Condition Monitoring

What is Condition Monitoring?

Factory managers need to be constantly aware of how well (or not well) all of the machines are operating. Condition monitoring is one way to keep track of each piece of machinery’s status and to quickly pick up on any anomalies that might point to a problem. 

A condition monitoring system is used to measure specific set parameters – as long as those parameters are being met, the machine is considered in good working order. If the system senses a change, an alert is sent so that preventive action can be taken. Machine condition monitoring goes hand-in-hand with production line monitoring, giving factory managers insight into the factory’s operations.

Often used as part of a predictive maintenance strategy, condition monitoring also helps to predict equipment failure, but it is based only on current data and does not use AI or machine learning to make predictions based on past data. 

Implementing a condition monitoring system can be a costly endeavor, but the costs are easily recouped by the prevention of unexpected machine failures and unplanned downtime.

How Does Condition Monitoring Work?

Condition monitoring has been around for a long time and used to rely on putting a wooden stick against the side of a machine to check the vibrations in order to determine whether the machine was running correctly. Thanks to technological innovations today’s equipment status monitoring can be done using automated tools.

There are three steps involved in condition monitoring:

• Install a condition monitoring system – usually, a small piece of hardware must be installed on each piece of equipment that is going to be monitored. 

• Collect baseline measurements – measure each machine’s performance including data on vibration, rotor speed, temperature and any other process sensors. This initial measurement becomes the baseline to which the future machine condition monitoring will compare.

• Let the system run – the system will work 24/7 evaluating each machine’s performance and providing diagnostics. When a potential issue is detected, relevant personnel can receive an alert and determine what action needs to be taken. Such action can include scheduling maintenance immediately or in the near future or just keeping an eye on the situation and continue operating the machine. 

Types of Condition Monitoring

There are a number of different types of techniques that can be used in condition monitoring. Most factories use a combination of machine condition monitoring techniques that use sensors as well as those that involve physically checking oils for contamination. Using a combination of methods provides the fullest picture of each machine’s operating condition. 

Examples of condition monitoring types are:

• Electrical monitoring – a deviation in electrical parameters – such as frequency response, induction and pulse response – is used to identify triggers and faults.

• Electromagnetic measurement – magnetic fields are used to identify cracks, corrosion and other defects. 

• Laser interferometry – laser-generated light waves are used to find surface and below-surface defects in composites and other materials.

• Motor circuit analysis – computerized tests are run on electric motors to examine their condition and check for electrical imbalances and other potential sources of failure.

• Oil analysis – oils and other fluids are checked for contaminants which are a sign of wear and overheating.

• Performance monitoring – visual inspections by engineers. Being able to combine the engineer’s expert eye with the data gathered by technological tools is one of the benefits of condition monitoring.

• Radiography – radiation imaging is used to look for internal defects.

• Thermography – temperature mapping helps identify overheating in electrical connections, leaks in pipes and weaknesses in pressure vessels.

• Ultrasonic monitoring – high-frequency sound waves can detect anomalies including leaks and cavities in equipment, bearing and rotating parts. 

• Vibration analysis – as a machine starts to wear out, the parts will vibrate in unusual patterns. Monitoring the vibrations can give an early warning of misalignments and imbalances. 

What are the Benefits of Condition Monitoring?

Condition monitoring provides advantages when it comes to scheduling maintenance, reducing downtime, decreasing operating costs and improving safety. The key benefits of condition monitoring include:

• Avoid downtime – ongoing equipment status monitoring means knowing immediately when a problem arises and therefore fixing it quickly, preventing unnecessary downtime. With less downtime, orders are more likely to be completed on time with no need for overtime work, keeping both customers and employees happy.

• Optimize maintenance scheduling – condition based maintenance can be used to schedule maintenance only (yet immediately upon discovery) when it’s needed. This is as opposed to many preventive maintenance programs that schedule maintenance at particular intervals of time whether it’s needed or not. 

• Make repairs more efficient – condition monitoring reveals exactly where in the machinery the fault or defect lies, making it easy for the technician to go straight to the source and fix the problem. 

• Improve safety – malfunctioning machinery can pose a safety threat to operators and other personnel. By using a condition monitoring system, problems can be fixed before they become a real safety issue.

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Best Practices in Condition Monitoring

Following are best practices for factories to keep in mind when implementing condition monitoring:

• Human resources – ensure that an employee or number of employees are assigned to be responsible for the condition monitoring system. They should be well-versed in how to use it and should have protocols in place for when the system flags potential issues.
• What to monitor – not every piece of equipment necessarily has to be monitored. It’s important to identify which ones are the most important to monitor based on the situation of the particular factory. In general, condition monitoring is usually used for rotating equipment, machines that are used continually, any equipment that involves toxic material, and any parts that operate at high speeds and/or have no alternatives if they are not working. 
• Benchmarks – benchmarks should be set based both on the baseline measurement taken when installing the system, but also based on industry standards.
• Parameters – it’s important to be strategic when choosing the parameters that will be tracked and that represent the “normal” working order. Choosing the right parameters will limit the number of false alarms that may be raised.