Turning Heads

By Editor 09-Apr-2020

Seeing was believing at this Okuma open house event

Most anyone who’s worked in a machine shop for any length of time has at some point attended a trade show or machine tool distributor’s open house. There they saw canned demonstrations of CNC machines busily carving up chunks of brass, mild steel, or aluminum into business card holders and tic-tac-toe games. And while these giveaway trinkets are certainly fun stuff, suitable for lining the tops of desktops and toolboxes alike, wouldn’t it be refreshing to see some real parts being machined, preferably from a tough material like Inconel, titanium or stainless steel?

Coming together in Charlotte

If you were part of Okuma’s Winter Showcase event in North Carolina last year, you saw exactly that. Early in December, the machine tool builder again pulled out all the stops, hosting 600+ customers, journalists, and tire-kickers to two days of decidedly-not-canned machining demonstrations.

The attendees were treated to more than two dozen CNC machine tools under power, most of them making chips. These included an MU-8000V LASER EX super multitasker with laser metal deposition, the company’s first such hybrid additive machine, and the GENOS M460V-5AX, a trunnion-style 5-axis vertical machining center offering high productivity, a small footprint, and a surprisingly low-price tag for a machine tool of this caliber.

There was also an LB3000 EX-II lathe with barfeed vibration detection, a MULTUS B300II turn-mill center with collaborative robot part handling, MA-500HII horizontal and MCR-A5CII double-column machining centers, and a MULTUS U3000 multitasking machine with ATC, sub-spindle and lower turret.

An impressive lineup, to be sure, but there was one demo that had a large number of show attendees talking, even those responsible for setting it up. “It was pretty cool to see, especially when you consider that we were cutting titanium, a very hard and difficult-to-machine material,” says Okuma applications engineer Lee Johnston.

Use the Force

He’s talking about CGTech’s Force, a physics-based NC program optimization module that works within the company’s flagship VERICUT toolpath simulation software. Working with representatives from CGTech and Sandvik Coromant, Johnston used the program to give show goers something far more exciting than the usual machine demonstration, programming a Ti-6Al-4V titanium bracket for an aerospace customer, then optimizing its toolpaths with VERICUT Force.

“We had the same demo on two vises so we could run them side by side, one with the standard program and one that was optimized,” says Johnston. “It was a good test. We reduced cycle time from an hour to just under 40 minutes, which was remarkable enough on its own, but you could also hear and see the difference in how the tools were cutting, and tell that the optimized program was easier on the machine. This is probably the best thing to happen to programming since trochoidal toolpaths.”

Above average

VERICUT Product Specialist Pete Haas explains that Force works by analyzing the NC toolpath, evaluating the changing cutting conditions and increasing or decreasing the feedrate to achieve the ideal chip thickness for any given material. Compared to CAM systems and online machining calculators, which attempt to determine the average chip thickness and base the programmed feedrate on that, Force calculates the optimal feedrate for every single line of machining code.

“To give a simple example, think about driving to work each morning,” Haas says. “You encounter straight sections, curves, and sharp turns, and have to slow down or speed up depending on the road conditions. Machining also involves constantly changing conditions, but CAM systems don’t account for this. They generate a single feedrate that may be too aggressive on tight turns and too slow on the straightaways. Force, on the other hand, uses physics to calculate cut by cut throughout the changing conditions and determine the optimal feedrates.”

The result, according to Haas, is greatly reduced cycle time, improved tool life, better part quality, and less wear and tear on CNC machine tools. It works on any material and any machine, and can even be used on legacy programs.

A healthy dose of skepticism

Johnston wasn’t the only one surprised by Force’s capabilities. Even CGTech Technical Support Engineer Chris Davala, someone with 20 years of experience as a machinist and programmer and who now spends his days working with VERICUT customers across the country, said the demo was an eye opener.

“To be honest, I was a little skeptical of all that I’d heard about Force,” he says. “This was my first hands-on experience with the product, and it’s not that I didn’t have faith in the people who developed it, but there were some bold claims made about the potential gains. I can truly say that, after seeing Force in action, it’s made a believer out of me.”

That’s an easy thing to say for someone employed by the product’s developer. Yet Sandvik Coromant MTS specialist Richard Howard worked alongside Davala and Johnston while setting up the demo. He supplied the cutting tools and toolholders used for the demo, specified the initial machining parameters, and backs up what they say.

“As a tooling specialist, I am extremely impressed with how ‘spot on’ the Force software is,” he says. “CGTech has done an amazing job of optimizing programs while taking into consideration tooling geometries and resulting loads. Anyone interested in higher efficiency and prolonging tool life should look into this. Force is one of the most interesting and innovative developments I have seen.”

Who needs it?

Anyone familiar with Okuma machine technology might consider Force unnecessary. That’s because the OSP control offers advanced features such as Machining Navi, SERVONAVI, Super-NURBS, and adaptive machining technology. How can a 3rd-party software package make a top-notch machine tool perform even better? There are several answers to that question:

  • Force has the ability to break up the NC code into smaller bites, adjusting feedrates as necessary to make the chip thickness both constant and maximized.
  • Its optimization capabilities are proactive rather than reactive, so everyone knows what to expect before pushing the cycle start button. Machine tools and CAM systems can’t do that.
  • Performance issues are clearly identified up front, and the programmer can drill into various graphs that illustrate projected cutting forces, chip thickness, feedrates, and more.
  • For new materials, new machine tools and cutters, or even new programmers, Force eliminates the guess work that would otherwise occur.

The result is an NC program that’s both safer and more predictable, with low risk of tool breakage or scrapped parts. Operators have more confidence. Lights-out machining is made easier. Profit margins are improved. Best of all, Force-optimized toolpaths “save a great deal of time during roughing,” says Sandvik’s Howard. Parts are machined more quickly, and cutting tools last much longer.

The big picture

Pete Haas sums it up like this: “Force provides the NC programmer with information he or she has never had before. You can quickly and easily visualize what’s happening cut-by-cut as the tool moves through the material, and it’s now possible to visualize excessive forces, inefficient cutting parameters, metal removal rate, power consumption, torque, and tool deflection. Force charts also expose cutting condition improvement opportunities. With a single click on the Force chart, the user is taken to the exact location in the program and to the graphical review window for further analysis. The end result is full utilization of the cutting tool as well as complete leveraging of the machine tool’s capabilities.”

Okuma’s Lee Johnston agrees. “Force definitely received lots of attention at the event,” he says. “I think it was the first time that most of the people there saw it in action, and I heard over and over again how this is game-changing technology. In many ways, it’s exactly that. We were cutting titanium and saw significant improvement, but I think Force is just as suitable for machining easier materials like aluminum, and for other general purpose work. I look forward to using it on future projects.”

Pull quotes

“Force is probably the best thing to happen to programming since trochoidal toolpaths.”

“I can truly say that, after seeing Force in action, it’s made a believer out of me.”

“It’s optimization capabilities are proactive rather than reactive. Machine tools and CAM systems can’t do that.”

“Force provides the NC programmer with information he or she has never had before.”

“We don’t just improve the existing NC program we expose the potential for greater improvements and make it happen – true optimization.”