The Benefits of Lean

So how does a manufacturer get lean? Let’s look at an electronics assembly plant as an example. A good starting place for the lean process might be the systems assembly and test line. Inventory value is high, parts come from a variety of suppliers, and there is usually great potential to save floor space and labor.

Electronics suppliers often provide components in large, bulky containers full of material. Each container represents several days or weeks worth of inventory, and there’s usually a backup container sitting on the floor behind it. This entire inventory is rarely necessary. Eight hours or less of inventory should be adequate.

The problem with keeping a lot of inventory—besides its cost—is that the amount of material takes up a lot of space and it looks messy and unorganized (against the 5 S Philosophy). Using the lean approach, the line is set up according to value being added by the operator. All parts and tools necessary to assemble the product are then fit into the operator’s value-adding space.

Lean lines feature individual, U-shaped work cells that allow for fluctuating manpower. When demand increases, operators are added to the cell. When demand decreases, operators are moved to more vital cells. This ensures that manpower is always deployed where it’s needed most. Traditional “Push Lines” with four operators are transformed to U-Shaped Work Cells with 1-2 operators.

These cells are set up with dissimilar machines and processes that require a combination of assembly and test. The U-shaped cell allows for operating a maximum number of assembly processes and test functions in a relatively small area and enables one production employee to move easily from assembly process to machine to machine with a minimum amount of move time within the cell. When a product leaves the U-shaped cell, it is complete in terms of the systems assembly and ICT/Functional test. To achieve the same degree in traditional manufacturing, the product would have been scheduled, queued, routed, and through numerous and different work centers.

Cells can also eliminate production steps, because operators are required to perform multiple functions. For example, operators can perform inspections as part of their normal job functions, rather than having one operator assemble the product and another inspect it down the line. Not only does this consolidate tasks, it also prevents rework problems that occur when inspections take place later in the assembly process.

Another benefit of lean lines is that they are safer than mass production lines. A lean line has very little inventory backup, allowing operators to clearly see each other. On mass production lines, they may be hidden behind a wall of inventory, in addition to increasing the chance of injury.

Lean cells are devoid of floor debris, such as metal bands, pallets and cardboard. Operators in a cell are close enough to communicate with one another, which not only promotes teamwork but also cleanliness and efficiency. On a mass production line, workers tend to be spread across a large area, making communication difficult and often resulting in a disorganized work space.

Lean manufacturing frees up floor space, therefore, adding value-per-square-foot of the facility (a significant performance metric).