CNC machining plastic injection mold plates in the classroom

After finishing their undergraduate education many Mechanical Engineering graduates join industry and design parts that require computer-numeric-control (CNC) machining, but too few graduates have the know- how to actually use a CNC machine to produce a complex CNC part. If students were more familiar with the process of programming, fixturing, and running a CNC machine, many of the manufacturing difficulties and costs could be avoided in the design phase. In order to address this issue a CNC machining course has been developed that requires students to design and machine plastic injection mold plates for an interesting, unique 3D part. Plastic injection molding was chosen for it´s prevalence in industry and for the many interesting design constraints that must be overcome when designing for injection molding. This work shows an innovative, structured, small group approach to teaching the computer aided drafting, machine shop, and design skills necessary to achieve better production part designs.