Reconfigure factory floor to make it cleaner, simpler, and more intuitive. Nothing is random: everything has a designated place.
Rigorously study the root cause of every defect and complaint. Then, even if it means stopping production, fix the problem once and for all.
Map out every process, make people own it, and rewards constant improvements. For every action, ask why and how it could be done better.
Convert top management into disciples of the process and make proselytizing part of their job. Non-believers can head for the exits.