SKF Lubrication solutions for construction machines and equipment
2016 July 01, 09:00 GMT
Automated lubrication offers compelling benefits for mine and quarry operators seeking lower costs and higher productivity, explains Matt Preston, Lubrication Application Engineer at SKF.
The end of the resource supercycle has forced an abrupt change of focus for basic materials companies. Years of rising demand and high commodity prices meant maximising output was the overriding priority for operators. Today’s world of dramatically tighter margins means the emphasis has shifted decisively to efficiency improvements and the control of costs.
In this environment, companies are under considerable pressure to find new ways to boost the productivity of their assets. They want to maximise output per unit of labour, and to ensure that machines run as efficiently and reliably as possible.
The search for optimal efficiency is by no means easy, however, requiring companies to consider complex trade-offs between cost and output, and to take a holistic view of the performance of their entire operations. Take preventative maintenance for example.
Everyone knows that equipment needs to be looked after if it is to perform at its best. And unplanned stoppages due to equipment breakdowns take a significant toll on operating efficiency. But maintenance activities carry their own costs, including labour, materials and the downtime necessary to complete the work. Worse, incorrect maintenance procedures can actually degrade equipment performance, or even cause breakdowns.
One of the most fundamental parts of any maintenance programme is lubrication. Bearings, chains and many other elements of mining and quarrying machinery require regular lubrication to reduce friction and wear. The amount of lubricant required for a component like a bearing is determined by the physical space available inside it. The required lubrication interval is determined by the rate at which that lubricant is degraded, which in turn depends on the speed, load, temperature and degree of environmental contamination to which it is exposed. Manual lubrication approaches tend to compromise both quantity and frequency. It can be difficult for maintenance staff to deliver precisely the required quantity of lubricant to each bearing, for example, and the natural response of most technicians is to over, rather than under, lubricate. Similarly, the cost and inconvenience of manual lubrication means operators tend to extend lubrication intervals as much as they can, increasing the risk of damage due to lubricant starvation.
Less waste, fewer failures
One route to a better balance of costs, risks and equipment performance is the replacement of traditional manual lubrication strategies with an automated approach. Automated lubrication systems can be programmed to deliver precise quantities of lubricant at regular intervals, without the need to stop the machine to allow for access by a technician.
Automated systems provide a host of direct and indirect benefits to equipment operators. It is not uncommon for grease consumption to cut by a third or more, simply by ensuring that bearings and other parts receive the optimum quality of lubricant. Optimising lubricant quantity increases equipment performance too, since over-lubricating bearings can increase friction and accelerate wear. Automated systems can also optimise lubrication intervals, for example, by delivering smaller quantities of lubricant more frequently than would be economic using a manual approach. Automated systems don’t forget to lubricate critical bearings, as human technicians can. And since an automatic system delivers lubricant through sealed supply lines direct to the point of use, there is less risk of dust and dirt being introduced into the component during the lubrication process.
By relieving maintenance technicians of routine re-lubrication work, automated systems also allow operators to make better use of their human capital.
Maintenance staff can spend more time on higher value activities, such as analysing the root cause of equipment problems and pursuing continuous improvement activities. There are also direct health and safety benefits from the reduced need for staff to access inaccessible and potential dangerous areas. Finally, automated lubrication provides real environmental benefits, from reduced energy consumption thanks to optimal equipment performance to a reduction in the quantity of excess lubricant released into the environment.
Automated lubrication systems come in a wide range of designs, from simple, single-point lubricators such as the SKF SYSTEM 24 range to highly sophisticated centralised systems that can control lubrication to multiple points on a large machine.
The latest centralised lubrication systems can be controlled using industry standard CAN-bus technology. This provides further benefits for operators, simplifying the installation and wiring of the system controls, and allowing the lubrication system to be tightly integrated with other components on the machine. In quarrying, for instance, it allows each section of a hydraulic excavator – such as slewing ring, boom, arm and bucket – to be lubricated independently, according to specific operating conditions. It also allows separate control and monitoring of each section, alerting operators to errors before major problems develop.
One German construction company used CAN-bus technology to integrate centralised lubrication into a fleet of 50 off highway machines. For example, it has equipped one type of Atlas wheel loader with a single pump unit to serve a zoned progressive lubrication system. Each zone is controlled by electronic valves and functional monitoring is performed using cycle switches, which are engineered to detect problems such as a lack of lubricant. Lubrication is fully integrated with the on-board computer via electronic control. It can be configured through the on-board display where the operator can view lubrication errors by zone across the machine.
For that operator, centralised lubrication has reduced grease consumption by around 28 percent across the entire fleet, equivalent to 668 kg of lubricant. The company estimates that these savings could be boosted by a further 20 percent as its increasing understanding of real world lubrication requirements help it to optimise the way the system is configured and used.
Getting it right
The installation of automated lubrication systems isn’t a panacea for equipment reliability challenges. To work well, systems have to be designed and installed carefully, with proper consideration given to the lubrication requirements of the application, the types of lubricant used and the re-lubrication strategy adopted. Not all lubricants are suitable for all automatic lubrication systems, for example, and different lubrication systems have different effects on the structure of the lubricant they dispense. Similarly, re-lubrication intervals must be defined in a way that prevents the lubricant from being stationary inside the lubrication ducts, especially when exposed to extreme temperatures that could promote premature degradation. Nor are automated lubrication systems a fit-and-forget option for operators. Periodic inspection is required to identify installation issues such as damaged fittings, leaking or blocked pipes or lubricators not dispensing at the right pace. And the quantity of lubricant in the system must be regularly monitored.
For many mining and quarrying companies, however, automated lubrication could be one more important weapon in the on-going battle against rising costs and poor efficiency.
This article was featured in the July 2016 edition of Solids & Bulk Handling magazine.