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Tube & Pipe

The whole picture

By Gretchen Salois

Above: Breakdown of the Laser Triangulation Principle showcasing how material is scanned.

What lies beneath a smooth exterior is what counts

February 2015 - Appearances can be deceiving—especially during the welding process. Once a bead is laid, subsequent finishing can camouflage underlying weaknesses by leaving a misleadingly smooth, flawless finish. However, an operator can remove the guesswork of whether a weld will hold by monitoring the process with a live feed from a welding camera. 

Tube and pipe products are typically made from steel strips rolled into a cylinder and the edges are longitudinally welded together at a weld box to form the final product. After the weld box, a short length of the tube mill, from 1 to 4 ft., typically features a scarfing/grinding tool that removes the weld bead. Once the tube passes through the scarfing or grinding tool, the weld bead can be so cleanly removed that sometimes it is hard to tell where the weld was made. 

At this point, the tube is pretty close to round from the outside. But in order to determine how perfectly the welding and forming are achieved, mill workers must inspect the tube immediately after the weld box but before scarfing or grinding, explains Cameron Serles, president, Xiris Automation Inc., Burlington, Ontario. 

“The best point of inspection is before grinding away any weld bead,” he says. “That’s how you know you’ve got properly formed material and a good weld.”

FFJ-0215-tube-image1

Most tube and pipe mills want to avoid a problem known as mismatch, a condition where the two edges of the pipe come together but are slightly uneven, with one side having a higher profile than the other. As the material is welded, the mismatch is in place. Then, when ground, any excess material on the weld bead is removed as well as part of the parent material. 

“You’ll take the whole weld bead down and actually end up taking some of the parent material on the higher side of the mismatch to make the outside round,” explains Serles. “While the tube may look great at this stage, if the customer were ever to take a cross-section of the tube, they would notice that the parent material on one side of the weld is thinner compared to the other, causing a potential weakness in the final product.”

Constant vigil

St. Marys, Ontario-based Caledon Tubing, a subsidiary of automotive parts manufacturer Martinrea International Inc., performs resistance welding, and sought a better way to ensure a weld’s integrity. Its operators also found that problems can begin when the excess weld seam material is removed.

Caledon installed the Xiris WI 2000P camera within 5 ft. of the weld process. “And the Xiris 3-D laser scans at a ridiculously fast rate,” says Wayne Huettlin, Caledon’s process engineer. The company produces tubing used for automotive components including brake, fuel, vapor and fuel transmission lines, which must adhere to ASTM specifications. 

The camera can scan the product and generate an inspection result at 125 times per second. “I have really fast live feedback available to me almost instantly,” which allows operators to find process issues before they become defects, adds Huettlin.

“If something goes south, our operator knows about it really quickly,” he continues. “The PLC-tied system automatically detects marks and cuts that piece of tube out. So if it fails, it doesn’t make it out the door.”

Using the camera, Huettlin also records snapshots and failed images and keeps a record of all defects and defect parameters. “I like to have a history available which I keep on a server. While rare, it’s peace of mind knowing if someone has a quality complaint six months from now, I can paint a picture of what was happening at that point in time,” Huettlin says. “We never had that ability before.”

Inspection approach

An automatic inspection system that uses laser triangulation, the Xiris WI 2000P looks at the tube’s surface and compares it to an ideal model. By looking at the top of the tube, the Xiris camera will infer how accurately the tube has been shaped and welded. Earlier Xiris cameras were able to detect some errors but the maker has frequently improved the camera’s abilities while also expanding the defect types and end product configurations the system could inspect. 

Xiris cameras initially were able to inspect five defect types specific to laser-welded tube production. “We quickly realized that laser-welded tubes were a small part of the overall tube market so to address the rest, we also needed to address the problems specific to plasma, TIG and ERW welded tubes,” Serles says. Engineers at Xiris also wanted to tackle the full size range of the tube and pipe market, from a low of 1⁄8-in. diameter used in the needle market up to 6-ft. diameters used in oil and gas, power generation or FFJ-0215-tube-image2water treatment. Xiris needed a family of sensor sizes to be able to see the full range of weld bead widths and heights with sufficient accuracy.

“We have expanded our product range to be able to cover tube diameters of at least 1⁄8-in. all the way up to about 80 in. diameters because the camera system isn’t ‘one size fits all,’” Serles says. Xiris has built a number of sensor heads that offer a small, medium and large field of view.

