More than half of bearing failures are the result of improper lubrication. Shops know that bearing replacement can be costly, and lost production time can multiply those costs.
The majority of bearings are lubricated manually, which typically means the machine is stopped and a worker is physically applying grease, resulting in machine down time and often less than ideal lubrication application. Automated lubrication systems can take the guesswork out of machine maintenance, decreasing down time and increasing a shop’s bottom line.
From Steam Era To Digital Era
Automated lubrication was first developed for use on steam engines in 1860. These first automated lubricators were imprecise, as they used steam pressure to dispense lubricant. Steam-pressure lubricators were replaced at the turn of the century by more consistent mechanical lubricators, but these only lubricated at a set rate. Again, not ideal.
Modern automatic lubrication has moved into the digital age, and companies such as Graco, headquartered in Minneapolis, offers complete systems with programmable controllers that run on a schedule tailored for each unique application. Unlike their crude predecessors, automated systems can add lubricant on a precise schedule, applying only what is necessary for optimal performance.
Advantages of Automation
A grease gun is cheap and is the go-to lubrication tool of choice for most shops. However, the grease gun only lubricates on a set schedule, and even a weekly lubrication schedule may not be sufficient for some bearings. Bearings in heavy use can “wear out” lubricant in a short period of time and require more frequent application of lubricant.
An automated lubrication system can apply a smaller amount of lubricant on a more frequent basis, keeping lubricant fresh and effective. It can also reduce down time since the machine is being lubricated while its running. Lubricating a bearing while it is running is ideal, since the lubricant flows throughout the moving parts.
There’s also an advantage to lubricating the part in small doses vs. periodic large doses such as less wasted lubricant and more consistent lubricant flow throughout the part. With more consistent lubrication, machines run more efficiently, more precisely, and save energy.
Machine lubrication often introduces safety concerns. Even when lock out/tag out procedures are followed, maintenance workers are often asked to enter small or cramped spaces to access parts. And with less consistent lubrication, parts replacement increases, therefore increasing the possibility of work-related injury. Finally, no one wants to shut a running machine down, so this can spread a lubrication schedule out beyond the limits of the lubricant’s lifespan.
Converting To Automation
An automated lubrication system such as those Graco offers consists of a metering device, pump, controller, and injectors. The metering device is the heart of the system and controls how much lubricant is flowing to the given part. A pump supplies lubricant to the metering device, and the pump is run by a controller that is programmed for when and how often the machine receives lubricant.
Finally, the system requires adequate tubing and fittings to handle the type of lubricant and pressure being used in the system, and the tubing feeds injectors which are placed at the lubrication site to dispense the lubricant. It is important to note that fluid will always choose the path of least resistance, so using individual lines for each lubrication point is critical. Using a T fitting is not an option when constructing an automated lubrication system.
Automated lubrication systems can be as simple or as complex as needed, and additional parts such as sensors, filters, and check valves can also be integrated into an automated lubrication system, but each system will have unique demands.
According to Dan Jensen, Graco Industrial Lubrication Equipment Global Product Manager, customers utilizing automatic greasing units have seen an increase in machine up time due to the greasing system providing the proper amount of grease to the lubrication points. This ultimately has increased end users bottom line earnings and allowed their employees to focus their efforts on tasks other than machine greasing.
Once up and running, an automated lubrication system requires only periodic checks to insure reservoirs are full and that the system is online and running properly. Automated lubrication save time, energy, and reduce safety concerns that come with periodic maintenance.
This story originally appeared in the May/June 2018 issue of Precision Manufacturing, the Journal of the Minnesota Precision Manufacturing Association (MPMA).