Dr. Eric Warren and his manufacturing team may not pump out as many cars as a large-scale automotive plant, but like a big auto company, Warren’s group shares the same manufacturing pressures to improve its components and make them faster.
As the technical director and vice president of Michael Waltrip Racing (MWR) (www.michaelwaltrip.com), Warren oversees all the engineering, production, fabrication and assembly of the 100 to 120 racecars the Nascar team builds, one-at-a-time, each year. The cars are built from scratch, and the team produces 1,500 to 2,000 different parts for each car. Nearly nothing is farmed out.
The team continually evaluates every component to improve its performance, make it stronger and reduce its weight. The lighter a car’s overall weight, the faster it is, and shaving a fraction of an ounce off a part while maintaining its integrity can make a difference, especially when considering that the qualifying times typically differ by only two-tenths of a second for the car that comes in second and the car that comes in 35th.
Track speed is not the only factor that’s important for a Nascar team. Just as much racing around is done in production to quickly have cars ready to go to the track. Having a car at a race as early as possible gives the race team more time to tweak it for the particular racetrack they are at. With that said, Michael Waltrip Racing focuses a lot of its part-making efforts on reducing cycle times.
Gains in production capability through such technologies as CNC machine tools and advancements in fabrication have helped the team accelerate its part production. As a result, Michael Waltrip Racing has cut the time it takes to build a car from 500 man-hours, or about 20 days, down to 250 man-hours, or about 2 weeks.
According to Warren, speed and low-volume are the name of the game, but those requirements can actually limit the technologies the team can implement. For example, he said it would not be beneficial for the shop to produce car hoods on a stamping press.
“Yes, the production speed and consistency would be there, but we don’t produce the volumes to justify a press. Plus, part designs are constantly changing, and we can’t afford to spend the time and money required to re-tool a press for every design change. Part volumes are what really sideline us from implementing a lot of today’s manufacturing technology,” Warren said.
So what does Warren and his team look for in manufacturing equipment? It has to reduce part cycle times and be easy to use and set up. The team also evaluates how much labor it takes to operate versus how many parts the shop can produce with it within a set time.
One piece of equipment that meets the team’s requirements is a recently installed abrasive waterjet cutting system from Jet Edge Inc. (www.jetedge.com). The system has allowed Michael Waltrip Racing to bring more outsourced parts in house, eliminate the inconsistency of cutting parts by hand and reduce the workload of the team’s CNC mills.
Michael Waltrip Racing’s system is a Jet Edge 4-ft by 8-ft High Rail Gantry powered by a 50-hp 60,000-psi IP60-50 intensifier pump. The fully 3-axis programmable system features dual Permalign II abrasive cutting heads on a 4-ft spreader bar that are capable of cutting complex parts out of virtually any material. In addition, there is SigmaNest CAD/CAM nesting software developed by SigmaTek Systems and a closed-loop filtration system and abrasive-removal system from Ebbco Inc.
A digital readout for multi-head positioning digitally displays cutting head positions to eliminate manual measurement. A pneumatic drill automatically pre-pierces materials that are prone to delamination prior to cutting them. This feature is especially beneficial in cutting Michael Waltrip Racing's front horizontal splitter panels that are now required by Nascar to provide front down force on racecars.
Splitter panels are made from polycarbonate, and conventional hole drilling often damages the material’s laminated surface. The waterjet cuts the holes without damaging the material. Michael Waltrip Racing produced its first panel with the waterjet cutting system in less than 13 minutes, and that included waterjet cutting time and milling time.
Michael Waltrip Racing runs its waterjet machine pretty much nonstop, but Jeremy Vanderleest, Michael Waltrip Racing waterjet operator, said that he frequently has to interrupt one job to do “hot” jobs. But, he said the machine easily goes back and forth from job to job.
“The high-rail gantry system gives the machine its repeatability. So, I don’t have to constantly re-set program zero for each program, which further speeds the cutting process,” Vanderleest said.
Besides polycarbonate, Vanderleest cuts parts from steel, foam, rubber, aluminum and tungsten on the waterjet machine. For front spindle suspension components that are made out of 4140 alloy steel, the waterjet rough cuts the 2-in.-thick parts to save time and cutting tools.
Michael Waltrip Racing machines about 175 front spindles per year, and used to manually cut out their profiles with a bandsaw. The parts then would be finish cut on CNC mills.
Vanderleest now rough cuts the spindles on the waterjet in 35 min, saving three hours in overall machining time. And, because there’s less stock for the mill to remove, the team goes through fewer cutters.
Prior to the waterjet machine, Michael Waltrip Racing cut a lot of parts by hand or purchased them from outside suppliers. By cutting more of these parts on the waterjet, the team saves money and eliminates the time wasted transferring parts back and forth to outside vendors.
Rear corner windows are among the parts that Michael Waltrip Racing once had to cut by hand. Each car gets two sets of these windows, and the two sets each have different duct configurations in them. But once a design is settled on, the windows are, for the most part, consistently the same.
Vanderleest explained that manually cutting one window took about four hours, and it wasn’t a consistent process. He now cuts one window on the waterjet in five minutes, and eliminates the guesswork as to exact sizes. He can hold part tolerances to within 0.003 in. to 0.004 in.
In addition to the waterjet machine, Michael Waltrip Racing’s machine shop areas house 4-axis Haas VF series CNC machining centers and Haas lathes. The shop also runs manual mills and lathes, and it is looking into implementing robotics for welding and, in some instances, for part loading machines.
