GLEASON CORPORATION • KEEPING THE WORLD IN MOTION ™

ear designers around the world are seeking to increasetheir use of hardened gears to squeeze optimum

performance out of smaller, quieter transmissions andgearboxes. After all, highly accurate hardened gears offergreatly improved strength and wear resistance (service life),while at the same time delivering a greater load carryingcapacity (higher torque) than larger gears.

But if the use of hardened gears solves many problems, it can also create a few. For example: where to find the super-accurate cubic boron nitride (CBN) plated wheels highlyprized for the precision finish grinding of hardened gearsafter heat treat? Sourcing these wheels has always beennotoriously difficult. Lead times are often long, qualityusually suspect, and costs painfully high — until now.

Controlling the process at Gleason Cutting ToolsCorporation. Today, a new multi-million dollar facility in the heart of the Midwest is doing what few thought would bepossible just a few years ago: turning out hundreds of highprecision, uniform, single layer CBN and diamond platedproducts for use in the hard finishing and grinding of beveland cylindrical gears as well as other non-gear profiles.

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Gleason Cutting Tools’ new superabrasives wheel plating facilityis helping gear manufacturers keep pace with increased demandfor high-performance hardened and ground gears.

Bill Stauffenberg, Plated ProductsSupervisor at Gleason CuttingTools Corporation, claims that thewheels made in this Loves Park, ILfacility are simply the best in theindustry, and he has the facts toprove it.

“Holding profile tolerances of0.0001" to 0.0002" (one to two ten-thousandths of an inch) is routinefor our wheels, and we haveproduced profile tolerances of0.00005" (50 millionths of an inch) for some aircraft gearapplications,” says Mr.Stauffenberg. “I think many in theelectroplating industry would beshocked to learn that this is evenpossible. However, in the gear-making industries these accuraciesare imperative because of thecritical nature of gear profiles andsurface finishes. There is verylittle margin for error.”

Roger Hackman, Gleason CuttingTools’ Vice President, Technologyand Quality adds that their abilityto consistently produce these kindsof results wheel-to-wheel enablesthe company to do what few in the electroplating industry would dare: furnish customers with aguarantee of quality, accurateestimates of tool life (number ofgears that can be produced), andrecommendations on feeds andspeeds to achieve optimumperformance.

Mr. Hackman attributes much of the company’s success to itswillingness to invest in all of theresources needed to control theproduction of these products inhouse. This includes:

• The use of advanced CNCequipment for blanking, turning,heat treating and finish grinding

of the A2 steel body (called thecore) — all done in accordancewith ISO 9001 InternationalQuality Standards;

• Inspection of the core and itsprofile after finish grindingusing super-accuratecomputer-driven CoordinateMeasuring Machines (CMM);

• Application of a single layer of abrasive CBN or diamondcrystals that are mechanicallybonded to the body with a layerof electrolytic and electrolessapplied nickel, performed in an ultra-modern electroplatingfacility;

• Full-profile grinding of a couponby the finished wheel, and finalCMM inspection of the profiledcoupon, with verified wheelprofile and expected K-chartresults furnished with everywheel.

Single layer, multiple benefits.The advantages of using singlelayer CBN (or diamond) platedgrinding wheels are well-known.The single layer structure — CBNor diamond crystals of a specifiedsize bonded to the wheel profile ina thin layer of nickel — isconsiderably harder than ferriteand other conventional abrasives.

It also offers the most compressivestrength, best wear resistance, andhighest heat conductivity — all inan open structure that facilitateschip clearance at even the heavieststock removal rates. Yet, creatinga CBN single layer with anythingapproaching the precision neededto achieve the tolerances andsurface finishes found on today’sgear profiles can’t be done withoutthe special technology andexpertise found in Gleason CuttingTools’ plating facility.

“CBN and diamond abrasivecrystals are available in manysizes, from an average diameter of35 microns (0.0014") for 400/425USA MESH, to 76 microns(0.0030") for 20/30 USA MESH,”explains Mr. Stauffenberg.“However, if you were to simplyapply, say, a 100/120 MESH crystalsize right off the shelf, thedeviation in crystal size would beenough to ultimately throw thewheel profile out of tolerance. Sowe employ a unique method tomore precisely control their sizeand shape.”

Gleason Cutting Tools has developeda system of ‘quarter sieving’ or ‘subsieving’ the crystals prior to theelectroplating process. The crystalsare put through a series of highquality electroformed sieves,ultimately ensuring that theparticle-to-particle size separationin a single layer is within just 5 microns (0.0002").

This is just one of a whole series ofsteps that Gleason Cutting Toolsbelieves are required to ensure thatthe wheel ultimately produces theresults specified by the customer.Among the most important inachieving uniformity of the abrasivelayer is Gleason’s proprietaryelectroplating chemistry. After a thorough ultrasonic cleaning to ensure cores are free ofcontaminants, the cores are put in engineered precision maskingfixtures to protect non-plated

surfaces. An electrolytic processthen uses nickel to tack down theabrasive to the exposed wheelprofile. The duration of this processand the required amperage isprecisely controlled based on theabrasive size and the surface area it covers.

But it’s the next step in the processthat's really critical, according toMr. Stauffenberg. “Once we’veachieved this initial bonding of asingle layer of CBN to the wheel, it’snecessary to ‘tack down’ the layerand encapsulate the crystals bybuilding up the nickel to perhaps50-60% of the height of a crystal,”says Mr. Stauffenberg. “Mostsuppliers continue to use theelectrolytic process — we’ve proventhat electroless nickel plating at thisstage provides a more uniformthickness and higher hardness ofthe nickel plating. Simply put: ifyou can’t control the layering of the nickel you can’t control thetolerances of the profile. Electrolessis the only way to gain this control.”

The finished wheel is then putthrough a rigorous inspectionprocess that includes themicroscopic evaluation to verifyparticle distribution, and the full-profile grinding (on an actual CNCgrinder) and inspection of a graphitecoupon, thus verifying that thewheel will achieve the desiredaccuracies.

More leads, less leadtime.Since the facility ramped up to full

production, Gleason Cutting Toolshas seen the demand for its high-quality products rapidly increase —and its leadtimes decrease. Despitethe fact that the facility nowproduces the industry’s highestquality CBN and diamond platedwheels, it has been able to reduceleadtimes for these products wellbelow the industry average of 10 to12 weeks. “We’ve actually managedto reduce our delivery from manyweeks on new wheels down to sixweeks or less,” says Mr. Hackman.“Nor are we limited to just gearapplications or new wheels. We’vefound a receptive audience in otherindustries as well for non-gearrelated applications. We are also an excellent source for the replatingand refurbishment of all types andsizes of wheels.”

www.gleason.com sales@gleason.comFor Worldwide Locations and Additional Information.

1351 Windsor RoadLoves Park, IL 61111 USATel: 815-877-8900Fax: 815-877-0264

Maschinen und Werkzeuge GmbHMoosacher Straße 42-46D-80809 München GermanyTel: +49 89 35401 0Fax: +49 89 35401 640

Plymbridge RoadEstoverPlymouth PL6 7LQ EnglandTel: +44 1752 739 661Fax: +44 1752 724 429

1000 University AvenueRochester, NY 14607-1282 USATel: 585-473-1000Fax: 585-461-4348

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