Avoiding the drudgery of deburring and finishing operations
The deburring and finishing of machined and fabricated parts is a necessary but often disregarded step in the manufacturing process. As a result, some shops still approach this task much as they did in the previous century, relying on manual deburring and polishing methods over more modern, automated, and predictable means. This is time-consuming and wasteful. It leads to inconsistent part quality and even increased machine downtime as operators attend to buffing wheels and drill presses, their CNCs idle. Worse, a simple mistake at this stage of the manufacturing process can mean scrapping out a workpiece that took hours or even days to produce.
This article has neither the time nor space to provide a detailed explanation of the dozens upon dozens of deburring and finishing technologies available today, but it will touch on some of the more common ones. For example, a Timesaver or equivalent rotary brush machine is a great way to deburr many flat workpieces. Belt-style versions of these machines perform similar tasks by straight-lining or graining parts, whereas rotary drum and vibratory bowl finishers filled with abrasive media can tackle even the toughest burrs on machined, stamped, or laser-cut parts.
There’s also thermal deburring, an improbable process that applies an explosive charge to blast away burrs. Electrochemical machining (ECM) uses an electrolytic fluid to dissolve burrs and does so in a surprisingly accurate manner. Abrasive flow machining (AFM) is commonly used in the automotive and hydraulics industries to deburr and polish complex internal part features, just as abrasive blasting smooths surfaces on everything from camshafts to cargo ships.
The Need for Non-Wovens
Then there are belts, discs, brushes, and other abrasive media, all of which make short work of burrs and rough surfaces. An expert on these is Michael Radaelli, senior product manager, non-woven abrasives at Norton | Saint-Gobain Abrasives, Worcester, Mass. He noted that the industry continues to develop ever more capable and productive abrasives, among them the company’s Rapid Prep XHD line of non-woven abrasive products. “By leveraging modern abrasive grains, bonding methods, and other technology improvements, shops can often reduce the number of steps needed to achieve the desired surface quality,” Radaelli said. “This helps cut labor time, abrasive inventory, and especially operator fatigue when right-angle grinding.”
He suggested that manufacturers make several common mistakes when selecting abrasives. During deburring operations, for example, operators must have the skill and experience needed to ensure they do not change part geometry and size, lest they inadvertently scrap the workpiece. This is often the result of using too coarse an abrasive, applying too much pressure, or simply choosing the wrong abrasive altogether. Similar problems can occur when removing parting lines on castings, or during blending and finishing operations on welded products.
Radaelli pointed to various field tests with the new Norton products. A manufacturer of emergency vehicles enjoyed a 26 percent faster cut rate and twice the abrasive life on its line of aluminum ladders after switching to XHD abrasives. A well-known locomotive builder eliminated two hand-grinding operations on welded carbon steel structures. A supplier of computer cabinets went from 480 to 1,040 in2 (3,097 to 6,710 cm2) per wheel using non-woven abrasives, with room to spare.
Read more: Helping Your Parts Shine On