Tuesday, March 2, 2010
Balance the Work and Free Up Workers
When you have moved workstations closer together, so that product can be moved through the process one piece at a time, there is no longer the waste in accumulating batches of product that just sit there, but you are likely to discover some additional waste, previously hidden by the batch process. Now some people in the process must wait for product to work on, or must wait for the next process step to be completed, so that the product in process can be passed to that operation.
Having people wait is wasteful. They are just standing or sitting there without adding value. Often, instead of just standing there, they will do something to keep busy. These are wasteful activities. Even if they are adding value by building ahead, it is wasteful because the result of their activity is going to just sit. When material just sits there, we run the risk of bad things happening to it.
In one assembly process where the workstations had been moved close together, and there was now a flow of one piece at a time, the last person on the line had the responsibility of making up a box, putting the product in the box and taping the box shut. Because she had time on her hands, instead of simply waiting for the next part she would make up boxes ahead of time and stack them at the end of her table. At one point she had more than a dozen, stacked high. Someone walked by and brushed against the stack. The entire production of boxes fell to the floor and scattered over an area.
The worker had to stop everything else and pick up all the boxes placing them on the table in a high stack again. While I watched, the stack was once again scattered across the floor. The “rework” of re-stacking the boxes each time they were knocked over does not add value and the process of stacking and knocking over the boxes can damage them.
I have seen stacks of made-up boxes moved onto storage racks next to boxes that were still flat and un-opened. The line had changed over to a different product, and the inventory of opened boxes had to be stored while a new box was put on the line. A box that has been opened, taped, and stacked has a much greater potential for being damaged than one that has been kept flat, as it was received from the supplier.
The impulse of the worker is to keep busy. To most workers it does not feel right to stand and wait, so they find something that seems productive to keep busy. It also keeps them out of trouble. Supervisors and managers are likely to question why someone is just “standing around.”
We need to change the way we think about a couple of things. We need to let go of the idea that each person has a proprietary workstation, with equipment and tools that “belong to” that operator. We need workers who can run several of the operations in a production line (in some cases all of them) and not be tied to one station. For the purpose of balancing the work a worker may do a portion of the work done at one station, then turn around and work the station behind her. Another worker finishes the work on the first station and takes the piece being worked on to the next station where he starts the process.
In Japan I had the chance to see a production line, making a component for a copier machine, in which one operator moved through the entire line, loading and unloading automatic processes, and doing manual operations that included, finally, wrapping the component in special paper and packing it in a box. In another work cell a single operator loaded, unloaded and inspected a flywheel that was going through a series of machining operations.
We need to change our thinking about people being idle and what we communicate about activity. If we see people who are waiting for material or are waiting to deliver their work to the next step, this gives us information about opportunities to improve the process. It is waste that we can see. If everybody keeps busy for the sake of keeping busy, the waste is hidden.
We will discuss a way to calculate the distribution of work to optimize a work cell in a future post. If the workers participate in the redesign, and they understand the approach of eliminating waste, they can go a long way to figuring out on their own how the work needs to be redistributed once the workstations have been put closer together in a work cell.
In practically ever case where we put workstations closer together and apply one-piece-flow, we find that we can do the same work with fewer people. How we think about, talk about, and take action about this fact has important implications for success of an on-going effort to make work more productive and effective. If we talk about “eliminating” people, and act upon it by laying people off, we will build resistance in the workers to these changes. They may work quite hard to prove that the new way doesn’t work. On the other hand we can think, talk, and act about “freeing up” people. We take the best of the people, free them up, and used them to help us extend the improvement process to other processes.
If we need to reduce headcount, we do it through attrition. We can also see that part of management’s job, particularly of those in Marketing, is to sell the freed up capacity of the enterprise. I have worked with companies that were considering moving operations to Mexico, because they believed their capacity had reached its limit. In fact, we were able to free up so much capacity that the move was no longer necessary.