Growing in Productivity and Precision

Founded as the Carbide Grinding Co. 50 years ago, the Waukesha, Wisconsin-based firm triggered a bit of a rumble in the jungle of its own when second generation owner Kevin Cranker introduced the variable-helix, variable- index Gorilla Mill in 2005. The tool was such a hit that the company changed its name.

Now known as Gorilla Mill, the company is a three-shift operation in a 24,000-sq.-ft. facility with dozens of 5-axis tool grinders, a full blank prep department, QC equipment, and centralized coolant filtration and mist extraction, with all utility lines running in trenches underneath the production floor.

ANCA Inc. in Wixom, Michigan, played a significant role in developing the tool, said Operations Manager Nathan Cranker. “In a lot of ways, it was thanks to ANCA that we were able to develop the Gorilla Mill. Because even back on our RGX and TG7 machines, which are ancient, their software had the capability to manufacture the parts we dreamt up.”

Cranker also noted ANCA’s frequent software upgrades, which boost tool throughput. “When we found ANCA, it just stuck immediately. The software was very user friendly, so we were able to understand it quickly.”

There are other endmills on the market with similar features, but the Gorilla Mill’s geometry is patented and remains a challenge for grinders from other builders, Cranker said.

With a few frustrating exceptions, he added that since the toolmaker first switched to CNC, Gorilla Mill has built its business on ANCA machines, including the new MX7 Ultra.

Gorilla Mill already had a stable of MX7 Linear machines, which continue to perform well. So why the Ultra? “We have aerospace customers who demand plus zero and minus five ten-thousandths of an inch on the diameter and an end form on ballnose tools,” Cranker said. “And the tolerances are getting tighter … It seems the MX7 Ultra was designed for situations like this. [Tools] fluctuate maybe a tenth or two here or there, and only over a long period of time.”

ANCA reports that the MX7 Ultra can hold such tight tolerances over long production runs without operator intervention. First, Cranker said, the machine’s control resolution is 1 nm, which is 10 to 100 times finer than competing machines, including the MX7 Linear. Another bit of “magic” is the new control algorithm, which capitalizes on the improved control resolution to move through contours quickly and precisely. The Ultra also has Motor Temperature Control (MTC), a patented system that varies the current to the motor, rather than relying on liquid running through a chiller, to keep the spindle within 0.5° C. This minimizes spindle growth even as grinding conditions change.

“The original MX7 is a fantastic machine, but — and I don’t say this in any way to throw a negative light — it requires a little more hands-on maintenance from the operators to make tight tolerance tools in high volume,” Cranker said.