Above: Designed to finish and deburr outside surfaces, NamPower disc brushes increase part quality, reduce cycle time and replace demanding manual operations.

Fabricator uses brush technology to automate process, eliminate grinding and improve part quality

January 2014 - Removing unwanted material and rough edges left over from machining operations is a vital step to achieve a smooth, high-quality part.  Yet conventional deburring methods can drain time and money from a fabricator’s manufacturing processes. Because deburring is thought to add no value, little consideration is given to estimating its cost—an expense that can quickly add up, depending on the workpiece or industry. 

For Orange Vise Co., deburring parts involved taking them offline and using a variety of abrasive tools by hand. This rigorous exercise was followed by what company founder Eric Sun calls a messy grinding process. The Orange County, Calif., company manufactures CNC machine vises and quick-change fixturing components using a high-speed horizontal machining center. Vises are constructed in different sizes with beds that are heat treated and tempered. Cast iron vise body, carriers and jaws have selective hardened surfaces that can measure as high as 60 on the Rockwell C Scale. 

The right stuff

To achieve a specific finish Orange Vise would grind these hardened surfaces because milling cutters were wearing out too quickly. The manufacturer also found it necessary to grind noncritical, unhardened surfaces to create a uniform appearance over the entire workpiece.

“This process involved removing, cleaning, and then repositioning parts several times in order to grind each face,” says Sun. “It was very time intensive.”

Looking to automate its deburring process and eliminate the need to grind part surfaces, Orange Vise began searching for alternatives. A new line of nylon abrasive brushes called NamPower, introduced by Brush Research Manufacturing Co. Inc., Los Angeles, in 2011, caught Sun’s attention. Brush Research has been solving finishing problems with its brushing technology since 1958. It is known for its Flex-Hone tool and miniature brushes, which deburr and finish the interior surface of metal borings. “Brush Research’s goal has always been to develop value-driven solutions,” says Jonathan Borden, national accounts manager for Brush Research. “We’re seeing resurgence in economic growth and have focused our efforts on providing tools that can help customers respond faster to rising production demands and meet shorter delivery windows.” Offering a tool like NamPower, specifically designed for finishing and deburring outside surfaces, was a natural next step.

NamPower disc brushes remove burrs, blend edges and improve surface condition while increasing part quality and reducing cycle times. Brush Research developed the line for use with both semiautomatic and fully automatic equipment to replace demanding manual operations. The new brushes offer two different fill configurations. The Dot style provides general purpose deburring and surface finishing while the Turbine style offers a higher density fill for more aggressive deburring.

Sun says he chose the Dot style and reduced spindle speed to achieve the smoothest finish possible and approximate the ground surfaces on a CNC vise. “We started using the NamPower brushes for deburring and quickly discovered they provide a really nice surface finish,” he says. “The finish was good enough that we were actually blending it without ground finishes. On large surfaces that required multiple passes, there were no visible blends. The whole thing looked like it was done in one pass. Needless to say, the brushes also sped up the process quite a bit.”

An ideal marriage

Unlike conventional disc brushes that are made with either ceramic or silicon carbide, NamPower brushes include both abrasives. “Ceramic performs the bulk of the cutting and extends tool life, but it cuts a little rougher,” says Borden. “Silicon carbide acts as a buffer and cuts finer than the ceramic, giving an improved surface finish.” 

Borden says that use of just one abrasive would require two brushes, multiple setups and production passes adding unnecessary time to part production. A silicon carbide brush used on its own also means added costs in tool life and cycle times. 

“We combine the advantages of both types of abrasives,” Borden explains. “NamPower’s other unique advantage is its flow-through coolant feature. In most conventional applications coolant is applied from a brush's exterior, which means spray is directed from the outside inward. However, the spinning brush limits the coolant's ability to penetrate and reach all of the bristles. Our design allows coolant to flow from the center of the brush for better lubricant dispersion, which reduces heat and allows the brush to run at greater cut depths.”

Orange Vise also found the Dot style NamPower brush flexible enough to conform to component features of different heights, making it suitable for use on other parts. “We weren’t expecting to use the brushes so much,” says Sun. “We’re finding more and more uses for them. The same brushes work for aluminum, steel, cast iron and several other materials without us having to swap them out very often.” 

Abrasive filaments for the brushes are made from nylon, selected for its resistance to fatigue, moisture and chemicals. Filaments are rooted in a fiber reinforced thermoplastic base giving the NamPower brush rigidity and stability for good performance and long tool life. Like flexible files, the filaments conform closely to part contours, smoothing and polishing part edges and surfaces for maximum burr removal rates and a superior finish.

Saving time

One of Orange Vise’s primary uses of the brushes is for edge blending, particularly on chamfered parts. While the carbide end mill used to cut the 45-degree chamfer does not normally leave a rough rim, the slightest amount of wear can cause burrs. Previously, someone inspected each part and removed any burrs by hand. Now the NamPower brush allows the manufacturer to automatically deburr chamfered holes and edges.

The company also performs engraving on the underside of its vise jaws, a process that doesn’t require deburring. However, achieving a finer engraving on the top entailed using a 45-degree V-bit, which left behind burrs. Sun chose the NamPower brush to remove the burrs rather than grinding them out. “Grinding would have been a lot more work,” he says, noting the brushes don’t involve extra effort to use. “It adds maybe 30 seconds to the process.”

The brushes are self-sharpening. Linear construction ensures sharp new grains continually contact with the work surface, then wear off, exposing fresh cutting particles. As a result, the tool provides consistent deburring action throughout the length of the brush bristles. 

“We use the NamPower brushes just about every day and they continue to work just as well as they did on day one,” says Sun. FFJ