What is Cell?

A location where the processing steps for a given item take place immediately one after another, so that parts, documents, etc. can move in a flow very close to continuous, whether one unit at a time or in small batches, maintained throughout the complete processing sequence.

The U shape (see figure) is common because it avoids walking very long distances and makes different combinations of tasks possible for operators. This is an important consideration in lean production, because the number of operators in a cell will change as demand changes. A U shape also allows the first and last steps of the process to be performed by the same operator, which is useful for maintaining the work pace and a smooth flow.

Many companies use the terms cell and line interchangeably. There is a school of thought that believes materials should flow through cells in a right-to-left direction relative to the operator, because most people are right-handed and it is more efficient and natural to work from right to left. However, many efficient processes flow to the left and many flow to the right. It is simply a matter of assessing, on a case-by-case basis, whether one direction makes more sense.

Related Article: "Lean in the printing industry: a case study" - Author: Osiran Lima- Lean Institute Brasil. Read the full article here.

"Implementation of the proposed cellular layout Based on customer orders (sales), a demand of 2,700 units/day was determined for the products processed in the notebook assembly cell. The cycle time (takt time), which is the quotient of available hours/day by required production/day (MONDEN, 1984), was set at 10.7 seconds/unit produced.

Thus, we have:

Next, a systematic analysis of the operations was carried out with a view to creating the "operational value stream" and increasing the utilization rate of labor and equipment. To this end, the following actions were taken:
- Grouping of the operations "drill the notebook block" and "make the spiral";
- Grouping of the operations "inspect the notebook block" and "join cover and block";
- Grouping of the operation "assemble box" with the operations "inspect and pack notebooks" and "discard packaging";
- Separation of the manual and machine elements in the operation "insert and cut spiral" (JIDOKA concept).

This analysis resulted in a new operational sequence (Figure 4), through which we observed the following improvements:
 Reduced labor;
 Reduced standard time;
 Reduced equipment;
 Fewer operations;
 Elimination of transport.

Figure 4 - Operations in the notebook assembly process

As a result, a more balanced process was observed (Figure 5), with the operations balanced and close to the cycle time (takt time). This new grouping made it possible to establish and maintain a steady work pace through continuous flow and enabled monitoring throughout the work shift, ensuring that the demand pulled by the customer was met every day.

Figure 5 - Grouping of operations applied to the cellular layout

Labor, equipment and shop-floor resources were optimized, since the workstations were brought closer together and arranged in a "u" configuration. Figure 6 shows the new physical layout, occupying an area of 102.27 m2."

Figure 6 - Cellular layout