Quick Change A-Stand Design
Date
2018-12-05
Authors
Kim, Dongha
Quan, Yafei
Truong, Timmy
Zhou, Zeitan
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Abstract
This report presents the final design of the quick-change hydraulic powered A-Stands that successfully meets client’s requirements. The main requirement of the client is to reduce the welding fixture changeover time from 45 minutes to 5 minutes. The final design uses a retractable shaft mechanism built into the heads of the drive end and idle end A-Stands. This allows the A-Stand shafts to quickly connect to, and disconnect from, the welding fixture yokes. Therefore, the welding fixtures can be easily lifted off, and lowered onto the A-Stands, improving the welding fixture changeover process compared to the existing A-Stand design.
In the existing A-Stand design, the process requires to move the entire A-Stand to connect to and disconnect from welding fixture yoke. This requires use of forklifts due to the A-Stand shaft being fixed in place to the A-Stand head and the heavy weight of the A-Stand. This is the most time-consuming process in the welding fixture changeover. The retractable shaft design eliminates this process therefore it significantly improves the changeover time. As a limitation of this project, obtaining actual changeover time is not possible due to not having a working prototype. However, because of the simplicity of the new process, the target time can be achieved theoretically.
The final design is achieved by an iterative design process built on the retractable shaft concept which was determined as the best approach to achieve a quick changeover. The performance of the critical components is verified through analytical stress analysis, stress-life analysis, and preliminary finite element analysis (FEA). Standard operating procedure and failure modes and effects analysis are used as a preliminary safety analysis. Preliminary drawings are provided for details of the final design components. In addition, a preliminary cost analysis is conducted for client’s reference when weighting the benefits.
The final A-Stand design meets client’s requirements making it a successful design. The A-Stands have been determined analytically to support client’s required load of 4,000 [lbs] with a safety factor of 3. The A-Stand shafts meet client’s requirement for 15-year service life. The final A-Stand design is retrofitted on the existing A-Stand base...