CAM Keeps Racing Teams on Track
Latest CAM packages help motorsports teams compete effectively
By Patrick Waurzyniak
In the fast-paced world of motorsports, shaving off a few seconds can mean the difference between winning and losing a race. With the latest CAM software for machining parts, racing teams and their machine shops can quickly and efficiently produce components that help them stay in the game.
Racing teams competing in the NASCAR and Top Fuel dragster circuits depend on the latest in CAM machining and simulation software to help them gain a critical edge over the competition. With CATIA V5 solutions from Dassault Systèmes S.A. (Paris) and the V5 manufacturing software from Dassault subsidiary Delmia Corp. (Auburn Hills, MI), engineers for the NASCAR racing team Evernham Motorsports (Charlotte, NC) have deployed CATIA's V5 CAM solutions for machining, Virtual NC software for NC programming, and simulation software tools in its racing component designs and validation.
Competing in NASCAR's Busch and Nextel Cup series, Evernham Motorsports races two Dodge Chargers and a Dodge Ram truck on the circuit. "They start off with the street version of the Charger, then take pretty much everything out and rebuild it from scratch," notes Peter Schmitt, Dassault vice president. "The only thing that's really used in NASCAR is the nose of the Charger; they start off with the standard engine, but then they customize it and end up with a 900-hp (672-kW) machine."
With the V5 software, Evernham engineers design engines and structural components for its race car frames, and the team also builds frames for other teams. "Evernham does the entire mechanical design in CATIA, including validation of kinematics, and they use our NC toolpath generation and NC verification tools, along with applications from our partners for optimizing vibration with computational fluid dynamics," explains Schmitt.
In NASCAR racing, the difference between first and last place often is fractions of a second per lap, a gap that Eric Warren, technical director of Evernham Motorsports, believes will only get smaller. "As they tighten the rules, it becomes more important to understand how the car works from an engineering perspective," Warren says. "When the difference between first and last place is 0.2 sec per lap, trial-and-error in the shop or on the track no longer works."
To stay competitive, Evernham Motorsports took an engineering-centric approach to building its machines. Evernham's teams turn out a new engine design every four months. A body configuration lasts no more than two months. Construction of a car, start to finish, can take as little as 18 days, including building a chassis from scratch and custom-forming most of the sheetmetal for the body by hand.
When Warren joined Evernham in 2002, he inherited a mismatched set of engineering tools that couldn't keep pace, and he soon replaced those tools with CATIA V5 and Dassault's Smarteam software, which intelligently stores, maps, and tracks all of Evernham's CATIA V5 product designs and related engineering data, allowing quick access to specific knowledge from the company's voluminous database. Smarteam also provides the proper structure and context for all data, enhancing Evernham's ability to iterate from existing designs, and freeing time for innovation.
Steve Oliver, deputy director of design services, is in charge of Evernham's engine development program. His team's goal is to produce more horsepower with less weight, an endless cycle of designing, analyzing, and machining parts dozens of times daily. "We used to design in one package, analyze in another and machine in a third, and they all had different user interfaces," Oliver says. "With CATIA V5, it's one click to move from design to analysis, and then another click to move to NC programming. That's invaluable because each of our engineers performs all three tasks, and they only need to learn one user interface. A lot of packages are really good at only one or two. CATIA V5 is great at all three. It has cut at least 50% off our development times."
Oliver's engineers spend their days asking "what if?" in a rapid-fire cycle that searches for any fractional advantage. The faster they can move between design, analysis, NC programming, and back again, the better their chances of discovering a major breakthrough that will pay off on the track. "We're constantly iterating to get more power," Oliver says, "and we push all the parts to the limit all the time."
The need for speed drives the Top Fuel dragster racing team of High-Speed Motorsports Inc. (Anaheim, CA) to rely on Mastercam from CNC Software Inc. (Tolland, CT) to produce quality machined components for engines and bodywork on its car. "What it allows me to do is to design components and improve what we have," says Tom Shelar, team manager for High-Speed Motorsports. "The first phase of what we were doing was the cylinder head design, improving the port flow and making a better cylinder head so the car would perform better."
The High-Speed Motorsports team started out by reverse-engineering a cylinder head, Shelar says. "We had a starting point on a cylinder head. We digitized it on the machine using Mastercam, with a touch probe on the machine in full five-axis mode," Shelar says. "We generated those routines inside Mastercam, generating the probing cycle using a five-axis toolpath.
"We post it out, captured the point data, brought the data back into the 3-D space that puts it right back into the model, then we refined it from there," Shelar adds. "We've basically designed the cylinder heads, the intake manifold, which is the last project we did with Mastercam X, and did the complete design there. We've also done the injector, the scoop, the canards or the wings on the car, the front nose piece—those types of things that we designed trying to improve the performance of the vehicle."
With Mastercam, Shelar says his racing team redesigned the intake manifold to enable replacing it at the track without needing to remove the cylinder head. "In the case of the intake manifold and the cylinder head, with the original factory design, you would have to completely remove the intake manifold and then take the cylinder head off, because there were 16 bolts in the intake manifold. We redesigned it to where there are now six studs that hold the manifold on, and with the change in the design we can pull three studs off on one side and actually slide the head out from underneath the intake manifold."
