“How do you know the web is baggy?” (This double-checks the assumption that the trouble at the customer is bagginess instead of some other problem in disguise).
“Can you tell before you run the web whether it will give you troubles?”
The operator showed me where/how/why the bagginess misbehaves on the tender part of his process. Then he said that the ‘leaners’ gave him trouble. “Leaners,” said I, “what are leaners?” He brought me to a pile of rejected rolls that would not run and tipped one on edge and said “See, they lean.” Of course, the great majority of bagginess is really a caliper/thickness/weight profile problem in disguise. On narrow rolls in particular, these carrot-shaped rolls will not stand straight. Since nonwovens (as well as some other types of producing machines) do not lend themselves to easy ‘fixing,’ we still had one customer and money saving option left. That is, rejecting marginal material before it leaves the supplier’s plant. We did so by improving on the operator’s eyeball judging the amount of lean (which was a pre-screen). Any rolls that looked marginal were measured with a digital level. About 1-2% of the worst rolls (as determined by rejects and a statistical capability study) were culled. Yes, waste is expensive, but rolls rejected by the customer are even more so. So, the learnings here were many.
1. Talk to the operator directly and with humility (they know things you don’t)
.2. Sometimes you may need to invent measurement techniques, but use statistics to check your work before foisting on the world
.3. The order of troubleshooting is not fix first, then understand if you have time as seems to be management’s preference. It is see first, then measure if possible, then cull, then fix if/as possible. In other words, the last step in a long chain to success is to fix the problem.