Constant velocity controllers (CVCs) are developed and marketed by Miceli Technologies Inc. (MTI; Essex, ON, Canada). According to the company, a CVC processes a minimum of 50,000 blocks of code per second in 8-simultaneous-axis machining. Compare that to established CNCs and their processing rates (about 3000 blocks of code per second, and only in three axes), and you understand why MTI founder Carlo Miceli is so convinced his company's development will have huge ramifications for any company that needs to cut metal. He's even offering a money-back guarantee if you don't see huge improvements.

CVCs now have a track record of a few years. As Miceli relates in this interview, the results so far have been impressive with the CVC controllers maintaining an average feed rate above 90% of the programmed feed rate. The company's website includes references to some companies that already use CVCs on their machine tools.

PlasticsToday: Why does the world need another machine tool controller?

Carlo Miceli: The existing controllers and the ways in which they manage machine tools are unsatisfactory. The vast majority of machine tools rarely operate at anywhere near the feeds, speeds and metal-removal rates for which they are programmed-let alone their advertised capabilities.

Because there have been no real options until now, users and owners just put up with it. MTI's innovation, constant velocity cutting or CVC, is the first commercially viable change in the status quo.

PT: So, what is the innovation?

CM: In a nutshell, CNC hardware and software working in sync to maintain a constant metal-removal rate. With ordinary CNCs, as the machine spindle goes into a turn or around an inside corner, the axis drives slow down and then speed up again. The innovation in CVC technology is to keep the metal-removal rate constant (and high), allowing only a few percentage points' variation. This speeds up chipmaking and produces better surface finishes.

Existing machine tool controllers are unable to maintain a constant velocity in axis-drive feed rates (distance per minute) and spindle speed (revolutions per minute or RPM). This is because existing controllers cannot process all the necessary math data efficiently. They have to slow down drastically whenever geometry requires a sharp change in direction, often to between say 5% and 10% of what was programmed. In fact, the highest average feed rate achieved by our competitors is consistently under 50% of what was programmed. Our CVC controller maintains an average feed rate always above 90% of the programmed feed rate. This is huge!

In large, complicated machining jobs, productivity takes this big hit tens of thousands of times, even hundreds of thousands, at each direction change. This is true even in a relatively small mold job with a million blocks of code in its machining program. Many owners wrongly blame their machine tools. The real culprits are the controls. This is simply an inability of its control to "think" fast enough. As a matter of simple physics, no machine tool can ever be built that can outperform the MTI controller.

 MTI is applying for Canadian and U.S. registered trademarks for ConstantVelocityController.

PT: What are the economics?

CM: Maintaining specified metal-removal rates with CVC maximizes surface quality in finishing cuts. MTI users tell us they have eliminated nearly all secondary finishing operations. In roughing and semi-finish machining, CVC maximizes metal removal rates, getting jobs done at least 20% faster, and as much as 75% faster.

Consistent metal removal rates regularly extend cutting-tool life as much as 300% and always by more than 50%.

Maintenance and support costs are also lower. Owners of older CNCs pay high prices for custom-made, sole-source replacement parts that are available only from the control's manufacturers. One customer told me he came to MTI because of an OEM price quote of $9000 for a memory upgrade, a single circuit board with only one supplier.

CVC also takes the lingering risks out of unattended machining, running jobs after everyone has gone home. We follow the MTConnect initiative--a new data-communication protocol for remote real-time digital monitoring--and all the relevant ISO standards. One of our CVCs is being used to refine advanced machining techniques at TechSolve in Cincinnati, formerly the Institute for Advanced Manufacturing Sciences.

Our users tell us that CVC's smooth motion control reduces the stresses on the machine tool's mechanical components, and eliminates vibration. That means much longer times between failures, lower maintenance costs, more machine uptime / availability and, again, greater productivity. It's like the difference in wear-and-tear on your vehicle between stop-and-go city driving and the sustained speeds of the open highway.

This also has major advantages in cutting tool life.

PT: What about returns on investment?

CM: Our customers tell us they recoup their CVC investments in six to nine months. As ROI goes, that's pretty dramatic. [Laughs] Maybe we should raise our prices.

Our customers are conservative business owners who must keep all their assets working for their customers. An important part of CVC's appeal is helping ensure that the customer's design intent--tight tolerances, for example, and high-quality surface finishes--pass unscathed into the tooling and machined parts.  

Delivered on time, too.

PT: Any ROI statistics?

CM: Not in a general sense but our users regularly tell us things like "standing here looking at the machine tool make chips without any scientific measurement, productivity is noticeably better." Beyond that, no two companies measure return on investment the same way.

Of course, they all include cycle times, floor-to-floor times, decreased scrap rates, cutting tool life, productivity of the machine and its operators, machine utilization and so on. But the values and relative weights they assign to each determine how they count their costs, how they structure their overhead, and their business model.

PT: Then what do you tell prospects who ask about ROI?

CM: We direct them the ROI calculator on out Website at miceli-technologies.com/productsROI.php.

More importantly, however, we offer a complete money-back guarantee. As we state on our Website miceli-technologies.com/productsGuarantee.php: "Your machine tool will cut complex 3D geometry in half the time it did before the MTI retrofit, based on the industry-standard Mercedes Test geometry. We guarantee that you can expect a 100% improvement in performance. Your machine will run extremely smooth and quiet."

PT: Are there any disadvantages in CVC, any challenges the new technology presents to users and machine owners?

CM: None. Not a single one. Zip. Nada.

PT: Benefits to programmers?

CM: CVC's accuracy gives programmers a new tool in their productivity toolkits. Almost immediately, that raises their expectations. They re-evaluate traditional cutting practices and constraints. Old assumptions about capabilities are looked at with a fresh set of eyes.

