MACHINE VISION INSPECTION SYSTEM
provides error proofing to improve
quality and productivity

ATR-Strothmann has installed its Inspection.IQ. machine vision system at one of Magna International's Canadian divisions. This new facility uses advanced hydroforming presses, tube bending machines, and robotic welding cells to manufacture truck frames  and chassis for DaimlerChrysler and other customers.

Inspection.IQ verifies the presence or absence of over 100 studs and holes on every truck frame produced at the plant. When holes or studs are missing or located in the wrong position on the frame, assembly line productivity decreases and line cycle time increases -- costing thousands of dollars in down time and repairs. Inspection.IQ ensures that only defect-free components are sent to a customer's assembly plant.

ATR-Strothmann's Inspection.IQ system is located in its own station at the end of a highly automated robot welding line. It employs more than 50 machine vision cameras and 80 light sources to obtain quick, non-contact frame verification. "When new holes or features are introduced to the product line, more cameras and lights can easily be added to the existing configuration," said Dan Paquette, ATR-Strothmann's Vision System specialist. He adds, "This makes Inspection.IQ with machine vision technology far more cost effective than using traditional probes and sensors, which can involve complex and expensive upgrades."

Inspection.IQ logs each truck frame inspection into a database, complete with the frame's unique JSN number. The log files create an inspection history where, if required, inspection results and a bitmap image for every frame can be retrieved and viewed. This allows Magna and its customers to meet the latest government regulations. The recently released Transportation Recall Enhancement, Accountability and Documentation (TREAD) act requires motor vehicle equipment manufacturers to submit information that will assist government administrations to identify defects related to automotive safety.

"The harsh plant floor environment offered many challenges to overcome," observed Paquette, "Airborne dirt, oil, and dust particles, along with vibration and electrical interference from nearby heavy welding equipment had to be considered when installing the Inspection.IQ system. ATR used specialized optics to overcome the ambient light interference, and a switched lighting solution to reduce optical noise.

"The work cell's tight dimensions presented a difficult mechanical issue in how to mount the large number of required cameras and lights. Inspection.IQ's standard 1" tube fixturing allowed for both floor and ceiling mounting without interference with the automated part transfer equipment."

The complexity of the truck frames also posed a challenge. The best system configuration for an application is influenced by part shape and reflectivity; material color, size and location; station layout, part transfer speed and cycle time; and desired inspection resolution. But, because Inspection.IQ allows for up to 64 cameras with a host of configurable parameters. ATR Strothmann is able to accommodate such complex parts.

Inspection.IQ is now positioned to provide payback to Magna and contribute to improved productivity, quality, and regulatory compliance at its customer's assembly facilities.

ATR-Strothmann develops and markets industrial automation, information and vision system solutions as well as manufacturing linear and rotary robotic components and systems used in handling a variety of materials in multiple process applications.

ATR-Strothmann

BIG FANS DRIVE FROST TO THE FLOOR
a company in Alaska finds a solution to its stratification problems

An estimated 20-25% of the earth's surface has an underlayment of permafrost, permanently frozen ground that can range from 1,000 feet in parts of Alaska to over 5,000 feet thick in Siberia. Permafrost is defined by how long it has stayed frozen - anywhere from two years to 10,000.

Permafrost makes an excellent foundation as long as its stays frozen, but a building changes the way heat moves in and out of the soil. A heated building will warm the soil beneath it, which melts the permafrost. When the permafrost melts, the building settles, which could ultimately destroy both the building and its natural foundation. To prevent thawing, design engineers need to consider special ventilation and insulation techniques to keep the ground beneath a building in its frozen state.

Duane Honrud knows firsthand how building construction works in the arctic - and how it doesn't. Honrud, who spends two weeks on the job and two weeks off and commutes by plane 750 miles from Anchorage to work on Alaska's North Slope, is an industrial designer for ConocoPhillips oils and natural gas facility.

Keeping the Floors Frozen

Honrud and his team faced a critical problem with the building that houses the compound's gas-fired generator, a jet engine mounted in place and fueled by gas taken off the North Slope. It's this generator that supplies 45 megawatts of power to the company's many buildings.

