Hydrostatic Table Research Articles

Pengaruh Shortage Cargo terhadap Kegiatan Transhipment Batu Bara di PT. Kartika Samudra Adijaya Site Berau

One of the most common obstacles is the difference in the amount of coal transported during the transhipment process compared to before the transhipment was carried out. This difference tends to lead to a reduction in the amount of coal (shortage cargo) which is certainly very detrimental to the recipient company which causes the transhipment process to occur more than once, thus disrupting the company's schedule and operations, resulting in the parties involved experiencing financial losses. This study was conducted to determine the influence of draught survey factors, hydrostatic table and cargo losses and how the influence of each factor simultaneously causes cargo shortages in transhipment activities, testing using comparative causal quantitative research methods using multiple linear regression data analysis techniques which were then processed using the SPSS version 23 program. The results obtained indicate that there is an influence of draught survey, hydrostatic table and cargo losses on transhipment activities and partially have an influence of 9%, 1.6% and 2.5% respectively. The variables of draught survey, hydrostatic table and cargo losses simultaneously cause cargo shortages so that it affects transhipment by 71.2%. while the remaining 28.8% is suspected to be influenced by other factors outside the research variables.

Analysis of Log Cargo Handling Management

Log cargoes are bulk cargoes and could be loaded in holds on the deck. Logs have their own characteristics and particular treatments, especially when loaded on the deck. In this case, loading logs was conducted in two ports where specific skills and good preparation were needed because there was a possibility on missing cargo calculation. There are some methods of cargo calculation which were carried out manually and using the program. This research used fishbone and descriptive qualitative analysis. The purpose of this research was to make log cargo handling easier, more effective and efficient for one port to another port. The result showed that the implementation of loading management was done in four stages including planning, organizing, actuating and evaluating. In the first port, logs are loaded in holds and not contained fully. Then in the second port, the rest of logs were completely loaded on the deck. There is a difference on the cargo calculation because of the ontaking value of hydrostatic table.

초정밀 유정압 테이블에서 냉각장치의 변수 설정이 온도특성에 미치는 영향

Temperature characteristics of supply oil in an ultra-precision hydrostatic table are largely influenced by parameter setting in an oil cooler such as the location of reference sensor and cooling temperature. In this paper, influences of the parameter setting on the temperature variation in the hydrostatic table are experimentally analyzed to suggest the guidelines for practical application. In case of using temperature of inlet oil as a reference sensor in the oil cooler, temperature rise of the supply oil is smaller and thermal settling time is faster than that of using temperature of outlet oil as a reference sensor. The experimental results also show that temperatures of table, rail and return oil can be made almost same, and thermal settling time can be decreased by setting cooling temperature in the oil cooler to be lower than atmospheric temperature.

Measurement of Five DOF Motion Errors in the Ultra Precision Feed Tables

Five degrees-of-freedom (DOF) motion errors of an ultra precision feed table were measured in this study. The laser interferometer was used to measure the yaw and pitch errors and the reversal method was used for the roll error measurement. The linear motion errors in the vertical and horizontal directions were measured using the sequential two point method. The influence of angular motion errors on the linear motion errors while applying the sequential two point method was compensated with the data from the laser interferometer and the reversal method. Capacitive type sensors and an optical straight edge were used while applying the reversal method and the sequential two point method. To demonstrate the effectiveness of our measuring scheme for the ultra precision feed tables, five DOF motion errors of a hydrostatic table driven by a linear motor were measured and presented. From the measured repeatabilities of 5 DOF error motions, it was estimated that the measuring accuracies were ±0.02 μm for the horizontal and vertical linear motion, ±0.04 arcsec for yaw motion, ±0.05 arcsec for pitch motion and ±0.02 arcsec for roll motion.

Motion Error Compensation Method for Hydrostatic Tables Using Actively Controlled Capillaries

To compensate for the motion errors in hydrostatic tables, a method to actively control the clearance of a bearing corresponding to the amount of error using actively controlled capillaries is introduced in this paper. The design method for an actively controlled capillary that considers the output rate of a piezo actuator and the amount of error that must be corrected is described. The basic characteristics of such a system were tested, such as the maximum controllable range of the error, micro-step response, and available dynamic bandwidth when the capillary was installed in a hydrostatic table. The tests demonstrated that the maximum controllable range was 2.4 /im, the resolution was 27 nm, and the frequency bandwidth was 5.5 Hz. Simultaneous compensation of the linear and angular motion errors using two actively controlled capillaries was also performed for a hydrostatic table driven by a ballscrew and a DC servomotor. An iterative compensation method was applied to improve the compensation characteristics. Experimental results showed that the linear and angular motion errors were improved to 0.12 µm and 0.20 arcsec, which were about 1/15th and l/6th of the initial motion errors, respectively. These results confirmed that the proposed compensation method improves the motion accuracy of hydrostatic tables very effectively.