Difference Between Lean Manufacturing & Mass Production

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Most businesses, regardless of the theories they support, want to get the most from their labor dollar and produce the highest possible number of quality products they can in the shortest amount of time. Mass production and lean theory are two approaches to doing this. Their approaches can be targeted at similar results yet their respective functionalities are quite different.

Features of Mass Production

Mass production is a manufacturing process or technique that began during the industrial revolution. According to Willamette University, "Mass production is the name given to the method of producing goods in large quantities at low cost per unit." Primary features of mass production are the assembly line and interchangeable parts. With these tools, all products pass through the same stages of development at a rapid pace. Each worker knows their specific step in that process, and product yields can, theoretically, continually rise with increased efficiency.

Identifying Lean Theory

Lean theory, in many ways, lies in opposition to some aspects of mass production. In essence, however, lean theory attempts to streamline a broad variety of business practices in order to enhance efficiency, prevent mistakes and waste as well as to optimize the performance of labor resources. Mass production, in many respects, seeks the same end. But lean theory equips the practitioner with a different set of approaches, ones that can be more easily adapted to diverse end products rather than ones which are exact reproductions of the other.

What Is One Piece?

Mass production values the assembly line process, where workers handle multiple products at the same stage of production. The products are then ferried through to the next stage. In the end all reach completion together. Lean practice values "one piece" production, where a single item is shepherded through production from start to finish, then others are started at different intervals. This is one location of primary difference between mass production and lean theory.


While advocates for mass production would argue that their method gains the highest output, supporters of lean theory contend that this is not the case. First, they state that mass production can be just as time consuming, if not more so than one piece production. Additionally, it takes longer to achieve any final product because each item must wait for the others. Finally, lean theorists suggest that mass production does not allow a producer to adequately diversify or customize individual products as per a client's needs or demands due to the rigid and unalterable structure of the process.