Lean Stream Blog

Lean Ideas, Lean Tools for Material Flow

2009-06-29T23:25:00.000-07:00

The leading innovative manufacturers are improving cost efficiencies and WIP inventory by 50% with customized work space (Pipe/Rack Materials) to increase floor, employee, and material flow efficiency.

Lean manufacturing produces value in reduced inventory, scrap, rework and lead-time from order to delivery. Lean also creates value because less floor space is required for product assembly and less time is needed for changeover. Finally, lean generates value by enabling employees to function at maximum efficiency through streamlining the manufacturing cycle and increasing production—without adding costs.

The Benefits of Lean

2009-06-28T23:30:00.000-07:00

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).

Lean Equipment

2009-06-27T23:43:00.000-07:00

The initial investment in converting to lean can be less than $10,000. Obviously it’s not realistic to revise an entire plant for that amount, but there are small steps that can pay immediate dividends.

The best lean assembly lines are supported by modular material handling systems. These systems are made up of pipe/rack structures that are simple, mobile, adjustable, reusable and temporary. These structures, such as workstations, flow racks, and mobile carts, help operators eliminate waste and increase production while performing a job.

Simple. Ideally, material handling structures alongside an assembly line should be constructed of fundamental components. The drawings required to make the structures should be elementary, and only basic tools and skills should be necessary to assemble the structures. If required, an operator should be able to create a structure to solve a problem independently within hours of identifying the situation’s requirements.

Mobile. Material handling structures should be easily relocated. If the workstation needs cleaning, the material handing structure should easily be rolled out of the way so the floor can be swept.

Adaptable. For certain, customers, products and demand will all change. These structures must be adaptable to these changes.

Re usability. On mass production lines, structures are welded and painted for onetime use. With reusable structures, a flow rack one day could become a table or a cart the next.

Temporary. Ideally, structures should be designed and built to last just for the current product’s life cycle or until the next improvement is implemented. This is not to say that the components themselves should not be extremely durable.

An effective material handling system must meet all of the above criteria. In addition, the flexibility of the system empowers the employees, as it generates ideas and encourages creative thinking. Employees can investigate more effective methods of using a material handling system in performing tasks. Having the power to implement positive change is a strong intangible—people enjoy working in that environment.

Facility size isn’t a factor in deciding to use lean material handling systems. They work as effectively for manufacturers that employ thousands as they do for plants with less than 25 employees.

There is no definitive blueprint for a lean plant. There are lean plants that do not use material handling systems, just as there are mass production plants that do use them. However, to achieve the greatest value in manufacturing, the most beneficial combination is a lean philosophy that relies on a material handling system to help eliminate waste and promote continuous improvement. In other words, a lean line and methodologies are an effective method for improving the bottom line.

For more information or for a free material flow consultation visit, please contact Robert Jones at Lean-Stream (Robert@lean-stream.com).

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