NC shop boosts its custom part business with dynamic milling toolpaths
When making over-the-counter and prescription soft-gel products, the dosage that fills each gel cap must be precise. It follows, then, that the system for metering the amount of formulation demands the same exacting level of precision. Such is the requirement at leading contract manufacturers of nutritional and pharmaceutical soft-gel products. To keep their metering pumps and production equipment accurate and reliable, they look to Progressive Tool & Manufacturing Inc. (Greensboro, NC).
“Contract manufacturers use custom machinery that pumps the medicine at very specific rates,” said Ryan Thompson, design engineer at Progressive Tool. “Obviously, accuracy and consistency are important. We’ve been making and refurbishing parts for medical metering pumps for more than a decade.”
Founded by brothers Daniel and Richard Thompson, Progressive Tool has been making specialty machine parts and gages in central North Carolina since 1984. Mostly, the company makes custom parts—in five to 10 part runs on average—rather than production machining. Its customers range from the medical industry to defense contractors to aerospace companies doing prototype testing, and more. “About once or twice a year, we make three or four hundred of something for a customer,” said Ryan. “But, we’re mainly a shop that makes the things that make, measure, or assemble things.”
Employees are Skilled Toolmakers
Progressive Tool is different from general machine shops. One thing that sets it apart, according to founder Richard “Dick” Thompson (Ryan’s father), is that all of the company’s employees are skilled toolmakers. “Even if they’re apprentices,” Dick said, “they’re toolmaker apprentices. Everyone can take a part from drawing to manufacturing.”
According to Dick, toolmakers do everything—from setting up the material and squaring up the parts to running the CNC machines to making the programs to doing their own setups and making their own fixtures. “We don’t have just machine operators or part-loaders,” he added.
The company supports its apprenticeship training in tool and die making, something it has done for 30 years. All shop employees have either finished a four-year apprenticeship or are now serving in one.
To make specialty parts, the company uses four-axis CNC milling machines, multiaxis CNC lathes, and CNC sinker and wire EDMs in concert with a powerful CAD/CAM software that allows toolmakers to generate machine tool programs that can achieve extremely tight tolerances.
“We use Mastercam [developed by CNC Software Inc., Tolland, CT] to control all of our CNC machines,” Dick said. Calling it “an essential link,” he noted that his company’s toolmakers don’t do any programming at the machine tool. “We do everything through the software.”
The company maintains a reputation as one of the highest quality shops in the area for custom parts. That reputation is earned, said Dick, by not compromising on accuracy. The majority of the jobs involve parts with very tight tolerances, he said. Citing a medical job as an example, Dick described the process Progressive Tool used on a metering pump: “We grind the slide valves flat and parallel to 0.0002″ [0.005 mm] over a part of hardened stainless 0.500″ × 2″ × 10″ [12.7 × 50.8 × 254 mm] to achieve a 6 µin. [0.1524 µm] finish.”
“We usually start with a solid model. We take it into Mastercam, create toolpaths, and use the original design geometry from the model to run our toolpaths,” said Dick. Though some customers use wire frame and design data from 2D drawings, Progressive Tool prefers to use solid models.
Upgrading to Dynamic Milling
Progressive Tool has been using Mastercam for about 20 years. At the same time that the company purchased a lathe with a sub-spindle, C and Y axes, and live tooling, it upgraded to Mastercam 2017. With that upgrade came new toolpath capabilities that wowed the toolmakers.
Dynamic milling (or Dynamic Motion technology) uses proprietary algorithms programmed into the software to automatically detect changes in the material as the tool cuts through. The tool remains engaged with the material, minimizing air cuts and allowing the machines to be pushed to full capacity. Thompson remembered how cautious his guys were. “Our toolmakers had seen demonstrations about Dynamic milling and were skeptical,” Dick said. But when they returned from training provided by Barefoot CNC (Morganton, NC), a Mastercam reseller, they never looked back.
At the same time, Dick noted that Dynamic milling doesn’t suit every part and every job. However, with the right application and the right cutting tools, Dynamic milling “not only works, it’s amazing,” he said. One part the company made in 304 stainless that used to take about an hour to rough and finish now takes 18 minutes. “It’s three or four times faster than our old way of doing it,” he said.
Another job—cutting plastic—is running 200 ipm, (5 m/min) spinning at 6000 rpm. And, he reported, when cutting aluminum and steel, the shop can run at speeds pushing 50 ipm (1.2 m/min), depending on the depth of cut. “Typically, they try to go between full diameter depth to 1½ times the diameter. If it’s a ¾” [19.05 mm] cutter, we’re comfortable going anywhere from ¾” to 1¼” deep,” Ryan noted.
Lately, toolmakers have been pushing some of the machines. “Everybody’s kind of pressing it to see how much faster we can go,” Ryan said.
Even at increased speeds, he described the shop’s newfound ability to rough and finish a part with the same tool as “the difference between night and day.” Instead of taking depth cuts with end mills, where it’s just taking off that bottom 0.050″ to 0.0100″ [1.27 to 0.254 mm], he said, “We are taking full depth of cuts and incremental stepovers at incredible speeds. In addition to running higher speeds, we’re actually extending tool life. And that’s saving us a bundle.”
Taking on More Jobs
The software, together with new production equipment, is paving the way for the company to take on more jobs and expand its business. “Even when we’re making 10 and 20 parts, the time saving is substantial,” said Ryan. Ryan noted that, because of the feeds and speeds possible, Progressive Tool will need to upgrade some older equipment. “Machines from the ‘80s just can’t keep up any more,” he said.
The younger Thompson went on to list other developments resulting from the 2017 software upgrade. The company’s lathe with a sub-spindle and multiaxis active live tooling has opened up many new business possibilities.
“With the mill-turn, we have parts with a dozen set-ups that we are now able to do in one setup. Not only are we saving time, but we can now accept more—and different—jobs!”
The software upgrade provided Progressive Tool with Mastercam’s Verify solid model cut verification/machine simulation feature. Dick called it “a huge time saver” on every toolpath the company runs. “I can think of a few projects where, while we were working on it using Verify, we were able to say, “No, wait! We can’t do it this way. We have to slip around and hit it from the backside, and are able to recreate new toolpaths efficiently.”
Today, backed by confidence in its combination of new equipment and new software, Progressive Tool is taking on projects with complex geometries and tight tolerances, expanding its long-time specialty work—custom parts.
The time-savings benefit of Dynamic milling alone, said Ryan, has put Progressive Tool in a better position to get more jobs. “Whether it’s medical, defense, automotive or nuclear, our customers rely on us to quote accurately and fairly. The software has even helped us with that.”
According to both Thompsons, upgrading to Mastercam 2017 helped reduce lead times, production times and extend tool life, helping Progressive Tool meet its business goals while upholding its reputation in custom parts.