Page 37 - MetalForming April 2012

jet-cutting process is extremely flexible, but when I experienced the speed and accuracy possible with the Mach 4, we knew we had to have one.”
Victory Over Stream Lag and Taper
Two types of part-quality issues typi- cally plague abrasive waterjet cutting: stream lag and taper. Both of these accu- racy hurdles can be cleared by signifi- cantly reducing cutting speed, but cycle time and cost per part rise with equal significance.
Stream lag—evidenced by the exit
point of the waterjet lagging behind the
entrance point—causes geometry errors
as it sweeps out cone shapes instead of
circles, and causes corner wash-out on
inside corners. And, V-shaped taper nat-
urally occurs as the power of the waterjet
dissipates during cutting. The faster the cutting speed the greater the kerf-taper error, which can be as much as 0.01 in. per side. As with stream lag, slowing cutting speed will min- imize taper, but will restrict productivity and increase garnet consumption per inch of cut.
Flow’s Dynamic Waterjet with Active Tolerance Control avoids taper and stream lag during flat-stock cutting, says the company, maximizing cutting speed. The technology com- bines control software with precision machine-tool design and an articulated end-of-arm wrist.
Ownership Has its Advantages
Since Kronos installed its Mach 4 FlowJet waterjet-cutting system, outfitted with a 13- by 6.5-ft. table, costs compared to outsourcing its cutting work have reduced dramatically. “For example,” says Bogensberger, “we had previously out- sourced work to a gear manufacturer at a cost of $103.00 per gear. With our FlowJet, cutting the same gear now costs about $1.40, without the need for any secondary machining. That’s savings we can pass directly onto the customer.”
Additionally, Kronos can easily scale ring gears for its wind turbines, or the vane head size, to meet specific cus- tomer performance requirements or space constraints. And with its waterjet-cutting machine, it can make such product- design and configuration changes up to the last minute without the delay or extra charges when outsourcing.
The flexibility of the waterjet-cutting process allows the company to cut virtually any material, whether stainless or carbon steel, aluminum alloys or rubber. “We made a Lexan display case with interlocking joints,” says Bogensberger, “and didn’t have to use even a single screw to assemble the case. We waterjet-cut slot and peg configurations instead, also avoiding the need for fixturing during assembly.”
Sales director Frank Garavelli describes another waterjet-
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MetalForming/April 2012 35
Since Kronos installed this Mach 4 FlowJet waterjet-cutting system—outfitted with a 13- by 6.5-ft. table—costs compared to outsourcing work have reduced dramatically, allowing the company to pass savings directly onto its customers.
cutting success story. “We have a new customer that was pur- chasing raw material, sending it to a blanker and then onto a metal-processing facility,” he says. “Parts fabricated on a punch press required secondary deburring, and the parts had a 0.030-in. dimensional variance from top to bottom. In all, six different operations performed by various suppliers were required to produce parts to print.
“Now, fabricating the parts on our FlowJet,” continues Gar- avelli, “we simply order the raw material, cut and form the parts and they’re ready for assembly. There’s no need to deburr or hone down uneven edges.”
Support for Other Green Applications
Since adding waterjet cutting to its inhouse resume of fab- ricating processes, Kronos has been able to expand its cus- tomer base beyond the wind-energy market and into other green markets. For example, it’s fabricating aerodynamic skirt-side fairings for long-haul trucks, to reduce drag and improve gas mileage.
“With our FlowJet, we can customize the look to meet trucker or fleet-design requirements,” says Bogensberger. “Whether it’s a logo, contact information or an applique to match artwork on the truck, we can quickly meet customer expectations.” Other new ventures have included custom flooring applications and even cutting 5-in. 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 percent,” surmises Bogensberger. “Due to our ability to pro- totype and offer design flexibility for our wind turbines, as well as perform custom work, we calculate our return on investment at 22 months.” MF
Article provided by Flow International, Kent, WA; 253/850- 3500, www.flowwaterjet.com.