FFJournalThe magazine for today’s fabricating & forming technology www.ffjournal.net

A TREND Publication

May 2008 ®

Greater productivity through higher-wattage resonators

inaBOTTLELightningLightning

Laser Technology BY RUSS OLEXA, EDITOR-AT-LARGE

More

FFJournal® May 2008

New resonators

increase cutting

capabilities POWE

ER

One constant heard from users is theneed for more powerful resonators to cutthicker materials, such as 1.25-in. steel,and to cut thinner materials faster. Andthe manufacturers have heard their pleas.New resonators offer the high wattageneeded to cut thicker materials or havebeen redesigned to cut thicker materialsbut with lower wattage.

Therefore, this article is about those newresonators from laser system manufactur-ing companies that build their own res-onators (not just resonator producers) andhave introduced new resonators within thelast year to year and a half. There are manycompanies that build laser systems, butonly a few of them build their own res-onator. Others, such as Finn-Power andAmada for example, buy the resonatorfrom companies that specialize in produc-ing them, like Rofin-Sinar or Fanuc.

The heart of any laser system is the res-onator that initiates the beam. Two typesare commonly used. One is an Nd:YAG(Nidium Yitrium Aluminum Garnet),where the YAG is a solid crystal, and theother is a gas laser that uses CO2 gas in-stead of a solid crystal. The CO2 laser iscommonly used for metal cutting whilethe Nd:YAG is used for welding, somecutting and especially for marking, scrib-ing and specialty drilling.

While a solid crystal can be used tocreate a laser beam for cutting, usingCO2 gas creates a wavelength that has thethermal properties needed for metal cut-

ting. Wavelengths produced by othergases or solid-state lasers don’t have thesame energy potential.

Thicker material cuttingDemand for thicker material cutting ledPrima Laser Systems, Chicopee, Mass., tointroduce its CV Series Fast Axial Flow(turbine-style) CO2 laser resonator. The 5-kW system can cut up to 1-in. steel,thick aluminum plate and stainless steelfrom 0.6 in. to 0.8 in. with faster speeds.

Pieter Schwarzenbach, vice presidentof laser technology at Prima, says that theCV Series produces high power with ex-ceptional beam quality for difficult mate-rial processing. “Its new design stressessimplicity, low operating costs and high re-liability, reducing maintenance,” he says.

Schwarzenbach says that if a companyhas a two-year-old laser that cuts a signifi-cant amount of thick steel, stainless or alu-minum, the higher wattage and cuttingspeeds of the CV Series should be con-sidered as a replacement. With it, he saysa company can cut more parts with thesame amount of assist gas used with itspresent resonator, or decrease the amountof assist gas to save costs.

He says that the beam has a highbrightness for excellent power density andDC excitation for superior electrical effi-ciency. It uses a magnetic bearing turbinethat eliminates bearing changes, a res-onator structure for fast warm-up and tem-poral and spatial stability and a solid-state

TO GAIN GREATER PRODUCTIVITY FORcutting sheet metal, laser manufacturers are alwaysdeveloping and introducing new resonators. Some re-duce cutting time or cut thicker materials while also

decreasing or eliminating maintenance, which adds up to lowerpart cycles and more parts produced.

May 2008 FFJournal®

Trumpf increases productivity with a diffusion-cooled, highly intense cutting beam.

power supply for reliability and low-main-tenance. It also features a user-friendlyPC-based controller with advanced re-mote diagnostics and a single cabinet de-sign for access to maintenance points.

The resonator features machined alu-minum end plates for increased opticalstability and a resonator design that offerssymmetry and near-zero growth during op-eration for a more stable beam. Advancedcomposite elements are used along with akinematic mounting for increased beamquality and pointing stability.

The oil-less, solid-state power supply fea-tures high-voltage components protectedfrom environmental contamination and afast rise time to cut complex contours with-out overheating.

New solid-state power Frank Arteaga, laser product manager atBystronic Inc., Hauppauge, N.Y., saysthat the company’s 6-kW RF resonatorwas the result of an evolutionary processto meet the needs of those wanting morepower to cut thicker materials with lessmaintenance.

