Using Simulation to Improve the Efficiency of CAM and CNC Instruction

Derek M Yip-Hoi

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Conference: 2013 ASEE Annual Conference & Exposition
Location: Atlanta, Georgia
Publication Date: June 23, 2013
Start Date: June 23, 2013
End Date: June 26, 2013
ISSN: 2153-5965
Conference Session: Simulation and Programming
Tagged Division: Manufacturing
Page Count: 15
Page Numbers: 23.1336.1 - 23.1336.15
DOI: 10.18260/1-2--22721
Permanent URL: https://peer.asee.org/22721
Download Count: 1403

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Derek M Yip-Hoi Western Washington University

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Dr. Derek Yip-Hoi graduated with a Ph.D. from the University of Michigan in 1997. He has worked in academia since as both a research scientist and teaching faculty. He currently is an associate professor in the department of Engineering Technology at Western Washington University. His area of specialization is CAD/CAM. In addition to ASEE, he is a member of ASME and SME.

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Abstract

Using Simulation to Improve the Efficiency of CAM and CNC InstructionThe use of industry-type CNC machines, as opposed to “trainers”, for learning NC operations inEngineering Technology programs, presents several challenges. Key amongst these is the potential fordamage to the machine, tooling, work piece and injury to users from improper operation. To preventthese occurrences, significant effort must be expended on the part of instructors and lab personnel invetting programming assignments completed by students, and in supervising set-up and operation of amachine. Faced with fewer resources and increasing class sizes, simulation techniques are becomingincreasingly useful to help departments better manage their resources, and not just for the educationalbenefit of the student.This paper describes efforts to utilize simulation in several courses in a Manufacturing EngineeringTechnology program that heavily utilizes CNC technology. To do this, accurate digital models of CNCmachines have been created using a CAD system, and converted into simulation models within anindustry standard NC verification application. For each of the classes that utilize a CNC machine, thesimulation model, along with tool and fixturing libraries, are available for students to use in verifying theprograms they create for assignments and project work. Students are introduced to the simulationsoftware at the start of an introductory course to CNC operations, through a single homeworkassignment. The effort in using models is minimal: Selecting tools from a library, adding and positioningstock geometry (and final part when a machining accuracy comparison is required) in a fixture (often aKurt machinist’s vice), setting up the work coordinate system (G54 location), and loading the NCprogram. These steps mirror those that will be performed by the student on the actual CNC, and so arereinforcing the student’s experiences. Evidence of how the use of simulation is helping to increase thepreparedness of students, reduce the occurrences of programming errors and machine crashes, andimprove the efficiency of time spent in the lab will be presented.Additionally, this paper will discuss how the same simulation environment used by students in preparingprograms for machining in the CNC lab, can be used during lectures to assist the instructor in explainingthe concepts of manual part programming. Examples that were previously written by hand, with theprogrammed actions being illustrated on a white board, are now displayed graphically during thelecture. This aids students in visualizing the effects of various programming instructions, and isparticularly useful in explaining the more challenging concepts such as cutter-compensation. By makingthese available outside of class, students are better able to review the lecture materials to deepen theirunderstanding of manual part programming. Students are also required to use simulation in homeworkprogramming assignments. With this, they are able to test the effect of each line of code they write asthey create a program. This can be viewed as a form of immediate feedback that encourages students tocritically evaluate and correct their work prior to submission. It offers a “first line of defense” inproviding assistance, and is helpful to the instructor in this regard. A final benefit of this approach to theinstructor is that it can be used to assist in grading these same homework assignments.

Citation
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Yip-Hoi, D. M. (2013, June), Using Simulation to Improve the Efficiency of CAM and CNC Instruction Paper presented at 2013 ASEE Annual Conference & Exposition, Atlanta, Georgia. 10.18260/1-2--22721

TY  - CPAPER
AB  -                 Using Simulation to Improve the Efficiency of CAM and CNC InstructionThe use of industry-type CNC machines, as opposed to “trainers”, for learning NC operations inEngineering Technology programs, presents several challenges. Key amongst these is the potential fordamage to the machine, tooling, work piece and injury to users from improper operation. To preventthese occurrences, significant effort must be expended on the part of instructors and lab personnel invetting programming assignments completed by students, and in supervising set-up and operation of amachine. Faced with fewer resources and increasing class sizes, simulation techniques are becomingincreasingly useful to help departments better manage their resources, and not just for the educationalbenefit of the student.This paper describes efforts to utilize simulation in several courses in a Manufacturing EngineeringTechnology program that heavily utilizes CNC technology. To do this, accurate digital models of CNCmachines have been created using a CAD system, and converted into simulation models within anindustry standard NC verification application. For each of the classes that utilize a CNC machine, thesimulation model, along with tool and fixturing libraries, are available for students to use in verifying theprograms they create for assignments and project work. Students are introduced to the simulationsoftware at the start of an introductory course to CNC operations, through a single homeworkassignment. The effort in using models is minimal: Selecting tools from a library, adding and positioningstock geometry (and final part when a machining accuracy comparison is required) in a fixture (often aKurt machinist’s vice), setting up the work coordinate system (G54 location), and loading the NCprogram. These steps mirror those that will be performed by the student on the actual CNC, and so arereinforcing the student’s experiences. Evidence of how the use of simulation is helping to increase thepreparedness of students, reduce the occurrences of programming errors and machine crashes, andimprove the efficiency of time spent in the lab will be presented.Additionally, this paper will discuss how the same simulation environment used by students in preparingprograms for machining in the CNC lab, can be used during lectures to assist the instructor in explainingthe concepts of manual part programming. Examples that were previously written by hand, with theprogrammed actions being illustrated on a white board, are now displayed graphically during thelecture. This aids students in visualizing the effects of various programming instructions, and isparticularly useful in explaining the more challenging concepts such as cutter-compensation. By makingthese available outside of class, students are better able to review the lecture materials to deepen theirunderstanding of manual part programming. Students are also required to use simulation in homeworkprogramming assignments. With this, they are able to test the effect of each line of code they write asthey create a program. This can be viewed as a form of immediate feedback that encourages students tocritically evaluate and correct their work prior to submission. It offers a “first line of defense” inproviding assistance, and is helpful to the instructor in this regard. A final benefit of this approach to theinstructor is that it can be used to assist in grading these same homework assignments.
AU  - Derek M Yip-Hoi
CY  - Atlanta, Georgia
DA  - 2013/06/23
PB  - ASEE Conferences
TI  - Using Simulation to Improve the Efficiency of CAM and CNC Instruction
UR  - https://peer.asee.org/22721
DO  - 10.18260/1-2--22721
ER  -