City College has almost 9000 ft2
of shop space with seven
CNC milling machines, several manual machines, and three 3D printers as well as two computer labs. Students don’t move into the computer lab until the fi rst two courses are completed. The Basic Principles/Machine Tech class uses the manual machines to teach the prin- ciples of milling operations, including safety procedures and blueprint reading. The next class, Intro to CNC and EDM, teaches students how to set up and operate CNC machine tools, including how to calculate and create a basic NC program. The way the program is designed the student will become someone we can give a blueprint or workpiece to, go through the entire process with a minimum amount of help and, when they’re done, can turn in the completed part. All of the students need to create their own NC code, cal- culate their speeds and feeds, set up the machine, load the code, edit as needed, cut and inspect the part. We teach our students to be very strong in hand coding so they will be able to edit programs that have been created in CAD. Employers really like that the students know how to do that. The Intro to CAD/CAM class takes the students into the computer lab and introduces them to CAD/CAM program- ming using Mastercam CAM software, which is used the most in industry. The students are basically using Mastercam to generate code but the curriculum also gets into contours, pockets, hole drilling, tapping and reaming, along with all the associated working fi les that go with those operations. The introductory class teaches the types of CAD/CAM work students will fi nd in actual job shops.
Students then attend lab classes with extended lab hours—there are no formal lectures, just videos for each of the projects, all of which are found on my web page. At this point, students are encouraged to do more thinking on their own. Their fi rst project or two use hand coding and we teach them to use macros and loops and how to integrate their CAD/CAM programs into a project. This is also when we introduce them to four-axis programming, as well as Master- cam’s Dynamic Milling to achieve faster, more effi cient metal- cutting operations. By teaching them both regular toolpaths and Dynamic toolpaths, we’re making them more marketable when they leave us. As they proceed, the work is progres- sively harder and they receive less help from the staff in order to make them more self-reliant.
Instructors teach how to calculate feeds and speeds by giving students the parameters but not the speeds and feeds
March 2017 |
AdvancedManufacturing.org 87
to use. So, if they’re cutting and they realize the cutter is go- ing too fast or too slow, they need to adjust just as if they are adapting to real life shop-fl oor conditions. The Advanced Mastercam course teaches the toolpaths for surfaces and solid modeling. Students are also taught 3D printing by selecting their toolpaths and cutting the part in Mastercam as a solid model. Using a verifi cation process, the program is saved as an .STL fi le and loaded into one of the 3D printers. This rapid prototyping operation lets the students see, in plastic, what the part will look like when machined out of metal on one of the CNC mills. Since many of the older students are owners of smaller shops or managers in larger plants in the San Diego area and are attending City College to gain profi ciency in the newer technologies like Dynamic Milling, they are familiar with the training and education received by potential new recruits. In many cases, these experienced students are the decision makers at their companies. When they need a new hire who will be really good at CAD/CAM operations in their shop, they know we have them right here. The instructors design projects that feature drilled holes and reamed holes, and taps and pockets and contours, and just about everything else that can be programmed in Mastercam and machined on a CNC mill. When our students learn how to make the projects in our curriculum, they will be able to perform the same op- erations on anyone’s real-world project. The program is supported by the Center for Applied Competitive Technologies, a program that falls under the California Community College Chancellor’s Offi ce Economic and Workforce Development Program. The CACT, under the EWD invests in manufacturing education throughout California by contributing funding and specialized industry training, through on-site training, low-or-no cost technical assistance and educational workshops. Does it work? The MACT program at San Diego City College is proof that the collaboration between industry and education has created a model for thoughtful and successful manufacturing training long into the future.
Jack Bollinger Professor of Machine Technology San Diego City College.
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