How to Design and 3D Print Precision Puzzles and a Visor Connector

Mechanical engineering students often lack understanding of geometric dimensioning and tolerancing. Washington State University developed a hands-on approach using 3D printing projects to address this gap. This guide outlines the steps to design, model, and 3D print interlocking puzzle pieces and a car visor connector, emphasizing geometric tolerance and fit.

Steps to Design and 3D Print Precision Puzzles:

1. Design four interlocking puzzle pieces that fit snugly and are easy to assemble/disassemble by hand. Ensure the design is suitable for a 5-year-old and remains intact when picked up.
2. Model the puzzle pieces in SolidWorks, creating parts, assembly, and engineering drawings with appropriate clearances. Consider the size limit of 1″ x 1″ x ½” for each piece, excluding connector geometry.
3. 3D print the models using PLA or TPU material and test the fit of the 3D printed parts. If the pieces do not fit, reflect on the design problem and identify areas for improvement.
4. Select appropriate tolerances for the connector geometries, indicating them on the part drawings. Use hole/peg gauges to determine the typical clearance needed between connecting pieces.
5. Inspect the printed puzzle pieces using calipers to measure the connecting features and verify they fall within the specified tolerance zone. Analyze how a manufacturer would respond if parts do not meet specifications.

Steps to Design and 3D Print a Car Visor Connector:

1. Design a replacement car visor bracket that mimics the original design or looks different, but meets intended functionality. The bracket must securely hold the visor in both stowed and deployed positions without sagging.
2. Model the visor connector in SolidWorks, considering the existing mounting holes/fasteners and maintaining stiffness after multiple cycles of stowing/deploying. Use a 3D scanner or calipers to reverse engineer the original bracket.
3. 3D print the model using PLA or TPU material, carefully adjusting clearances to account for the material’s shortcomings. Consider a single-piece or two-part design with interlocking or reinforcement features. 4. Test the 3D printed bracket for fit and functionality, ensuring it holds the visor at the correct angle and the screws fit properly. Revise the design based on testing results to improve overall performance.