(GunReports.com) — The use of manual processes for surface finishing operations can be far more costly than properly automating the processes with the right tools. Repetitive motion tasks and other ergonomic deficiencies not only result in discomfort and injuries, but also in operator fatigue that shrinks productivity and compromises product quality.
In the case of RCBS, a member of ATK’s Security & Sporting Group and a leading producer of high-quality ammunition reloading equipment for over 60 years, concerns about just such a scenario involving a manual surface finishing operation resulted in a company goal to eliminate the risk of injuries and operator fatigue problems. It also led to significant, productivity and quality gains that were later estimated in the 60-70% range.
Among its product offerings, RCBS offers a variety of steel reloading dies for rifles and pistols. These dies are typically sold in sets for each caliber to be reloaded.
“We produce 100’s of thousands of these dies every year,” says Tim Taylor, a RCBS engineer. “So the achievement of consistent, high quality surface finish as well as avoidance of worker discomfort became a high priority that got a lot of attention.”
One of RCBS’s production processes involved the hand finishing of steel ammunition reloading die bores, where workers wrapped emery cloth on rods and polished the internal surface of the dies which required extensive manual labor on every die.
“The problems with this laborious process included some inconsistencies in the surface finishes,” explains Taylor. “But this resulted from ergonomic factors, and those were a big, big consideration. Because this was a repetitive-motion job, some workers experienced discomfort or problems with wrists, shoulders and backs.”
According to Taylor, this led RCBS to explore process improvements, including CNC equipment and tools.
At a trade show Taylor discovered what looked like a possible solution to his surface finishing and ergonomic requirements, a flexible ball-style honing brush made by Brush Research Manufacturing (BRM) that could be tailored to meet the die bore finishing and also attached to RCBS’s recently acquired CNC equipment.
The BRM tool, known as the Flex-Hone®, is used widely throughout industry for de-burring, plateau honing and deglazing. Available in many sizes and finishing materials, this unique brush-hone is composed of a shaft from which extended nylon filaments mounted with hundreds of abrasive grit globules attached. This customizable precision hone is used on materials ranging from soft nonferrous materials to carbide and ceramics to easily remove even microscopic shards and fragments, and is highly effective for edge blending, plateau honing, polishing and chamfer operations.
The company’s Flex-Hone for Firearms line already enjoys a positive reputation within the industry for extending the life of firearms. Beyond producing a beautiful finish, the hone removes the microscope “peaks” and “valleys” that can affect the performance and life of the firearm As a result, many firearm manufacturers are utilizing the Flex-Hone for Firearms in their final finish requirements.
In use, the Flex-Hone’s unique, flexible construction makes the tool both self-centering and self-adjusting to compensate for any wear. In accordance with the abrasive type and grit size, precise surface finishes ranging from mirror finishes to cross-hatching are automatically accomplished.
“After we decided to test the Flex-Hone, BRM gave us some recommendations and basic guidelines,” says Taylor. “I had a spare CNC mill, so I made up a fixture and started trying the process at different speeds and feeds. It took several process changes before we were able to consistently achieve our stringent surface finish requirements.”
BRM developed a series of fine grit models for die applications where RCBS used progressively finer grits to achieve their results.
Taylor says that the surface finish of the RCBS steel dies is sub-micron (roughness value) when they come off the machine. After the Flex-Hone finishing operation, the surface finish is improved by a factor of eight.
“Depending on the die, we use multiple hone sizes as well as varying grit materials and number of strokes,” Taylor says.
With the steel die finishing solution a success, RCBS decided to try the flexible hone solution on its dies that feature a much harder carbide material.
“On those we use a unique Flex-Hone brush with diamond crystal grit, and basically achieve the same type of results in terms of automation and finish,” Taylor says. “The finish looks like a mirror when we’re done.”
Initially, Taylor wrote a very basic honing program for the CNC mill. Once he decided to go online with the process, he wrote a parametric program to automate the process. Essentially, the CNC operator inputs four or five different parameters, e.g. bore length and ID. The CNC performs the necessary calculations, and then selects the corresponding Flex-Hone brush. Based on the input, the CNC also calculates the number of tool strokes, RPM, and so on.
“The new automated process is a real game changer,” Taylor says. “It is probably 60-70% more efficient than doing it by hand. Also, there was a substantial increase in quality. It is better and faster. But the ergonomic improvement – removal of the potential for operator discomfort and injury – alone would have been enough to justify the new process. For instance, there are no more repetitive motion injuries because there is no more repetitive motion in the polishing. So, that is a 100% improvement.”
Established in 1958, Brush Research Manufacturing has been solving difficult finishing problems with brushing technology in the sophisticated environments of nuclear energy, aerospace and computer technology as well as industrial applications.
For more information, contact Brush Research Manufacturing, Brush Research Mfg. Co., Inc., 4642 East Floral Drive, Los Angeles, CA 90022; Phone: (323) 261-2193; Fax: (323) 268-6587; email: info@brushresearch.com or visit the web site: www.BrushResearch.com.