After initially using Mastercam on engine components, the Top Fuel team progressed to refining the dragster's body with the software. With better designs for ports and other engine components, High-Speed Motorsports added more streamlined designs of the car body, and cut its previous 6.0-sec elapsed times in drag races by two-tenths to 5.8 sec.
Porting cylinder heads faster with five-axis machining and PowerMill CAM software from Delcam plc (Birmingham, UK) has enabled Wegner Motorsports (Markesan, WI) to supply high-performance racing components for virtually every NASCAR racing division, including winning multiple Busch Grand National series championships. Started in 1975 by Carl Wegner in a machine shed in the backyard of his central Wisconsin farm, Wegner Engines now employs more then 30 people and occupies more than 7500 ft2 (697 m2) of the original backyard.
A big part of Wegner Automotive's success is CNC cylinder-head porting. Intake and exhaust ports are designed to squeeze horsepower out of an engine. "Cylinder head ports make the biggest difference in the performance of any engine," says Casey Wegner, Carl's son and head of the CNC department. "They will make or break you. If the horsepower of an engine is less than expected, the head design is the first thing anyone looks at."
Cylinder head ports allow air and fuel to travel through the cylinders. During the porting process, technicians reshape the ports to maximize the volume and velocity of air moving through the engine. Wegner estimates that his company produces more than 30 types of cylinder heads for various vehicles and engines.
The difficult part of the art in each head is making each port the same. With hand work, it is almost impossible to be perfectly consistent across a set of heads. That is where scanning the ports and CNC machining come in. Once created manually, Wegner has the inside surface of the ports scanned and a data base created. It then takes the resulting NURBS surface file and brings it into Delcam PowerMill software, which can process multipatch surfaces. Within PowerMill, Wegner engineers specify tools and toolpaths, check for clearances, and program five-axis machining. The resulting CAM file is sent for milling on a Bostomatic 505 five-axis machining center.
Within one to two days, an entire set of cylinder head ports can be recreated from an original, machined, tested, and installed into an engine. "The process is made possible by the ability to scan inside a port and automatically surface it with high accuracy," says Wegner. "Each port has to have the same flow within a few cfm."
The ability to turn out a complete set of cylinder head ports that duplicate a hand-ground original is making a major difference in Wegner Automotive's business. "We can have a cylinder head handed to us in the beginning of the week, prepare a duplicate set, and install it in an engine ready for a race team by the weekend," says Wegner, noting he starts with a cast port and works out port designs based on the engine application.
"Previously, with a three-axis VMC with a fixture to provide two more axes, it would take us 20-26 hr to port a head," Wegner says. "Now, with the Bostomatic 505 CNC machining centers, we can complete an average head in about two-three hr using four different tools. So you can see how the Delcam software and the full five-axis CNC has helped us to be much more responsive to the racers, our customers."
Saving time programming is another major help, as PowerMill lets Wegner try out the programs and simulate the tool and toolpaths before uploading to the machine, so operators know right away if a program will work efficiently. Wegner does not have the luxury of test cuts and try-outs with the tools, which are expensive. Using Delcam has enabled the shop to have longer tool life, shorter cycle times, and no crashes on a more-productive machine.
Better control over the point distribution within five-axis toolpaths also lets Wegner take advantage of the improved ability of the Bostomatic control to handle large amounts of data. Increasing the number of points in the toolpath lets Wegner accomplish even machining with less vibration and more consistent loading on the tool—resulting in better surface finish and less wear of the cutter. "People in the industry are impressed at how nice the walls of our ports look, compared to the master," Wegner says.
Modeling engine components in NX CAM software from UGS Corp. (Plano, TX) helped Joe Gibbs Racing (Huntersville, NC) find success on the track. Since implementing NX, the racing team has won three NASCAR championships as the software enables designers and machinists to work against the clock, and fine-tune its engine and suspension configurations to specific tracks and race conditions.
"With NX, we have the capability and flexibility to make any part in the few days we have between races," notes Mark Bringle, manufacturing director for Joe Gibbs Racing. "We're running 10 CNC machines 20 hr/day making parts for the cars." The team's use of NX has expanded to the point that nearly every part and subassembly, including the entire engine, has been modeled in NX, with a part library that contains approximately 400 parts. About 80% of those are replacements for parts that are worn out during races. The rest are new parts being designed for R&D purposes.
With the software, almost all parts can be made in-house very quickly, and big tasks like grinding ports out of the manifold and cylinder heads, to increase horsepower, are completed much faster. "When we had guys grinding ports by hand, it took 70 hr to complete a set," says Bringle. "Now, the CNC machine does it in seven hours."
The shapes of the ports, which are complex surfaces, were modeled in Imageware, then used by NX Generative Machining as the basis for the CNC toolpaths. Bringle frequently uses the toolpath simulation capability of Generative Machining to evaluate new machining processes. "By doing this on the computer," Bringle explains, "we don't waste machine time to see how a cutting process will go.
This article was first published in the January 2007 edition of Manufacturing Engineering magazine.