On-Machine Measuring Instrument of Workpiece Compliance Using Laser Interferometer

2020 ◽  
Author(s):  
Masataka Furusawa ◽  
Daisuke Kono
Keyword(s):  
Machine Tool ◽  
Impact Test ◽  
Laser Interferometer ◽  
Measurement Instrument ◽  
Measuring Instrument ◽  
Crucial Issue ◽  
Compliance Measurement ◽  
Machining Conditions ◽  
Workpiece Vibration ◽  
Thin Walled

Abstract Workpiece vibration is a crucial issue in machining of thin-walled workpieces because of their large compliance. The workpiece compliance should be considered in setting machining conditions to suppress the vibration. However, the conventional impact test is laborious, and its result depends on the operator’s skill. In this study, an on-machine measurement instrument was developed to measure the compliance of thin-walled workpieces. The developed measuring instrument can be attached to the machine tool spindle for automatic compliance measurement. The workpiece compliance measured by a swept sine excitation using the developed instrument was comparable to the compliance by the conventional impact test.

Modeling and Identification of Geometric Error Based on Screw Theory

2014 ◽  
Vol 941-944 ◽  
pp. 2219-2223 ◽  
Author(s):  
Guo Juan Zhao ◽  
Lei Zhang ◽  
Shi Jun Ji ◽  
Xin Wang
Keyword(s):  
Machine Tool ◽  
Laser Interferometer ◽  
Screw Theory ◽  
Geometric Error ◽  
New Method ◽  
Geometric Errors ◽  
Volumetric Error ◽  
B Spline ◽  
The Individual

In this paper, a new method is presented for the identification of machine tool component errors. Firstly, the Non-Uniform Rational B-spline (NURBS) is established to represent the geometric component errors. The individual geometric errors of the motion parts are measured by laser interferometer. Then, the volumetric error for a machine tool with three motion parts is modeled based on the screw theory. Finally, the simulations and experiments are conducted to confirm the validity of the proposed method.

scholarly journals Development and validation of an organizational justice measurement instrument for a South African context

2015 ◽  
Vol 5 (1) ◽  
pp. 28-38 ◽  
Author(s):  
Ophillia Ledimo
Keyword(s):  
Factor Analysis ◽  
South African ◽  
Measurement Instrument ◽  
Diversity Management ◽  
South African Context ◽  
Measuring Instrument ◽  
Organisational Justice ◽  
Perceptions Of Fairness ◽  
African Context ◽  
Different Dimensions

Measuring organisational justice in a South African context is a concern as the concept is multi-dimensional and there is no comprehensive definition; therefore, an integrative and well-developed measure of organisational justice can advance the measurement and analysis of this concept. This study investigates the development and validity of an organisational justice measuring instrument (OJMI), and determines the relationships between the different dimensions of the concept organisational justice. Data was gathered from 289 participants, employed in a public service organisation. To analyse the data the descriptive and inferential statistics used are Cronbach alpha coefficient, means, the explanatory factor analysis (EFA) and the confirmatory factor analysis (CFA). It was found that the model fitted the data well and the measurement of each dimension, namely strategic direction; distributive, procedural, interactional, informational, diversity management; customer relations; service delivery innovation as well as ethical leadership and management justice were confirmed to be statistically significant and positive. These results indicate that OJMI is a reliable and valid measure that organisations need in order to measure perceptions of fairness, and to monitor trends of fair practices. The validated measuring instrument for organisational justice and the conducted analysis of the interrelationships between the different dimensions of the concept will enable organisations to initiate proactive and reactive interventions to facilitate justice and fair practices.

Study on the Stability of High-Speed Milling of Thin-Walled Workpiece

2010 ◽  
Vol 97-101 ◽  
pp. 1849-1852
Author(s):  
Tong Yue Wang ◽  
Ning He ◽  
Liang Li
Keyword(s):  
Aluminum Alloy ◽  
Machine Tool ◽  
High Speed ◽  
Modal Parameters ◽  
Inertia Effect ◽  
Cutting Force Coefficients ◽  
High Speed Milling ◽  
Machining System ◽  
Thin Walled ◽  
The Stability

Thin-walled structure is easy to vibrate in machining. The dynamic milling model of thin-walled workpiece is analyzed based on the analysis of degrees in two perpendicular directions of machine tool-workpiece system. In high speed milling of 2A12 aluminum alloy, the compensation method based on the modification of inertia effect is proposed and accurate cutting force coefficients are obtained. The machining system is divided into “spindle-cutter” and “workpiece-fixture” two sub-systems and the modal parameters of two sub-systems are acquired via modal analysis experiments. Finally, the stability lobes for high speed milling of 2A12 thin-walled workpiece are obtained by the use of these parameters. The results are verified against cutting tests.

An Application of the Fractal Theory in the Design of Heat Sink for Precision Measurement Instrument

2005 ◽  
Vol 295-296 ◽  
pp. 717-722 ◽  
Author(s):  
S.R. Lee ◽  
Z.G. Li ◽  
B.G. Wang ◽  
H.S. Chiou
Keyword(s):  
Heat Transfer ◽  
Temperature Variation ◽  
Temperature Control ◽  
Heat Sink ◽  
High Performance ◽  
Laser Interferometer ◽  
Fractal Theory ◽  
Measurement Instrument ◽  
Measurement Instruments ◽  
Heat Sink Design

