IDEA: Ask machine operators, not supervisors, what is wrong with the machines they operate.

Ask the machine operators directly what they see and believe is wrong with their machines, the pieces of equipment that they work on every day.  Of all people, they are the best to ask this question.  They personally know since they work there every day. Ask these operators on a regular basis if there quality issues, excessive mechanical issues, which machines are the least productive and cause the largest problems, which are the easiest to operate and most importantly, which machines do they make the most money (given they are on incentive programs). If they are on incentive or bonus programs for good production counts, you will hear everything you want to know.