No Hands Required for Deburring

Parts manufacturers achieve a variety of advantages when performing CNC deburring in a machining center or robotic setup instead of manually. The gains include deburring with a high level of efficiency and repeatability and extended tool life. Deburring by hand is also a tedious operation that workers do not look forward to performing.

“The more you can get done in your equipment rather than by hand is definitely where everyone is heading,” said Steve Alviti Jr., vice president of Bel Air Finishing Supply Corp. in North Kingstown, Rhode Island.

Nonetheless, there are still plenty of people deburring manually, he added. “We see a lot of that every day.”

For medium to “gross” deburring, Bel Air Finishing supplies the FM-DBR7-1D and FM-DBR7-SC-ADJ series CNC deburring toolholders from Kato Machinery Co. Ltd. in Japan. According to the company, the former, or 1D, series is suitable for automated front- and back-side edge finishing of machined features, such as holes, in a single pass while the latter series is for front-side deburring and chamfering in CNC machining centers and automated systems.

“You’re saving a lot of time after your machining process by doing that deburring in the CNC machine,” Alviti said.

Compared to using the holders in a vertical or horizontal machining center, he noted that about 10 to 15 percent of end users debur with the tools in a robotic system. “I would tailor it to whatever the client’s solution is.”

The 1D series provides 10 mm (0.39″) of floating tension and compression to compensate for dimensional tolerances and prevent chatter, Alviti explained, and the fully adjustable spring-load SC-ADJ series provides 10 mm (0.39″) of floating compression. “You’re able to simplify your process into one step with one tool.”

Floating CNC deburring toolholders use a spring-loaded or telescopic mechanism that allows the cutting tool to move axially while maintaining consistent contact with the part. The 1D series features three spring-load options for controlled pressure: yellow (soft), green (medium) and red (hard). Using the yellow option leaves a smaller landing on the targeted edge than the other two, while the red one leaves the largest, or thickest, landing on the part edge.

Alviti added that if an end user is deburring different types of edges on one component or deburring different types of parts, adjustments can be made on the toolholder without removing it. “The harder that you have that spring tension, the more aggressive deburring you’re getting, plus the larger chamfer that you leave behind.”

Another way to adjust the spring-loaded capabilities of those holders is by changing the machining parameters, Alviti said. “If you want the chamfer to become smaller on each step, you would increase the feed and speed. If you want the chamfer to become larger, you would reduce the feed and speed.”

Bel Air Finishing will not perform deburring trials in a CNC machine, but the company will conduct evaluations to determine if the deburring toolholders are an appropriate solution, he said. The majority of the time a toolholder is suitable, but it can be overkill when a shop already has a post process in place that can perform the needed deburring. “You don’t want to add an extra step in your machining op when you don’t have to.”

When the application is appropriate, such as deburring a high volume of cast automotive parts like housings and hydraulic pumps, Alviti said a CNC deburring toolholder is an effective tool for the job. “We haven’t seen a burr that’s been bad enough to beat it.”

Prepare to Float

Tapmatic Corp. is another provider of toolholders for CNC deburring. The company offers the DeBurr-Z holder with straight shank and ER collet that floats in both the compression and extension direction, allowing the deburring tool to follow the top edges or underside edges of the workpiece even when these edges are not clearly defined, Tapmatic reports.

Floating in the compression direction, said Mark Johnson, president of the Post Falls, Idaho, toolmaker, allows the burr cutting tool to follow and deburr the top edge of the workpiece. “You don’t have to program it exactly to follow the edge because the holder has 10 mm of compression float, maintaining that contact as long as it’s within that 10 mm range.”

Conversely, the tension float, which is also up to 10 mm, allows deburring of the underside edge, he added. A common application is deburring castings, such as cast iron, steel and aluminum ones for the automotive and aerospace industries.

When deburring a workpiece with a high level of hardness or when a large edge break is required, Johnson explained that an end user can adjust the preload of both the compression spring and the extension spring without replacing springs or taking anything apart. “It’s all adjusted through a collar, or sleeve, on the body of the DeBurr-Z. You don’t have to remove it from the machine or from the shank.”

With a deburring tool in position, the spindle speed is typically from 5,000 rpm to a maximum of 10,000 rpm, and the feed rate is anywhere from about 30 to 80 ipm, depending on the workpiece material and the desired edge break, he said.