Every machine has its own unique life cycle. Hence, at any point in time, the machinery may be at different stages of their respective life cycles in the manufacturing plant. From this, we can conclude that the breakdown of any machine is the result of it nearing the end of its lifespan. Thankfully, with proper maintenance, this cycle could be extended and the machine can be made almost as workable as it was in its peak.
This is where condition-based maintenance comes in. It can provide manufacturers with an effective way to measure and recognize equipment-related issues so that it can be fixed at their earliest convenience. This article will shed more light on the precise definition, usage, types, benefits, and drawbacks of condition-based maintenance so that you can ensure the plant operations run smoothly.
Purpose of Condition Based Maintenance
In simple terms, condition-based maintenance is a strategy that concentrates on the present condition of the equipment. Here, all measurable aspects of an operating machine are constantly recorded and monitored to look for early signs of deterioration. The main objective is to detect operational issues so they can be fixed as soon as possible before any permanent damage can take place.
Because of this strategy’s reliance on facts and figures, it can aid the plant owner’s in identifying the current stage of the machine’s life cycle. This provides the added advantage of improved decision making regarding the plant’s workforce, timetables, and finances.
To illustrate this condition-based maintenance strategy and how it is used, we may suppose that a manufacturing plant has a pressure sensor installed in its water tanks. This allows the plant technicians to monitor pressure levels and helps them to identify where or when a leak is most likely to happen even before the problem arises and gets out of hand. Similarly, sensors can be used to measure other variables such as temperature, humidity, light levels, etc.
Circumstances Suitable for its Use
To effectively use condition-based maintenance, plant owners must ensure that the following four conditions are met:
- The machine of interest must have a trait that can be measured. Without a quantifiable variable, it would be impossible to determine productivity and compare its levels from different time periods.
- Measurement of the chosen variable must preferably be conducted when the machine is new or in prime condition so that any future failures can be predicted and maintenance is done ahead of time.
- Condition-based maintenance works best for most critical machines. This is determined by a criticality analysis that shows which machine is most prone to failure and its consequences on the plant owner’s operations.
- Finally, for best results, it is highly recommended to have a maintenance team where members can expertly collect and process data as well as make appropriate decisions depending on the results.
How Condition Based Maintenance Differs from Other Types of Maintenance
In addition to CBM, there are two other strategies called preventive and predictive maintenance. All three share the same benefits of decreased downtime, heightened productivity, optimized resource allocation, and improved inventory management. However, there are still some differences that set these two apart from CBM as we will see below:
CBM versus Preventive Maintenance
In the case of preventive maintenance, there is a strong focus on past events. For example, suppose in the last year a manufacturing plant’s pump broke down after every four months therefore, based on this data, the owner decides to carry out productive maintenance this year and lubricate the walls of the pump every three and a half months as a preventive measure.
However, for CBM, the owner would only have to concentrate on the present condition of the pump. Past data would have no place in his calculations.
CBM versus Predictive Maintenance
This is where the waters get murky as CBM and predictive maintenance share some similarities with each other. Both require a constant flow of data collected by testing through mobile gadgets or recording via sensors.
However, this is where the similarities end. Predictive maintenance relies on complex algorithms to which the data is fed. The algorithm then generates predictions on how the machine will function in the future. With CBM, there is no need for complex algorithms or mathematical calculations. Everything is simplified into a single set of three numerals. The first number indicates the machine’s present condition while the second and third numbers represent an upper and lower value for this condition.
To illustrate, suppose the vibration for a rotating machine is being measured. The machine’s vibration must not exceed a predetermined upper and lower limit or else productive maintenance will need to be done to bring its vibration value back within the range.
Different Methods Under Condition Based Maintenance
Condition-based maintenance is done with the help of performance indicators which are measured using different tools and techniques. These techniques consist of:
This monitors fluctuations in vibrations to determine the possibility of future machine failure. Vibration is impacted by changes in amplitude, intensity, and frequency. Sensors can measure the variations in these quantifiable variables and carry out calculations to identify any irregularity in the machine’s vibrations and function.
