and tool holder) and asymmetric dynamics (i.e., two-fluted end mill) due to uneven geometry in two principal directions. This paper presents a stability model of dynamic milling operations with combined stationary and rotating dynamics. The stationary modes are superposed to two orthogonal directions in rotating frame by considering the time- and speed-dependent, periodic dynamic milling system. The stability of the system is solved in both frequency and semidiscrete time domain. It is shown that the stability pockets differ significantly when the rotating dynamics of the asymmetric tools are considered. The proposed stability model has been experimentally validated in high-speed milling of an aluminum alloy with a two-fluted, asymmetric helical end mill.

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