Design for vacuum systems

Diepen, T. van (2015) Design for vacuum systems.

Abstract:The assignment described in this report is executed for Centro de Tecnologia da Informação Renato Archer. A government based research facility situated in Campinas, Brazil. Several of the research programs conducted there, involve the use of advance vacuum systems. To improve the research possibilities with these systems, additional equipment is necessary. Therefore the assignment is the redesign of three pieces of equipment that are used in vacuum systems. A rotary feedthrough for a planetary system. And a sample introduction system and a sample holding system for a double chamber vacuum system. In the first part of this report a feedthrough to optimize evaporation decomposition is designed. To create a film with a more uniform thickness, CTI recently designed a planetary system. However this system lacks a driving principle. This is the assignment for part 1. The first step in completing this assignment is analysing the system and its restrictions. The resulting main requirements are that the system should be manufacturable at the workshop of CTI, and only be made of materials that are in stock at CTI. Furthermore the system should not reduce the quality of the vacuum in which the experiments are conducted. The second step is to create two concepts, using the input from the analysis. The first concept is based on magnetic decoupling to drive the shaft of the planetary system. In the second concept the actuator directly drives the shaft. This requires a dynamic seal, in the form of a rotary feedthrough. Based on the requirements the first concept is selected to be further developed. The result is a final design which is ready to be manufactured in the workshop. This has not been done yet during the writing of this report. So the final result is not available, and cannot be tested and evaluated. In the second part, two systems are designed to improve experiments on measuring the work function of a surface of a material. At CTI, the work function is currently measured in a small vacuum chamber. Due to the size and because it is a single chamber vacuum system, the results are not reliable. To improve the results CTI procures a double chamber vacuum system. To make the system confirm with the technical necessities and to decrease the costs, two parts of the feedthrough are designed and manufactured at CTI. These are the sample introduction system and the sample holding system. The designing of both systems is the assignment of part 2. To create both designs firstly an extensive analysis of the situation and of the restrictions of both systems is executed. This resulted into two programs of requirements (one for each system). The most important requirements are: the sample must never drop, the systems are manufacturable by the workshop of CTI, and the friction between parts made of the same materials should be reduced as much as possible. Secondly several ideas for the sample introduction system are created, of which two are selected and developed into a concept. Both concepts involve a rotating movement to grab and release the sample. And both concepts are optimized to reduce interference with the experiments. Finally one concept is chosen based on the requirements. The final design involves a lever movement to grab and release the sample. And a spring is used to prevent dropping the sample. Thirdly the sample holding system is designed. CTI already created an idea for the system. This idea further developed into a final design. In this design the shape of the holding system is optimized for easy manufacturing and for reduction of interference with the experiments. Lastly the sample holder is able to guide the introduction system. Finally the two systems are optimized and made compatible with each other. The results are two fully developed systems that are ready for production. During the writing of this report the introduction system has not been manufactured yet. However the holding system is manufactured and tested. The results are positive and the system is already in use.
Item Type:Internship Report (Master)
CTI, Brazil
Faculty:ET: Engineering Technology
Subject:52 mechanical engineering
Programme:Mechanical Engineering MSc (60439)
Keywords:Vacuum, Vacuum Systems, Design
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