Simulation of Solar Race Car Speeds Production
When Kansas State University’s Solar Racing Team decided to build a completely new solar race car from the ground up, Harlow Aircraft and Insight Consulting were ready to help in any way they could. The Solar Racing Team’s molds required 36 hours of machining time, but with the help of VERICUT® software from CGTech, the Cincinnati machine tool used didn’t miss a minute of regular production time.
A solar race car is a light weight, low power vehicle designed and built exclusively for “raycing” (a combination of “race” and “ray” from the sun). Like most other highly technological race cars, solar cars do not represent a practical means of transportation.
They generally only seat one person, have very little cargo capacity, lack creature comforts such as air conditioning and CD players, can only be driven during the day, and must be accompanied by lead and chase vehicles equipped with flashing lights when traveling on public roads. Like other race cars however, they do offer an excellent opportunity to develop future technologies that can be applied to practical applications.
Solar raycing is an activity in which organizations and individuals design, build, and race vehicles that are entirely powered by the sun’s energy. There are all sorts of reasons people get involved in solar raycing—alternative energy research, engineering challenges, etc.—but there is little doubt pure competition plays a major role.
K-State started its Solar Car program in 1995, after the Sunrayce passed through Manhattan, KS. Several KSU students were in attendance and decided to start their own team. Starting out with just a small group of friends, the team has now grown to over 35 members who spend in excess of 300 hours a week working on the next Solar Car, as a purely extracurricular pursuit. In less than two years, The Solar Racing Team is able to see their ideas move from the design room to the pavement of America’s highways.
In 1997, the Solar Racing Team entered their first car, Solution, in the Sunrayce and placed 24th out of 36 teams. In 1999, their second car, Apollo, was raced from Washington D.C. to Orlando, Florida in Sunrayce and placed 9th out of 29 teams. CATalyst, the third car, raced to a fifth place finish in the 2001 American Solar Challenge in a field of 30 teams. CATalyst raced again in the summer of 2003, finishing 2nd in the Formula Sun Grand Prix and 8th in the American Solar Challenge. Working night and day to get the new car, Paragon, ready in time for the 2005 North American Solar Challenge, the Team hopes to dominate the competition at this year’s race.
The North American Solar Challenge, the main competition, is a biannual cross-country solar race open to competitors from around the world. In 2001 and 2003 the race stretched over 2200 miles from Chicago to Los Angeles.
The next North American Solar Challenge will be held in July 2005 and will cover an unprecedented 2500 miles over eleven days. The competition begins in Austin, Texas mainly following U.S. Highway 75 and Canadian Highway 1 to the finish line in Calgary, Alberta, Canada. Including KSU, there are currently 42 teams scheduled to compete in this year’s race.
The KSU solarcar racing team also competes in the Formula Sun Grand Prix, a closed track race held every year in Topeka, KS, and the team is looking forward to attending their first World Solar Challenge rayce in Australia in September of 2005. On even-years (02, 04, etc.), Formula Sun is basically just practice for the real rayces, but on odd-years, Formula Sun is the qualifier in order to compete in the North American Solar Challenge.In building this new car, the team wanted to build upon what they have learned from building the past three cars. Paragon looks completely different from any of the previous three cars. Using Pro/Engineer to design the new car, the team sought weight reduction, higher efficiency, and drivability, all while maintaining reliability. Additionally, the new body was designed to have twenty percent less frontal drag than CATalyst, their previous car.
The past success of the team is a direct result of hard work and strong supporters. Corporations, government organizations, and individuals all provide the team with donations of materials, time, and knowledge. Harlow Aircraft Manufacturing is one such corporation that has donated its resources to the Solar Race Team.
“When I was approached by Jeremy Wood from the Kansas State Solar Car Team, I was more than eager to assist. The team was looking for a company that could support the manufacturing of a two piece mold for their solar car design,” said Jim Barnes, President of Harlow Aircraft Manufacturing.
Size was the critical factor since the mold was 6’x12’ with complex surfaces. The team told Barnes that they would like to do a presentation on the history of the solar car project and explain what they were requesting from Harlow Aircraft Manufacturing. Barnes agreed to the presentation and called a meeting of all of the support disciplines.
“After the presentation it was unanimous: everyone liked the project and wanted to do whatever was needed to support K-State’s Solar Car Team. Once that was decided, the Solar Car Team provided us with the design and, with the help of Kevin Elliot of Insight Consulting providing Harlow with the programming support, the project was started,” said Barnes.
