Editor’s note: This is an excerpt from Manufacturing Money (Amazon Digital Services, 2015) by Jason Furness and Michael McLean.

Larry was clearly angry. Carl had used his tools (again) without asking, and even worse, hadn’t returned them (again). Larry told me he had given Carl some “tough feedback.”

Manufacturers’ waste-reduction initiatives are rarely as effective as they could be. When reducing waste, inventory is often the main target. But how do you right-size inventory in an environment of constant variability? In a word: kanban.