Hitting high-output target with custom tooling

Naples, Florida-based Azimuth Technology is a precision manufacturer of personal defense products, firearms, firearm components, and firearm accessories for the military, law enforcement, and civilian markets. The shop has decades of success in industries requiring precision-manufacturing capabilities where the stakes are high and product failure can mean the difference between life and death.

The bolt carriers Azimuth manufactures for military AR-15 rifles exemplify their commitment to producing high-stakes, precision-engineered products. The components are the heart of the rifle, and there’s no margin for error when it comes to accuracy and repeatability in manufacturing them. With the pressure on, the shop re-evaluated its tooling for a critical bolt carrier reaming operation.

Bolt carriers are made from 8620 steel, and the reamed hole houses the firing pin. There are three different diameters inside the part, and the two reamed holes measure 0.437" and 0.281" in diameter with an average surface finish requirement of Ra 32 and depth of about 5.00".

The holes are reamed on turning centers, and Azimuth was experiencing serious tool life and breakage issues with the long-reach, solid-carbide reamers used for the process. Because the tools were so rigid and lacked flexibility, they would unexpectedly break or produce crooked holes and Azimuth would have to scrap the whole part.

Finding a solution

Azimuth’s Turning Supervisor Danny Tang and Robotics Specialist Jesse Delashmet were confident there was a more efficient reaming option and reached out to tooling supplier Ceratizit. The two companies collaborated on a two-piece tool design to possibly provide a solution. However, actually producing one proved easier said than done, so Ceratizit mobilized Jim Dell and Kenny Green, engineering specialists for custom and precision tooling.

Dell and Green developed a two-piece 8" long tool with a tool-steel shank, threaded carbide helical reamer tip, and through-coolant capability. Once applied, Azimuth’s bolt carrier reaming precision and tool life shot up to new levels.

“I didn’t think the two-piece reamer design would present much of a challenge,” Tang says. “When we introduced the concept to a couple of tooling vendors, they refused to even consider developing the tool. Ceratizit was willing to take on the challenge and has been as invested in the tool’s success as we are.”

Cost savings, increased output

Once Azimuth incorporated the new Ceratizit tool, production went from 1,800 holes with the solid-carbide reamers – when those tools didn’t unexpectedly break – to more than 24,000 holes with one Ceratizit reamer. The shop experienced 54% cost savings at this operation based on an output of 300,000 bolt carriers per year.

Being threaded was the key to the new tool’s exceptional performance. While its cutting/reaming head is still carbide, the threaded steel shank provides flexibility for the tool to accurately follow the existing hole.

With that flexibility, the reamer finds the hole and compensates for any inconsistencies occurring with the turning machine’s turret. The carbide section is shorter so it’s stronger, while the steel body allows the tool to flex.

Range of benefits

Prior to the new reamer, operators would spend more than 30 minutes changing it out, while changing the tip of the Ceratizit tool takes 10 seconds.

“We were not only losing machining and production time,” Tang says, “we were forced to pull our skilled individuals off other jobs to change out the broken reamers. This is because when a tool snaps in half, you must recheck and reset all aspects of the operation.”

Delashmet says the original reamers were also expensive to replace, which compounded the costs of scrap parts and unpredictable tool life.

Additionally, with the newly developed Ceratizit tool, the shop can run the reaming operation 3x faster. Combined with the quicker setups, Azimuth benefits from shorter part cycle times as well. Plus, since the tool is a step reamer it helps lower cost per part by reaming two diameters simultaneously as well as finishing the bottoms of each.

“Our robotic cells basically run uninterrupted and shaving off even a few seconds from the reaming operation has a huge impact on output,” Delashmet adds. “There’s very little downtime in between cycles, so every second counts in the cells.”

Automating operations

Azimuth performs the first set of operations – facing, O.D. turning, drilling, and reaming – on its bolt carriers in two constantly running automated cells. Within the cells, one robot tends to two turning machines – loading and unloading parts from trays holding 96 pieces each. Once a tray of parts is completed, one operator who tends both cells simply slides the completed tray out and replaces it with a new one.

Automated production and the geometries of the bolt carrier holes make chip control/evacuation a critical aspect of the reaming operation. The straight two flutes of the previous reamers hindered chip evacuation, and if there were any irregularities in the part hole, those tools also experienced instability, vibration, and flute chipping. All could cause poor hole surface quality.

Conversely, the Ceratizit two-piece reamer has helical flutes efficiently channeling chips up and out of the holes. The new tool also has multiple flutes, so cutting is more evenly distributed, making it more stable and less prone to chipping due to vibration.

Relationships matter

When Azimuth decides to re-evaluate a process such as the reaming operation, what often triggers the decision is tool breakage and any other factor that creates production stoppages. Azimuth gives their employees free reign to change or adjust processes to optimize production.

“We’re never forced to follow a specific procedure,” Tang says. “If a problem arises, we’re empowered to think outside the box, which is exactly what we did with the Ceratizit reamer.”

Tang recognizes Azimuth’s strong relationship with Ceratizit’s Technical Sales Engineer Sean Delaney. “It’s because of Sean that we often recognize where we could be solving a problem or simply optimizing a process, and we do a lot of tool testing with him as well. For us, initial cost isn’t the deciding factor because we’re more than willing to invest in a tool that performs well, improves operations, and boosts output. Ceratizit came through on all three.”

Azimuth Technology https://www.azimuthtechnology.com

Ceratizit https://www.ceratizit.com

2024 SHOT Show Supplier Showcase Booth #51512