Xiris also developed an algorithm that tracks the laser line to improve measurement of accuracy so precisely that, in some cases, operators can view, through magnification, down to 7 µm or about 0.00033 in. “This allowed us to see very small and subtle defects you might get in certain welding processes and notify line operators of an early process issue before it becomes a problem,” Serles says. 

Producing an environmentally robust system that could survive the harsh environment of tube mills was also a main aim of designers at Xiris. This included making the sensor head moisture proof, adding metal guards and pressurized air to keep machinery coolants, smoke and steam from penetrating the electronics or contaminating the optics of the sensor head. 

Real-time woes

The most common problem seen with grinding and scarfing, according to Caledon’s Huettlin, is removal of too much weld seam. “It was really hard to keep track of that before because we didn’t have a live feed telling us exactly where the problem occurred,” he recalls. “An operator would grind coatings off and look for defects but that relied on finding the defect at the exact spot where the error occurred.”

There could be 100 ft. of material without any defects and one bad spot, but unless the inspector randomly chose that particular section, it might not be caught and “you wouldn’t know until the customer complained,” Huettlin says. “That’s not acceptable. We needed something that would instantly catch and contain when something failed.”

Before installing the Xiris system, Caledon had limited means to inspect weld seam defects, but has since experienced a significant drop in defects and the amount of scrap it accumulates. 

“For instance, I had 7,000 ft. of coil and the camera detected a defect and cut out about 100 ft. of defective area without shutting down,” Huettlin says. Operators later confirmed the findings and examined the coils before they left the shop floor to ensure they were fine. 

“In the old days, that 100 ft. could have made it out the door and we wouldn’t have found out until receiving feedback six months to a year down the road,” he says. “We’d be scratching our heads trying to put in a corrective action for something. 

“Today we have live reports and trend reports that keep a pulse on the process, allowing us to keep track of every step far faster than the best operator ever could,” he continues. “We didn’t have that comfort level before. The live feedback allows operators to make adjustments sooner than later, and if it’s beyond parameters, we shut down the mill instead of making scrap.” FFJ

Sources

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AIR FILTRATION

HYDRAULIC PRESSES

NESTING SOFTWARE

SERVICE CENTERS

Camfil APC - Equipment Beckwood Press Co. Metamation Inc. Admiral Steel
Camfil APC - Replacement Filters Triform

PLASMA TECHNOLOGY

Alliance Steel
Donaldson Company Inc.

LASER TECHNOLOGY

Messer Cutting Systems Inc.

SOFTWARE

BENDING/FOLDING

AMADA AMERICA, INC.

PLATE

Enmark Systems Inc.
MetalForming Inc. Mazak Optonics Corp. Peddinghaus Lantek Systems Inc.
RAS Systems LLC MC Machinery Systems Inc.

PLATE & ANGLE ROLLS

SigmaTEK Systems LLC

BEVELING

Murata Machinery, USA, Inc. Davi Inc. Striker Systems
Steelmax Tools LLC TRUMPF Inc.

PRESS BRAKE TOOLING

STAMPING/PRESSES

COIL PROCESSING

LINEAR POSITION SENSORS

Mate Precision Tooling AIDA-America Corp.
Bradbury Group MTS Sensors Rolleri USA

STEEL

Burghardt + Schmidt Group

MATERIAL HANDLING

PRESS BRAKES

Alliance Steel
Butech Bliss Fehr Warehouse Solutions Inc. AMADA AMERICA, INC.

TUBE & PIPE

Red Bud Industries UFP Industrial Automec Inc. BLM Group
Tishken

MEASUREMENT & QUALITY CONTROL

MC Machinery Systems Inc. Prudential Stainless & Alloys

CONVEYOR SYSTEMS

Advanced Gauging Technologies SafanDarley

WATERJET

Mayfran International

METAL FABRICATION MACHINERY

PUNCHING

Barton International

DEBURRING/FINISHING

Cincinnati Inc. Hougen Manufacturing Flow International Corporation
ATI Industrial Automation LVD Strippit

SAWING

Jet Edge Waterjet Systems
Lissmac Corp. Scotchman Industries Inc. Behringer Saws Inc.

WELDING

Osborn Trilogy Machinery Inc. DoALL Sawing American Weldquip
SuperMax Tools

METAL FORMING

HE&M Saw Strong Hand Tools
Timesavers FAGOR Arrasate USA Inc. Savage Saws T. J. Snow Company

 

MetalForming Inc.

 

 

 

MICROFINISHING TOOLS

 

 

 

Titan Tool Supply Inc.

 

 


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