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F. Menalo, G. Mohamed, M. I. Mohamed, A. A. Abuelezz, M. Adly, A. A. Khatab
DEVELOPMENT OF PRIMARY VICKERS HARDNESS TESTING MACHINE

This paper describes a primary Vickers hardness standard, which was developed by National Institute of for Standards (NIS), of Egypt. It is utilized synthetically the optics, precise mechanism, electronics, computer and automatic controlled technology. The CCD image system is employed, which makes the standard measuring of Vickers hardness value automatically and manually, so the indentation can be realized and accuracy can be improved .The machine has been evaluated through comparisons with the Physikalisch-Technische Bundesanstalt (PTB) Germany.

Dieter Schwenk
LEEB HARDNESS-CALIBRATION-MACHINE

For the calibration of hardness reference blocks according to the German standard DIN 50156 -hardness test according Leeb -MPA NRW has realized a new concept of hardness reference standard machine. A laser interferometer is used for the continuous measurement of distance and time. In a post process the speed of the indenter will be evaluated from the measurement data. The conception of the machine, measurement capabilities and the effects of variation of test parameters are reported in the following paper.

Dieter Schwenk
CONSIDERATION OF THE UNCERTAINTY OF MEASUREMENT DURING THE CALIBRATION OF HARDNESS TEST MACHINES

The uncertainty of measurement is always characteristic of the test set-up and the test procedure. Only at the end of the calibration the uncertainty of measurement is transferred to the measured object concerning the exactness of the scale design. The problems with the inclusion of the uncertainty of measurement in the conformity according to ISO 17025 at the calibration of material test machines is often founded in the too little number of single measurements, as e.g. at the calibration of the test force on hardness test machines according to ISO 6508. The number of single measurements in the calibration specifications of the test standards should be increased and variably arranged for the particular calibration requirement. The consideration of the uncertainty of measurement is condition of any metrological result evaluation.

Tassanai Sanponpute, Veera Tulasombut, Rugkanawan Kongkavitool, Apichaya Meesaplak
INTERLABORATORY COMPARISON ON ROCKWELL HARDNESS MEASUREMENT IN THAILAND

Hardness laboratory of National Institute of Metrology Thailand (NIMT) was a pilot laboratory and responsible for coordinating the interlaboratory comparison in Thailand. The two comparison protocols, comparison on Rockwell scale B hardness measurement and comparison in scale C hardness measurement, were set up for participant to choose according to their application. The artifacts used in these comparisons were hardness reference blocks and machinery part such as cylindrical axles and metal sheets. The measurement result and uncertainty budget were reported to pilot laboratory and are used to compute deviation from reference value and En numbers. Most laboratories had En numbers under 0.5 while few laboratories had En numbers between 0.5 to 1. Only one laboratory, who declared unusual BMC, had En number higher than 2.

Montree Pakkratoke, Natchapon Luekiatphaisan, Hisayuki Aoyama, Tassanai Saneponpute
COMPACT MICRO FORCE GENERATOR WITH TANDEM LEAF SPRING AND VCA ON MICRO ROBOT FOR MICRO HARDNESS AND STIFFNESS TEST

This paper presents the development of compact size force generator mechanism with voice coil actuator and piezo driven micro robot for surface hardness and stiffness investigation. This small force generator is composed of voice coil actuator and tandem leaf spring mechanism. The small force can be controlled by electrical current which is supplied to coil and positioned precisely at the balance point with the parallel leaf spring with no mechanical friction. And the full bridge strain gauges on both side of double leaf spring can detect small force which is applied to the micro indenter. This unique layout can provide good linearity and small force up to 20 mN with 0.05 mN resolution. The displacement of the indenter head also can be measured by the laser displacement sensor for monitoring the depth behaviour of the indenter during whole dwell time. Since the overall size of this force generator is compact enough to implement on the piezo driven micro robot, it can be possible to employ them in such the SEM chamber for in-situ measurement.
In the primary experiment, the performance of small force generator unit is compared with the hardness standard block at first and then the surface hardness distribution is investigated with the help of the micro robot as it can transport the sample material precisely with 1 μm resolution.

Edward Aslanyan, Peter Krasowski, Aleksandr Doynikov, Victor Pivovarov
IMPROVEMENTS OF THE NATIONAL HARDNESS PRIMARY STANDARD MACHINE ON VICKERS SCALES

The present paper discusses the results of the research conducted during the improvement of the national hardness primary standard machine on Vickers scales. The improvement consisted in the creation of an automated complex for measuring the indentation diagonal length through the indentation transfer via a digital camera to the computer controlling the measurement process. The peculiarities scales of order were taken into account while examining the hardness primary standard machine and determining the metrological characteristics. The modernization of the national primary standard machine allowed to minimize measurement uncertainty, increase productivity and improve working conditions on the standard machine.

A. Abu-Sinna, Yon-Kyu Park, Dae-Im Kang, Min-Seok Kim
OPTIMUM DIMENSIONS OF DWM LOADING FRAME

In this paper, we are willing to know the influence of the loading frame stiffness through finite element method. FEM modelling has to be run with different force application criteria, and different dimensions of loading frames. In addition, different dimensions of loading frame have been dedicated to run the experiments.
The upper plate dimensions showed the superiority over all other loading frame components, and consequently the priority of the rigid loading frame. Hence, supplementary measurements as well as FEM modelling were performed to identify the exact influence and generalize the conclusions through different types of loadcells.
An empirical formula (IX/F) was calculated for comparing different behaviours of loadcells using different models of loading frames. In addition, three types of loadcells were examined for final conclusion.

Zhong Ruilin, Wang Jian, Yao Hong, Ding jin’an, Cai Changqin, Zhang Yue
RESEARCH ON MEASURING MAGNETISM OF WEIGHT USING GAUSSMETER

Magnetism is very important for high accuracy class weights. There are several ways to measure magnetism of weights according to OIML R111. In NIM, a new magnetism measure device has been set up to measure magnetism of weights by using gaussmeter. This device compose of a rotation platform, stick pole, control panel , computer and gaussmeter. The gaussmeter is installed on the stick pole. The platform can move horizontally and let the center of the weight just below the probe of the gaussmeter. Also the platform can rotate around and the gaussmeter can detect the largest indication, and the result can be calculated by computer. The support capacity of the platform is 50 kg, so the magnetism of large weight can be measured by this device. The effectiveness of this device is showed by several tests.

Octavian Postolache,, Pedro Silva Girão
CALIBRATION AND APPLICATION OF A PRESSURE MAPPING SENSOR

The paper presents the hardware and software for the calibration of a pressure mapping system and the application of the sensor in ballistocardiography recording for humans vital signs unobtrusive monitoring.

Ebtisam H. Hasan, Günther Haucke, Rolf Kumme
EFFECT OF DIFFERENT LOADING SCHEMES ON CREEP AND CREEP RECOVERY FOR FORCE MEASUREMENTS

The creep and creep recovery are important characteristics of force transducers. Thus, this study is focused on the measurements of creep and creep recovery for transducers of different capacities.
Creep measurements are carried out according to three different loading schemes, revealed that the creep values measured at maximum loads and reached after time intervals from 30 to 300 seconds like proposed in a new draft of ISO 376 from the moment of load application. The effect was higher in direct loading (one step to reach the maximum load) than those obtained from the two other schemes (chosen loading steps distributed all over the full range up to maximum load and according to automatic machine calibration (M/C) software that designed to cover all the range up to maximum load). Effect of creep on hysteresis value is also investigated.

Page 708 of 977 Results 7071 - 7080 of 9762