Developing a million-hole drill: Supply Chain & Logistics

A missed business opportunity motivated West Ohio Tool Co. to develop a drill that can produce up to a million — or more — holes in die-cast aluminum without the need to refurbish the tool.

The development process, which took six years, began when a longtime automotive OEM customer wanted to switch from solid-carbide to PCD-edged tools to drill die-cast aluminum transmission cases, the Russells Point, Ohio-based toolmaker reported. At the time, West Ohio Tool didn’t offer that type of drill, so the customer went to another toolmaker.

Even high-quality carbide drills require regrinding after about 20,000 to 25,000 holes, and the drills become too short to use after about 10 regrinds.

“Each regrind costs money and means downtime,” said owner and founder Kerry Buchenroth. “PCD offered the possibility to minimize all of that, but it’s expensive and notoriously hard to work with.”

Grinding superhard PCD necessitates the use of diamond grinding wheels, which wear quickly because every amount of PCD removed from the workpiece equates to the same amount of diamond worn away from the wheel. However, because PCD contains cobalt, it conducts electricity and is suitable for EDMing. But that process can be time-consuming.

To grind or EDM PCD first requires brazing PCD to a carbide tool body. That’s typically not an issue because PCD has a carbide substrate that is brazed directly and efficiently onto the body, explained Kaci King, co-owner and chief financial officer. Yet the PCD that the toolmaker determined was best for the drill didn’t have a carbide substrate.

“If we couldn’t get the PCD wafer brazed onto the body,” she said, “we couldn’t even grind it.”

Therefore, West Ohio Tool needed suitable brazing equipment for the task and obtained a machine that the company felt would work.

“The equipment used is proprietary information,” King said. “We were the first one in the entire world to have that piece of equipment.”

She said after working with the equipment manufacturer for a week, West Ohio Tool didn’t achieve the desired results. Rather than immediately shipping back the machine, the toolmaker decided to experiment on its own for another week.

“Our team was able to find a way to get that done,” King said.

With that hurdle overcome, West Ohio Tool required a suitable grinding machine. She said a machine tool builder delivered a grinder that it claimed could do the job by grinding and eroding PCD, but the machine didn’t succeed. West Ohio Tool returned the grinder.