One question I commonly get during Noria training classes is: "Our plant has X number of machines. How many lube techs do we need to do a proper job of lubricating them?" While the question may seem simple, the answer is not. You see, it depends on a number of factors.
First and foremost, we must consider physical plant layout. While it may be easy for one technician to maintain 500-plus machines that are laid out in a linear fashion on a single floor, many sites - particularly older plants where expansion has forced machines into every nook and cranny - take more time for even the most experienced tech to navigate, particularly where stairs are involved.
Next, we must consider machine complexity. If most of the assets are simple machine trains (e.g. electric motor, coupling, pump), the number and complexity of lubrication tasks are fairly simple. But, if the machines have multiple oil or grease points in hard-to-reach places, each machine could take a considerable amount of time to maintain.
Then, we need to consider accessibility. If each lube point is easy to access under normal operating conditions, the act of lubricating the machines becomes simple. However, if there are accessibility issues requiring partial disassembly of covers or guards, the time to get to the lube point may exceed the time required to perform the task. In fact, if for safety reasons the task can't be performed without full lockout/tagout, you can opt to make minor modifications in order to turn a downtime task into a runtime task.
Another consideration is the degree to which automation is included in basic machine relubrication. While single- or multi-point lube systems must still be periodically checked and can't be considered as "set it and forget it" add-ons, their use, particularly for hard-to-access lube points, can be a major time-saver.
Finally, we must look at the degree to which condition-based lubrication tasks have been assigned. While tasks such as regreasing motor bearings or changing oil in a process pump are relatively quick and simple, multiplied across multiple plant assets, the time requirements can be significant. Where feasible, convert routine preventive (time-based) tasks to condition-based tasks driven not by the calendar or hour meter but by feedback data from simple inspection or more sophisticated predictive tools (oil analysis, vibration analysis or ultrasonic).
So, how do you determine the correct staffing levels for lubrication? First, take a look at what work is currently being done in order to rationalize the lube PM list. Studies show that up to 50 percent of all PM tasks either provide no value or are themselves detrimental to the machines. In optimizing lube PMs, consider eliminating as many time-based PMs as possible in favor of condition-based tasks. Also, look at machine design and configuration to determine if downtime tasks can become runtime tasks.
Once you rationalize the list of lube PMs, the next step is to organize the required tasks into routes that are ordered and scheduled in the most efficient, logical manor. This is where many companies miss the mark. While it may seem logical to group like tasks into one lube route (e.g. electric motor regreasing), this can create some real inefficiencies as techs visit the same often-remote location several times a day - perhaps first to grease the motor bearing, then to take an oil sample from the gearbox sitting beside the motor, and finally to grease the pillow block bearings coupled to the gearbox. Instead of grouping tasks based on task type, try to issue work plans and routes based on geographic location to minimize travel time and optimize efficiency. In doing so, routes should include the automatic creation of required "tools" (grease gun with product X, oil sampling kits, etc.) so that kitting for the route becomes simple.
Finally, associate a time stamp with each task or route. For example, imagine a route with 50 tasks; each task should take six minutes to complete. Factoring in 60 minutes for kitting and travel time, the full route should take six hours, or 75 percent of a man-day (assuming an eight-hour shift). Once each route or task type has been time-stamped, it's a straightforward job to convert the total required time to a total required full-time equivalent (FTE) headcount for lubrication.
But wait, you say! What about TPM and operator-assisted lubrication? Whether or not your company subscribes to lean principles, it shouldn't be a factor. There are a finite number of tasks that must be performed, and each task takes a finite number of hours/minutes to complete. So, whether the work is being done by dedicated lube techs, mechanics who are part-time lubricators, or operators, the total number of FTEs required to lube the plant is unchanged.