June 24, 2007
June 24, 2007
June 27, 2007
12.245.1 - 12.245.17
Application of CADD/CAM to Engineering Technology Courses and Some Real Life Projects
Computer-assisted drafting/design (CADD) and computer-assisted machining (CAM) are very powerful tools both in engineering education and industry. At Middle Tennessee State University (MTSU) we have a strong CAD/CAM curriculum. Our Engineering Technology students learn two-dimensional CADD and solid modeling in our three CADD classes using software such as AutoCAD, Inventor and SolidWorks. The two Machine Tool Technology classes help students learn the basics of CNC machining, rapid prototyping and laser engraving while incorporating their CADD abilities. In the advanced class the students design and build an air motor from scratch learning how CADD and CAM are directly linked. They design the parts using CADD and the parts are created using a Fadal vertical machining center (VMC) CNC unit, a CNC lathe, and a StrataSys fused deposition modeling (FDM) rapid prototyping machine that extrudes molten ABS plastic layer by layer to create a 3-dimensional part. The air motor capable of rotating a 14x6 propeller at over 2200 rpm has six cylinders with a rotary configuration (cylinders move radially) while receiving air supply through ports. Power is transmitted from the motor shaft to a propeller through a 6 to 1 (geared up) planetary gear unit. The advantage of the planetary gears is that they are compact and still produce the desired speed ratio. The air motor is used in our Fluid Power class to demonstrate the working of a pneumatic motor. The planetary gear unit is used in Dynamics to illustrate the rotation of a rigid body about a fixed axis and calculation of physical quantities such as angular velocity, acceleration and momentum. Spur or helical gears with the involute tooth profile are used in the planetary unit. The involute is generated in two dimensions using AutoCAD and imported to the Inventor three-dimensional modeling software for generating 3D models. In our Engineering Technology and Industrial Studies (ETIS) department we compete in several national contests such as the moon buggy, mini-Baja, solar bike and solar boat. Size, strength-to-weight ratio and performance are key factor in all these vehicles. A planetary gear unit is used in some of these projects for speed reduction or increasing between the motor shaft and the drive shaft because of its compact size and inherent high torque capabilities. The planetary components on the 6-cylinder rotary engine are ABS plastic and the Moon-buggy’s and the Mini-Baja’s components are machined from aluminum and steel.
Sridhara, B., & Taylor, R. (2007, June), Application Of Cadd/Cam To Engineering Technology Courses And Some Real Life Projects Paper presented at 2007 Annual Conference & Exposition, Honolulu, Hawaii. https://peer.asee.org/2796
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