Characteristics of High Rotational Speed Polishing with Oscillation Speed Control

2005 ◽  
pp. 355-358
Author(s):  
Kenichiro Yoshitomi ◽  
Atsunobu Une ◽  
Masaaki Mochida
Keyword(s):  
Rotational Speed ◽  
Speed Control ◽  
High Rotational Speed

Characteristics of High Rotational Speed Polishing with Oscillation Speed Control

2005 ◽  
Vol 291-292 ◽  
pp. 355-358
Author(s):  
Kenichiro Yoshitomi ◽  
Atsunobu Une ◽  
Masaaki Mochida
Keyword(s):  
Rotational Speed ◽  
Removal Rate ◽  
Speed Control ◽  
Experimental Results ◽  
Simulation Program ◽  
Depth Of Field ◽  
Wafer Surface ◽  
High Rotational Speed ◽  
Laser Lithography ◽  
Stock Removal

The miniaturization of semiconductor devices is advancing rapidly. The requirement for wafer flatness is becoming increasingly stringent as the use of shorter wavelengths in the latest laser lithography results in a smaller focusing depth of field. In our research, a flatness of 0.1 µm has been achieved over an entire 12" wafer surface by planarization with oscillation speed control type polishing. However, in addition it is necessary to increase the removal rate in order to reduce the polishing time. Although high rotational speed polishing is a solution to meet this requirement, the polishing characteristics change with the rotational conditions. Using a simulation program, we calculated that the stock removal saturates as the rotational speeds of the wafer and polishing pad are increased beyond a certain point. Also, experimental results showed that at high rotational speeds actual stock removal is significantly less than that indicated by the simulation, and that too much slurry causes unnecessary etching.

Performances of HSK Tool Interfaces under High Rotational Speed

CIRP Annals ◽  
2001 ◽  
Vol 50 (1) ◽  
pp. 281-284 ◽  
Author(s):  
T. Aoyama ◽  
I. Inasaki
Keyword(s):  
Rotational Speed ◽  
High Rotational Speed

The Coupling Characteristic of HSK Tool-Holder/Spindle Interface for High-Speed NC Machine Tool

2014 ◽  
Vol 590 ◽  
pp. 121-125 ◽  
Author(s):  
Wen Kai Jie ◽  
Jian Chen ◽  
Deng Sheng Zheng ◽  
Gui Cheng Wang
Keyword(s):  
Machine Tool ◽  
Rotational Speed ◽  
High Speed ◽  
Nonlinear Finite Element Method ◽  
High Rotational Speed ◽  
Tool Holder ◽  
Nc Machine Tool ◽  
Machine Tool Accuracy ◽  
Nc Machine ◽  
Coupling Characteristic

The coupling characteristic of the tool-holder/spindle interface in high speed NC machine has significant influence on machine tool accuracy and process stability. With the example of HSK-E63, based on nonlinear finite element method (FEM), the coupling characteristic of the tool-holder/spindle interface under high rotational speed was investigated, the influence of interference, clamping force and rotational speed on the contact stress and the sectional area of clearance were discussed in detail. The results can be used as theoretical consideration to design and optimize the high speed tool-holder/spindle interface.

scholarly journals Investigations of Inducers Operating With High Rotational Speed

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Björn Gwiasda ◽  
Matthias Mohr ◽  
Martin Böhle
Keyword(s):  
Rotational Speed ◽  
Test Bench ◽  
Pressure Rise ◽  
Working Fluid ◽  
Cfd Simulations ◽  
High Rotational Speed ◽  
Rotating Speed ◽  
Performance Pressure ◽  
Computational Fluid Dynamics Cfd ◽  
Suction Performance

Suction performance, pressure rise, and efficiency for four different inducers are examined with computational fluid dynamics (CFD) simulations and experiments performed with 18,000 rpm and 24,000 rpm. The studies originate from a research project that includes the construction of a new test bench in order to judge the design of the different inducers. This test bench allows to conduct experiments with a rotational speed of up to 40,000 rpm and high pressure ranges from 0.1 bar to 40 bar with water as working fluid. Experimental results are used to evaluate the accuracy of the simulations and to gain a better understanding of the design parameter. The influence of increasing the rotating speed from 18,000 rpm to 24,000 rpm on the performance is also shown.

scholarly journals Turbomachine Design for Supercritical Carbon Dioxide Within the sCO2-HeRo.eu Project