The project consisted of two halves–bottom and top. The bottom was machined first. This effort took about 24 hours from start to finish. By using VERICUT® software from CGTech, Elliot was able to test the NC program for any problems before it was ever cut on the machine.
VERICUT is an advanced solids-based software program that interactively simulates the material removal process of an NC program. “By using VERICUT, I was able to verify the accuracy and quality of the NC program using a computer, instead of tying up the machine,” said Elliot. Inefficient motion or programming errors that could potentially ruin the part, damage the fixture, or break the cutting tool were corrected before the program was run on the machine tool.
Elliot only needed three things to verify the NC program: a stock model, a cutting tool description, and the G-code. After these elements were defined, VERICUT cut the three-dimensional solid part. [See image] Whenever an error was detected, VERICUT provided a complete history of the error. By clicking on the error in the simulated tool path, the actual NC program command that caused the error was displayed for quick error identification and correction.
Elliot also pointed out that VERICUT gave him comprehensive tools for viewing and analyzing the cut models. The part could be quickly zoomed, sectioned, reversed, and rotated at any angle. The part can also be displayed in translucent mode, revealing areas not visible in a solid model such as the intersection of drilled holes. VERICUT takes accurate three-dimensional measurements of all model features including machined surfaces such as fillet radii, corner radii, hole diameters, distances/angles, gaps, wall and floor thicknesses, part volumes, and depths. The cut model can then be compared to the original design model to perform constant gouge checking and identify excess material left on the part.
“Essentially, we downloaded the tape, and the machine ran for 24 hours. VERICUT simulated the entire machining process on a computer so that Harlow did not need to take its machine tool out of production to prove-out the NC program.”
– Jim Barnes, president Harlow Aircraft Manufacturing
In addition to displaying material removal at the workpiece level, VERICUT simulates entire machine tools just as they appear on the shop floor. The program also simulates NC machine controls and supports advanced control functions. The result is fully realistic machine tool animation. The program automatically checks for machine tool collisions and over travel, greatly reducing the possibility of a devastating machine crash, its associated repair costs, and loss of production.
With all of the resources being donated there was no room for error. The machine was only open for the weekend (Saturday and Sunday) and needed to be back in operation on Monday morning. Elliot knew he only had one shot and, after simulating the NC program in VERICUT, he was confident that everything was correct.
“This greatly cut down on the time usually spent proving the tape,” said Barnes “Essentially we downloaded the tape and the machine ran for 24 hours.” In other words, VERICUT simulated the entire machining process on a computer so that Harlow Aircraft Manufacturing did not need to take their machine tool out of production to prove-out the NC program.
“Everything went flawless. The total machine time was 36 hours with excellent results,” said Barnes. “I am very happy to be part of this project and am very grateful to Kevin Elliott of Insight Consulting, our Plant Manager David Hunter, and our 5-axis Operator Robert Calisti, for donating their time and weekend to support Kansas State and their community.”
Harlow Aircraft Manufacturing was started in 1954 as a tool and die shop working with customers in the Midwest such as Boeing, Cessna, and Beechcraft. In 1981 Harlow was purchased by Phillip Friedman. With his direction, the company has grown into a fully integrated aerospace manufacturing and assembly facility specializing in complex electro mechanical assemblies. Harlow currently produces fully integrated throttles and pedestals for Cessna Citation X, Sovereign, Raytheon JPATS, and Premier programs. (www.harlowair.com).
About Insight Consulting:
Insight Consulting was started in 2003 with the goal of bringing advanced technology and high speed machining techniques with modular tooling methods to the machine shop industry. Insight strives to meet three goals 1) To reduce the programming time and increase programming accuracy. 2) Reduce machine time with high speed machining. 3) Reduce setup time with modular and programming techniques. They partner with businesses to accomplish these goals. (www.insightfortomorrow.com)
Headquartered in Irvine, California CGTech specializes in numerical control (NC/CNC) simulation, verification, optimization, and analysis software technology for manufacturing. Since 1988 CGTech’s product, VERICUT® software, has become the industry standard for simulating CNC machining in order to detect errors, potential collisions, or areas of inefficiency. With offices worldwide, VERICUT software is used by companies of all sizes, universities/trade schools, and government agencies.
More information on solar raycing can be found at the following websites:
KSU Solar Car Team: www.engg.ksu.edu
North American Solar Challenge: americansolarchallenge.org/
Formula Sun Grand Prix World Solar Challenge: www.wsc.org.au/