Kids’ Toy Bracelets

Computer Integrated Manufacturing: Winter 2019


My team of four was tasked with designing and manufacturing an injection-molded plastic toy for the course Computer-Integrated Manufacturing II. We created a customizable charm bracelet based on sketches from a group of fourth-grade students.



Design For Manufacturing

The bracelet has four different pendants, each based on one of the kids’ drawings. They can be snapped on the bracelet via a separate clip component. A D-shaped post on the top of the clip press fits into a corresponding hole in the pendant, and the clip attaches around the bracelet with a snap fit. These components were designed for manufacturing, applying constraints and considerations for CNC machining the molds (tool size, round corners, etc.) and for injection molding the final parts (wall thickness, draft angle, etc).

Using NX, we first modeled the bracelet and its subcomponents and then used these part models to design and model the mold.

Manufacturing ProcessES

We created programs to CNC machine the molds, and manufactured them on a Haas vertical mill.

We injection molded 20 complete assemblies of the bracelet using polypropylene. The injection time, pack time, cooling time, and melt temperature were optimized in order to repeatably manufacture high-quality parts.


We successfully executed the design and manufacture of the toy bracelets and were happy with the final product both aesthetically and functionally. We were able to give bracelets to the fourth graders whose sketches inspired the product, and they were delighted to see a tangible implementation of their ideas. Our project placed second out of 18 teams in the class at the end-of-quarter project fair competition.

Skills Used

  • NX (Solid Modeling)

  • CNC Machining

  • Injection Molding

  • Design For Manufacturing