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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

On-line Gap Measurement Techniques for Steel Mill Non-contacting Conveyance System

Yang, Yung-Yi 25 August 2009 (has links)
On-line gap measurement techniques for steel mill non-contacting conveyance system, which can supply accurate, rapid and high-sampling rate gap measurements, have been proposed. To realize the entire process, by considering the operational environment in a steel mill and combining with those available system dimension measurement instruments, an image-based scheme with proper image processing and parameter calibration process has been developed. The possible sources that affect the air-gap detection accuracies have also been thoroughly investigated, and a comprehensive measurement database and a recursive modification technique have been successfully established. In order to achieve stable control for site implementation, an integrated optical inspection system which combined with the high-speed rate line-scan camera has been designed. From the experimental results, the proposed system can both provide accurate gap values at the static state, and offer stable control operations at the dynamic state. It is believed that the proposed scheme provide innovated guidance for the related conveyance applications in the steel mill.
2

New Approaches for Utilizing Planar Inductive Sensors for Gap Measurement Proximity and Lubricant Oil Wear Debris Monitoring

Jiao, Dian 12 April 2021 (has links)
No description available.
3

Evaluation of On-Machine Gap Measurement Strategies in Jet-Electrochemical Machining

Yahyavi Zanjani, Matin, Hackert-Oschätzchen, Matthias, Martin, André, Schubert, Andreas 05 February 2018 (has links) (PDF)
Jet Electrochemical Machining (Jet-ECM) is a manufacturing technique that applies a free electrolyte jet to generate the desired shapes [1]. Since the principle of the technique is the same as other techniques of Electrochemical Machining where the material removal takes place based on the anodic dissolution of workpiece, the working distance, which is the distance between nozzle’s front surface and the workpiece surface, is one important parameter of the process. The working distance affects the current density and consequently the geometry removal. The control of the working distance can be done based on the data gathered before and during machining by surface measurement [2]. This measurement usually is done by using electrostatic probing to detect a limited amount of points of the initial workpiece surface. Since electrostatic probing is comparatively slow, laser triangulation represents an alternative technique to detect a larger amount of points before machining within significantly shorter time [3]. In addition to electrostatic probing and laser triangulation, the actual working distance can be measured during the machining process to realize constant working distance. This can be done by detecting electrical signals like the actual total current. This method can be combined with pre-machining measurement by laser triangulation in order to ensure the prevention of any collision between the nozzle and the workpiece. In this study, on-machine metrology techniques for measuring the working gap as well as current measurements will be compared. Besides, the advantages and disadvantages of these techniques will be systematized. In further studies, the possibility of combining the techniques will be investigated to enhance Jet-ECM with more accurate measurement techniques.
4

Evaluation of On-Machine Gap Measurement Strategies in Jet-Electrochemical Machining

Yahyavi Zanjani, Matin, Hackert-Oschätzchen, Matthias, Martin, André, Schubert, Andreas 05 February 2018 (has links)
Jet Electrochemical Machining (Jet-ECM) is a manufacturing technique that applies a free electrolyte jet to generate the desired shapes [1]. Since the principle of the technique is the same as other techniques of Electrochemical Machining where the material removal takes place based on the anodic dissolution of workpiece, the working distance, which is the distance between nozzle’s front surface and the workpiece surface, is one important parameter of the process. The working distance affects the current density and consequently the geometry removal. The control of the working distance can be done based on the data gathered before and during machining by surface measurement [2]. This measurement usually is done by using electrostatic probing to detect a limited amount of points of the initial workpiece surface. Since electrostatic probing is comparatively slow, laser triangulation represents an alternative technique to detect a larger amount of points before machining within significantly shorter time [3]. In addition to electrostatic probing and laser triangulation, the actual working distance can be measured during the machining process to realize constant working distance. This can be done by detecting electrical signals like the actual total current. This method can be combined with pre-machining measurement by laser triangulation in order to ensure the prevention of any collision between the nozzle and the workpiece. In this study, on-machine metrology techniques for measuring the working gap as well as current measurements will be compared. Besides, the advantages and disadvantages of these techniques will be systematized. In further studies, the possibility of combining the techniques will be investigated to enhance Jet-ECM with more accurate measurement techniques.
5

Investigation of the wear behavior of the slipper in an axial piston pump by means of simulation and measurement

Ivantysyn, Roman, Shorbagy, Ahmed, Weber, Jürgen 25 June 2020 (has links)
Axial piston pumps are universal displacement machines that are used in a vast variety of applications. Their high pressure resistance and ease of operation make them very popular, especially in mobile applications. Some applications require more robust pumps with an extended lifetime, particularly those that operate in remote environments such as marine type or mining operations. Especially new applications like displacement control have high demands on pumps such as through shaft operation (many pumps on one shaft), high dynamics and multi-quadrant operation. These demands create challenges in terms of lifetime expectancy and robustness for pump manufacturers and machine OEMs. Currently most axial piston pumps go through a run-in process. During this process the softer bronze parts shave off and change their shape according to the necessary one for the pumps’ proper operation. This process is highly dependent on the design of the parts and their manufacturing tolerances. In this paper the run-in process of the slippers of an axial piston pump was investigated by means of measurements of the gap height and wear profile as well as simulation. The measurements show a clear change of profile and gap heights for the first 120 h of the pumps operation. After that the gaps stabilize. The numerical simulations made with the program Caspar FSTI were coupled with contact wear models to output wear profiles. Different models will be introduced and compared with measurements. Both the amount of material removed and the performance of the pump before and after run-in will be discussed.

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