“Bystronic’s Bylaser 6-kW RF laser res-onator offers a solid-state power supply de-signed by Bystronic, which replaces theolder vacuum-tube type for older DC andRF Bystronic resonators,” he says. “Thetechnology offers zero maintenance andimproved electrical efficiency. Cost sav-ings are realized by eliminating the re-placement of high-voltage or RF-tubecomponents that have a limited life span.Bystronic’s RF technology uses low-fre-quency RF, (less than 1 Mhz), loweringcomponent cost.

“Another Bylaser enhancement is theCNC-control monitoring of the res-onator optics’ temperature and automaticpower calibration features,” he says.“Temperature sensors are located in theoutput window and the end mirror,which monitor each component’s tem-perature. If one of the optics reaches ahigh temperature outside of its typicaloperating range, the system will give awarning and shut down the resonatorpower depending on the severity of thetemperature increase. This feature pro-vides additional operating security for un-

attended shift operations and for cuttingreflective materials such as aluminum.”

Bystronic’s automatic power calibrationrecalibrates the resonator in minutes if thepower drops below 10 percent of the re-quested wattage, enabling users to con-tinue to operate their machines at fullproduction speeds even though an opticmight be on its last hours of operation.Arteaga says that Bystronic’s 6-kW res-onator can cut up to 1-in. steel or stain-less steel and up to 5⁄8-in. aluminum.

Resonator cuts 1.25-in. steelMitsubishi Laser, Wood Dale, Ill., intro-duced its 40 CF-R 4-kW CO2 resonatortechnology, built from Mitsubishi’s CFX-series resonators for the company’s LV-PlusII laser system. This resonator, andthe company’s next generation 60 CF-R6-kW CO2 resonator, are designed tomeet customer expectations for ad-vanced cutting, says Jeff Hahn, laserproduct manager.

“We came up with enhancements inour resonator as to where componentsare placed,” he says. “Our resonator in-

cludes the power supply, thedamper and vacuum pumpall in one unit for faster andeasier maintenance. Both res-onators reduce rise time/falltime, giving the laser beam atruer square-wave form. Thisprovides a more consistentbeam power and low powerdistribution while cutting anddelivers a more consistentedge quality with more powerstability even when used atlower wattage. The uniformlow-current discharge pro-vides low power stability forimproved micro machiningand etching.”

Mitsubishi resonators have a cross-flowdesign that eliminates the turbine andglass tubes used to excite the gas for low-cost ownership, says Hahn. “We’ve neverreplaced a resonator in the last 21 years.”

The resonator’s Brilliantcut technol-ogy produces a cutting surface roughnessequivalent to the typical machined fin-ish. Brilliantcut provides optimal pro-cessing conditions and reduced taperand discoloring on the heat-affectedzone, says Hahn.

A new Jet Pierce technology decreasespart time by allowing material to bepierced faster and more aggressively dur-

ing small-hole processing. Mitsubishi’s Di-amond-Path technology maintains con-sistent beam quality by using a constantbeam-length system. It provides cuttingstability up to 1,150 ipm.

Mels Eye, the optional intelligentprocess monitoring system has autofo-cusing and other detection features to en-sure cut quality. Burn detection trackseach cut, and when it’s no longer sus-tained, the laser system automaticallyrestarts. Pierce detection increases pro-ductivity by eliminating the buffer inconventional oxygen piercing.

Mitsubishi’s 40 CF-R can cut up to 1-in.

mild steel. The 60 CF-R cuts up to 1.25-in.mild steel, 1-in. to 2-in. stainless steel and3⁄4-in. aluminum.

Faster cuttingTrumpf’s RF excited TruCoax 3200 (3.2-kW) CO2 laser resonator in the TruLaser2030 family of machines gets morepower from a smaller resonator forgreater performance, especially in thickermaterials, says James Rogowski, productmanager of 2-D lasers for Trumpf Inc.,Farmington, Conn.

