Roll Dryer Bearing Damage Prediction by Shock Pulse Method - HD
Condition Based Maintenance (CBM) program in the Dryer Section PM2 area detected damage to the Roll Dryer 1 FS bearing using the Shock Pulse Method (SPM HD). The damage, caused by water-contaminated lubrication, overload, and exceeding the bearing’s lifespan, was identified early, allowing for planned repairs and preventing unplanned downtime.
🔧 Condition Monitoring & Bearing Replacement Dryer 1 FS PM2
📍 Area: Paper Machine 2 – Dryer Section
📅 Period: March – October 2025
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🧠 Background
As part of the Condition Based Maintenance (CBM) program in the Dryer Section PM2 area, the condition of the Roll Dryer 1 FS is monitored using the Shock Pulse Method (SPM HD) method to detect damage to the bearing element early.
The main goal is to ensure optimal bearing conditions and prevent unplanned downtime due to critical component failures.
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📊 SPM HD Analysis Results
Based on data from Condmaster Ruby, the HDm/HDc trend shows a gradual increase until it reaches the red alarm zone by October 2025.
The results of the spectrum analysis showed high amplitudes in BSF (Ball Spin Frequency) and BPFO (Ball Pass Frequency Outer) — a strong indication of damage to the outer race bearing.
No significant imbalance or misalignment was detected.
🔹 Operating speed: ±890 RPM
🔹 Bearing type: SKF C3036 C4
Interpretation:
Damage occurs due to repeated overload and bearing life that has exceeded the lifetime, without any previous replacement records.
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🧾 Field Examination History
📅 March 21, 2025
Normal visual condition, no defects visible
Clearance: 0.17 mm
Clear oil, without contamination (Image 4⃣)
📅 June 25, 2025
Clearance increased to 0.19 mm
Oil is indicated to be contaminated with water, lubrication begins to decrease
Indications of internal corrosion found on the housing (Image 5⃣)
📅 October 9, 2025
Bearings dismantled and found spalling on the outer race
Clearance: 0.21 mm with fine grams (thin metal particles)
Housing damaged, M30x20 rethreaded
Bearing replaced with SKF C3036 C4, actual clearance 0.22 mm
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📸 Photo Documentation
1️⃣ Data spectrum – harmonic enhancement BSF & BPFO
2⃣ HDm/HDc & COND trend chart – progressive breakdown phase
3⃣ Outer race – spalling and surface wear
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⚙️ Actions & Recommendations
✅ Bearing replacement as per OEM specification (SKF C3036 C4)
✅ Repair of the housing (M30x20 thread) for installation stability
✅ Perform preventive lubrication at shorter intervals
✅ Regular monitoring of oil humidity
✅ Perform post-replacement re-baseline measurement to establish a new reference value of healthy bearing conditions
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💡 Conclusion
Bearing damage is caused by a combination of water-contaminated lubrication, overload, and excess operating life.
Through SPM HD monitoring, indications of damage are detected early before the failure occurs, so that repair actions can be carried out in a planned and efficient manner.
🧩 CBM is not just about detecting faults — it's building a system of continuous reliability.
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