Output lost due to an unplanned stoppage cannot be recovered without cost implications and in the meantime, customers are likely to go elsewhere, perhaps never to return. Other repercussions of equipment failure can include a deterioration in the quality of your product and potential impact on your business’s environmental, health and safety performance.
With this in mind, many companies have adopted one or a combination of several maintenance approaches to ensure the integrity of their production systems.
While strategies such as 5S, reliability centred maintenance (RCM) or total preventative maintenance (TPM) can be extremely effective, these are some of the more difficult of the lean tools to implement because of the shift in culture that’s required.
To successfully adopt TPM it must be built on the foundations of a lean culture and the process could take as long as two to five years to fully implement. This can be discouraging and as a result, plant maintenance is often the area of potential lean process improvement that lags furthest behind.
But you don’t need to fully adopt TPM to introduce processes that help mitigate the risk of unplanned downtime. Below are some tips that will reduce plant downtime and increase productivity.
Operators who take pride in the condition of their equipment are much more likely to take proactive steps to ensure its smooth running, and while this outlook may require a culture shift within your business, the benefits to productivity will be significant.
Training should focus on the correct use of equipment and operators should be regularly assessed in this regard, with lapses addressed through further education. Of course there are time and cost implications to training your workforce, but these considerations are offset by the benefits inherent in implementing a training schedule that ensures your staff use their equipment as intended.
Operator manuals – whether paper-based or electronic – should also be kept up-to-date and operators notified of any relevant changes to process or procedure.
It can be difficult to determine how frequently components should be inspected but manufacturers can often help by suggesting predicted failure rates. You can also record and measure these failures yourself to fine-tune your maintenance scheduling. Failures can be recorded in a maintenance log that you may also be used to ensure that operators and technicians are complying with schedules.
Components that require regular inspection, maintenance and lubrication include bearings, gears, sprockets, shafts and any other moving parts. Components with friction material – such as pads or linings – also require regular inspection as they’re prone to wear due to their function.
Seals and gaskets will eventually dry out and begin to crumble away, preventing an effective seal and allowing the ingress of contaminants.
Oil or lubricant analysis should be carried out regularly by experts in this field, who will be able to identify contaminants and provide insight into which components require attention.
Other machine parts that do not require daily lubrication should still be monitored closely for signs that lubrication is necessary. There are condition monitoring and sight glass products on the market that are extremely effective in aiding in this process.
It’s also important that the appropriate lubricant is used, with many specific types available for use on different components. The plant or component manufacturer will be able to advise.
Contamination – particularly water ingress – can be harmful to machinery and is a significant cause of equipment failure. Seals and filters should be monitored and replaced when necessary to prevent contamination, and lubrication is also essential to avoid corrosion.
Things to watch out for include misaligned or worn belts, pulleys, gears and sprockets. Replacing these components as part of a scheduled maintenance programme will have significantly less impact than were they to fail, and in some cases failure of such components can lead to the catastrophic failure of the system itself.
Increased vibration is another sure sign of a problem, perhaps caused by belt misalignment or unbalance of rotating components. Rotors include rollers, shafts, flywheels, armatures and fan blades, all of which must rotate with the centre of mass aligned with the centre of rotation.
When an unbalanced rotor spins it will do so inefficiently, causing vibration and likely doing damage to the component itself, the machine more generally, and even machine housings or foundations. When vibration is detected and the rotor found to be the cause, the component can be balanced to eliminate the problem. It’s also be wise to schedule the static or dynamic balancing of rotating components to ensure efficient operation.
Age of components is also a factor, with belts warping and seals drying and becoming brittle. Components can seize and bolts may loosen over time due to vibration. Age should be considered when monitoring equipment and preventative measures taken when it’s felt that a component may be nearing its end of life.
The 5S methodology (Sort, Set in Order, Shine, Standardise and Sustain) is the foundation of any TPM strategy and is a workplace organisation method that can help inform you as you strive to improve manufacturing productivity.
Plant and other equipment should be kept clean, with seals and filters monitored for deterioration, as these are essential to prevent contamination that will impact the performance of machinery. Desiccant breathers should always be kept in good working order to ensure they help prevent the ingress of moisture and/or dirt.
Electronics in particular are susceptible to damage by water ingress or dirt building up inside the cab. Sight glasses and other condition monitoring devices should be kept clean to ensure operators can easily monitor oil and lubricant levels.
Condensation can cause corrosion and the risk should be mitigated through dehumidification or oil-mist lubrication.
Belts, pulleys, friction material and seals should be checked as these are all prone to deterioration when equipment is not in use, and wires or cables should be checked for damage caused by any rodents you may share your facility with.
Brand new equipment is all too often stored in unsatisfactory conditions until installation is possible and it can be startling how quickly machinery can deteriorate when out of sight and not in use. Even where machinery is unlikely to be used by your company in the future, it can be important to ensure it’s stored in appropriate conditions as any deterioration could impact resale value.
The appropriate transit of equipment is also important, and large machinery should typically be covered, well secured and components protected from the rigours of transport through the use of anchorage or transit bolts where possible. It also pays to insure machinery during transit should there be any kind of mishap.
However, if unplanned downtime is undermining performance efficiency and disrupting production at your facility, adopting some or all of the measures outlined above will surely help you address those issues. And where TPM is the ultimate goal, adopting our tips could also act as a gentle introduction to the methodology for a workforce not quite ready for the culture shift.
Burnley Balancing is a Lancashire-based engineering company that specialises in static and dynamic balancing of industrial rotors.
Burnley Balancing www.burnleybalancing.co.uk