eld grinding is the removal of excess stock from welds. It’s a process that can produce variable results and impart high stress on employees’ bodies from both the vibration and awkward body positioning, such as outstretched arms.

Automating the grinding process traditionally has been difficult; however, Lincoln Electric and 3M have teamed up, combining robotic integration and abrasives expertise to create the Fab-Pak OmniClean system—an all-in-one robotic grinding cell that is pre-engineered to automate and optimize pre- and post-weld applications and has a single base design for easy installation and setup.

Another challenge facing weld grinding departments is the labor shortage, and “a robotic solution certainly addresses that,” points out Ryan Scott, product manager, business development at Lincoln Electric. With the Fab-Pak OmniClean system, “the automation solution has been developed into a standard robot system, making it simpler to install and shortening the timeline to begin using the system,” he adds.

Tyler Naatz, an advanced robotics application engineer for 3M, is fielding more inquiries about the Fab-Pak OmniClean robotic grinding system, particularly due to the difficulty of finding skilled workers. “Grinding is a very difficult job. Most people don’t want to do it 10 hours a day, every day. So retaining workers and finding people to do these jobs is very tricky.” He says there’s a common misperception that grinding is an art form. “In a lot of cases it can be, especially in finishing and polishing applications. But if you’re grinding minor joints on standard welds, it’s more about optimizing the abrasive with the tooling, [which] takes some of the artwork out of it. The Fab-Pak OmniClean cell helps make grinding a more consistent process. It has a headstock/tailstock positioner that can make it easier to move and access different parts of the weld,” reducing the ergonomic concerns, and “having the tool changing drawer available helps ensure the right abrasives are being used during the correct step in the process.”

The cell is equipped with either a 3-hp or 5-hp 3M Servo Rotary Tool, and the headstock/tailstock system includes a Fanuc robot equipped with a 3M Servo Rotary Tool and 3M Active Compliant Tool. The 3M Active Compliant Tool applies the correct amount of force for optimal grinding performance for specific applications and finishes. The 3M Servo Rotary Tool maintains consistent speed and horsepower when the abrasive is grinding.

Each cell comes with an abrasives starter pack with the choice of 3M Cubitron II Fibre or Scotch-Brite surface conditioning discs, which are designed specifically for weld cleaning. Discs can be stored in the cell’s media change drawer so that everything is within easy reach.

In addition to grinding being perceived as an art form, companies often choose to keep this aspect of production manual because of cost, product mix or the perceived complexity of automating. The Fab-Pak OmniClean system addresses many of these concerns. It was designed to be able to take over the workload on small to medium-sized parts, and “the time from having a system arrive on your dock to on the floor, powered up and grinding is exceptionally short,” says Scott. And if employees are familiar with running robots, “they pick it up pretty fast.”

Naatz says that the “Fab-Pak OmniClean grinding system can help save on abrasive utilization because of the system’s ability to “use the abrasives more efficiently and effectively to maximize the full life of the product. Part-to-part, companies generally see savings in their abrasive process.” He notes that if production increases dramatically, overall abrasive costs will trend upward, however.

The reduction of steps is another benefit the system offers. “The biggest one for weld grinding is eliminating the use of random orbital sanders in a manual process. Generally, the weld is removed with a fiber disk or a flat disk followed by a random orbital sander to break up the deeper scratches so they can’t be seen through paint or powder coating. Using the robotic cell—because of the consistency of the servo motors and the coverage it achieves—reduces the number of steps needed,” says Naatz.

Traditionally, automating welding comes before grinding, but adding automated grinding can provide a big “bang for the buck” in a heavy fabrication facility, Scott says. “A lot of times in welding applications, a customer isn’t as concerned with weld aesthetics. Automating welding comes first, and then the grinding follows as needed. A good goal is to automate 80 percent of all work. Companies will try to get to 100 percent, but sometimes that last 20 percent of work is made up of tricky and difficult parts. So, if you can have an operator who is loading parts and capable of touching them up quickly, that can lead to better overall production.”