Robert SHANDRO’s Post

While delivering a Failure Analysis training, discussions with participants highlighted a recurring question: “Even when designs look correct, why do components fail?” Looking across multiple case studies, clear patterns emerge in how failures develop in mechanical power transmissions … 1. Mechanical transmissions (gearboxes, belts, chains…) Most degradations still come from fundamental aspects: lubrication quality, contamination control, and alignment. These remain responsible for a large share of premature failures. Design flaws are less frequent, but when present, they can accelerate failures 2. Bearings always leave clues Wear tracks, surface distress, axial marks, cage polishing, spalling, … each pattern reflects a combination of load, lubrication condition, contamination, and operating environment. Once you know how to decode these patterns, it becomes clear whether the root driver was insufficient film thickness, debris, misalignment, overload, or progressing rolling contact fatigue. Bearings rarely fail silently; they document every step on their way to failure. 3. Shafts remember everything. Stress concentrations don’t forgive: a radius slightly too sharp, or a keyway over-machined, can reduce fatigue strength by 30–40% and dictate the life of the entire drivetrain. 4. And gears… always tell the story. Wear, scuffing, micropitting, tooth root fatigue, TFF … each pattern is a fingerprint of load, lubrication, and alignment conditions. Once you learn to read these “signatures,” the failure mechanism becomes obvious. Main takeaway: Failure analysis is not about isolated components. It’s about understanding how the drivetrain behaves as one system mechanically, tribologically, and operationally. Looking at the full transmission makes failure mechanisms far easier to interpret and prevents many of the issues we see in the field. One last point: Maintenance matters! Condition monitoring (vibration, temperature, oil analysis), preventive actions (lubrication routines, alignment checks, inspections), and predictive tools (vibration trending, debris monitoring, oil condition, AI-based diagnostics) are essential. Combined, they help anticipate failures, reduce downtime, and extend asset life. Cetim - Matcor Technology & Services Pte Ltd Cetim - Centre technique des industries mécaniques Cetim Engineering, Alejandro Mejia, Carla Canturri, PhD, Francis Blanc, Dalia Jbily, Simon Jolivet, Hanspeter Dinner, Raul Casali, #FailureAnalysis #Gears #Bearings #Shafts #Micropitting #ToothFlankFracture #Tribology #MechanicalPowerTransmissions #RootCauseAnalysis #MechanicalEngineering #ComponentFailure