Manufacturers, more so than ever, need to maximise the overall productivity of their assets.
From a maintenance perspective, that means minimising both unplanned downtime – breakdowns or equipment failures – and planned downtime for routine maintenance interventions.
Many companies are using new technologies to help them meet those objectives, automating previously manual maintenance tasks, for example, and adopting condition-based strategies to ensure maintenance is conducted exactly when required.
“Industrial maintenance is often seen as non-productive time. What many do not realise is that one of the easiest ways to achieve this is to keep machinery and equipment clean and ready for use,” says Mark Burnett, vice president of the lubricants and fuel additives innovation platform at NCH Europe.
Lubrication activities can be the root cause of up to three quarters of breakdowns in industrial equipment
Lubrication is one of the most fundamental maintenance activities. In fact, explains lubrication systems application engineer at SKF, Matt Preston, lubrication activities can be the root cause of up to three quarters of breakdowns in industrial equipment.
Accessing hundreds of separate lubrication points in a large machine is hugely time consuming, which prevents personnel using valuable shutdown periods for other activities that could improve overall machine performance and reliability.
Use of the wrong lubricant or the wrong quantity can damage equipment or shorten the operating life of components, and spilled lubricant can contaminate product or create health and safety problems.
“The life of rotating machine elements can be significantly extended by the use of greases appropriate to the different operating and environmental conditions, as well as the definition of and adherence to lubrication intervals and quantities,” states maintenance services information at Schaeffler UK.
Although often neglected, proper grease-lubrication of industrial equipment and machinery makes everything run smoother, more efficiently, and minimises problems associated with high temperature, friction, wear, rust, corrosion and extreme pressure.
The three most important areas that need to considered when choosing a lubricant are: how it handles heavy loads, how it handles heat and friction, and how it handles contamination
Mark Burnett, VP lubricants & fuel additives innovation platform, NCH Europe
“Despite the fact that at least 70% of greases are lithium based, newer calcium sulfonate greases offer superior multi-purpose performance, explains Burnett.
“The three most important areas that maintenance engineers need to consider when choosing a lubricant are: how it handles heavy loads, how it handles heat and friction, and how it handles contamination or particulate matter.”
Whether it’s the bearing on an industrial pump or a bucket pin on an industrial digger, machinery can exert heavy loads on the grease. Under heavy loading, lesser greases will quickly lose their structural integrity and get squeezed out of equipment.
“For heavy loading, NCH Europe developed K Nate, a calcium sulfonate grease made using a blend of tackifier additives and adhesive polymers that allow it to stick to surrounding metal as well as cohesive polymers that allow it to stick to itself.
“This formula means the grease can minimise the effects of excessive wear and heavy load shock conditions, withstanding a weld load in excess of 800 kg on a four-ball machine,” says Burnett.
Extreme contact temperatures, combined with operating and ambient heat in applications such as steel mills, where equipment such as blast furnaces, electric arc furnaces, casting machines, cranes, transfer cars and mill motors, can cause catastrophic failure. This leads to extended downtime, charred grease and unprotected bearings.
“To combat heat, maintenance engineers need to look for a grease that has a high-working temperature and dropping point, along with extreme pressure agents.
“For example, K Nate provides effective lubrication from -30 to 200°C continuously. It offers a dropping point – the point at which a grease moves from semi-solid to liquid form – of 288°C. A high dropping point reduces grease consumption, providing protection for longer,” says Burnett.
Water, dust and corrosion are understood to be the three biggest killers of industrial equipment.
Burnett explains: “No matter how much you try to minimise ingress, over time your grease will come face to face with these problems.
“Especially susceptible are applications such as packaging, card and paper processing plants where, despite the best ventilation and ingress protection, dust can infiltrate motor housings over time, clogging air filters and overheating windings.
“Dirt and other organic matter can mix with grease to become an abrasive powerful enough to score bearings, cause pitting on gear teeth, and lead to long-term microbial growth,” says Burnett.
Combined with exposure in outdoor environments, or steam and condensation in indoor plants, water washes away grease like there’s no tomorrow, leaving surfaces unprotected.
In many cases, periodic manual lubrication is still the best option, although companies can save time and improve results by using appropriate tools
Matt Preston, lubrication systems application engineer at SKF
This is another reason why continuous production plants can never be truly shut down, instead being serviced in a phased process.
If the plant is shut down entirely, lubrication dissipates, corrosion sets in and equipment seizes up when the system is restarted.
Picking the right lubrication strategy for a given asset will cut the time and cost required for preventative maintenance while also providing significant improvements in uptime and equipment service life.
“But there’s no one right answer for every asset,” explains Preston. “In many cases, periodic manual lubrication is still the best option, although companies can save time and improve results by using appropriate tools.
“Power-operated lubricators, like those in the Lincoln PowerLuber range, deliver precisely metered quantities of lubricant at the touch of a button, which is faster and less strenuous for maintenance personnel, and better for the machine.”
Increasingly, companies are choosing to automate the lubrication process with permanently installed systems that deliver small quantities of lubricant at appropriate intervals.
Those systems are available to suit any size of application, from a single bearing to an entire plant with hundreds of separate lubrication points.
The most advanced modern lubrication systems have a high degree of built-in intelligence. They can adjust lubrication rates according to machine utilisation, for example, and monitor their own performance, alerting operators if there is a problem with lubricant supply.
“They are increasingly flexible too. The new Lincoln EDL1 electrically driven lubricator [pictured above],” says Preston, “is a programmable pump that can be installed directly on a machine to inject grease at a pressure of up to 280 bar (4,060 psi) to the connected lubrication system or lubrication point.
“The EDL1 operates without the need for a separate compressed air supply and can be fed by a single low pressure lubricant feed line, which simplifies the pipework required in large installations.”
Even if you don’t neglect the regular maintenance and repair of your industrial machinery and equipment, using a high quality grease can be vital.
“From higher temperature and load endurance to a more sophisticated ability to combat contamination, a good grease makes all the difference,” concludes Burnett.