Above: The AGT400 measures everything from carbon and stainless steel to brass, copper and titanium. Thicknesses range from 0.007 inch to 0.312 inch.
Isotope thickness gauging increases service center productivity, fights waste
July 2013 - While observing the sleek red steel of a new BMW or the smooth metal curves of the 2014 Dodge Viper, one may not consider the journey these metals took—from humble slabs to stylish road warriors. From the start, precise metal thickness measurements are crucial building blocks to automotive fabrication. To ensure exact thickness, companies like SteelSummit, LaVergne, Tenn., turn to isotope thickness gauging systems, produced by Advanced Gauging Technologies LLC, Plain City, Ohio, for fast and reliable measurements.
“We currently have over 200 gauges in use throughout North America,” says Steve Venters, sales manager at Advanced Gauging. “We sell to metal service centers, distributors and steel producers/mills.”
Isotope thickness gauges have been around since the 1980s, and during the last two decades have started replacing their less-precise cousin, the handheld micrometer. The AGT400, Advanced Gauging’s newest gauging system, has become an asset to the automotive industry. “Manufacturers of automotive products have made a big push for quality, and the AGT400 provides excellent quality assurance,” says Venters.
So when steel service center SteelSummit, which provides approximately 75 percent of its slit and blank material to the automotive industry, needed a top-of-the-line metal thickness gauge, it knew exactly where to turn. “[Advanced Gauging] is a well-respected name in the industry,” says Randy Stebelton, director of quality and operations for SteelSummit. “We currently have three of their gauges, and from what I know of other gauges, Advanced Gauging has the best systems.”
The AGT400 measures an array of metals, from carbon, coated and stainless steel to brass, copper and titanium. “The thickness ranges that the AGT400 can measure will depend upon the actual material being processed,” says Venters. “Generally speaking, for most steel alloys the thickness range is 0.007 inch to 0.250 inch with the capability to expand the maximum range up to 0.312 inch.”
SteelSummit works mostly with ferrous materials—hot-rolled, picked and oiled, cold-rolled, coated galvanneal, hot-dipped, and electro—from 0.015 inch to 0.24 inch. And based on these thicknesses, the AGT400 was the ideal system for SteelSummit. “We look primarily at the types of material they are processing and the thickness ranges,” says Venters. “Other factors include line speed, coil widths or whether we will be providing a completely new AGT400 or upgrading a competitor’s older technology gauge.”
We all remember the atom from high school chemistry class—a basic unit of matter comprised of protons, neutrons, floating electrons and a nucleus. When an unstable atom attempts to stabilize, it emits an ionizing particle and radioactive decay occurs. Radioactive decay causes positively charged alpha particles or negatively charged beta particles to be released by the atom. This release of particles, emitted by the nucleus, produces an electromagnetic wave or gamma ray.
So what does this chemistry lesson have to do with thickness gauging? It’s the foundation from which this gauging system was built. Much like a smoke detector, the AGT400 uses the radioisotope Americium 241, which emits gamma rays that collect within the ionization chamber of the detector head. These gamma rays ionize the gas atoms and create an electrical current. Measuring the current determines the amount of gamma radiation present. Because steel blocks some gamma rays, the thicker the steel, the more rays are blocked. By monitoring the electrical current in the ion chamber, the AGT400 can determine steel thicknesses up to 0.312 inch with a ±0.0005-inch accuracy. “We find them to be really accurate,” says Stebelton. “We thoroughly trust these gauges.”
With two gauging systems already in place, SteelSummit didn’t hesitate to call Advanced Gauging when it needed a third. “There was no question; we just didn’t look anywhere else,” says Stebelton. “We know how easy the other two [systems] are to use and how reliable they are, and if you combine that with the service from Advanced Gauging, there is no comparison. We didn’t even consider others.”
The ease-of-use has been a major reason SteelSummit has purchased multiple AGT400 systems. “Anybody with basic knowledge of thickness gauging can look at it and totally understand it,” says Stebelton. “It’s just easy to use, very reliable and as far as reading the chart, I never had a customer tell me they couldn’t understand it.”
“It’s very operator-friendly,” says Venters. “The menu screens are Windows-based, so whether it’s a basic gauge operation, diagnostic or maintenance, all functions are pretty much available at the touch of a button.”
“We use [the systems] on every coil we run,” says Stebelton. “As they’re running, it’s a real-time look of what’s going on with the material. We use them on every coil, every day. There’s never a case that we don’t have them on.” SteelSummit says it references all three of its AGT400’s data several times a week. “We keep every gauge chart and there’s been many times where we need to go back and reference them; maybe a customer has a question or we need to see if a coil is applicable for another job,” says Stebelton.
On more than one occasion, the data has even aided SteelSummit in pinpointing and resolving potential customer issues. “Recently a customer complained of an out-of-gauge condition,” says Stebelton. “The first thing we did was pull the chart and didn’t find anything abnormal. We planned a visit with the customer, where it was determined they were reading thicknesses incorrectly with some handheld micrometers.”
Productivity is the lifeblood of any service center, and the AGT400 has been vital to speeding up efficiency and decreasing downtime. “There was a period of a few weeks when we had the new slitter installed but didn’t have the gauge installed on the machine,” says Stebelton. “So what that requires is that you stop the machine several times and check the thickness to make sure the coil is within gauge tolerance. With this system you literally put the coil in, turn the gauge on and you can monitor coils as they run, without stopping. The system will alert the operator if the gauge is outside the tolerance that you set.” Venters says the AGT400 eliminates the need for an operator to stop the line and perform manual thickness checks using a handheld micrometer.
On top of increased productivity, SteelSummit also enjoys a decrease in scrap. “Scrap reduction is achieved by ensuring the material being processed stays within specified tolerances, thereby avoiding the unnecessary use of excess material,” says Venters.
“We can run coils with this system in place and rest assured,” says Stebelton. “We can pinpoint exactly where our material may be out of gauge on a coil end. If we get a coil end that is out, we can pinpoint exactly where we need to cut that coil off so we’re not guessing and wasting good material. If you’ve got the information in front of you and you know the precise location within the material, you can make better decisions on when to scrap out-of-gauge conditions.”
Although increased productivity, decreased scrap and less downtime are all necessary for a successful company, it’s often the strong, established partnerships that are at the heart of every company’s long-term success. “It’s a good bunch of people to work with. If anybody called me up and said, ‘What do you think of Advanced Gauging?’ I would tell them that,” says Stebelton. “There are some suppliers that you deal with where you just wouldn’t consider using any other supplier; they are one of them.” MM