Ultrasonic sensors can help locate defects below the surface of a machine. The mechanism for this is to send pulses of ultrasound and record the resulting echo which is then converted to sounds audible to the human ear.
Doing this makes it easier for the technician to determine whether to be concerned that the machine has any defects or not.
Similar to vibration and ultrasonic analysis, the acoustic analysis makes use of sound. It uses a sensor and a microphone to diagnose whether a machine is working properly or not. Furthermore, it has the additional advantage of being able to work with gases, liquids, and vacuum leaks unlike vibration and ultrasonic analysis.
Infrared and Thermal Analysis
If any specific section of a machine becomes overly heated from operations and is past its acceptable range of temperatures, the machine is likely to burn, melt or become permanently damaged. To avoid this, infrared cameras and thermal sensors can be installed so the temperature can be carefully monitored and maintained. In the event that the machine gets too hot, the sensors will automatically alert the maintenance team.
If an electric current suddenly becomes too powerful or too low, the operation of the machine can become disrupted. In the electric analysis, an ammeter is used to measure electric current within a circuit and look for signs to see whether the machine is receiving abnormal quantities of current and accordingly take corrective actions.
Oil analysis monitors the condition of the oil being used for a machine as well as its components. It can help determine the fitness levels of the machine and collects data on the viscosity, acid levels, water content, etc. to discern the ability of the oil to serve as a lubricant.
In some plants, liquids or gases must be maintained at an appropriate pressure so they can move smoothly through pipelines. Hence, if there is a sudden decline in pressure, operations could become hampered. Or, if there is a steep rise in pressure, the system could blow up. Pressure analysis helps monitor the pressure of these fluids and gases, so maintenance teams can take action if their values fall outside acceptable ranges.
Here are some major advantages that you will see if condition-based maintenance is implemented:
- Because CBM helps keep track of variables, it has become significantly easier to predict a problem and fix it before it’s too late. This decreases unexpected downtime and work hours while boosting throughput.
- The time interval between each maintenance session becomes longer as they are done only when absolutely required. Thus, this further reduces downtime, accumulation of work, and costs.
- The production process is being less interrupted since CBM does not require dismantling the machines to check for issues.
- Since CBM keeps note of a machine’s statistics, it leads to faster detection of the problem and reduces breakdown costs.
- Being informed about the condition of your equipment means that you will be prepared with the right number of spare parts to fix any future problems which enhance inventory management.
- CBM leads to a safer workplace because it reduces the likelihood of equipment failures, and also keeps technicians informed about any problems that might occur in the future so they can plan ahead.
- Excessive maintenance can negatively impact the health of a machine. CBM helps in figuring out the perfect time when a maintenance session should be due.
Despite the fact that conditions based maintenance proves to be an excellent way to maintain the integrity of your machines, it still has its flaws. Some of the less serious problems you will encounter with this include:
- Difficulty in maintaining schedules because it’s hard to pinpoint when a productive maintenance session is due whereas preventive maintenance outlines a specific time period to carry out productive maintenance.
- Because productive maintenance and inventory are closely connected, you may need to carry more parts than necessary thus making inventory management slightly challenging.
Unfortunately, it gets worse if you take organization and costs into account. This is because CBM requires some skill and equipment to implement. You will also need to train your existing technicians to operate new equipment.
Furthermore, getting good sensors, fitting them into your machinery and periodic recalibration are some extra costs to consider. Finally, there is also the topic of CMMS software. The costs of all these can quickly add up.
Nevertheless, the point still stands that CBM does improve your operational productivity and reduces the chances of machine failure.
Luckily, some CMMS software provide a wide array of benefits and services that can help you overcome these problems and reduce costs as much as possible. Subsequently, using software for condition-based and predictive maintenance is becoming the norm among many manufacturing companies these days.
Before settling on any particular strategy, it is best to identify your company’s needs and thoroughly do your research. Hopefully, the above information has enlightened you. Best of luck with your search!