Stability Analysis in Face Milling Operations, Part 2: Experimental Validation and Influencing Factors

1999 ◽  
Vol 121 (4) ◽  
pp. 606-614 ◽  
Author(s):  
S. A. Jensen ◽  
Y. C. Shin
Keyword(s):  
Influencing Factors ◽  
Material Properties ◽  
Experimental Validation ◽  
Dynamic Change ◽  
Face Milling ◽  
Vibrational Modes ◽  
Entry And Exit ◽  
Structural Dynamic ◽  
Milling Operations ◽  
The Stability

This paper presents rigorous experimental validation results of the stability algorithm as developed in the Part I. The two experiments which will be presented here focus on; first, a workpiece whose vibrational modes constitute the weakest part of the overall system, and second, a machine tool whose vibrational modes are the weakest part of the system. Next, it discusses some of the influencing factors that affect the onset of chatter in face milling processes. The factors considered include cutting conditions, entry and exit angles, axial dynamics, cutter geometry, material properties and structural dynamic parameters. Lastly, it presents the effect of structural dynamic change under operating condition on stability lobes.

Structure Dynamic Modification and Optimization for High-Speed Face Milling Cutter

2004 ◽  
Vol 471-472 ◽  
pp. 663-667 ◽  
Author(s):  
Wei Xiao Tang ◽  
Xing Ai ◽  
H.Y. Wu ◽  
Song Zhang ◽  
H. Jiang
Keyword(s):  
High Speed ◽  
Milling Process ◽  
Face Milling ◽  
Relative Speed ◽  
Structural Dynamic ◽  
High Speed Milling ◽  
Structural Dynamic Modification ◽  
The Face ◽  
Dynamic Modification ◽  
The Stability

Due to the complexity of high-speed milling process by high relative speed and interrupted cutting, the face milling cutters possess the multi-order modes and the vibrating displacements of the cutting edges under each modes affect adversely both the surface roughness and the life of machine/tool system worse than other structures. In order to improve the stability of milling process, this work focuses on the influence of the variables such as structure geometries and constraint conditions on the eigenfrequencies and modeshapes of cutter. As an example, the dynamic characteristics of several face cutters are analyzed and optimized by structural dynamic modification (SDM) techniques.

Stability Analysis in Face Milling Operations, Part 1: Theory of Stability Lobe Prediction

1999 ◽  
Vol 121 (4) ◽  
pp. 600-605 ◽  
Author(s):  
S. A. Jensen ◽  
Y. C. Shin
Keyword(s):  
Structural Dynamics ◽  
Three Dimensional ◽  
Frequency Domain Analysis ◽  
Face Milling ◽  
Entry And Exit ◽  
Predictive Capability ◽  
Stability Lobe ◽  
Stability Lobes ◽  
Milling Operations ◽  
Milling Operation

This paper involves development of an algorithm to predict stability lobes in face milling operation. The modeling is based on frequency domain analysis and is an extension of Budak and Altintas to a three dimensional case. It considers the effects of insert and cutter geometry, cutting conditions, process nonlinearity, entry and exit angles and the fully dimensional structural dynamics of both the machine tool and workpiece, including axial dynamics which are often neglected by many researchers. In addition, the predictive capability of stability lobes by the presented models is compared with those results obtained by time domain simulations.

scholarly journals Experimental investigation of the machining characteristics in diamond wire sawing of unidirectional CFRP

2021 ◽  
Author(s):  
Lukas Seeholzer ◽  
Stefan Süssmaier ◽  
Fabian Kneubühler ◽  
Konrad Wegener
Keyword(s):  
Surface Quality ◽  
Influencing Factors ◽  
Material Properties ◽  
High Surface ◽  
Workpiece Surface ◽  
High Surface Quality ◽  
High Productivity ◽  
Surface Temperatures ◽  
Process Forces ◽  
The Wire

