Cells and Cellular Processing are at the heart of Lean. Their benefits are many and varied. They increase productivity and quality. Cells simplify material flow, management and even accounting systems.
Cells appear simple. But beneath this deceptive simplicity are sophisticated Socio-Technical Systems. Proper functioning depends on subtle interactions of people and equipment. Each element must fit with the others in a smoothly functioning, self-regulating and self-improving operation.
The proper design of Cells is an engineering problem. Like any other engineering design, it proceeds through a logical sequence of steps. At each step, the designers make compromises between conflicting requirements or technical limitations. Doing it well requires a deep and profound knowledge of the elements of a Cell, their functions, and their interactions.
Creating a Cell is more than placing a group of people performing individual processes together. Your Cell can be a straight line but ultimately the best normally will be a "U" shaped design. I typically like to place my operators inside the "U" and then have replenishment inventory catered to them from the outside of the "U".
You also need to make a significant decision regarding people:
1. Static People: where material moves between stations
2. Mobile People: who move material through the progressive steps of your Cell
Typically people will go with option 1 by having Static People but then you lose flexibility. However, this is a good way to test the Cell concept. If you do decide to go this way then work towards cross-training your people to perform all of the cell functions. That way you can always run your cell and adjust throughput to match customer demand. The max staff I normally place in a cell is a total number of stations less than one.
The other by-product of having people and material move through the cell operations is that your slowest operator will increase their productivity by at least 20% and you will be able to quickly see when your cell processes go out of balance.
Now for other fun stuff to consider ...
1: Select the Products
The goal of product selection is to find compatible families of products that a group of machines can process without undoing changeovers or other difficulties. Many difficulties result from attempting too much variety. Important tools are Enterprise Value Stream Mapping and Group Technology.
Some things to consider:
Which products belong together in a Cell?
What is the design production rate for the Cell?
Should we have reserve capacity?
2. Engineer the Process
Engineering the process requires a deep understanding of every process event as well as the times required for setup, personnel activities and machine cycles. From this, we calculate the number of people required and the number of machines or workstations.
Things to considering during this step:
What process steps do we need?
What is the best sequence of steps?
What equipment should we employ?
How much equipment of each type?
How many people do we need?
What lot size is appropriate?
3. Define the Infrastructure
Infrastructural elements support the process but do not touch the product. They are varied. Examples are:
Infrastructure is intangible and cell designs often fail due to a lack of awareness about it.
What methods for material handling?
How do we balance the workload?
How do we schedule production?
How much Work In Process is necessary?
How do we motivate people?
How do we assure quality?
4. Layout the Cell
The fourth task in Cell design is the physical layout. This is often straightforward if the previous tasks have been done thoughtfully. The Task Procedure diagrams can often be simplified. In many cases, you may start with the process chart and move directly to a layout.
Considerations when laying out the cell include:
What is the best physical arrangement?
How do we handle external constraints?
How do we integrate with the overall layout?
Once you identify your processes and how they can be re-engineered to embrace a Cell methodology you will wonder why did I not think of this before!! Really break that Paradigm and apply it to ALL of your office administrative processes ... you will get elated that you did.