Maintenance strategy machines and devices

There is some game on slot machines which involves hitting the heads of popup mascots with a hammer. That’s the way some businesses approach maintenance. They wait for the fault and only then remove it in emergency mode. This is no optimal approach. Maintenance on the machines is saved, but unplanned downtimes are a financial loss. It is even worse when the machine is part of a production line and, because of the failure of one piece of equipment, the entire line is stopped.

How about keeping a set of all spare parts in stock and a service team ready at all times in the event of a breakdown? Similar to a pit stop in Formula 1 – we quickly replace components with functional components and continue production. The question is who has the means to maintain high-cost service facilities.

So how do you get out of emergency stops without spending all your profits on prevention? The answer is to come up with the proper strategy.

Maintenance strategy – or which maintenance strategy for machinery and equipment?

Numerous books have been written about this. They recommend different approaches to the topic, but a recurring element is the need to look at certain parameters that characterise the plant. Several questions need to be asked:

• Critical assets. What machinery is critical to the production process?
• Work planning. When must it be done to generate revenue?
• Frequency. How often should reviews take place?
• Legal requirements. What rules must be observed?
• Money. Where are the sources of revenue the company has?

Maintenance of machines as a compromise

There is no doubt that the machines have to be maintained – maintenance and replacement of worn parts. During maintenance, the machine is not running and therefore – at the same time – not earning. However, without maintenance, the machine will break down more and more frequently and downtime will occur at indefinite times, disorganising the production schedule.
Scheduling machine shutdown and performing maintenance is certainly more beneficial. They can then be adapted to the production plan, depending on the work of other interdependent machines. This is particularly important in seasonal production when one can determine when a machine is highly profitable and when it is operating at reduced capacity due to lower demand.

Reactive and preventive action

It is important to answer the question as to what the losses will be if the machinery breaks down. If it is small, it is not worthwhile to undertake more expensive prevention. This is a reactive approach, ie the machine operates until the fault occurs.

However, it is more common to encounter a situation where every hour a machine (or even an entire line) is out of service represents a large loss, in which case preventive action must be opted for. This is especially true if the spare parts are not available off-the-shelf and require a certain waiting time for delivery, and are so expensive that it is not worth keeping them in stock.

Preventive Maintenance (PM)

Regardless of the condition of the machine, periodic inspections are conducted following a specific schedule. They are very safe because they give almost 100% assurance that the machine will be operational for some time. However, they do not take into account wear and tear in parts, so parts that could still function successfully can be replaced. This strategy is right for production critical machines.

Predictive Maintenance – Predictive Maintenance (PdM)

However, it is not possible to predict all failures based on routine inspections alone. There is a category of failures that can be avoided by observing certain statistics of machine functioning, for example the frequency of shutdowns as a result of the need to adjust the settings. If such a need – but not a fault in itself – occurs with increasing frequency, it indicates the gradual deterioration of a component. By having the data to detect such stoppage trends or long-term trends in the values of certain parameters, we can anticipate impending failure and adjust repairs to the production plan in good time, even before the machine breaks down.

Predictive maintenance involves predicting the occurrence of a failure based on data collected from multiple sources, including the use of statistics and trends that give precise information about an impending failure. This requires investment in data collection systems, but this approach considerably prolongs the overall life of the machines. A wide range of different information should be taken into account in the forecasts:

• Data from CMMS systems
• Production forecasts
• Production history
• Documentation
• Quality control standards or regulations
• Financial impact
• Labour costs and availability

Maintenance planning in connection with the production plan

One example of alignment of inspections to a production plan is a machine that produces mineral water bottles. During the summer season, it is expected that the machine will operate at full capacity. Long technical inspections are thus not recommended. It is much better to plan them for a period of reduced demand for bottles, i.e. during autumn and winter.

Summary

Proper communication between the crew and company management is essential to the development of a maintenance strategy. Well-trained and informed team members can be an important support to the operation of the plant since the crew is the first to be able to detect emerging problems. CMMS systems are an essential tool in this communication. They allow the transmission of information directly from the production chain to management. This information may also be reviewed in terms of statistical indicators and, on this basis, used as a basis for production planning decisions, taking into account the necessary revisions. A properly planned CMMS may provide useful information for maintenance work. It allows you to schedule the required work and parts. A properly prepared machine maintenance and inspection strategy is an integral part of the management strategy for the company as a whole.