Tech Directions - January 2008 - (Page 17)

with designing exterior car surfaces by working with Mastercam’s C02 car program to gain familiarity with such concepts as lofting, surfaces, and creating optimal cutter toolpaths for aerodynamic designs. Then students create a scale model of next year’s design and refine it based on wind tunnel tests. At the beginning of the following school year, students participate in the Connecticut fall Electrathon using the car Nathan Hale-Ray students designed for the previous year’s spring competition. The idea is to get the students accustomed to the techniques and teamwork they will need to compete effectively. That includes learning to freewheel (back off the power) down hill, make efficient pit stops, and change drivers, which includes adding ballast to compensate for lighter-weight drivers competing at less than 180 lbs. Students also must learn to monitor progress of the race and communicate necessary tactical adjustments to the drivers via radio. Even though only two students will drive in the competition, everybody will have to make important contributions during race day. This experience factor is so important that Freeman has found a way to get in an additional practice prior to competitions. Thanks to the generosity of Consumers’ Union, the students get to make a practice run on a nearby test track where the staff of Consumer Reports puts late model automobiles through their paces. the chain drives, which are designed and toolpathed for CNC machining and cut from aluminum with a router. In addition to aluminum, students also make parts from wood and plastic. “The kids have a three-wheeled vehicle design that allow them to use BMX bicycle wheels on the front spindle. They designed a spindle bracket (assembly and front end geometry) that accommodates the Ackerman steering system, making it possible to go around turns without having a lot of tire scuffing that would produce additional roll resistance,” Freeman explained. The advantage of making their own parts is being able to find ways to manufacture to closer tolerances. This, in turn, reduces weight or friction so the vehicles will travel as far as they possibly can. “We have done really well at Electrathon competitively,” said Freeman. “I won’t say it is just because we have the fancy equipment and Mastercam. I give the kids a lot of credit for their creativity. Having these tools allows our students to design and build things to incredibly close tolerances.” The manufacturing processes by which students ultimately produce the Electrathon vehicle bodies are not always the same. This year’s students used a complex composite manufacturing process similar to those frequently used by Connecticut’s military and aerospace manufacturers. Students produced a scale model of the vehicle a slice at a time by cutting 2"-thick sections from Styrofoam. Each section is drilled so that they can be held in place with internal rods. The completed plug is finished with a Duratec primer, which produces a high gloss finish. This plug is used as a form for fiberglass, which is draped around it to create a mold. Finally, the mold is used to produce the composite plastic car body. “This can be pretty high tech stuff,” Freeman said. “This year, we used a vacuum bagging method where you wet-out your materials in Scaling Up and Manufacturing In the fall, Nathan Hale-Ray High School students begin scaling up and manufacturing their new vehicle design. Actually, there is nothing in the rules of the contest that requires the students to design or manufacture parts for their vehicle. They can use a kit, which is what the Nathan Hale-Ray students did the first year. Today, however, it’s a point of pride to make some of their own parts. If the students can design and build it, they will. That even includes producing the sprockets for www.techdirections.com TRANSPORTATION/CAD/CAM 17 http://www.industrialpress.com/en/help/tabid/89/tabid/97/default.aspx http://www.industrialpress.com http://www.industrialpress.com http://www.techdirections.com

Table of Contents Feed for the Digital Edition of Tech Directions - January 2008

Tech Directions - January 2008 Technically Speaking Contents Direct from Washington The News Report Technology's Past Technology Today Mastering Computers Transportation/CAD/CAM Communication Manufacturing Pre-engineering Special Feature: Annual Media Review Free for the Asking More than Fun

Tech Directions - January 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.