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People and Machines |
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In the section on “Timing the Operation”
we looked at the activities of the person performing the operation.
Now it’s time to look a little farther at how people interact
with machines. There are a
number of ways that a person can work with a machine - here are a few
examples - PERSONS ACTIVITY EXTERNAL TO THE MACHINE CYCLE |
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| PERSONS ACTIVITY INTERNAL AND EXTERNAL TO THE MACHINE CYCLE |
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| PERSONS ACTIVITY INTERNAL TO THE MACHINE CYCLE |
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| PERSONS ACTIVITY INTERNAL TO MULTI-MACHINE CYCLE |
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| PERSONS ACTIVITY INTERNAL-EXTERNAL TO MULTI-MACHINE CYCLE |
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The above example shows a person operating 3 machines. The person is being kept busy but the machines are idle for some of the time. It is IMPORTANT to spend a bit of time understanding the sequence because we will have to use this concept when we get to “Serious Lean”. For the moment however, it illustrates how to sketch out the relationship between a person’s activity and multiple machine cycles. Hey! We are still not ready to go to the pub, so lets take another look and concentrate on machine 1. |
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| If we look at the person we can see that the first bold activity is to unload and load machine 1. Machine 1 then starts to run automatically. Meanwhile the person walks to machine 2, which is waiting to be unloaded. When the person finally returns to machine 1, it has been stopped for 2 seconds having already completed its machine cycle. The person then repeats unload and re-load of machine 1. You will see that the person was away for a total of 20 seconds tending the other two machines. The machine cycle was 18 seconds so it was idle for 2 seconds. If the machine cycle had exceeded the 20 seconds that the person was away then the person would have waited for the machine to stop (see below). This sounds simple – it is, so remember it later when we are looking at lean cell construction. |
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