7 wastes - motion

First of all, let me introduce the wastes in motion by some cases in assembly. It was a most common case we saw in assembly line, it is so common because it looked not a serious issue or waste in our mindset. However, if we make a calculation for the wastes we made by that way, the result will make us so surprise why we ignored the issue. Actually, everything we did in process can be calculated its performance or waste by a very simple analysis. The problem is we always think the way we did is common practices and lie to ourselves it is not a issue.

The first case, let's say the opreator needed to move one step to her left-hand-side to pick up the WIP for next process as shown in the figure above. The process takes 30 seconds to complete. The first question is how long for one step we move? In order to have a simple calculation, I says one step is around 50cm. Also, I given the operator is working 8 hours per shift, therefore, the calculation is 8 hrs X 60 mins X 60 seconds / 30 seconds X 50cm = 48000cm or 480m. The next question is that 480m is value-added for the production? If not, the third question is how many workers are working in the same way in the production? You can complete the calculation by yourself and find it would be a very long distance they moved but it was non-value-added. If your IE counted the process one by one, they would say it was only 1 to 3 second and not a big deal. However, if you have 1000 workers and they are all working in that way, what do you think now?

The second case was also common and caused by the layout design. The operator needed to turn around to pick up the WIP and all the conditions are the same. The calculation is 8 hrs X 60 mins X 60 seconds / 30 seconds X 1 turn (180+180 degree) = 960 turns. It does not needed to think is that value-added or not, I just want to ask what do you feel after you rotary your body for 960 turns?

OK, let's stop the motion wastes in manual process here and we start to think some other case. In the lean concept for office, do you find the motion wastes as well? Did you bring a document to another floor of office for signature? Did you mail a document to another site for your boss to approve? Do you find there are so many blank to need to fill but nobody care what is that actaully? But you need to spend time to check for the information for that...If we consider the information like a flow as process or material, you can find there are so many wastes as well. The information also flows between the people, and there are so many people is not needed the information actually but it wastes much time to flow through all the chain.

For the material flow, you need to check about the locations for storing material. I meant the material in all kinds of status, such as raw material, WIP and finished goods. Are they stored in the proper location? If not, the motion wastes also happened in material flow. That's why you need so many store-keeper to handle the material.

The last point I wanted to talk is the equipment or machine design. I visited one automotive manufacturer in Japan but I dont want to state her name, I have an idea came from her equipment design. It was a automatic assembly for engine with many process included such as milling, grinding, drilling, taping and heat treatment. The body of enginer was carrying along the line through those process, sometime, the body needed to turn around in 180 degree, or turn up side down. Anyway, the body was handling by the robotistic arms to put it in right position. As my observation, the time for the robotistic arm for handling the body was longer than the mechaning process. For my point of view, it was also a kind of motion wastes. If the line can be design as the mechaning station in different pattern, may be the body of engine was no need to handle as I saw but just carried along the line in one position. The speed of process would be much shorter.

Finally, we need to consider the motion wastes in different mindset. It was not only happen in manufacturing process, even in information flow and material, we always can find it appeared in different situation. Give me some ideas of example if you found the situation as well.