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Preventative Maintenance

Are you looking for ways to reduce costs and generate cash?

Reducing the amount and cost of scrap can significantly improve the internal costs of your Are you losing production time to equipment failures? Are you conducting repairs that are preventable and reactive? Do you have recurring component failures, such as seals, bearings and gaskets?

If you answered ‘yes’ to any of these questions, the chances are that you have a problem with the design or execution of predictive maintenance. Fixing or replacing production-critical equipment is like chasing down an escaped animal: Necessary, effort-intensive and better avoided in the first place.

Done well, predictive maintenance allows you to close the stable door before the horse bolts, saving significant time and cost, while keeping production on-line.

The savings from getting preventative maintenance to work are sizeable, as indicated by the two charts below. The graphs show results from sites where preventative maintenance strategies were either not in place for key equipment or not being executed well prior to engaging PIP.

1. What is Predictive Maintenance?

Predictive Maintenance is a philosophy and approach to maintenance that aims to optimize the economics of a piece of equipment by predicting when maintenance is required. It allows maintenanc e to be provided at the optimum tradeoff point between maintenance cost, extending equipment life and maximizing throughput.

Predictive maintenance compares measured physical parameters with known operating limits, so that equipment problems are detected and corrected before a major failure occurs, as shown in the conceptual chart below. Predictive maintenance prevents the expensive repair and loss in revenue associated with equipment failure.

Physical parameters include pressure, resistance, vibration, voltage or temperature. Relevant parameters are regularly reviewed to detect and rectify potential problems before they become large and costly, and disrupt production. The key methods of making these predictions are shown below:

Techniques for predicting deterioration and failure

Getting predictive maintenance to work is tough. The essentials to install it as a living, working principle are:

A. Equipment strategy – enables prioritization of maintained equipment and determines key maintenance tests and actions
B. Prediction – sets up equipment inspection to determine when maintenance is required
C. Assessment of response – determines right response given condition
D. Response – enables care or maintenance to be carried out (e.g., lubricate, turn off and repair)
E. Hard-wiring – ensures all of the above are second nature in the business

A. Equipment strategy

Most companies have too many pieces of equipment to be able to address them all the same way. We recommend putting an equipment strategy in place, to rigorously prioritise opportunities, ensuring focus is put on the highest impact items first. This approach creates stability and momentum among staff as they are able to focus on a manageable number of strategies rather than an apparently infinite number for all equipment. The process for developing an equipment strategy is laid out in detail in our article “Time for a change? Revisiting your equipment strategies”.

As shown in the chart below, once equipment has been prioritized, it becomes easier to systematically maintain the critical few. This approach prevents management from trying to do everything at once - poorly.

The initial equipment strategy, once in place, forms the platform for preventative maintenance by keeping track of the important milestones and indicating where to focus next.

Organisations without equipment strategies run the risk of having to manage both breakdown costs and rising over-maintenance costs. There is an optimum economic tradeoff point for a piece of equipment. The key to preventing unnecessary costs is to ensure that your equipment strategy allows you to work in the optimum ‘blue zone’.

B. Prediction

In order to prevent damage and failure in equipment we need to be able to predict it. This is done through inspection and condition monitoring, in particular looking out for:

• Changes in vibration
• Changes in temperature
• Particles in lubricating oil

These changes can be detected by both formal and informal techniques, of which the most useful is often your crew’s and supervisor’s own senses. If used correctly (and safely!) your people’s eyes and ears can detect problems with equipment long before failure occurs.

The more formal monitoring tools and techniques that will assist with the overall condition monitoring approach include:

• Thermography - by identifying an abnormal temperature profile, we can identify problems or
• Oil Analysis - provides three indications of the effectiveness of a lubrication system:
• Condition of oil - Is oil specification suitable?
• Condition of lubrication system - presence of water or silicon indicates repair may be required
• Condition of equipment - presence of machine particles indicates wear
• Vibration Analysis – used to diagnose:
• Imbalance or misalignment
• Mechanical looseness
• Flow-induced vibration
• Belt drive problems
• Ultrasonic Analysis - used to diagnose:
• Valves passing fluids
• Bearing problems

C. Assessing response

We see considerable time and money being spent treating failure symptoms while maintenance costs creep up. This step trains and then ensures the maintenance team is conducting root cause analysis of the identified abnormality. Ideally, this approach should be built on your existing good practices.

If basic monitoring, scheduling and planning aren’t in place, root cause analysis will point to these deficiencies. Typical outcomes of these analyses are identification of the wrong amount or type of lubrication; contamination; shaft misalignment; unbalanced equipment; and missed inspections and overhauls. “Process” or “human” causes often relate to lack of proper follow-up of failures.

D. Response

It’s crucial that you have well-communicated, simple roles and responsibilities for preventative maintenance personnel and others in the organisation that will be involved in the process. Below is an example of a simple RACI chart that can be used for communicating the process and clarifying specific roles for all functions associated with the process. This ensures that all actions are implemented – a pre-requisite for true predictive maintenance.



RACI - identifies who is Responsible, Accountable, needs to be Consulted, needs to be Informed about a task or action.

E. Hard-wiring

The wiring phase ensures that the predictive maintenance process, roles and responsibilities are well managed and sustained. This phase is about effective, continuous implementation of the practices by the organisation. Utilising PIP wiring tools ensures strong execution throughout the organisation.

The first step is to put in place a system to track performance. This requires a session to agree targets and KPIs for the function. These typically include:

• equipment availability
• maintenance budget
• other resources required

The next step is to set regular and formal reviews of performance using Results-Action-Reviews (RAR) at all levels of the maintenance department. A RAR consists of the following steps:

1. Review results – did it work? How are the KPIs tracking?
2. Review actions – did we do what we said we’d do?
3. Agree future results and actions
4. Prioritise future actions
5. Assign resources to advance highest priorities
6. Communicate key information

This creates a closed loop to review performance by tracking actual KPI results against targets, using pareto charts to highlight problems and taking appropriate actions. This is then followed with supervisors doing effective short interval control to ensure, for example, that actions don’t slip into the next day.

There is a misconception that predictive maintenance is unduly costly: that it costs more for regularly scheduled downtime and maintenance than to operate equipment to the point of failure.

This may be true for some components; however, it’s important to compare not only direct costs, but also the long-term benefits associated with predictive maintenance, including avoided costs for lost production time, and savings due to increased effective equipment service life.

Good predictive maintenance may cost a little more up front, but it keeps a very costly horse from bolting down the track.

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