Technology Spotlight - Beyond the traditional in automated deburring

Figure 1
An automated deburring machine that uses oscillating abrasive and bush discs can prove to be a cost-effective alternative to traditional wide-belt deburring equipment.

Tony McCue, president of AM Machinery Sales Inc., Warminster, Pa., has seen sheet metal cutting and punching technology advance over the past half-century, and he wonders why the same hasn’t occurred with traditional abrasive finishing equipment.

“As time has gone on, have they really improved upon them? Not really, because people believe they work just fine,” he said. “Why mess with them?”

McCue is talking about the wide-belt deburring machines that have been around since the 1960s. They grind the metal surface as parts move underneath them. This type of machine requires a powerful motor and a rigid frame to support the aggressive material removal process.

McCue said he doesn’t believe these machines can meet metal fabricators’ deburring needs of today, particularly as they relate to modern laser cutting technology. Lasers can produce such a clean cut and square edge that the sheet metal parts can prove to be a cut hazard. The wide-belt machines simply dig into the metal, scratching the surface and creating a sharper edge. This is costly and defeats the purpose, he said.

McCue said he has a better way to approach automated deburring. It’s the DiscMaster, made by Loewer Maschinen of Germany, and it doesn’t rely on wide abrasive belts at all (see Figure 1).

The unit has four motors, all attached to one major support that is lowered to make contact with parts that are fed through on a conveyor. The first two motors power two deburring discs that oscillate over the workpiece. The discs, about 10 inches in diameter, have an aluminum backing, a foam rubber pad at the center, and a Velcro® pad on the exterior onto which abrasive pads can be placed. The rubber discs demonstrate an ability to flow over the edges and into and out of holes to remove the sharpness. The back motors run two brush discs, which also oscillate over the entire conveyor area and handle the final rounding of edges.

The machine can handle parts from 1/2 in. diameter to 60 in. wide and is designed to tackle most metal up to ½ in. thick. No special fixtures or expensive perforated conveyors are needed to hold the parts in place when they come into contact with the deburring and edge-rounding discs.

“The discs are presented in such a way to let the abrasive get on top of small parts without slinging them around. The pressure is applied in a downward manner. There is limited side-to-side pressure,” McCue said.

Given the costs for the discs when compared to larger abrasive belts and barrel brushes for wide-belt deburring machines and the reduced power needed to run these discs, a fabricator can expect to lower its operational costs, according to McCue. He put the savings at 75 to 80 percent of what the total abrasives and electrical costs would be for a wide-belt machine.

For fabricators who may be looking at a machine to supply a certain grain finish on stainless steel parts, McCue said he has some advice for them: Just buy the prefinished metal from the mill. Again, the operational costs of a wide-belt machine are going to be substantial, he said.

McCue estimated a four-head machine would be necessary to produce a grain finish similar to what a mill could provide. Two heads with abrasive belts are necessary to finish the surface into acceptable shape, and two heads with brushes are needed to deburr the leading and trailing edge of the parts and to leave an aesthetically pleasing finish.

With the cost of such a machine, the cost of the abrasive belts and brushes, and the multiple times that an operator would need to feed the parts through the machine to get the required finish, a metal fabricator would have to finish 31 sheets of parts per day to recoup the initial investment and pay for ongoing costs, McCue said. That’s why working with prefinished metal makes sense in these instances.

Many metal fabricators are already cutting sheet metal with a protective film on it. Once the cut parts come off the laser cutting machine, an operator can feed them, with the film still attached, into the DiscMaster and not worry about damaging the surface finish. The oscillating abrasive and brush discs attack the exterior edges and interior cuts, rounding exposed areas and keeping the protective film in place.

“Just peel the paper off and it’s good to go,” McCue said.

McCue added that as laser cutting continues to grow as the method of choice in metal fabricating he expects manufacturers to show more interest in automated deburring machines. He thinks it’s a good time for them to consider another means to tackle those sharp-edged parts.

AM Machinery Sales Inc., 215-293-0333, www.ammachinerysales.com