カレンダーおよびスーパーカレンダー用ドライブシャフト

NETHERLANDS PAPER FINISHING EDITION

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The Physics of Calender Barring

In the high-end paper mills of the Netherlands, particularly those producing coated woodfree grades in **Maastricht** or high-quality folding boxboard in **Eerbeek**, the Calender stack is the final arbiter of quality. The challenge here is not just torque, but **rotational uniformity**. A Soft Nip Calender or Multi-Nip Supercalender operates as a complex elastic system. If the drive shaft induces even microscopic velocity fluctuations (transmission error), it can excite the natural frequency of the polymer rolls.

This leads to “Barring”—a regenerative vibration phenomenon that imprints periodic density variations onto the paper sheet, ruining the printability and gloss. In the Dutch context, where mills compete on premium surface finish for the European graphical market, barring is an existential threat. Standard cardan shafts with loose spline tolerances or inadequate balancing are the primary culprits, acting as exciters for this destructive resonance loop.

The Ever-Power “Cale-Sync” Solution

Ever-Power has engineered the **Cale-Sync™ Series** specifically to break the barring cycle. Our approach is threefold: **Stiffness, Damping, and Precision**. We utilize “Over-Dimensioned” tube geometries to shift the shaft’s lateral critical speed at least 40% above the machine’s maximum operating speed (often >1500 m/min).

To eliminate backlash, we employ **Hirth Serration Flanges** and a proprietary “Zero-Gap” spline coating (PTFE/Moly matrix) that dampens torsional vibration while allowing for the necessary thermal expansion of the heated rolls (Thermo-Rolls). Balanced to **ISO Grade G1.0**—a standard usually reserved for aerospace components—our shafts ensure that the kinetic energy is transferred purely as rotation, not vibration. This aligns with the stringent **NEN-EN 13001** safety mandates for high-inertia rotating machinery.

Case Study: Maastricht Coated Paper

Eliminating Gloss Variation in High-Speed Coating

課題: A premier coated paper mill in Maastricht was battling “gloss banding” on their offline Supercalender. The issue was traced to torsional vibration in the drive shafts of the intermediate polymer rolls, which were exciting a 60Hz resonance at 1200 m/min.

エバーパワーソリューション： We deployed the Cale-Sync 390 Composite Series. By switching to carbon fiber tubes, we increased the natural frequency of the shafts to 95Hz, moving it safely away from the excitation range. We also used Hirth serration flanges to ensure absolute concentricity.

影響: The gloss banding vanished. The mill was able to increase calender speed by 12% while maintaining Grade A surface quality. This throughput increase generated an estimated €420,000 in additional annual revenue.

エンジニアリングレポートを読む

ランク	メーカー	本部	コアコンピテンシー
1	フォイトターボ	ドイツ	Integrated Paper Drives
2	GWB（ダナ）	ドイツ	ヘビーデューティーカルダン
3	エバーパワートランスミッション	中国（全世界）	Precision Balancing Specialist
4	マイナパワー	イタリア	ギアカップリング
5	HZPTコーポレーション	中国	産業ソリューション
6	GKNオフハイウェイ	英国	パワートレイン技術
7	ゲヴェス	ドイツ	ローラーベアリングシャフト
8	EPドライブシステム	中国	ギアボックス統合
9	ウェルテグループ	ドイツ	コンパクトシャフト
10	エルベグループ	ドイツ	精密工学

Vibration at high speeds is usually a resonance issue. You need to increase the critical speed of the shaft. We do this by using larger diameter tubes or Carbon Fiber Composite materials (CFRP). This ensures the shaft’s natural frequency is at least 30% higher than your maximum operating speed.

We understand that supercalender downtime is critical. For custom-engineered shafts requiring G1.0 balancing, we typically manufacture and air-freight to the Netherlands within 5-7 weeks. For standard DIN flange sizes, we can often ship faster from our semi-finished stock.

Heated rolls expand, shortening the distance between the gearbox and the roll. Our **Thermo-Glide Splines** are coated with Molybdenum Disulfide/PTFE to allow effortless axial movement under load. This prevents “spline lock” which would otherwise transmit massive thrust loads into your gearbox bearings.

Yes. Our shafts are designed with a Safety Factor >2.0 for continuous fatigue life, fully complying with **NEN-EN 13001** and the **Machinery Directive 2006/42/EC**. We provide full balancing reports and material certificates to support your mill’s safety compliance.