Promoting Safety Throughout the Design-Build-Test Curriculum

The undergraduate mechanical engineering curriculum at the University of Michigan has a unique teambased, DesignBuildTest spine of required classes. In each of these design courses, students are tasked with solving an openended problem using the appropriate engineering skills and tools. Laboratories and equipment are made available to students for fabrication and testing of their design concept, giving them realworld exposure to engineering. In an effort to continue to keep our students safe, we have implemented several safety procedures for all undergraduate students working on projects. In this paper we present the procedures that are currently used for promoting the safety of our undergraduate students while they are building and testing their projects for these classes. We aim to provide students with appropriate guidance regarding the use of the tools, equipment, and laboratories which they use to build their projects. After describing the structure of the courses and the facilities available, we detail the procedures that are used, in context relative to the current literature and similar programs at other institutions. Specific aspects presented here include machine shop training, exercises on the mill and lathe, procedures for checkout of tools, safety plans, and approvals of both engineering drawings and manufacturing plans. We offer suggestions for procedures that could be adopted by other academic institutions. Introduction Yearly, about one thousand students are at some point in our DesignBuildTest curriculum as they work towards their Bachelor’s degree in Mechanical Engineering. As an institution, we have a responsibility not only to keep these students safe while giving them handson, realworld engineering experiences required for industry, but to teach them to consider safety as part of future design and fabrication. Student outcomes prescribed by ABET state that students should graduate with an ability to design a system, component, or process to meet desired needs within realistic constraints, including health and safety and manufacturability. In addition, graduating students should demonstrate an ability to use the techniques, skills, and modern engineering tools necessary for engineering practice (ABET, 2015). To this end, our department provides stateofthe art facilities for design and fabrication, and we aim to provide students with appropriate guidance regarding the use of the tools, equipment, and laboratories which they use to build their projects. A review of the websites of our six closestranked peer institutions indicates that while they all require students to complete machine shop training before they can use the machines, and some institutions also require the students to sign a safety agreement after completing the training, there is barely any mention of the level of planning (beyond a standard engineering drawing) that students may be required to complete before making individual parts as part of projectbased courses. An exception is noted by Kemsley (2011), who indicates that Yale University has now implemented a safety review of all machine shop projects before students can begin work. The purpose of this paper is to describe the safety procedures that we have put in place and to offer some suggestions for procedures that could be adopted by other academic institutions. DesignBuildTest Spine Our undergraduate mechanical engineering curriculum has a unique teambased, DesignBuildTest spine of required classes, one in each of the four years. Students are first exposed to technical problemsolving, teamwork, and realworld engineering in ENG 100, a course offered by the College of Engineering. Engineering 100 is a projectbased class in which students work in teams on a somewhat openended design project and work individually to understand firstyear level technical content and professional communication. This teamwork is continued in ME250 , Design and Manufacturing I. This is the sophomore level course, in which students work in teams of four to design and build a remotecontrolled machine that must compete to perform specific tasks in an arena. The teams apply what they learn in lecture about engineering drawing, CAD and solid modeling, use of mechanical elements (such as bearings, gears, and springs), engineering analysis, and manufacturing processes. Working from a kit of materials to manufacture the components using the student machine shop, they get handson experience using machine tools such as a milling machine, lathe, laser cutter, and water jet cutting machine, as well as a 3D printer. The students learn to choose a strategy, generate concepts for the design, perform analysis on their concept, and then design and assemble the individual components. These designs are tested and verified before a competition at the undergraduate symposium every semester. A similar competitiontype project is given in ME350, Design and Manufacturing II . This is the junior level course, where the emphasis is on the modelbased design of mechanical and mechatronic systems. The students learn the design of mechanisms, the design of mechanical elements for strength, and mechatronics. Mechatronics is the synergistic integration of mechanics, electronics, control theory, and computer science within product design and manufacturing, in order to improve and/or optimize its functionality. ( French standard NF E 01010 ) The concluding course in this sequence, ME450, Design and Manufacturing III , is the senior level course. This course gives students an opportunity to collaborate in teams to apply a design process from eliciting user needs through to prototype validation on an openended design challenge as part of a capstone design experience. Complementing these Design and Manufacturing courses are two Laboratory experiences. Laboratory I introduces the student to the basics of experimentation, instrumentation, data collection and analysis, error analysis, and reporting within the context of fluid mechanics, thermodynamics, mechanics, materials, and dynamical systems, while Laboratory II projects are designed to demonstrate experimental and analytical methods as applied to complex mechanical systems, with an emphasis on laboratory report writing, oral presentations, teambuilding skills, and the design of experiments. Unfortunately, in giving students these realworld experiences and work environments, accidents at universities do happen and have happened. (Benderly, 2016) It is the goal of the mechanical engineering department, instructors, and staff to ensure that students have the tools, environment, and education to design an artifact that is safe and to fabricate and test it safely. For each course within the DesignBuildTest sequence, students are responsible for submitting information that is specific to that course. Consistent across all classes in the sequence is the requirement of having a manufacturing plan for parts fabricated in the undergraduate machine shop. We feel that a manufacturing plan, written by the student, is an important tool for promoting students’ safety because it requires the students to consider all aspects of fabrication before coming into the machine shop. This includes finding the correct tool speeds and method of fixturing the workpiece. We require the students to write a manufacturing plan for each part they intend to make, and then have the graduate student instructors and machine shop personnel review that plan along with the engineering drawing, before the students come to the shop. This process is described in more detail in a later section. In this way, we aim to greatly reduce the occurrence of “rushing to get a job done”, knowing that mistakes and accidents could occur as a result. (Jiminez et al, 2014) Similarly, for a capstone design class in which each student team is building a unique project, we believe that requiring the students to write a safety plan and to get it approved by the instructors before construction will ensure that they will consider the safety risks that could occur during the build and test phases of their project, and to take corrective actions to eliminate or minimize these risks. Some peer institutions also have a similar requirement (Kemsley, 2011.) DesignBuildTest [Work space] Upon completion of renovation work currently underway, our students will have over 9,000 square feet of collaboration and fabrication space available to them throughout the DesignBuildTest sequence of classes: An undergraduate machine shop, and assembly room, and a mechatronics laboratory. Figure 1: Sequence of Courses in the Design and Manufacturing Spine (Source: Professor Diann Brei, University of Michigan) Staffing of and access to instructional labs The staffing of the instructional labs is in line with models followed by universities. Barrett et al. (2015) discovered that the most common model identified for staffing of maker spaces utilized a combination of student support and specialized staff personnel. Forest et al. (2014) noted that in Georgia Tech’s Invention Studio, training on the most complex equipment is handled by a university staff machine shop professional. At the University of Michigan, the mechanical engineering machine shop is staffed by two fulltime machine shop technicians who have significant prior experience working in machine shops. There are additional parttime employees (workstudy students) who are the attendants for the tool crib in which the machine shop tools (milling cutters, measurement tools, etc.) are housed. The mechatronics lab, described below, is staffed by one fulltime employee who is also the team leader of the machine shop technicians. He can fill in when one of the machine shop employees is on vacation. Students in the junior year use the mechatronics lab only under the supervision of a Graduate Student Instructor or the mechatronics lab supervisor. St