Above: IMS Systems Inc.’s customers have demanded that surface inspection and gauge measurement technology be adapted to apply upstream.

Even if it’s never been done before, an instrument maker finds ways to detect, measure and quantify flaws

May 2016 - Admittedly, it’s cheesy entertainment but “A Knight’s Tale,” a 2001 action/adventure film, features one of the best lines of dialogue: “You have been weighed, you have been measured and you have been found wanting.” Likewise, no one wants their product to be found wanting—and summarily rejected—by their customer. The best way to cull the flawed material before it makes it to your customer’s door is to measure and inspect. 

This is where IMS Systems Inc., Mars, Pennsylvania, the American subsidiary of Germany’s IMS Messsysteme GmbH, brings the weight of its experience and technological know-how to bear. IMS develops and manufactures non-contact X-ray, isotope and optical measuring systems that gauge the length, width, thickness and other dimensions of ferrous and nonferrous metals. Driven by customers’ evolving requirements, measuring systems—including surface inspection devices—do so much more than they did even a decade ago, that it’s hard to imagine the technology that develops 10 years from now.

Founded in 1980 in Heiligenhaus, Germany, IMS established itself in the United States in 2000. Over that time, “we have done well measuring material and understanding defects,” says IMS Vice President and General Manager John Buckman. 

With thousands of pixels and the correct, focused lighting, “imagine the resolution you get.” IMS has adjusted its cameras’ automatic exposure to view shiny material.

The company initially developed a two-dimensional surface inspection system, “but industry keeps pushing us [and] the farther we are being pushed up the supply stream, it has opened up our ability to use 3-D.” For example, steelmakers are using 3-D measuring technology to detect conditions in hot slabs coming out of their casters. 

“Slab surfaces are rough and, of course, you can’t see a lot in 2-D but, in 3-D, you can measure the height and depth of defects. That was revolutionary, and it seems to have caught fire worldwide,” Buckman says. Producers now routinely measure hot slabs and cold slabs in 3-D. Laser triangulation systems, in use at least 10 years on flat rolled products, have more recently expanded into long products. They detect potential issues on hot-cast billets and bars. “We measure profiles—how square the bar is and are able to see the height and depth direction of a defect on the surface of a long product,” he says. 

IMS’ research and development arm has been around 36 years. “If something needs to be measured and we don’t have the technology, we’ll create the technology.” 

Until fairly recently, much of the measuring and inspection technologies were focused on exposed automotive steel sheet but the number of applications has ballooned. Among IMS’ latest adherents are tube mills. Tube measuring and inspection systems are being installed at a Gulf Coast seamless tube mill and a tube wall thickness measurement system is going in at Tenaris, Bay City, Texas.

For the Gulf Coast tubing plant, says Buckman, “we invented a machine that measures tube for them in three dimensions. The oilfield product group likes to see inclusions and porosity. That had never been done before.” At Tenaris, he adds, “They are measuring tube wall thickness in the hot state, on the fly.”

He calls his company’s tube wall thickness gauge a “Cadillac for seamless tube, and virtually all seamless tube mills use this as they roll it in the hot state.” By seeing the defects at this stage, mills “don’t have to continue to produce bad pipe. They used to pull every 100 tubes and ultrasonically test it by hand. To test in real time is a bonus.”

IMS Systems can measure products in three dimensions. One can detect the squareness of a billet, or see the height and depth direction of a defect on surfaces.

Camera power

There is a distinct challenge to detecting flaws in the surfaces of shiny material, due to reflectivity. So IMS has developed surface inspection devices that project laser lines across material and measure the material at an angle. 

“The matrix camera has 12,500 pixels—you can imagine the resolution you get. That has enabled us to adjust the automatic exposure mechanism, which helps the camera to refocus and not be blinded.” That feature was developed in the last two years, he says, and “we have it applied it on flatness measuring gauges worldwide. It’s even more important for aluminum than steel.” 

Back to surface inspection technology, it is increasingly gaining a foothold in aluminum mills. “We build frames [for camera inspection systems] as wide as 111 inches for aluminum,” says Buckman. “Aluminum elongates and has to be cast wide so we add segments onto our gauges.

“When you scalp an ingot, the surface is coarse and has to be machined off. With a 26-inch ingot, you traditionally scalped 1 inch off each side, which gives you 24 inches. That elongates on rolling. Today, companies can now inspect 100 percent of the surface of the aluminum ingot, which means you have the total depth of a flaw measured and now you only have to scalp to that depth, so 1⁄2 inch or 3⁄4 inch rather than 1 inch. The yield savings can be tremendous.”

Retrofitting

IMS Systems just won a new contract with a long-time customer, Steel Dynamics Inc., which uses IMS equipment throughout its Butler, Indiana, steelworks.

“SDI uses an area scan system—one of our first systems—camera quality has come a long way and that equipment does not have resolution available today,” Buckman says. “We are replacing our own older systems with better systems. Retrofits are a big business for us. The frames are so sturdy and rugged that they last but the control systems may become obsolete. So at the fraction of the price of a complete installation, a customer can just upgrade the inspection and measurement technology within the existing frames, but customers can also ensure that the frames match more current tolerance requirements.

Surcon’s X-3D vision technology makes it possible, for the first time, to distinguish between surface defects and irregular textures on steel slabs.

Collect, quantify

IMS continually upgrades its software platform along with the measuring technology. “You have to quantify the data—it’s this kind of defect, or that kind,” explains Buckman. “We have a defect library that we create for the customer. We come in with a base of stuff we know but they may have defects unique to their process.”

He says IMS is perfectly geared to supplying a host of services. “Doing surface, dimension measurement—width, length, thickness and contour, we can calculate the weight of a slab very accurately. We know the density. This is all wrapped up together,” Buckman says, “and the trend is toward multifunction gauges like this. 

“We are wrapping other technologies into it. We archive data and help our customers evaluate what they are looking at. We can put it all together in one frame—we don’t need acres of real estate.”

The AM/NS Calvert steel plant in Calvert, Alabama, needed a plant-wide quality management system that didn’t just collect data but alerted operators when and where material was out of spec, at exactly X feet into the coil. So the company installed MEVinet-Q, the quality management system IMS developed for analyzing and storing production data from rolling mills.

“You can take this to enterprise level like Calvert did and we are going to do it for the Gulf Coast tube producer,” Buckman says. With MEVinet-Q, “You can track every piece from the slab yard to the finishing department and see the quality parameters every step of the way.”

Ten years ago, it was difficult to obtain high-quality lasers used in measuring and surface inspection systems, according to Buckman. “Many times the crystals came from outside the United States and the quality control was not really good. They would fail and be inconsistent batch to batch so we made our own. We had to hire engineers for that, too. We started making cold mill gauges in the U.S. just two years ago.”

The quest to collect, detect, quantify, and improve never ends. Buckman says IMS just added a surface inspection system at the exit end of a hot strip mill in the Southern U.S. The client, he says, is “seeing things they never saw before and they have to come up with new terminology for it.” MM