Eliminate Variations for Repeated Tasks

The more often as task is repeated, the easier it is to justify improving it. If you seldom perform a task, it doesn’t make sense to target it for improvement. However, often-repeated tasks may comprise the greatest percentage of your time, so improving them can have a large and immediate impact on productivity.

Columns From: 4/18/2011 Modern Machine Shop,
What tasks do you repeat the most, and what keeps you from consistently completing them in the most efficient manner possible? Of course, every company will have different answers to these questions. Indeed, every person within a company will have different answers.
 
So consider these questions from both a company-wide viewpoint and from a personal one. Does your company have jobs that are often repeated? If so, you should be targeting the most often-repeated jobs for improvement, as they will have the biggest impact on your company’s output. Do your employees have tasks they repeat on a regular basis? Then you should be targeting them for improvement as well. In most companies, each person has a core set of tasks they must perform over and over again. Improving these tasks will improve that person’s productivity, which in turn, will also improve the productivity of your company.
 
The biggest productivity-killers of often-repeated tasks are variations that occur from one time the task is performed to the next. As you look for ways to improve repeated tasks, be sure to eliminate variations. Indeed, simply eliminating variations may be all it takes to improve a given task. Regardless of how much engineering you do to improve a task, remember that until you’ve eliminated variations, there will be inconsistencies in the productivity related to performing the task.
 
With repeated jobs, for example, a variation in raw material hardness can require wasting time to change cutting conditions. A variation in cutting tool construction can result in unacceptable workpiece surface finish. A variation in workholding device placement on the machine table or cutting tool placement in the tool magazine can result in a longer cycle time. A variation in the amount of preparation performed prior to starting the job can result in longer setup time. Variations are productivity killers. Eliminate variations, and jobs will run consistently every time. 
 
It can be more difficult to eliminate variations in often-repeated tasks that people perform. If you haven’t provided guidance to help them learn how to perform their tasks, it’s likely that each person performing the task does it differently—and it’s likely that one of them is performing it more efficiently than the others. Getting several people to buy into a more efficient process after they’ve been doing it a different way can be difficult. 
 
Consider the task of workpiece loading on a vertical machining center. One person may clean and deburr a completed workpiece immediately after removing it from the machine while the machine is idle. Another may wait until after the next workpiece is loaded and the cycle is restarted to clean and deburr. Obviously, the person who cleans and deburrs while the machine is running will be much more efficient.
 
Another productivity-killing variation that often occurs among shop people is related to tightening fasteners. One person may apply so much force to a fastener that another cannot loosen it. Or worse, someone may not apply enough force to hold the component securely enough.
 
One more example is related to changing inserts on dull tools. If your operators have not received any special training, it’s likely that each will replace inserts at different intervals. You might even have some operators who replace all inserts at the beginning of their shifts, regardless of how dull they are.
 
You might also see variations in the way a given person performs an often-repeated task. One time he or she might set a wrench down on a work bench. Another time he or she might leave it in a drawer or on top of the machine. There are three places this employee will have to look every time he or she needs a wrench. This is only one example of personal variations from one time a task is done to the next. Depending on how much guidance you’ve provided, you may find many more. 
 
To eliminate employee performance variations among people who have been with your company for some time, I suggest determining who is performing a certain task best (both safely and efficiently). Then, they can show the others. This person is usually the most experienced and should be able to win the respect and confidence of the others. Most people, once they see a better way of performing the task, will quickly change their methods.
 

For new hires, you can eliminate productivity-killing variations by providing them with training. It is usually much easier to show new people what you want them to do and expect them to do it than it is to retrain existing employees.  

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