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Alexander Hacks ◽  
Sebastian Schuster ◽  
Hans Josef Dohmen ◽  
Friedrich-Karl Benra ◽  
Dieter Brillert
Keyword(s):  
Rotational Speed ◽  
Mechanical Design ◽  
Integrated Design ◽  
Mechanical Analysis ◽  
High Rotational Speed ◽  
Through Flow ◽  
Compressor Impeller ◽  
Final Design ◽  
Manufacturing Techniques ◽  
Future Work

The paper aims to give an overview over the keystones of design of the turbomachine for a supercritical CO2 (sCO2) Brayton cycle. The described turbomachine is developed as part of a demonstration cycle on a laboratory scale with a low through flow. Therefore, the turbomachine is small and operates at high rotational speed. To give an overview on the development, the paper is divided into two parts regarding the aerodynamic and mechanical design. The aerodynamic design includes a detailed description on the steps from choosing an appropriate rotational speed to the design of the compressor impeller. For setting the rotational speed, the expected high windage losses are evaluated considering the reachable efficiencies of the compressor. The final impeller design includes a description of the blading development together with the final geometry parameters and calculated performance. The mechanical analysis shows the important considerations for building a turbomachine with integrated design of the three major components: turbine, alternator, and compressor (TAC). It includes different manufacturing techniques of the impellers, the bearing strategy, the sealing components, and the cooling of the generator utilizing the compressor leakage. Concluding the final design of the TAC is shown and future work on the machine is introduced.

Criteria for the Stability Limit Prediction of High Speed Centrifugal Compressors With Vaneless Diffuser: Part I — Flow Structure Analysis

2020 ◽  
Author(s):  
Carlo Cravero ◽  
Davide Marsano
Keyword(s):  
Rotational Speed ◽  
High Speed ◽  
Stability Limit ◽  
Vaneless Diffuser ◽  
Centrifugal Compressors ◽  
Vaned Diffuser ◽  
High Rotational Speed ◽  
Lower Accuracy ◽  
The Stability ◽  
Computational Resources

Abstract High-speed centrifugal compressor requirements include a wide operating range between choking and stall especially for turbocharging applications. The prediction of the stability limit at different speeds is still challenging. In literature, several studies have been published on the phenomena that trigger the compressor instability. However, a comprehensive analysis of criteria that can be used in the first steps of centrifugal compressors design to predict the stability limit is still missing. In previous work the authors have already presented a criterion, so called “Stability Parameter”, to predict the surge line of centrifugal compressors based on a simplified CFD approach that does not require excessive computational resources and that can be efficiently used in the preliminary design phases. The above methodology has demonstrated its accuracy for centrifugal compressors with vaned diffuser, but a lower accuracy has been detected for vaneless diffusers. Before proceeding to identify additional criteria focused on compressors with vaneless diffuser, an in-depth fluid dynamics analysis has been necessary. This analysis has been also carried out through fully 3D unsteady simulations to allow identifying the real phenomena linked to the trigger of the instability of centrifugal compressors. It has been found how these phenomena are strongly related to the rotational speed, in particular have been shown the key role of the volute at high rotational speed.

scholarly journals Combinatory Attitude Determination Method for High Rotational Speed Rigid-Body Aircraft

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Liangliang An ◽  
Liangming Wang ◽  
Ning Liu ◽  
Jian Fu
Keyword(s):  
Rigid Body ◽  
Rotational Speed ◽  
Attitude Determination ◽  
Unscented Kalman Filter ◽  
The State ◽  
Determination Method ◽  
State Equations ◽  
High Rotational Speed ◽  
Motion Equations ◽  
Accuracy Measurement

In this paper, we present a novel multisensor combinatory attitude determination method that enables high-accuracy measurement of the attitude of a high rotational speed rigid-body aircraft. We analyze the external moments of the aircraft during flight and develop the method using theoretical deductions based on the motion equations of a rigid body rotating around the centroid. The proposed method fuses the data measured from GPS, gyrometer, and magnetometer and uses the improved unscented Kalman filter (UKF) algorithm to perform filtering. First, appropriate assumptions and simplifying approximations are made for around-centroid motion equations of a rigid body according to the motion characteristics of the high rotational speed aircraft. Using these assumptions and approximations, the constraint equations between the Euler attitude angles and flight-path angle, trajectory deflection angle are derived to serve as the state equation. Second, the roll angle with error is calculated using the geomagnetic field model and the geomagnetic intensity measured by a three-axis magnetometer and then fused with the angular velocity information obtained from the gyroscope for constructing the measurement equations. Finally, the state equations are discretized using the Runge–Kutta method during the UKF prediction stage, improving the prediction accuracy. Simulation results show that the proposed method can effectively determine the attitude information of the high rotational speed aircraft, achieving high level of reliability and accuracy thanks to the combination of information from GPS, gyroscope, and magnetometer.

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