Temperature variation on accuracy and stability in measurement instruments is an important issue. High performance and miniaturized instruments have rigorous requirements on temperature. Heat transfer and temperature control are important in instruments design. For laser interferometer, temperature variation will adversely affect the frequency stability of the laser and the measuring precision. In order to effectively stabilize the frequency, a simple and effective heat sink design for laser interferometer is presented. It is based on the fractal theory and the heat transfer characteristics to allow higher dissipation for temperature control to generate higher heat transfer area in a finite space. Experimental results in frequency stabilization clearly show that this method is effective.

scholarly journals Machining Process for a Thin-Walled Workpiece Using On-Machine Measurement of the Workpiece Compliance

2019 ◽  
Vol 13 (5) ◽  
pp. 631-638 ◽  
Author(s):  
Takuma Umezu ◽  
◽  
Daisuke Kono
Keyword(s):  
Measurement System ◽  
End Milling ◽  
Numerical Control ◽  
Cutting Conditions ◽  
Machining Process ◽  
Experimental Result ◽  
Depth Of Cut ◽  
Machining Processes ◽  
Workpiece Vibration ◽  
Thin Walled

Demand for highly productive machining of thin-walled workpieces has been growing in the aerospace industry. Workpiece vibration is a critical issue that could limit the productivity of such machining processes. This study proposes a machining process for thin-walled workpieces that aims to reduce the workpiece vibration during the machining process. The workpiece compliance is measured using an on-machine measurement system to obtain the cutting conditions and utilize the same for suppressing the vibration. The on-machine measurement system consists of a shaker with a force sensor attached on the machine tool spindle, and an excitation control system which is incorporated within the machine tool’s numerical control (NC). A separate sensor to obtain the workpiece displacement is not required for the estimation of the displacement. The system is also capable of automatic measurement at various measurement points because the NC controls the positioning and the preloading of the shaker. The amplitude of the workpiece vibration is simulated using the measured compliance to obtain the cutting conditions for suppressing the vibration. An end milling experiment was conducted to verify the validity of the proposed process. The simulations with the compliance measurement using the developed system were compared to the results of a conventional impact test. The comparison showed that the spindle rotation speed for suppressing the vibration could be successfully determined; but, the axial depth of cut was difficult to be determined because the simulated vibration amplitude was larger than that found in the experimental result. However, this can be achieved if the amplitude is calibrated by one machining trial.

scholarly journals PERAN SELF-REGULATED LEARNING TERHADAP EMOTIONAL EXHAUSTION YANG DIMEDIASI OLEH STUDENT ENGAGEMENT PADA SANTRI

2019 ◽  
Vol 3 (2) ◽  
pp. 423
Author(s):  
Dinda Nabila Sholihah ◽  
Riana Sahrani ◽  
Rahmah Hastuti
Keyword(s):  
Student Engagement ◽  
Emotional Exhaustion ◽  
Measurement Instrument ◽  
Boarding School ◽  
Measuring Instrument ◽  
Measuring Device ◽  
Purposive Sampling ◽  
Self Regulated Learning ◽  
Regulated Learning

Santri merupakan seseorang yang belajar agama Islam dan mendalami agama Islam dalam sebuah pesantrian atau pesantren. Dalam menjalankan kegiatannya sehari-hari, santri terikat dengan berbagai macam peraturan dan kegiatan yang menyebabkan kecenderungan dari munculnya emotional exhaustion pada santri. Dalam penilitian ini, akan dibahas mengenai peranan self-regulated learning terhadap emotional exhaustion yang dimediasi oleh student engagement pada santri. Metode yang digunakan adalah kuantitatif non-eksperimental dengan teknik pengambilan data purposive sampling dan criterion sampling. Adapun alat ukur yang digunakan terdiri dari alat ukur self-regulated learning yang diadaptasi dari alat ukur self-regulated learning dari Pintrich dan Groot (1990), alat ukur emotional exhaustion yang diadaptasi dari alat ukur yang dikembangkan oleh Schaufeli, Martίnez, Marqués-Pinto, Salanova, dan Bakker (2002), serta alat ukur student engagement yang diadaptasi dari alat ukur student engagement dari Schaufeli dan Bakker (2003). Pengambilan data dilakukan di lima pondok pesantren yang terdapat di wilayah Bogor dan Bekasi pada bulan Oktober – November 2018 dengan melibatkan 424 partisipan penelitian berusia 11 – 20 tahun. Berdasarkan hasil yang diperoleh, self-regulated learning secara negatif signifikan memengaruhi emotional exhaustion (tc’ = -6,336; p= 0,000 < 0,05) dan student engagement tidak memediasi peran self-regulated learning terhadap emotional exhaustion (tb’= 1,153; p = 0,250 > 0,05). A santri is a person who studies Islam in a pesantren or Islamic boarding school. In carrying out their daily activities, students are bound by a variety of regulations and activities that tend to cause emotional exhaustion in students. In this research, the role of self-regulated learning on emotional exhaustion mediated by student engagement on santri will be discussed. The research method used is quantitative non-experimental technique with purposive sampling and criterion sampling. The measuring device used consists of a self-regulated learning measuring instrument adapted from a self-regulated learning measuring instrument from Pintrich and Groot (1990), an emotional exhaustion measuring instrument adapted from a measuring instrument developed by Schaufeli, Martίnez, Marqués-Pinto, Salanova, and Bakker (2002), as well as student engagement measurement instrument adapted from the student engagement measurement instrument from Schaufeli and Bakker (2003). Data were collected at five Islamic boarding schools in Bogor and Bekasi over October - November 2018 involving 424 research participants aged 11-20 years. Based on the results obtained, self-regulated learning negatively and significantly affects emotional exhaustion (tc '= -6.336; p = 0.000 <0.05) and student engagement does not mediate the role of self-regulated learning on emotional exhaustion (tb' = 1.153; p = 0,250> 0,05).

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