Image-Based Barcode Reader Gives NASCAR Teams Extra Assurance about Their Wheels

June 212013
Image-Based Barcode Reader Gives NASCAR Teams Extra Assurance about Their Wheels

By John Lewis, Market Development Manager, Cognex Corporation, Natick, MA

Champion Tire and Wheel operates an automated facility that moves 1,000 race car wheels a day from a truck trailer back into storage after a race. Each barcoded wheel moves along a conveyor line through a variety of inspection stations before it is stored. In the past, when a laser scanner was used to read barcodes, about 200 wheels were kicked out to a manual inspection line each day because their barcodes could not be read. Operators captured those barcodes manually but this data was not entered into the computer system tracking wheel use. Also, those wheels missed one of the inspection stations.

Champion replaced the laser scanner with a Cognex DataMan 302L image-based barcode reader, which is much better at handling degradations in barcode quality. The DataMan’s read rate at Champion is 97%. The barcodes that can’t be read have been damaged and are replaced. The new reader has eliminated the time that was spent manually capturing barcodes and ensures that all wheels go through all inspection stations and get tracked by the company’s computer system. “The Cognex reader does a much better job of identifying and reading the barcodes,” said Todd Carpenter, the company’s general manager. “It helps us ensure that every wheel we send to a race delivers the performance the teams expect.”

Handling wheels for racing teams

Champion Tire and Wheel, based in NASCAR country about 15 minutes north of Charlotte, North Carolina, fills a unique niche in the world of auto racing. The company provides what is called “wheel service” for nearly all of the NASCAR teams, which means that Champion transports the teams’ wheels to and from the racetracks so that they don’t have to.

“Carrying wheels is a major source of wear-and-tear on the teams’ race haulers,” said Carpenter, who explained that teams use about 60 wheels per car per race. “Also, if the teams handle their own wheels, they need space to store them when they aren’t racing and they have to handle the tire mounting and dismounting. It’s clearly advantageous to have someone else take care of these things so they can focus on racing.”

In addition to transporting bare wheels to the race tracks, where the tires are mounted by Goodyear, Champion hauls the mounted assemblies back to Charlotte where the used tires are dismounted and sent to recycling. Then the wheels are cleaned, restocked, re-indexed, and reshipped to the next race track.

Each of the teams that contracts with Champion owns its own wheels, typically about 260 wheels per team, consisting of both single-stem and double-stem versions of the 15-inch steel wheels dictated by NASCAR regulations.  Champion paints each team’s ID on the wheels and tracks them in its computer system. The teams can log in to Champion’s system to see the status of their wheels and which ones are going to which races. In all, Champion houses approximately 20,000 wheels in its secure, climate-controlled facility.  It has a fleet of more than 30 semi-truck and trailer rigs that travel 60,000 miles per truck per year to haul wheels to and from the tracks.

Engineering forms the foundation

Champion became the dominant wheel service provider by building its business on an understanding of what race teams need, and by using the principals’ background in engineering to ensure that the company handles wheels in a way that ensures good performance.

“We try and look at what we do from a crew chief’s perspective and ask ourselves how we would want our wheels and tires handled if we were them,” Carpenter said. “Because we’re engineers, we have automated our approach with the main objective being consistent and predictable wheel performance.”

Wheels move along the conveyor line for inspection at Champ Champion Tire and Wheel. Moving the wheels on a conveyor system also reduces the risk of damage

For example, rather than stacking them or bouncing the wheels, Champion moves them through its facility on a conveyor system because that is less likely to cause damage. In addition, every wheel that Champion handles is barcoded and scanned every time it moves in and out of its facility, creating a complete history of that wheel. And as each wheel comes back from a race, it undergoes a thorough inspection process that checks the roundness of the wheels and the lug holes as well as lateral and radial runout.

Every wheel that Champion handles is barcoded and scanned every time it moves in and out of its facility, creating a complete history of that wheel

This inspection process ensures that damaged wheels are not returned to stock.  “If something should happen to cause a wheel to go out-of-spec,” Carpenter explained, “our barcode systems won’t allow for that wheel to ever be checked out of our facility.”

Problems with hard-to-read barcodes

In the past, the company used a laser scanner to read the barcodes on the wheels. The scanner was positioned on the conveyor line after the tires were dismounted and the wheels were washed just before they reached the station that checks the lug holes. The scanner had an 80% read rate, in large part due the heat and a duty cycle that caused the barcodes to wear out and become harder to read.

When the scanner couldn’t read a barcode, the wheel was kicked over to an inspection line for manual reading with a scan gun. Because Champion handles nearly 1,000 wheels a day, 200 wheels each day had to be read manually. Typically the operators would try to run those wheels through the line a number of times to see if they could get the scanner to read. When that didn’t work, someone had to use a scan gun to manually read those codes. This took an extra 20 to 30 minutes per day and the scan gun data didn’t get entered into the computer system. Also, those wheels missed the lug hole check.

Image-based reader outperforms laser scanner

A demonstration at a trade show convinced Carpenter to replace the laser scanner with an image-based barcode reader which is better at capturing hard-to-read barcodes. Image-based readers capture an image and use a series of algorithms to process it and make it easier to read. An algorithm searches the entire image for the code and identifies the position and orientation of the code for easy reading. Other algorithms handle degradations in code quality.

Champion installed a DataMan 302L image-based barcode reader from Cognex. The DataMan 302L is part of the Cognex DataMan 300 series, which was developed to handle the most difficult-to-read codes. The 302L is a fixed-mount device with a high resolution (1280x1024) sensor for reading very small codes in a large field of view as well as codes placed on small components.

A Cognex DataMan 302L reads the barcode on a wheel

In addition, the 302L delivers maximum depth-of-field flexibility through its use of a liquid lens module. The liquid lens uses two iso-density liquids — oil is an insulator while water is a conductor. Varying the voltage across the liquid-liquid interface leads to a change of curvature, which in turn changes the focal length of the installed optical lens. The key advantage of the liquid lens for Champion is that it keeps the code in focus even when the distance from the camera to the code is changing, which happens because the barcodes can be located anywhere on the wheels. Other advantages of the liquid lens are its ruggedness (no moving parts), fast response times, good optical quality, low power consumption and compact size.

Another view of the DataMan 302L reading a barcode

Instead of 200 wheels per day being kicked out to the inspection line, only 30 need special handling now. The 3% of the barcodes that aren’t read now are caused by barcodes that have been damaged too greatly to be read. “We replace the labels now if they can’t be read by the DataMan,” Carpenter noted. That saves time and eliminates the hassle of trying multiple times to get the kicked-out wheels to go through the scanner. “There’s less frustration for the operators now,” Carpenter said. More importantly, the use of the DataMan ensures that all wheels are entered into Champion’s computer system when they return from a race, and lug hole inspection is performed on every wheel.

“Our company’s focus is on giving race teams the confidence that their wheels are handled appropriately and inspected thoroughly so that they perform optimally on the track,” concluded Carpenter. “The DataMan reader from Cognex plays an important role in enabling us to do that.”

For more information, contact Cognex,One Vision Drive, Natick, MA 01760-2059 USA. Tel (Toll Free): 1-877-COGNEX1 (1-877-264-6391), Fax: +1 508 650-3344, Email: pr@cognex.com,Web: http://www.cognex.com

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