PT: Do you have an example?

CM: Most programmers today still specify a ±0.001-inch tolerance for chordal deviation in machining curved surfaces. CVC lets them go to a tenth, ±0.0001 inch, or even better.

They can say good-bye to secondary operations for surface finishing. This is a big new ability for programmers, even with existing capabilities for tracking cutter deflection and compensating for temperature change and other variables. Without CVC, tightening tolerances this dramatically would make even the best of today's CNCs run too slowly to maximize machine tool performance.

This means the programmer can define his geometry better than ever before without sacrificing time. The more data you throw at CVC, the better the cutter paths and the finer, tighter speed and motion control.

PT: How did you develop the basics of the control?

CM: I graduated from St. Clair College in Windsor, [Ontario] where I later became a professor. I taught in the CAD/CAM, CAE and CNC curriculum there for 10 years. In 1997 I joined a sales and service organization to represent a leading CAD/CAM software developer. We were their No. 1 value-added reseller in the world four years in a row. I have worked for several automotive moldmakers as an engineer where complex tooling was always a challenge and also spent many years in machine-tool field service.

This experience gave me a deep understanding of how machine tools and CNCs actually connect, and how they interact with CAM systems. Over the years, much improvement was made in our customers' productivity.

However, time and again a bottleneck made itself obvious-the average feed rate of machine tools. No matter how new the machine or what options were installed on the control, machining complex geometry was painfully slow. At every change in direction, the machine's feed rate plummeted and zoomed back up again.

Increasing controller memory and using "look ahead" technology did not improve the situation enough: fundamental changes were needed. As the years passed and experience accumulated, the customer's frustrations cropped up over and over. Much of their machining equipment fell short of its billings. Equally obvious: most of the machine tool industry was not terribly interested in addressing those frustrations.

After several years of thorough analysis we came to the conclusion that the CNC controls on the market were not able to move machine tools anywhere close to their designed mechanical capabilities; the iron was capable of so much more than the electronics. From this discovery, the MTI Constant Velocity Controller (CVC) was born.

In 2002 MTI turned all its resources to bear on the task of re-thinking how CNC controllers were engineered. Input was gathered from all sectors of the industry. Ideas were tested and myths were disproved. Many prototypes were installed in the field and we gathered years of feedback from operators, managers and technicians. The final result is an extremely robust and reliable CVC offering. The MTI controller accomplishes our initial goal of running a machine tool at an average feed rate that reflects the true capabilities of the iron it is attached to, while always respecting the machine tool's intended design specifications.

PT: Why does look-ahead capability figure so prominently in CVC?

CM: Look-ahead means that the control can "see" several steps ahead of where it is and to "know" what lies ahead in thousands of blocks of program code. That's the only way to keep axis feeds and spindle speeds balanced.

Our controls can read up to 50,000 blocks of program code per second and our look-ahead algorithms have 80 high-accuracy smart buffers. No other controller comes close but these "specs" don't really tell the story.

All modern CNCs have some look-ahead capability. Our major competitors have look-ahead algorithms. And all of them make some calculations about how to behave when they get to a point where directional change is needed.

The high code-reading speed and those 80 buffers let MTI's CVCs do all the look-ahead before the machine-tool operator ever hits Cycle Start. This is a radically new approach to look-ahead and it is completely different than what our competitors do. Because the CVC has done all the calculations before the program runs, it gives us the ability to adjust and finesse the cutter paths if needed.

PT: You've been in business for a few years but have stayed somewhat below the radar. Why?

CM: We have had more than enough to do in building our business. We long ago realized we needed to tightly control our growth to what our people and finances can sustain. MTI has no debt.

MTI has chosen where and with whom it works very carefully ... and that is our route to brand name recognition. We have raised the bar in machining and triggered a paradigm shift in controls. It takes time to do all this properly, and to overcome the inevitable skepticism.

PT: Why hasn't anyone else jumped on this?

CM: The controllers companies are jumping on it. They are always looking at improving algorithms and adding bells and whistles but they have a deep-seated problem. Their technologies go back decades to the original building blocks of CNC.

The architectures of the best of today's controllers represent the work of thousands of engineers. But with any platform, the passage of time exposes limitations. Some builders have been painted into corners and are running out of options.

The big challenge for them is do they throw away 40 years of work, scrap everything they know, and start all over again? The answer is no. It's like trying to add 10 new floors to an old five-storey building. They have a structure in place that ties their hands. This is where we feel we have a sustainable competitive advantage.

PT: Can you point to some advantages CVC has over a modern CNC?

CM: There are many but let's look at just one-cutting tool life. Constant-velocity cutting eliminates all but the smallest ups and downs in the chip load on the cutting tool's flutes. This minimizes shock damage, which is the single largest determining factor in cutter longevity. Every customer reports a considerable improvement in cutter life span, some as much as 300%.

Moreover, outside corners will be razor sharp, inside radii will not be gouged and surfaces will be smooth and clean. The requisite accuracy and precision is due to the MTI control processing data to 15 decimal places. So cutter life is much longer and surface finishes are better.

PT: How does CVC stack up against retrofitting conventional CNCs?

CM: We are price-competitive with the high-end conventional controls but far more cost-effective. Our customers' ROI is significantly shorter, as I mentioned, and very different in that we provide much greater product flexibility.

PT: Is this an OEM business or a retrofit business?

CM: Both. We started with retrofits for moldmakers and tooling suppliers, where surface-finish specs are the tightest. These early jobs gave us invaluable insights as to how machine tools and controls interface. We currently do all our own turnkey retrofits locally. We have retrofitters in place in other parts of the U.S and Canada.

We have a very successful OEM agreement with GBI Cincinnati in Ohio. This gives GBI's Revolution machine tools a significant competitive advantage.