June 14, 2009
June 14, 2009
June 17, 2009
14.41.1 - 14.41.11
A Laser Micro-Machining DOE to Investigate Material Removal Volumes
This paper presents the results and lessons learned from a design of experiments (DOE), developed to better understand the factors that affect volume of material removed (MRR) during a laser micro-machining process. The Oxford Laser micro-machining center was brought into the Engineering & Technology Department’s laboratory to be used for precision part marking and laser machining on the micron-level. The laser has a 0.1- m precision in the x-y plane— about 0.2% of a human hair diameter. It has 5-axis CNC (computer numerical control) capabilities with dual wavelength capability—a 266-nm laser and a 532-nm laser—and can machine via the CNC axes or the high-speed galvanometers. These high-end capabilities, coupled with many other “bells and whistles” make this laser machining center highly versatile. In this research, a four-factor full-factorial DOE was performed to gain a fundamental understanding of the input parameters necessary to micro-machine 301 stainless steel. The four factors investigated in this research were power, frequency, hatch spacing, and feed rate; the output variable was volume of material removed. While frequency, closely followed by power proved to have the greatest effect on the output, none of the main effects or interactions proved to be statistically significant. The DOE results from this research were used as examples in a new senior-level quality course, which introduces DOE as a subject to senior Engineering Technology students. The real life DOE results provide a powerful classroom advantage to the typical textbook data, in that students see the real-life application more readily. The next step in this research is to refine this particular DOE and transition into regression analysis, where a mathematical model can be generated to predict (and control) the volume of material removed.
Western Carolina University (WCU) is a comprehensive state university situated in the mountains of western North Carolina - with approximately 9,000 graduate and undergraduate students. WCU serves a region that continues to employ heavily in the manufacturing sector, which ranks number one with 19.3% of all jobs in the western portion of the state1, which is why the Engineering Technology (ET) program continues to prepare its graduates through both its on- campus and distance education degree programs. The ET program exposes its students to a multitude of industry-related courses, including CAD/CAM, polymers, rapid prototyping, fluid power, numerical methods, occupational health and safety, automation, and quality. The adoption of Six Sigma techniques in the past decade has placed a high priority on quality in the workplace, and accordingly in the classroom2.
The Engineering Technology curriculum recently added a senior-level undergraduate quality course (Advanced Quality Systems) to follow the junior-level Quality Systems course. A more in-depth quality course, Quality Assurance, is available to the graduate students at WCU. The addition of the senior-level quality course has given undergraduate ET students the chance to dig
ASEE holds the copyright on this document. It may be read by the public free of charge. Authors may archive their work on personal websites or in institutional repositories with the following citation: © 2009 American Society for Engineering Education. Other scholars may excerpt or quote from these materials with the same citation. When excerpting or quoting from Conference Proceedings, authors should, in addition to noting the ASEE copyright, list all the original authors and their institutions and name the host city of the conference. - Last updated April 1, 2015