Externe Dämpfung bei Hochgeschwindigkeitsspindeln*/External damping in high speed spindles - Comparative investigation of the influence of a damping bush on the stability behavior during milling

2015 ◽  
Vol 105 (05) ◽  
pp. 257-262
Author(s):  
C. Brecher ◽  
M. Fey ◽  
J. Falker ◽  
B. Möller
Keyword(s):  
Machine Tools ◽  
High Speed ◽  
Comparative Investigation ◽  
Cutting Depth ◽  
Stability Behavior ◽  
Vergleichende Untersuchung ◽  
Process Behavior ◽  
The Stability ◽  
Main Spindle ◽  
Machine Structure

Die dynamischen Eigenschaften der Maschinenstruktur sowie der Hauptspindel bestimmen maßgeblich das dynamische Prozessverhalten von Werkzeugmaschinen. Über eine gezielte Dämpfung an den Lagerstellen der Spindel soll die stabile Schnitttiefe erhöht werden. In diesem Fachbeitrag wird der Einfluss einer Dämpfungsbuchse am Loslagersitz auf das statische, dynamische und das Bearbeitungsverhalten durch die vergleichende Untersuchung zweier Hochgeschwindigkeitsspindeln betrachtet.   The dynamic process behavior of machine tools depends on both the characteristics of the machine structure and the main spindle. By means of an additional damping of the bearing bushes, the stable cutting depth of the main spindle is to be increased. In this article, the influence of a damping bush at the floating bearing seat on the static, dynamic and stability behavior is investigated by comparing two high speed spindles.

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.

Optimized Design and Performance Study of High Speed Five-Axis Machine Tools

2020 ◽  
Author(s):  
Tzu-Chi Chan ◽  
Jyun-Sian Yang
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristics ◽  
Machine Tools ◽  
High Speed ◽  
Spectral Response ◽  
Work Piece ◽  
Static And Dynamic Characteristics ◽  
Five Axis ◽  
Speed Accuracy ◽  
Machine Structure

Abstract With the development of machine tools trending toward high precision, intelligence, multi-axis, and high speed, the improvement of the processing performance and rigidity of the machine is considerably important. The objective of this study is to design of a high-speed five-axis moving-column machine tool and perform structural analysis and optimization. We study the static and dynamic characteristics of the five-axis machine tool, design and improve the mechanical structure, and optimize the structural configuration of the machine. The entire machine structure is further analyzed and enhanced to improve its static and dynamic characteristics, including static rigidity, modal, transient, and spectral response characteristics. The static and dynamic characteristics of the machine structure directly affect the machine processing performance, and further affect the work piece precision machined by the tool. Through this study, the design technology for speed, accuracy, and surface roughness of the machine tool are further improved.

Stability of Flexible Rotors With a LeBlanc Balancer

2011 ◽  
Author(s):  
Leonardo Urbiola-Soto ◽  
Marcelo Lopez-Parra
Keyword(s):  
High Speed ◽  
Particle Image ◽  
Flexible Rotor ◽  
Rotating System ◽  
Stability Behavior ◽  
Piv Technique ◽  
Flexible Rotors ◽  
Image Velocimetry ◽  
The Stability ◽  
Stability Limits

Although the liquid balancer has nearly a century of having been introduced by LeBlanc, little information is available on the dynamic response and stability behavior of this kind of device. Earlier author’s research using a high-speed camera and a Particle Image Velocimetry (PIV) technique showed the existence of a fluid backward traveling wave inside the balancer cavity. This damping phenomenon helps enhance the unbalance response of the rotating system and also raises the stability limits. This paper shows that a flexible rotor employing a LeBlanc balancer has remarkable increase in the threshold speed of instability for aerodynamic cross-coupling and viscous internal friction damping.

scholarly journals Effect of Time-Varying Moving Structures on the Spatial Accuracy of Five-Axis Machine Tools

2021 ◽  
Author(s):  
Tzu-Chi Chan ◽  
Jyun-Sian Yang
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristics ◽  
Machine Tools ◽  
High Speed ◽  
Time Varying ◽  
Spatial Accuracy ◽  
Static And Dynamic Characteristics ◽  
Five Axis ◽  
Speed Accuracy ◽  
Machine Structure

