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Kronos Energy Solutions operator using their Flow waterjet
Flow waterjet at Kronos manufacturing facility
Kronos operator loading material on to their Flow waterjet

Kronos Energy Solutions

Highly Accurate Waterjet Expands Renewable Energy Manufacturer's Capabilities

An alternative energy supplier has a goal

To help people by producing and delivering affordable alternatives to high cost green efforts.

That is why they were pleased to learn that environmentally friendly waterjet cutting has matured to meet their exacting requirements for production, custom and prototyping work. 

Outsourcing is costly

Kronos Energy Solutions of Cordova, TN, designs and manufactures vertical axis, small wind turbines for rural, urban and marine environments. John Bogensberger, president and CEO of Kronos, had years of experience working in a high production manufacturing operation building door units from light gauge metal. 

"I first saw waterjets at an IMTS show in 1998. I was intrigued with the process because it produced no toxic gases, dust, or dangerous chemicals. But I felt I couldn’t justify them in a high production environment cutting sheet metal."

In 2009, Bogensberger started Kronos Energy Solutions and originally outsourced much of their work. Outsourcing is an excellent way for new companies to have parts cut and machined without the upfront capital investment. They can then focus on fabricating the parts into the final end product while testing various machine tool processes before making a final investment decision.

However, outsourcing can also cause delays if the shop doesn't get the part right or if you need to make design changes. Kronos was also finding that the secondary processing to remove the heat affected zone (HAZ) and dross caused by flame cutting was time consuming. Stamping parts left a ragged edge that still needed to be removed.

Outsourcing to a shop using conventional waterjets eliminated the need for secondary processing to deal with these issues "but there was still taper to contend with," explains Bogensberger.

"We use a specialized gear configuration that requires very tight tolerances. So we still needed to do follow-up machining."

Then Bogensberger attended the 2010 FABTECH show in Atlanta to see the latest machine tools and it was there he was first introduced to Flow's Mach 4 cutting system with Dynamic Waterjet® XD.

"The advances that Flow has made in waterjet technology are impressive. We've always known that a waterjet is extremely flexible but when we found out the speed and accuracy that the FlowJet can produce, we knew we had to have one."

The Latest Advances in Waterjet

Two types of part quality issues plague abrasive waterjet cutting: stream lag and taper. Both accuracy errors can be minimized by significantly reducing cut speed, but cycle time and cost per part rise with equal significance.

Stream lag is the phenomenon where the exit point of the jet cutting the part lags behind the entrance point. This stream lag causes geometry errors as it sweeps out cone shapes instead of circles and causes corner wash-out on inside corners.

V-shaped taper naturally occurs as the power of the waterjet dissipates while cutting through material. The faster the cut speed, the greater the kerf taper error, as much as 0.01" per side. As with stream lag, the typical way to reduce this taper has been to slow down the cutting speed.  This not only reduces the number of parts that can be cut each day but also increases the amount of garnet (the majority of the cost of abrasive waterjet cutting) used per inch.

Dynamic Waterjet with Active Tolerance Control™ is one of the most important advancements in the history of abrasive waterjet technology for flat stock cutting.

Invented and patented by Flow in 2001 specifically to counter taper and stream lag in flat stock cutting,  it ensures that the waterjet is cutting at top speed by combining the simple to use yet powerful software with precision machine tool design and articulated wrist. Parts are cut faster and at a lower cost per inch.

After several years of design and testing, Flow now offers these same cutting enhancements to beveling and 3-D cutting with Dynamic Waterjet XD.  Previously, it took hours to properly program a single 3-D part in a waterjet environment.

FlowXpert™, Flow's CAD software, takes into account the behavior of the waterjet stream and makes programming faster and more intuitive. Using the advanced SmartStream™ mathematical models, this breakthrough motion system ensures that the cutting stream is correctly positioned. Cut speed is increased two to four times faster and with less taper than conventional 5-axis systems.

"We built Dynamic XD to combine Flow's Dynamic Waterjet cutting capabilities with an advanced multi-axis system to cut complex 3-D parts. Unlike traditional multi-axis systems that take hours to program, this system is designed to be easy to use and allows the flexibility needed to cut production runs or one-off prototype parts," says Tim Fabian, global product manager, Flow International. "We took our 2-D concept of art-to-part in a minute and applied it to the 3-D world. If your geometry is clean, you can produce a 3-D waterjet cutting program in as little as a minute." 

Advantages of Owning an Accurate Waterjet

Kronos purchased a 4 meter by 2 meter (13’ x 6.5’) Mach 4 system to ensure they weren’t limited by the cutting table size.

"The first thing we noticed was our part costs were dramatically reduced," says Bogensberger. "For example, we had previously outsourced work to a gear manufacturer at a cost of $103 per gear. With our FlowJet, cutting the same gear now costs about $1.40 without the need to do any follow-up machining. And we can pass that savings directly onto the customer." 

Additionally, they can easily scale ring gears or the vane head size to meet specific customer performance requirements or space constraints. With their waterjet, they can make product development and configuration changes up to the last minute without the delay or extra charges when outsourcing.

A waterjet's flexibility also allows them to cut virtually any material, whether stainless, aluminum, carbon steel or rubber. "We made a Lexan display case with interlocking joints. Not a screw was used, just slot and peg configurations so there was no fixturing required," says Bogensberger.

The FlowJet allows them to provide low cost, high quality services to their customers.

"We have a new customer that was buying raw material, sending it to a blanker and then on to a metal processing facility. They would use a punch press that produced ragged edges, which the customer would have to deburr. There was also a 0.030" variance from top to bottom," explains Frank Garavelli, sales director.

"It took a total of 6 different operations by various suppliers before they got the part back to process. With our FlowJet, all we do is order the raw material, cut and form the parts and it's ready for their final process. There's no need to deburr or hone down uneven edges." 

Because of the Dynamic XD accuracy, Kronos is able to stack the material and cut 8 parts at a time. "Flow has definitely made the waterjet into a production machine," says Bogensberger.

The waterjet has also helped them to expand the types of businesses they support beyond being a part of the wind and energy supply chain.

"Wind energy is one way to reduce fossil fuel consumption.  Another is to help make that fuel consumption more efficient," says Garavelli.

"Long haul trucking, for example, uses a lot of fuel. So we designed aerodynamic skirt-side fairings to reduce the drag and improve gas mileage. With our FlowJet, we can customize the look to meet trucker or fleet design requirements." 

Whether it's a logo, contact information or an applique to match artwork on the truck, Kronos now has the capacity to quickly meet their customers' expectations. Other new ventures have included custom flooring applications and even cutting 5" concrete for a church sculpture.

"The bottom line is that the FlowJet has expanded our capabilities and improved our net income by at least 20%," explains Bogensberger. "Due to our ability to prototype and offer design flexibility for our wind turbines as well as custom work, we calculate our ROI at 22 months."