Injection Molded Yo-Yo

Project Overview

Objective: Design & manufacture at least 50 working plastic snap-fit yo-yos using a combination of injection molding & thermoforming

Role: Designed and manufactured press fit sawtooth gear (1 of 4 pieces to the yo-yo), compiling control charts, CAD renderings, final report write-up

Skills: Design for manufacturing, CAD modeling, injection molding, process control monitoring

Result: Successfully built >50 working yo-yos through a process that remained within control limits

Project Description

This undergraduate mechanical engineering course introduces students to modern manufacturing with four areas of emphasis: manufacturing processes, equipment/control, systems, and design for manufacturing. The course exposes students to integration of engineering and management disciplines for determining manufacturing rate, cost, quality and flexibility. Topics include process physics, equipment design and automation/control, quality, design for manufacturing, industrial management, and systems design and operation.

This culminates in the students working in teams eight to design a working press fit yo-yo. The requirements are that at least one piece of the yo-yo must be manufactured using thermoforming, and at least one piece must be manufactured using injection molding. Since this is a design for manufacturing class, the team need manufacture a run of at least 50 fully assembled yo-yos (at least 100 of each part) and monitor variation in the critical dimensions from part to part. These variations are then monitored using control charts (such as x-bar and r charts) to understand process variability and see if their design and manufacturing methods are in control or not.

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