Abstract Machine tools are constantly in motion during machining; however, studies have not considered the effect of the dynamic and static characteristics of the machine caused by the movement of the structure over time. In this study, the time-varying moving structure in the spatial coordinate arm is analyzed to improve the spatial accuracy of the motion of a five-axis machine tool in the cutting area. The objective is to design a high-speed five-axis moving-column machine tool and to perform structural analysis of spatial accuracy. We studied the static and dynamic characteristics of a five-axis machine tool, designed and improved its mechanical structure, and optimized its structural configuration. With further analysis, the entire machine structure was enhanced to improve its static and dynamic characteristics. The static and dynamic characteristics of the machine structure were found to directly affect its processing performance and the precision of the workpiece machined by the tool. Through this study, the design technology for speed, accuracy, and surface roughness of the machine tool was further improved.

scholarly journals Development of a vibration free machine structure for high-speed micro-milling center

2021 ◽  
Author(s):  
Arnab Das ◽  
Shashank Shukla ◽  
Mohan Kumar ◽  
Chitransh Singh ◽  
Madan Lal Chandravanshi ◽  
...  
Keyword(s):  
Machine Tool ◽  
Surface Finish ◽  
Machine Tools ◽  
High Speed ◽  
Micro Milling ◽  
High Speed Machining ◽  
Element Analysis ◽  
Dimensional Precision ◽  
Ultra Precision ◽  
Machine Structure

Abstract The demand of ultra-precision micro-machine tools is growing day by day due to exigent requirements of miniaturized components. High accuracy, good dimensional precision and smooth surface finish are the major characteristics of these ultra-precision machine tools. High-speed machining has been adopted to increase the productivity using high-speed spindles. However, machine tool vibration is a major issue in high-speed machining. Vibration significantly deteriorates the quality of micro-machining in terms of dimensional precision and surface finish. This paper describes a design methodology of a closed type machine structure for vibration minimization of a high-speed micro-milling center. The rigid machine structure has provided plenty of stiffness and the damping capability to the machine tool without utilizing vibration absorbers . The models of the machine structures have been generated and assembled in AutoCAD 3D . The performances of the integrated micro-milling machine tools were determined by finite element analysis. The best model has been selected and proposed for manufacturing. Additionally, simulation results were validated by comparing with experimental results. Eventually, after manufacturing and assembly, experiments have been performed and determined that the amplitude of vibration was approaching towards nanometer level throughout the working range of the high-speed spindle. The machine tool was capable to fabricate miniaturized components with fine surface finish.

Discussion—Session III: High speed machine tools for aircraft production

1955 ◽  
Vol 34 (4) ◽  
pp. 224
Author(s):  
F.C. Cooke ◽  
S. Radcliffe ◽  
H.A. Chambers ◽  
C. Bromage ◽  
Menelaus ◽  
...  
Keyword(s):  
Machine Tools ◽  
High Speed ◽  
Discussion Session ◽  
Aircraft Production ◽  
High Speed Machine

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

LANDSLIDE RISK MANAGEMENT IN THE COASTAL ZONE OF THE KUIBYSHEV RESERVOIR DUE THE DESIGN OF HIGH-SPEED LINE "MOSCOW-KAZAN"

2017 ◽  
Author(s):  
Nikolai Petrov ◽  
Nikolai Petrov ◽  
Inna Nikonorova ◽  
Inna Nikonorova ◽  
Vladimir Mashin ◽  
...  
Keyword(s):  
High Speed ◽  
Computational Models ◽  
Stable State ◽  
Landslide Risk ◽  
Kuibyshev Reservoir ◽  
Stepped Surface ◽  
The Stability ◽  
Landslide Slope ◽  
The Village

High-speed railway "Moscow-Kazan" by the draft crosses the Volga (Kuibyshev reservoir) in Chuvashia region 500 m below the village of New Kushnikovo. The crossing plot is a right-bank landslide slope with a stepped surface. Its height is 80 m; the slope steepness -15-16o. The authors should assess the risk of landslides and recommend anti-landslide measures to ensure the safety of the future bridge. For this landslide factors have been analyzed, slope stability assessment has been performed and recommendations have been suggested. The role of the following factors have been analyzed: 1) hydrologic - erosion and abrasion reservoir and runoff role; 2) lithologyc (the presence of Urzhum and Northern Dvina horizons of plastically deformable rocks, displacement areas); 3) hydrogeological (the role of perched, ground and interstratal water); 4) geomorphological (presence of the elemental composition of sliding systems and their structure in the relief); 5) exogeodynamic (cycles and stages of landslide systems development, mechanisms and relationship between landslide tiers of different generations and blocks contained in tiers). As a result 6-7 computational models at each of the three engineering-geological sections were made. The stability was evaluated by the method “of the leaning slope”. It is proved that the slope is in a very stable state and requires the following measures: 1) unloading (truncation) of active heads blocks of landslide tiers) and the edge of the plateau, 2) regulation of the surface and groundwater flow, 3) concrete dam, if necessary.

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