Machine Parts Modeling and Prototyping by Additive and Subtractive Manufacturing
Authors: Bzymek Zbigniew M. , Hebert Rainer , Kosovay Dimitriy , Mealy Thomas , Summers Mark 
Published: April 2017

The Manufacturing Automation course in the Mechanical Engineering program at the University of Connecticut (UConn) was one of the most popular courses in the ME curriculum. The students’ benefits from the course were already described in the companion paper [1]. In this paper the advantages of prototyping and part production through Subtractive Manufacturing (SM) and Additive Manufacturing (AM) are described. The paper discusses parts fabrication done as subtractive and additive manufacturing operations. This was done in the scope of the UConn Engineering i.e. in the ME and MEM programs where Manufacturing Automation and Senior Design courses are taught. Such operations were possible thanks to the equipment available at UConn School of Engineering and thanks to the cooperation with the creator of the Mastercam software - CNC Software Inc and aircraft engines and equipment manufacturer - Pratt & Whitney of East Hartford. The integration of design and manufacturing in the course was done through putting together the operations of conceptual design, geometric design and modeling of the parts designed during the course. The models of parts done by AM were created using 3D printing in ME Laboratory out of acrylonitrile butadiene styrene and different kinds of plastic and in PW/UConn laboratory using laser and electron beam AM machines. To demonstrate further integration of design and machining automation, the students were introduced to complicated problems of surfaces crossing, connections of surfaces and edges of cross sections of the tops and valleys. Thanks to the support and cooperation of the CNC Software, Inc., it was possible to show the students how to cut complicated surfaces on different computer numerically controlled (CNC) machines that ranged from three to nine degrees of freedom specifically designed for accurate and repeatable metal working. In addition, the additive manufacturing (AM) capabilities were introduced in the course thanks to the support of Pratt & Whitney/UConn Additive Manufacturing Laboratory located on the UConn campus. The AM machines are Arcam and laser machines that use electron and laser beams to meld titanium powder. The fabricated parts of high strengths are useful as rapid prototypes or in some cases as substitution parts in an existing mechanical systems. Thanks to the UConn Engineering program and support of the corporations: CNC Software, Inc. and P&W, students were introduced to the spectrum of modern Rapid Prototyping and part sintering operations going through subtractive and additive manufacturing. The process details of the theory, practice of operations, and recommendation for use of the technologies discussed above, as well as possibilities of further applications, are described in this paper. After learning the fundamentals of these processes, students are prepared to design and analyze parts as well as the process required for different machining capabilities. Methods to introduce students to the concepts of using laser and electron beams AM machine as well the prototype machining are described in the paper. Conclusions recommending the teaching methods of product SM and AM machining concepts and lessons learned are also pointed out.