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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

A device developed for detecting the breakage of gundrilling

Yen, Yu-Tse 10 September 2008 (has links)
Gun-drilling is one of the highly efficient tools for deep-hole making. The drilled hole possesses good size, positioning, roughness, roundness, and straightness. When the deep-hole is drilled, it is easy to cause wear at the tool-chip and tool-work interfaces at the serious condition so that the gun-drill is subjected to larger feed force. If the feed force exceeds the critical load, then the cutting edge of the gun-drill is broken. However, nowadays the device to measure the feed force in the gun-drill press is not available. This study develops a gun-drill press which possesses two new functions as follow: (1) to measure and to record the feed force during the drilling process;¡]2¡^to return the gun-drill when the feed force exceeds a set value. These two functions can be used to detect the serious breakage of the gun-drill. According to the practice drilling test, the performance of this press can be obtained. Results show that the feed force can be measured using different feed speeds. The gun-drill can stop and return to its origin position when the feed force exceeds the set value. Hence, the performance test of this new machine meets the above-mentioned functions. Using this press, the relationship between the feed force and the wear of cutting edge is investigated at the same feed speed. Results show that wear occurs on the cutting edge of the gun-drill, and the wear area increases with increasing drilling time so that the feed force is also increased. The wear grows from the outer side of the cutting edge to the inner side.
2

Vliv geometrie a řezných parametrů nástroje na zbytkové napětí při obrábění tlakových zásobníků / The influence of geometry and cutting tool parameters on residual stress during machining of the pressure containers

Berka, Martin January 2016 (has links)
This thesis deals with the influence of changes in cutting parameters and tool geometry on residual stress inside the material. I examine the influence by deep drilling. Changing the cutting parameters concerns the alteration of the tool feed and the pressure of the coolant during the process. The influence of tool geometry is studied by using two different single edge cannon drills. The research was realized in cooperation with Bosch Diesel Ltd. The theoretical part includes a description of the injection system, in which a high-pressure container is contained. The high-pressure container was used to evaluate the influence of the cutting parameters and tool geometry on residual stress. Furthermore, the theoretical part deals with the deep drilling technology used and the theory of residual stresses. The practical part shows the measurement parameters and the corresponding results. In the conclusion of this thesis, a technical-economic evaluation of the measurement is conducted.

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