Vibration: The Cause or Effect of Machine Failure?

Alan Friedman’s name is synonymous with vibration analysis training and certification. Having trained and certified thousands of students in accordance with ISO 18436-2 Category I, II, III, and IV, Alan will be conducting an ISO Category I vibration course at the Reliable Plant Conference in Chicago, June 3-6, 2024. Course registration includes access to the exhibition hall, evening social events, and meals, so be sure to reserve your spot now!

The understanding of machinery vibration analysis often leads to confusion regarding whether vibration is the cause of a problem, the result of a problem, or both. This confusion can lead to significant errors in data analysis. Let us take a moment to clarify this matter.

Vibration as the Cause

Excessive vibration within machinery can instigate a cascade of problems. It can lead to fatigue failures in various components such as shafts, couplings, bearings, seals, pipes, and foundations. Additionally, it can induce quality issues in manufactured products. Consider the scenario of an HVAC fan vibrating near a computer chip printing machine: the vibration, traveling through the floor, can adversely affect the precision of the chip manufacturing process.

Furthermore, excessive vibration poses potential risks to human safety and comfort, even when direct harm is not directly inflicted. Think of the annoyance caused by an unbalanced ceiling fan going "whop, whop, whop!" while you’re trying to sleep. Talk about annoying.

A helpful analogy to help wrap your head around this is to envision driving a car at high speeds over rough terrain. Continuously subjecting the vehicle to such conditions will inevitably lead to damage due to excess vibration.

During my audits of companies’ vibration programs and data-analysis procedures, I often encounter a common misconception. Many tend to assess vibration levels solely based on graphs, identifying the highest peaks and assuming that as long as the vibration remains within acceptable limits, the machinery is functioning adequately. Alternatively, some rely on ISO RMS alarm charts for comparison. However, such approaches can overlook critical issues, as well.

In addition, it's important to consider the role of lubrication in relation to vibration as a potential cause of machine failure. Effective lubrication not only reduces friction between moving parts but also helps dampen vibration by forming a protective layer. Conversely, insufficient or degraded lubrication can exacerbate vibration problems and lead to accelerated wear or eventual failure of machine components. Therefore, proper lubrication practices are essential for mitigating vibration-related issues and ensuring the smooth operation and longevity of machinery.

Vibration as an Effect

In a condition-based maintenance (CBM) approach, we often interpret vibration as an effect rather than a cause. Analogous to the car scenario, imagine driving your vehicle to work routinely and suddenly noticing a new noise. Your immediate inference is that something must be wrong with the car.

However, it's crucial to recognize that this new noise merely signifies an effect or consequence of an underlying issue. Moreover, the magnitude of this noise may not correlate directly with the severity of the damage.

Consider a defect on the outer race of a rolling element bearing in a piece of rotating equipment. As the balls or rollers traverse this defect, they generate a repetitive clicking sound. Despite the relatively minor amplitude of the resulting vibration compared to other sources, such as water flow through a pump or shaft rotation, the bearing is indeed damaged. Merely assessing vibration levels in terms of absolute amplitudes can lead to overlooking critical faults.

Effect and Cause

In certain scenarios, vibration serves as both an effect and a cause. For instance, if a rotor is out of balance, the vibration amplitude will escalate at the shaft rate frequency (1x), indicating imbalance.

Why is imbalance concerning? Among many reasons, one major issue is that the heightened vibration that results from imbalance can inflict damage upon the machine.

Thus, this represents a scenario where vibration acts as both an effect and a cause simultaneously.

Expanding further, it's essential to recognize that vibration analysis is a nuanced field. Beyond the simple dichotomy of cause and effect, there are intricate relationships between various factors influencing machinery behavior.

For instance, environmental conditions, operational parameters, and material properties can all interact to modulate vibration characteristics. Therefore, a holistic approach to vibration analysis is imperative — encompassing not only the identification of causal factors but also the understanding of their interplay within the broader machinery context.

Moreover, the interpretation of vibration data requires a sophisticated understanding of signal processing techniques and diagnostic methodologies. Merely assessing vibration levels without contextualizing them within the operational environment can lead to erroneous conclusions. Therefore, practitioners must integrate theoretical knowledge with practical experience to derive meaningful insights from vibration data.

Furthermore, advancements in technology have revolutionized vibration analysis, enabling predictive maintenance strategies that leverage machine-learning algorithms and IoT (Internet of Things) sensors. These technologies facilitate real-time monitoring of machine health, allowing for proactive intervention to prevent catastrophic failures. However, their effective implementation necessitates not only technical expertise but also organizational readiness to embrace data-driven decision-making paradigms.

Vibration and Lubrication: A Symbiotic Relationship

The connection between vibration and lubrication in machinery maintenance is deeply intertwined, with each factor significantly influencing the other. Lubrication serves as a critical element in minimizing vibration-induced wear and reducing friction within mechanical systems. By forming a protective film between moving parts, effective lubrication minimizes surface-to-surface contact and dampens the propagation of vibration.

Conversely, the vibration patterns observed in machinery can offer valuable insights into the efficacy of lubrication practices. Anomalies in vibration, such as heightened amplitudes or shifts in frequency, often signal lubrication deficiencies, such as inadequate film thickness or contamination. Monitoring vibration signatures enables maintenance professionals to detect lubrication-related issues early, facilitating timely interventions to prevent equipment degradation and failure.

Moreover, the interaction between vibration and lubrication extends beyond mere problem detection to the optimization of maintenance strategies. Advanced predictive-maintenance approaches utilize vibration analysis alongside lubrication monitoring to develop customized maintenance schedules based on real-time equipment condition. By correlating vibration data with lubricant characteristics and performance metrics, organizations can optimize lubrication intervals, ensuring peak machinery performance while minimizing maintenance costs and downtime.

Making It Make Sense

Vibration analysis is a multifaceted discipline that requires a nuanced understanding of the dynamic interactions between machinery, operational conditions, and environmental factors. The symbiotic relationship between vibration and lubrication underscores the importance of holistic maintenance approaches that integrate various predictive technologies and methodologies. By recognizing the interconnectedness of these factors and leveraging synergies between vibration analysis and lubrication management, organizations can enhance equipment reliability, extend asset lifespan, and maximize operational efficiency in today's dynamic industrial landscape.

About the Author

Alan Friedman

Alan Friedman, aka the Vibe Guru, has over 30 years of vibration analysis experience, He has trained 1000’s of students arou... Read More