"It's a good-sized facility," says Honrud. "We keep the floor frozen with radiator systems and insulation. And we were doing a great job at it. At five feet off the floor it was 65 degrees, but below that - at about three feet, pipes and drain lines were freezing."

Honrud goes on to explain, "It all started when the pipes of the firewater misting system froze. When the firewater system goes, the generator shuts off. It's interlocked with operations, which shut down the power and isolate the building.

"We tried heat-tracing some of our firewater systems and tankage with electrical cable. The heat-tracing was a good safeguard, but not a solution."

Honrud and his team knew that destratifying the air was the simple solution to the problem. Unfortunately, the simple solution wasn't all that effective.

We installed four foot diameter ceiling fans," says Honrud. "We knew pushing the warmer air down from the ceiling would mitigate our problem by mixing the different air temperature layers in the building."

Destratification Solves Tricky Heating Problems

Mixing warmer level air with cooler, ground-level air is usually accomplished by some type of ceiling fan. This type of destratification can reduce the floor-to-ceiling temperature differential by over
75% in most commercial and industrial applications, according to Dr. Byron Jones, professor and
assistant dean of research programs at Kansas State University. He has spent his career investigating heat and mass transfer between the human body and its surrounding environment.

"Unfortunately, the 4 footers didn't work," says Honrud. "They move at a high rpm, and move air but not that much of it over a long distance."

Big Fans Mix It Up

As they researched the problem, one of Honrud's team members--a facilities engineer--was surfing the web and came across a fan company with an unlikely name--Big Ass Fans.

The company manufactures fans that some people would describe as big-ass. The smallest fan has a six-foot diameter while the biggest measures a whopping 24 feet, "The selling point for us was their slower RPMs and their airfoil design," says Honrud.

"The ceiling fans we were using just didn't have the power we needed," Honrud goes on to explain. "Big Ass Fan technology made sense. We know that every building has hot spots and cold spots. The fans move larger amounts of air in a more predictable pattern."

Honrud is referring to the physics of the fan air movement. Unlike high velocity fans with smaller diameters, the fans entrain large quantities of air over greater distances at slower speed. Installed near the ceiling, one fan generates a column of air equal to the diameter of the fan. When it hits the floor, that column of air moves outward until it reaches a wall, a partition, or another column of air from a Big Ass Fan. From there, it's pushed upward to the ceiling where it's then pushed down through the fan's blades. The result is a mixing of air levels that cannot be achieved by smaller diameter, high-revolution fans, which tend to smaller quantities of air in no predictable pattern.

Each of the three designs offered--Standard, Wickerbill, and the new Powerfoil--make it possible to run the fans at slow speeds, while still producing large quantities of air movement. The newest generation of high-volume/low-speed fans is the Powerfoil. It is especially superior for destratification, since it was developed and optimized for even greater energy-efficiency for the winter months.

The blades are hollow making them lightweight. This makes it easy on the 1, 11Ž2, or 2 hp motor (depending on fan size), which uses a gear reducer that provides almost frictionless power transmission.

A Big Fan

"Big Ass Fans really work for us," says Honrud of the two sixteen footers now spinning slowly from the plant's ceiling. "You can really feel the air movement, and that kind of predictable, directed air movement is what it took to eliminate stratification. The big fans move a high volume of air and keep it moving. They drove the frost right down to the floor, about two and a half feet from the old frost line. Our heaters weren't working overtime any more like they used to.

"When you're putting something new into an application," says Honrud, "you're taking a chance, but it just made sense to us. We tore out our old ceiling fans and installed the new ones. Everyone--from the top down--really likes them."

Summer in the Arctic

At the time of this interview, it was early June with arctic spring temperatures hovering around the freezing point.

Honrud explains that they won't install any more fans during the summer for other buildings. It's their construction season which they mostly devote to working outside.

"Minus 30 is our cutoff temperature for working outside. In summer, we can see temperatures into the seventies and sometimes in the eighties. Set at a faster speed, the fans will cool our employees, too."

Big Ass Fans

Canadian Industrial Equipment News October 2004

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