There are few mysteries to the art of deburring. Grab your favorite scraper blade, abrasive wheel, or Dremel tool and start smoothing those sharp, ragged edges.
The thing is, though, that nothing in the manufacturing world should be an art. Press too long or too hard on one of those edges and what was once a precision-machined, possibly very expensive workpiece is now bound for the scrap bin.
I-Robot
Not if Warren Reynolds, vice-president of operations at I-Cubed Industry Innovators Inc. in Stoney Creek, Ont., has anything to say about it. The machinery builder and robot integrator is well-equipped to automate this and other manufacturing operations. He and his team are currently working on “three water jets, one milling cell, two press tending applications, a wash station, and three buffing projects, two of which just hit the floor,” he says.
It’s an impressive amount of work for a company of 63 people, especially when you consider that this Canadian design and manufacturing firm has installations throughout North America, the U.K., and even one in the Bahamas. Reynolds laughs, “We were drawing straws for which of us would go there, but sadly, the customer ended up doing the install himself.”
Of these various projects, Reynolds places deburring near the top of the list in terms of complexity. He ticks off the many different ways to deburr a part, starting with the scraper blade mentioned earlier to esoteric technologies like abrasive flow machining (AFM), which uses a pressurized, abrasive-filled putty to smooth internal part features. All are candidates for automation, and all are seeing significant interest from manufacturers looking to reduce costs and increase part quality in the face of a labour shortage that just won’t quit.
As with manual deburring, however, finding the best approach to automated deburring is neither easy nor obvious. Sometimes you’ll have the robot pick the part up and present it to the deburring or buffing system, he explains, something I-Cubed is doing right now with some car bumpers. In other cases, you’ll equip the robot with a compliant tool—an air or electric-powered rotary head, for example, that has a flexible deburring media attached to it—and then trace it around the part periphery.
“There are a lot of variables to consider with any of these applications, but that doesn’t change the fact that more and more manufacturers are moving in that direction, even those doing high-mix, low-volume work,” says Reynolds.
Managing variables
He notes that it’s easier to minimize these application variables by starting with a 3D CAD model of the workpiece and importing it into an offline programming system, one that can provide an accurate simulation of the entire environment. Traditional teach pendants are only used for simple work—a straight edge, for instance, where all that’s needed is to show the robot a couple of points.
Natalie Adams is the product marketing manager for one of those systems: the Robotmaster brand of offline robotic programming software, part of the Hypertherm Associates family of products. She says their goal is to help manufacturers transition their manual, labour-intensive processes to automated systems by simplifying what many in the industry perceive to be a complex process: programming robots.
“Robotmaster is brand agnostic and works with all the major robot manufacturers, among them KUKA, FANUC, and ABB,” she says. “We’re seeing significant calls for programming of robotic plasma cutting, water jet, and welding, but it’s the polishing, sanding, deburring, and grinding operations that occur when the part is at its greatest value. Here’s where it’s especially important to get things right.”
Get busy
Adams agrees that teach mode is a viable option for training robots to perform simple tasks, but programming and simulation software is needed for most everything else. Not only is it faster and less error-prone than humans, but as with any offline system, programming can be done when the asset is busy doing work—making money, in other words.
And as with robots themselves, the results are more consistent than is otherwise possible. “Just like CNC machine tools, robots generate a higher quality part,” she says. “When you couple that with offline programming software, manufacturers can take that benefit even further, as the quality of the program is no longer subject to the skill of the person using a teach pendant. This consistency is achieved not just on a per-program basis, but across the entire manufacturing facility and even in remote facilities on the other side of the country. No matter where it’s deployed, you’ll be able to run the same program and repeatably achieve the same results.”
Despite Robotmaster’s ability to program many of the most popular brands of 6-axis robots, Adams is quick to point out that the company partners with a number of CAM providers. That’s because some shops prefer to program the deburring steps along with the machining operations in their CAM systems, she says, then import the data into Robotmaster to perform the robot programming, leveraging the powerful and easy to use tools and simulation environment to output error-free robot code.
Addressing the singularities
One of these CAM providers is CNC Software LLC of Tolland, Conn., makers of Mastercam. Channel marketing manager Ben Mund offers a very technical explanation for what is, in essence, a simple fact: robots have more axes of motion than CAM systems are accustomed to working with and is why CNC Software has partnered with Robotmaster to develop a Robotmaster plugin to Mastercam.
“Once you get beyond five axes—into the robot world, in other words—you introduce what are known as singularities. That means multiple solutions exist for every directional vector, which is where systems like Robotmaster excel. They can take Mastercam’s generic output and use it to solve all those complex singularities, then deliver usable code for the robot.”
Mund pointed out that it’s possible to write a postprocessor able to manage these complex, directional vectors, but it would “be ugly” and not provide the same level of visualization that dedicated robot programming systems deliver. CNC Software applications engineer Jesse Trinque seconds all this but points out that traditional deburring methods—automated or otherwise—are often unnecessary for owners of five-axis machining centres.
“Mastercam has a deburring function that’s quite easy to use, so some shops will take a lollypop cutter or chamfer tool and deburr parts that way,” says Trinque. “On a three-axis mill, however, it’s tough to reach everything, so they usually end up with some deburring outside the machine. But with a five-axis, these limitations go away. You can deburr everything inside the machine, and in many cases, use the peripheral edge of a finishing end mill to do so, saving you a tool change. So yes, robotic deburring definitely has its place, but this illustrates one more way in which five-axis machining centres are a game-changer for many shops.” SMT
