Bearing Protection KET Automatic Shield & Seal Pressing

Manufacturing a precision miniature bearing is a journey of extreme accuracy. Once the components are ground, the balls are loaded, the cage is riveted, and the exact volume of grease is injected, the bearing is mechanically ready. However, to survive in demanding environments like UAV motors, medical devices, or industrial power tools, the internal components must be protected.

At Ningbo Kexiang Bearing Technology Co., Ltd. (KET), the final assembly step on our fully automated line is handled by the Automatic Shield / Seal Pressing Machine.

The Importance of Bearing Closures: ZZ vs. RS

While KET produces "Open" type bearings for clean environments or oil-bath systems, the vast majority of our miniature bearings require integrated closures[cite: 8]. The two primary options are:

• Metal Shields (ZZ): These are non-contact steel shields pressed into the outer ring. They provide excellent protection against larger dust particles while generating virtually zero friction, making them perfect for ultra-high-speed operations.
• Rubber Seals (RS / 2RS): These are contact seals made from synthetic rubber. They physically brush against the inner ring, creating a highly effective barrier against micro-dust and moisture, ideal for harsh environments where contamination is a severe risk.

How the Automatic Pressing Machine Works

Installing these closures requires delicate force. If a metal shield is pressed too hard, it will warp and scrape against the inner ring or the cage, instantly ruining the bearing. KET’s Automatic Pressing Machine eliminates this risk through precision automation:

1. High-Speed Vibratory Feeding

The shields or seals are loaded into vibratory bowl feeders, which automatically orient and deliver them to the pressing station at high speeds. Optical sensors ensure that every closure is facing the correct direction before installation.

2. Uniform Micro-Pressing

As the greased bearing enters the station, the machine places a shield or seal on both sides simultaneously. A specialized pneumatic or servo-driven die applies a perfectly uniform, calculated pressure. This snaps the edges of the shield firmly into the retaining groove of the outer ring.

3. Deformation Prevention & Quality Check

The automated press is calibrated to the micron. It ensures the closure sits entirely flush with the outer ring without applying any excess pressure that could bend the thin metal shield inward. Immediately after pressing, the bearing moves to the final automatic noise testing station to verify that the newly installed shields are not causing any friction.

Why Automated Pressing Matters to Our B2B Partners

For buyers around the world, the integrity of a bearing's seal directly dictates the longevity of their final product. By automating the shield and seal pressing process, KET guarantees:

• 100% Grease Retention: A perfectly seated shield locks the exact volume of injected grease inside, preventing premature dry-out and failure[cite: 13].
• Contamination Defense: Flawless installation ensures no gaps are left for dust or moisture to penetrate the raceway.
• Consistent High-Speed Performance: By preventing shield deformation, we ensure the ZZ shields never contact the moving inner ring, maintaining zero-friction rotation.

With the completion of the automatic pressing stage, a KET precision miniature bearing is finally ready to deliver silent, stable, and long-lasting performance to our global partners.