Changeovers take time. Different models need different dies, different fixtures, and different settings. Usually, all of these have to be changed. During the changeover process, I’m making nothing. I am very tempted to make more than I need when I have everything set and ready to run. I may only need 100, but I will go ahead an make 500 or 1,000 units, because at least the machine was productive, and I can put the extra pieces on the shelf, ready for when they are needed.
Then they sit on the shelf. I didn’t need them when I made them. I t can turn out that now that I have made them, I won’t need them for a long time. Depending on what “they” are they can get dirty or damaged just from sitting. The can rust or otherwise deteriorate. In any case, I’d better keep track of them, because I need to know where I put them when I need them. So someone will have to keep (or enter into the system) an accurate record of how may I stored and where I put them.
When I need some again, I need to remember to look up how many I have already and where I put them. Sometimes we go ahead and make a fresh batch because we forget that days, weeks, even months ago, we made some of these.
