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A Unique Process
CERBEC® balls are made from the structural ceramic, Silicon Nitride. The degree to which Silicon Nitride realizes its unique mechanical, thermo-chemical, and tribological properties for bearing application lies in its microstructure and finish. Our bearing-grade Silicon Nitrides (NBD-200 & SN-101C) are precisely processed under highly controlled conditions to yield a fully dense, isotropic, patented microstructure specifically optimized for superior bearing performance. Our high-precision finishing gives CERBEC® balls distinct advantages over other Silicon Nitride balls. CERBEC balls are known world-wide for their ultra-smooth surface finish and precision-crafted geometry. We also apply a host of inspection criteria: density, dimensional measurement, radiography, geometry, surface finish, dye
penetrate, and visual criteria to insure the integrity of each and every CERBEC® ceramic ball.
CERBEC® Ball Processing
| | | Critical Issues |
| Raw Material | | Purity |
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| Milling Preparation |
| Chemistry & Particle Size Control |
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| Spray Drying | | Flow
Ability & Packing Density |
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| Forming | | Uniform Compaction |
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| PreFiring | | Binder Removal |
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| HIP Densification | |
Proper Micro structural Development for Hardness & Toughness & Rolling Contact
Fatigue |
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| Lapping |
| Geometry, Surface Finish, Surface Quality |
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| Final Inspection | |
Assured Quality |
How CERBEC Makes A Precision Finished Silicon Nitride Ball
The manufacture of CERBEC silicon nitride balls follows a prescribed, documented process which is ISO 9002 certified. We start with silicon nitride powder which is milled together in either alcohol or water with the appropriate sintering aids. For NBD-200, magnesium oxide is the major sintering aid and for SN-101C, yttrium oxide is used. At the end of the milling process, binders are added to the mix to enhance formability in later steps. The milled slurry is then spray dried to make a flowable, compactable powder. The powder is then pressed into a blank using uni-axial or isostatic methods. The “green” ball blank is then air fired to remove
binders, loaded into graphite crucibles with encapsulant glass, and Hot Isostatically Pressed (HIP) at extremely high temperature and pressure to optimize densification and microstructure. SGAC is the only silicon nitride ball
manufacturer that utilizes glass encapsulation HIPing. We believe this yields the most uniform and fully dense material which maximizes bearing properties. The densified ball blanks are then de-encapsulated and inspected before finishing operations. Once qualified for further processing, the balls are then roughed and finished in a series of steps utilizing free abrasive lapping with diamond since silicon nitride is such a hard and tough material. After finishing, the balls are inspected to assure that all geometry, finish, and material requirements are verified. The entire process is well controlled using SPC and exacting specifications.
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