“Any time you use a coaxial gas res-onator [like the TruCoax], the more sur-

FFJournal® May 2008

Laser Technology

The 5,200-W laser resonator from Bystronic represents just one of the company’s resonators, developed in-house.

The resonator is at the heart of any laser cutting system.

Electrode

BlowerHeat Exchanger

Hi-SpeedPower Sensor

PR Mirror Holder

Power Board

Dia

gram

: Mits

ubis

hi L

aser

, (M

C M

achi

nery

Sys

tem

s In

c.)

May 2008 FFJournal®

Although CO2 laser systems make up the vast ma-jority used, there’s a new diode laser availablefrom IPG Photonics Corp., Oxford, Mass., The

company produces a diode laser that allows high out-put powers for cutting andwelding. “It has betterbeam quality than what’sachievable through tradi-tional techniques,” saysBill Shiner, vice presidentof industrial sales. “Ourproprietary designs arebased on innovative diode-fiber tech niques and high-performance proprietarycomponents perfected byIPG over a 16-year invest-ment and innovation pe-riod.”

An IPG diode fiber optics laser, a 100 percent solid-state laser, doesn’t need maintenance when welding,and it has no optics or resonator gasses to replace. Ithas a wall-plug efficiency greater than 28 percent, nomirrors to align or replace, low cooling requirementsand can deliver the beam through optical fiber up to

200 m from the source. Its cabinet size is usually aquarter to half of the area of a traditional CO2 res-onator of the same power. Diode life is greater than100,000 hours with no yearly maintenance costs.

With a small focal area,it allows precise cuttingor welding and allows alonger focal length so thehead can have a greaterZ-axis variation and befurther away from thematerial.

“For high-speed cuttingof steel, the IPG laser pro-duces cutting speeds be-yond the limits of themotion equipment,” Shinersays. “They can integrateinto motion systems in-

cluding robots, scanners, conventional machine tools andcutting machines. For cost-effective use, it offers rapidswitching through the fiber optics to multiple work sta-tions. This allows multiple work areas to be served byonly one laser system, reducing costs for some applica-tions and at a low acquisition cost.”

Another Kind of Laser Light

face area you have inside the resonator be-tween the electrodes, and the more poweryou’ll get,” Rogowski says. “So we madechanges to the resonator to boost power.The higher-power resonator increases pro-ductivity with a diffusion-cooled, highlyintense cutting beam in an ultra-compactfootprint. The resonator is nearly solidstate and has few moving parts, only a vac-uum system and several switches. It does-n’t have a blower or parts that other CO2

resonators have. From a maintenancestandpoint, there’s none except for a gaschange every year or year and a half.” Cur-rently it costs less than $9 per hour to run,and Trumpf is working to bring expend-

able costs to less than $8 per hour, Ro-gowski says.

“As a laser manufacturer we want to in-crease our resonator sizes because of thedemand for more speed for thinner mate-rials and the ability to cut thicker materi-als,” he says. “This new resonator can cutup to 3⁄4-in. steel, 5⁄16-in. stainless steel and1⁄4-in. aluminum. It can cut the samethickness of materials that higher-wattage,fast-axial-flow CO2 4-kW resonators can.In fact, Trumpf’s TruCoax 3200 increasedcutting speeds up to 100 percent in cer-tain materials. This resonator gives a jobshop the security to cut whatever comesthrough the door.” FFJ

Bystronic Inc., Hauppauge, N.Y.,631/231-1212, fax: 631/231-1040,www.bystronic.com.

IPG Photonics Corp., Oxford, Mass.,508/373-1100, fax: 508/373-1103,www.ipgphotonics.com.

Mitsubishi Laser, (MC MachinerySystems Inc.), Wood Dale, Ill.,630/616-5920, fax: 630/616-4068,www.mitsubishi-world.com.

Prima Systems, Chicopee, Mass.,413/598-5200, fax: 413/598-5201,www.prima-na.com.

Trumpf Inc., Farmington, Conn.,860/255-6000, fax: 860/255-6424,www.us.trumpf.com.

Reprinted from FFJournal® May 2008 Copyright Trend Publishing Inc.