AbstractEspecially for slicing hard and brittle materials, wire sawing with electroplated diamond wires is widely used since it combines a high surface quality with a minimum kerf loss. Furthermore, it allows a high productivity by machining multiple workpieces simultaneously. During the machining operation, the wire/workpiece interaction and thus the material removal conditions with the resulting workpiece quality are determined by the material properties and the process and tool parameters. However, applied to machining of carbon fibre reinforced polymers (CFRP), the process complexity potentially increases due to the anisotropic material properties, the elastic spring back potential of the material, and the distinct mechanical wear due to the highly abrasive carbon fibres. Therefore, this experimental study analyses different combinations of influencing factors with respect to process forces, workpiece surface temperatures at the wire entrance, and the surface quality in wire sawing unidirectional CFRP material. As main influencing factors, the cutting and feed speeds, the density of diamond grains on the wire, the workpiece thickness, and the fibre orientation of the CFRP material are analysed and discussed. For the tested parameter settings, it is found that while the influence of the grain density is negligible, workpiece thickness, cutting and feed speeds affect the process substantially. In addition, higher process forces and workpiece surface temperatures do not necessarily deteriorate the surface quality.

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.

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.

The Stability of Potassium Ferrate in Water

2014 ◽  
Vol 881-883 ◽  
pp. 215-218
Author(s):  
Kai Luo ◽  
Gang Cao ◽  
Ming Yu Li ◽  
Gang Ren
Keyword(s):  
Influencing Factors ◽  
Potassium Ferrate ◽  
The Stability

The influencing factors of the stability for the potassium ferrate (K2FeO4), including pH, alkalinity, O3, KI, KClO3, KCl, NaClO3and Na2SiO3, were studied in this work. The results showed that the K2FeO4stability in water is best at about pH=10. The higher the alkalinity is, the stronger of K2FeO4stability would be. The O3had no effect to improve the K2FeO4stability. The K2FeO4stability would be best in water with 15mmol/L NaClO3, 10mmol/L Na2SiO3and 9mol/L alkalinity. Under this condition, the K2FeO4content would be 83.28% after 24h.

The creation of new research system for the investigation of surface quality by stones

2013 ◽  
Vol 4 (1) ◽  
pp. 43-48
Author(s):  
I. G. Gyurika ◽  
M. Gálos
Keyword(s):  
Research Team ◽  
Face Milling ◽  
Average Surface Roughness ◽  
Research System ◽  
Machining Processes ◽  
Average Surface ◽  
Milling Operations ◽  
University Of Technology ◽  
New Research ◽  
Cutting Speeds

Abstract The research on automated stone machining processes was very significant in the last two decades. Sawing, cutting and grinding of different stones like granite, marble, limestone became cheaper and more productive because of the results of researches. When searching through international specialised literature in the topic of stone machining with machine centres, theoretical summaries or researches can hardly be found. The aim of the researchers writing this article is — as a pioneer in Hungary, but also among the first internationally — to examine the optimization and technological problems in the area of stone milling processes. The researchers have developed a complex research system with the collaboration of two departments of University of Technology and Economics and an industrial stone machining firm, Woldem Ltd. to solve the problems. This paper summarizes the parts of this system. General steps and results of research processes are demonstrated by reference experiments. Face milling operations were made on a granite block with five different cutting speeds and then the researchers measured slip safety and average surface roughness values in case of different samples. Finally, upcoming tasks of the research team are summarized.

scholarly journals Research on the influencing factors of family firm innovation

2021 ◽  
Vol 235 ◽  
pp. 02017
Author(s):  
Yingrui Liu
Keyword(s):  
Influencing Factors ◽  
Family Involvement ◽  
Family Business ◽  
External Environment ◽  
Family Firm ◽  
Economic Activities ◽  
Firm Innovation ◽  
Strategic Focus ◽  
The Stability ◽  
Innovation Behavior

Family business plays an important role in the world’s economic activities, and has made great contributions to the stability and development of the economy of various countries. Innovation is an important but inexplicable part of the strategic focus of family business. Based on the existing literature, this paper discusses the factors that influence the innovation behavior of enterprises from the perspective of family involvement and external environment.

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