CNC Grinding and Automation Bring Unexpected Benefits

Launched in 1935 and in business at the same 20,000-sq-ft facility in Muskegon, Michigan, since 1942, Precision Tool Co. is, in some ways, about as old school as a shop can get. But in other, more significant ways, it has had the willingness to change with the times, and nowhere has that paid off more than in its adoption of CNC tool grinding technology.

The shop acquired its first CNC tool grinder in 1999 and hasn’t looked back since. In fact, Precision is now home to five state-of-the-art CNC grinding machines, some with integrated automation capabilities that have opened up new avenues of business.

The switch to CNC – and the lights-out production gained with the automation system – has had a far-reaching impact on the types of tools Precision now provides for its customers in the aerospace, automotive and other industries, as well as how those tools are manufactured.

For decades, Precision used manual grinding machines to produce mostly flat form tools, with its rotary tooling business limited to mostly regrinding work. CNC grinding would allow it to actually produce rotary tools, as well as grind lathe tools, insert forms and brazed tooling.

Precision’s first CNC tool grinding machine was a Walter Helitronic Mini Power from United Grinding. Business continued to grow, and about a year later, the the shop purchased its second Walter CNC grinder, a Power R machine.

The Helitronic Mini Power machine grinds and sharpens tools from 1 mm to 100 mm in diameter and up to 255 mm long, enabling production of complex tool geometries in a single clamping cycles. As slightly larger machine, the Power R uses up to six wheels to grind complex tools from 3 mm to 320 mm in diameter and up to 350 mm in length.

“We bought the Power R basically as a tool regrinding machine but discovered we could also use it to manufacture tools from blanks,” said Steven Henderson and Timothy Reck, co-managers at Precision Tool. “The machine enabled us to move from mainly regrinding to quoting and manufacturing new specialty tools.”

Both customer demand for specialty tooling and Precision’s comfort level with CNC technology soared to the point where more CNC grinders became a necessity. The shop then purchased a third Walter machine, a Helitronic Power that came equipped with automation capability in the form of a Walter Eco Loader.

Able to hold up to 20 tools, the fully integrated Eco Loader is mounted on the machine’s work table and features a gripper integrated into the grinding head, all of which maintains a small overall footprint and reduces load/unload cycle time. While the easy-to-use automation system was impressive, it initially had Henderson and Reck scratching their heads as to exactly where its capability fit in to the shop’s tool processing operations.

“The Eco loader came standard with the machine,” explained Henderson. “At the time, we thought that there may be chance to get some use out of it, but we basically considered it a feature more beneficial to those shops with extreme high volumes, unlike our medium to low lot size jobs.”

That thinking quickly turned around as Precision discovered that the loader enabled it to bid on and win a wider variety of jobs, including higher-volume production work. “While we are a specialty shop,” said Henderson, “we do get orders for 200, 300, 500 or 600 pieces, and the autoloader made us more efficient on those somewhat longer production runs.”

Purchased in 2012, the shop’s fourth Walter Helitronic machine also came equipped with integrated automation – an Eco Loader Plus that handles up to 165 tools depending on diameter. The machine also featured a steady rest and dual-pressure coolant pump, allowing processing larger size workpieces.

The shop’s fifth and most recent machine is a Walter Helitronic Mini Automation, which features an integrated Fanuc robotic arm for the highest degree of automation. The system automatically loads and unloads up to 1,500 stored tools ranging in size from 1 mm to 16 mm in diameter.

“This degree of automation with the Helitronic Mini Automation provides maximum flexibility for our lights-out production,” said Henderson. “Most of our jobs are 9.525 mm in diameter and smaller, so we can load hundreds of parts on the machine at a time.”

Precision’s stable of five CNC grinding machines, especially those with built-in automation, has resulted in far-reaching changes in its business approach. From a strictly manual grinding shop, the company has evolved to the point where about 75 percent of production is done exclusively on the CNC machines. A few jobs, such as flat form tools, mining bits and carbide-tipped drills, are still done manually, while roughly 10 percent of all jobs require both manual and CNC grinding operations.

“Of course the type of work has changed over the years,” said Henderson. “Before 1999, rotary tools made up a very small part of our business, probably less than 20 percent. Now, 90 percent of our production is rotary tools. But we still rely on manual machines.”

For its aerospace customers, Precision produces drills and reamers ranging from conventional step drills to specials for simultaneous machining of multiple diameters. “None of them are something you can just order out of a catalog – they all have special features geometry wise,” Henderson said. “Work materials include high-speed steel and carbide, as well as some brazed tools. But the majority is carbide.”

The shop’s aerospace tools are used in some tough applications – mainly machining sandwich composites composed of layers of mixed materials such as graphite and titanium. The tools require special geometries to stand up to mixed-material machining, and the Tool Studio software that runs on Precision’s three newest Walter machines facilitates fast and easy programming of variable helices and other special tool features.

Precision now runs lights-out for about 200 hours per month. As a result, the company has doubled its output while creating new high-tech jobs. Henderson credits the Walter machines’ automation capabilities with much of that production increase.

“We went from using automation here and there to being dependent on it,” he said. “It quickly became a key factor we incorporated into our business outlook, and we actively seek out work/jobs specifically for it.”

Automation and CNC capability also give the company the ability to respond to customer requests for rush tooling jobs. “Typical lead time for a batch of aerospace tools is four to five weeks, but if a customer has a special request that they need, for example, in a week, we can bail them out,” said Henderson.

“Walter CNC grinding and automation definitely changed our idea of what we can do and how we do it,” Henderson said. “We still need people who are knowledgeable about conventional grinding processes – some operations have to be done on manual machines for one reason or another. And we believe that our strong background in the conventional, manual equipment and now decades of solid experience with CNC is what differentiates us from the competition. Not every tool shop out there has that special combination of skill and talent to offer.”

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