Flexible Machines, Reliable Operations?

For decades, reliability has largely been viewed as a maintenance subject. When equipment fails, maintenance teams investigate, repair, replace components, and restore operations. Yet according to Yousef Rahmani, a rotating equipment specialist at Alfa Laval Sweden, this perspective is too narrow. Reliability is not the responsibility of one department. It is the outcome of decisions made throughout the entire lifecycle of an asset.

“Reliability is a chain,” Rahmani says. “It starts with design and continues through procurement, transportation, installation, operation, maintenance, and even end-of-life activities. Every phase affects the reliability of equipment.”

This broader understanding has led Rahmani to focus on a topic that receives surprisingly little attention despite its growing importance: the relationship between flexibility and reliability.

Modern industrial facilities increasingly demand flexibility from their assets. Production environments are changing faster than ever. Companies need equipment that can handle multiple products, varying operating conditions, fluctuating demand, and changing process requirements. Flexibility has become a valuable competitive advantage. The challenge, however, is that flexibility and reliability do not always move in the same direction.

“We often assume that adding flexibility is automatically beneficial,” Rahmani explains. “But every new flexibility feature should raise a question: what impact will it have on reliability?”

The answer is not always straightforward.

According to Rahmani, flexibility can take many forms. It may involve equipment capable of performing different functions, handling different process media, or operating across a wider range of capacities. A pump may be required to process fluids with significantly different viscosities. A compressor may need to handle multiple gases. Production assets may be expected to operate efficiently under varying loads.

In many cases, these capabilities are enabled through relatively small modifications or advanced control systems. From an operational perspective, the benefits are obvious. The equipment becomes more versatile and can adapt to changing business needs.

But flexibility often introduces complexity. And complexity can create new reliability challenges.

One example is the widespread use of Variable Frequency Drives (VFDs). These systems allow operators to adjust motor speed and therefore change the output capacity of equipment. VFDs have become a common tool for improving energy efficiency and operational flexibility.

However, expanding the operating range of machinery may unintentionally expose equipment to conditions that were previously avoided.

“When you change speed, you also change the dynamic behavior of the machine and the structure around it,” Rahmani says. “There can be specific operating points where vibration levels increase significantly because natural frequencies are excited.”

The equipment may continue running and deliver the required output. From a production standpoint, everything appears normal. Yet elevated vibration levels can accelerate wear, shorten component life, and increase the likelihood of failures. In other words, the machine is flexible enough to operate in that condition, but not necessarily reliable enough to do so for extended periods.

Rahmani refers to these situations as conflict zones between flexibility and reliability.

Identifying such zones early can have substantial benefits. During commissioning, for example, assets are often tested to verify functionality. Rahmani argues that organizations should go further and systematically evaluate reliability performance throughout the entire operating range.

“Operating over a wide speed range requires reliability assessment of the entire system across the full operating range,” he says. “You need to understand where potential risks exist before they become future maintenance problems.”

The rewards of this proactive approach can be significant. Detecting reliability risks during commissioning or early operation can reduce maintenance costs, improve uptime, extend equipment life, and enhance safety.

Some reliability issues may remain hidden for years before they develop into serious failures. By that point, organizations often face costly repairs, production losses, or even major incidents.

“Finding these areas early is much cheaper than dealing with the consequences later,” Rahmani says.

The concept is not limited to rotating equipment. The same principle can be applied across industrial systems and asset classes. Any modification intended to increase flexibility should trigger a parallel discussion about reliability. This is where Rahmani believes many organizations face a challenge.

Addressing reliability-related tensions requires collaboration between multiple disciplines. Designers, operators, production personnel, maintenance specialists, reliability engineers, and procurement teams all possess pieces of the puzzle. Yet these groups do not always work together when decisions are made.

“It is often easier to replace a failed component than to investigate why the failure keeps happening,” Rahmani says. “The root cause may actually be connected to how the equipment is being used or how it was originally designed.”

As a result, recurring failures can become accepted as normal operating conditions rather than symptoms of a deeper issue.

Rahmani believes industrial organizations should actively search for these hidden trade-offs. A useful starting point is to ask a simple question about every critical asset: What flexibility features does this equipment have, and how might they affect reliability?

Exercise can reveal opportunities that might otherwise remain invisible.

An operating mode that appears beneficial from a production perspective may be creating excessive stress on equipment. A process modification that increases throughput may be reducing asset life. A design change that expands functionality may be introducing new maintenance challenges.

Understanding these relationships enables better decision-making across the asset lifecycle.

The discussion is particularly relevant today as digitalization, automation, and advanced monitoring technologies continue to reshape industrial operations. Condition monitoring systems, predictive maintenance tools, and artificial intelligence can help detect failures earlier than ever before. Yet Rahmani warns that technology alone cannot solve every reliability problem.

“Advanced monitoring is valuable, but sometimes we need to look deeper,” he says. “Technology may tell us that a problem exists, but we still need to understand why it exists.”

That requires a mindset shift. Instead of viewing reliability as something that begins when equipment starts to fail, organizations should consider reliability from the moment flexibility is introduced. Every new operating mode, every new capability, and every design modification should be evaluated through both lenses.

The goal is not to choose between flexibility and reliability. Both are essential for modern industrial operations. The objective is to find the right balance.

“Think about flexibility and reliability at the same time,” Rahmani says. “Do not sacrifice one for the other. The best solutions come when we understand both.”

For maintenance, production, and asset management professionals, that may be the most important takeaway. Reliability is not simply about repairing equipment. It is about understanding the decisions that shape equipment performance long before the first failure occurs. And in a world where flexibility is increasingly demanded, recognizing the hidden tension between adaptability and reliability may be one of the most valuable reliability strategies of all.

Text: Mia Heiskanen Photos: Yousef Rahmani photo archive, SHUTTERSTOCK