June 15, 2019
June 15, 2019
June 19, 2019
Abstract MAKER: We demonstrate that incorporation of Geometric Dimensioning and Tolerancing (GD&T) into engineering drawings in a Senior Design reduces the number of design iterations, increases design quality, and enables both the handoff to manufacturing and easier manufacturing. This demonstration is accomplished by a Senior design group manufacturing an Alpha style Stirling Engine out of 6061 Al using a manual lathe and mill and using GD&T. We will compare this engine to another Stirling Engine built by a Senior design group in 2015 that was based on the coordinate dimensioned design by Senft . We compare the time it takes to manufacture both designs, as well as the design quality once they are fully manufactured.
The implementation of GD&T is not commonly taught in undergraduate mechanical engineering (ME) curriculums. More commonly, traditional coordinate dimensioning is used in the engineering drawings. If GD&T is taught in the curriculum, then it is not common the students get the opportunity to manufacture an assembly with tight tolerances that contained GD&T in the engineering drawings. For this Senior Design project, the students learn to machine all the parts to meet the GD&T specifications, and familiarize themselves with the necessary tools required to properly manufacture the Stirling Engine assembly.
For the Stirling Engine that is manufactured using traditional coordinate dimensioning, we demonstrate issues such as the piston jamming inside the cylinder, requiring a significantly longer time to manufacture the engine than when GD&T is used.
The ability to practice GD&T in student engineering drawings, as well as machining assemblies with GD&T specifications makes a more competent mechanical engineer, who knows how to reduce the total time and budget required to complete a satisfactory design project.
Oppenheim, T. (2019, June), Board 93: MAKER: Improving the Quality of Mechanical Engineering Senior Capstone Designs by Incorporating Geometric Dimensioning and Tolerancing During the Concept Design Phase Paper presented at 2019 ASEE Annual Conference & Exposition , Tampa, Florida. 10.18260/1-2--32463
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