Turning to milling for weld preps

Need to prep a pipe end for welding? For welders doing on-site work on a piping system, nothing beats a portable tool for making a standard 37½-degree bevel. A portable tool can go nearly anywhere, limited only by the length of the extension cord, and a typical tool is extremely versatile in the diameters it handles, often a range of up to 12 to 16 in.

But what if you need something more elaborate than a common bevel, especially in a production environment? Bevels, radii, and lands can be combined in an endless variety of combinations by varying the bevel angle, radius contour, and the amount of land. For manufacturing of complex end forms in a high-volume production environment, a dedicated machine is the way to go.

Manufacturing Solutions Industries Inc. (MSI), Beaumont, Texas, was founded in 1993 to build machines for a similar purpose, chamfering steel rod for producing fasteners. Since then the company has parlayed its experience in solids to develop a line of machines for beveling tube and pipe. Its ChamferMate® machines bevel pipe up to 8 in. dia. in cycle times often shorter than 20 seconds.

“A typical user of this equipment is a fabrication shop that works with process piping, whether the application is a refinery, chemical processing plant, or a power generation station,” said President Wayne Moncla. “Others include commercial refrigeration, boilers, and pressure vessels.”

The applications don’t end with piping systems. MSI’s customers include manufacturers that make end forms on tubing for all manner of products—exercise machines, off-road vehicles, and all types of specialized equipment.

About 90 percent of the machines are specified to perform a standard 37½-degree bevel for welding.

“Many of our machines go to welding schools to make coupons for training welders,” Moncla said. Schools could use hand-held bevelers, but a stationary machine provides a substantial time advantage, Moncla said, sometimes taking 20 seconds to do a job that would take 20 minutes otherwise.

“Students don’t need to use valuable training time beveling pipe ends,” he said.

For this market, the company produces a line of standard machines. Its C3A and C5A process diameters from ½ to 3 in. and ½ to 5 in., respectively, using pneumatic power for clamping and electric power for turning. Models C5H and C8H handle diameters from ½ to 5 in. and 1 to 8 5⁄8 in., respectively, and use hydraulic power for clamping.

These machines also are well-suited to many of MSI’s industrial customers. The ease of operation and fast cycle times allow some customers to bevel and saw simultaneously. In many applications, the saw operator has ample time to bevel both ends of the pipe before the next piece is cut.

“For one of our customers, this has eliminated the need for a skilled machinist to bevel the pipe in a lathe, saving quite a bit of time and money,” Moncla said.

Safety also plays a role in how the machines are designed. Because the cutting takes place deep inside the machine, the process doesn’t pose a risk to the operator. Safety interlocks prevent an overly zealous operator from attempting to run the machine with covers or panels removed. The hot, sharp chips also pose little hazard. As the turning process progresses, the chips get deposited into a bin inside the machine.

Modified Machines for Specialized Applications

Although standard machines are its bread and butter, MSI thrives on the challenges of building custom machines for the other 10 percent of its market. A typical application is a J bevel for orbital welding.

“J bevels have a combination of features,” Moncla said. “We set up the tooling to cut the bevel, radius, and land width to meet the orbital welder manufacturer’s specifications.”

Because the cutting tools are off-the-shelf carbide inserts, the machines are suitable for essentially any metal—carbon steels, alloy steels, stainless steels, nickel, zirconium, and titanium, among others.

MSI strives to make sure its machines fit into each customer’s existing operations. It raises or lowers the heights of its machines when necessary and assists its customers with custom material handling and feeding systems.

“One of our systems uses an inclined table and has one machine at each end of the pipe,” Moncla said. “The system feeds one end of the pipe into one machine, then backs it out and feeds the other end into the other machine.”

The Hole Isn’t in the Middle!

Tubes and pipes are rarely perfect. Every manufactured product has a little tolerance, so hollows often vary a little bit in shape and wall thickness. Tube and pipe producers do everything they can to keep the variances to a minimum, but fabricators still protest on occasion that the product they’re fabricating isn’t round and the hole isn’t in the middle. A turning machine makes round features, but centering them on an asymmetric workpiece can be a serious challenge.

“Our machines grip the OD,” Moncla said. “If the pipe is out of round, or if the wall thickness varies, or if the ID isn’t centered, a simple bevel won’t be perfectly concentric.”

In some cases, a turning machine can overcome these challenges.

“On J preps we usually bore the ID about ¼ in., providing a round mating surface,” Moncla said. “We had one application on a 4-in. pipe that coupled to another part with a slip fit. We built a machine that bores the ID to a depth of 6 in. so the mating part has enough surface area.”