2025 ASEE Annual Conference & Exposition

College-level sophomore and junior mechanical design-and-build laboratory courses are critical in helping engineering students develop practical skills for mechanical systems. However, many students struggle with basic mechanical components and fasteners, often failing to identify standard parts on sight. This lack of foundational knowledge, in conjunction with suboptimal project management habits, often results in over-reliance on adhesives. This is particularly problematic in situations where adhesives are used inappropriately—such as gluing gears to round shafts instead of using mechanical solutions like D-shafts, keys, or set screws. Even in cases where adhesives are correctly applied, overuse often results in poor tolerances, weak joints, misaligned parts, and overall structural instability.
To address this issue, this paper presents a customizable design-and-build Marble Machine project, where a critical rule prohibits the use of general adhesives as a joining method. Adaptable for undergraduate students ranging from freshmen to seniors, this project emphasizes proper mechanical assembly techniques. The absence of adhesives encourages exploring catalogs of mechanical components for efficient and economical solutions, reinforcing the importance of specification compliance and smart tolerancing, minimizing excessive vibration and ensuring stability.
The Marble Machine project’s complexity can be tailored to the varied skill levels, deepening the understanding of mechanical systems and avoiding temptations of quick fixes such as glue—especially when working with additively manufactured parts under tight deadlines. Students subjected to the no-adhesive rule seem to produce higher-quality projects, with better mechanical integrity and functional design.
The Marble Machine project and the restriction on adhesive use is measured both qualitatively and quantitatively. Devices are assessed for mechanical performance and knowledge of standard mechanical components and fasteners. Additionally, a survey is conducted to gauge students’ perspectives on the learning experience.
This project contributes to all seven ABET student learning outcomes, depending on how the assignment is customized, making it a highly effective tool for both skill development and practical education in mechanical design.