Over the course of ten weeks, my team of four Northwestern students - Charles Tokowitz, Simon Zhao, Brian Quandt and myself - manufactured an injection molded toy of the popular character "Pusheen the Cat" via CAD/CAM processes. The design concept is the result of a fourth grader's wish at Nettelhorst School, Illinois, participants of Northwestern University's STEM outreach program.
The project started from capturing the design intent on CAD and modifying it to the best injection-molding practices. This was then programmed to CNC milling operations that transfered the part geometry to aluminum mold blanks. Moving forward, we manufactured over 100 Baker Pusheens on the injection molding machine.
This project challenged our CAD skills, understanding of manufacturing parameters and optimization, and statistical anlysis of production runs.
Designed on NX, the challenge in capturing the design intent was to recreate the natural shapes of the Pusheen cat. Eventually, we utilized the freeform body modeling tool. Since NX did not permit the simultaneous extrusion of 100+ faces to the mold, features were exported to Solidworks to complete the extrusion on blank molds. Constantly translating between softwares made the design quite complicated and honed our skills in both programs.
Design parameters for manufacturing included avoiding undercuts, considering drafts and wall thicknesses, as well as for assembly which encouraged reducing the number of parts. Given that it was the team's first experience with industrial CNC milling, there were many mistakes that were learned along the way as well.