Tool Manufacturer Grows into Medical Tools via Precision Grinding
Article From: May 2021 Manufacturing Engineering, Alden Tool Co.
Companies often find success in specialization. That is true for Alden Tool Co. of Berlin, Conn., as well. The 74-year-old company found a niche in the surgical medical market. It developed the expertise needed over 30 years to meet that market’s unique requirements for surgical cutting tools, instruments, and components for the orthopedic, spinal, maxillofacial and cranial surgical specialties.
Like any contract manufacturer, Alden Tool’s production is low-volume and high-mix, producing engineered, custom surgical orthopedic drills, taps, and reamers. Alden does not provide catalog pricing or availability; each tool is custom designed. “We might provide 50 unique drills for a particular type of new surgical procedure,” said John Killeen, partner and CEO. “We manufacture to a customer’s blueprint. Often these medical device companies are very good at designing their implant. But they don’t have a lot of technical expertise on the cutting tool side.”
That is when Alden meets with its customer and goes through a design-for-manufacturing process to deliver the best tool at a competitive price. “A drill might be a drill, but there are idiosyncrasies for every customer that makes them different,” said Killeen.
He noted that his customers are primarily device OEMs. Once involved with a particular OEM, such end-customers tend to stick with that OEM, and in turn with Alden. Precision and fit are critical. It must be right 100 percent of the time.
Alden’s solutions must also be cost-effective. A significant challenge in converting “blueprints” is that, like most CNC machining today, Alden will receive a CAD model for the tool desired. However, “most CAD software is not tailored towards the cutting tool industry,” said Killeen. Add to that the fact that most engineering and technical schools do not feature training in CNC tool and cutter grinding, according to Killeen, and the challenge to making cutting tools is compounded. Design tools are lacking and expertise is needed.
That is where Rollomatic Inc., Mundelein, Illinois, Alden’s tool grinder supplier, enters the picture. Alden has six grinders for manufacturing these tools, employing three models of Rollomatic six-axis grinders—the GrindSmart 628XS, 629XS, and 630XS. “In many ways, a CNC tool grinder is a commodity item. Many suppliers can provide an acceptable device, but Rollomatic does a great job in specializing in the small tooling that’s used in the medical device sector,” said Killeen. There might be grinders with bigger envelopes or higher horsepower, but Rollomatic’s precision machines, coupled with expert servicing, hits a sweet spot in the market that Alden benefits from, according to Killeen. And Rollomatic offers more than the grinder.
For example, software supplied by Rollomatic helps with the challenge of converting a CAD model into a precision tool grinding program: VirtualGrind Pro comes with all Rollomatic GrindSmart five- and six-axis CNC grinding machines. “When they make changes to the software, they’re very upfront with you,” said Killeen. “They keep you in the loop and keep your machines up to date with the latest improvements.” According to Rollomatic, all software updates are free throughout a machine’s lifespan.
A number of features are worth noting, including a library of 70 examples that come with the software so that users like Alden can create variants of existing models. A job manager helps produce a series of tools with different geometries from a blank. Paths and operations are editable as functions. Just as important, the software integrates automatic compensation functionality by making measurements during the machining process for unattended production.
Since the programming is offline, the actual grinders can continue making parts (and money) while Alden engineers are setting up the next job. “We find it very useful to simulate what the actual end-item is going to look like and show that to our customers,” said Killeen. “When you simulate it, you’ll often find that it doesn’t look quite right or something’s off. And we’re able to provide that feedback well before the parts are in the machine, so we eliminate a lot of downtime. The ability to program offline allows us to get close to the net shape before we even start, eliminating the hours it takes to program a job directly on the machine.” When a test cut is made, as it must, it is much closer to the final product, with just a few adjustments needed, according to Killeen.
It wasn’t luck that made Rollomatic the tool grinder of choice for Alden. “We were approached in the early ‘90s by medical companies to help grind tools for surgical applications,” said Eric Schwarzenbach, president of Rollomatic Inc. The drills in orthopedic surgery tend to be long and thin, and made of stainless steel. This is quite a bit different than the comparatively “short and fat” drills made of carbide or tungsten alloy for other industrial applications.
“That brings challenges to the workholding and to the type of grinding that we apply to the tool,” said Schwarzenbach. “Sometimes they come to the grinding process with more runout than you would see [in an industrial] drill. [The medical community] needed to find a solution so that these long and thin parts could be, first of all, held in workholding for grinding with a consistent result, but also an automation solution so that those parts could be loaded and unloaded without any operator intervention in unattended mode.” Since long, thin stainless steel tools tend to be weak, any deflection during grinding will result in size inconsistencies. Finish is also critical. A bad finish will generate heat, “and in orthopedic procedures, anything above 50°F [10°C] at the tool alters the structure of the bone negatively,” said Schwarzenbach.
The solution Rollomatic developed concentrated on workholding, using a carefully chosen collet for driving the tool—a V-block to hold consistent concentricity with a steady rest that captures the part during grinding, according to Schwarzenbach. “When Alden came to us, we had a ready-made solution that Alden took advantage of,” he said.
Still, there was more than technology and a ready-made solution that went into Alden’s choice of tool grinder suppliers. “One of the real reasons that we decided on Rollomatic is the people in the company,” said Killeen. There are many competent suppliers of precision tool cutter grinders, he noted. “What separates Rollomatic in our mind from some of these other manufacturers is their people. Eric Schwarzenbach and his team, we feel, are truly dedicated to the success of the companies that they sell their equipment to.”