The Process of Quality

To apply these principles, we need to understand our process, which starts with a process map — a sequenced list of actions performed to accomplish the work. This is often done graphically, as shown in Figure 1, but it can also be done with a simple list.

For purposes of our discussion, we will consider a generic process common to many businesses — storing product. This is only a starting point. In actual practice, we may need to take a closer look and explode some steps into greater detail, but this will suffice for our discussion.

Beginning with overall output requirements for storing product, the process goes like this:

• All cartons are palletized in a prescribed, stable pattern;

• Loads are wrapped securely according to packaging specifications;

• Loads are clearly labeled in defined locations with prescribed content;

• Cartons, loads, wrapping and labels are free from damage;

• Loads physically reside in the same locations logged in inventory records;

• Inventory count exactly matches physical inventory.

These requirements, along with supporting documents (such as packaging specifications), define what the process must produce. Knowing these requirements, we could inspect the process output to confirm that it is operating correctly.

While inspection has been used for many years as a primary means to ensure quality, it should not be relied upon as the only way. Inspection can detect gross problems or high-frequency problems but is not effective or efficient at detecting infrequent, subtle problems. For example, inspection could easily detect a badly damaged load but might overlook a slightly smeared barcode label. Moreover, anything detected by inspection has already occurred and will cost money to correct. Remember that our focus needs to be on prevention rather than correction. If we prevent problems from occurring in the first place, we never need to inspect for them and never have to worry about what slipped past the inspection process.

We need clear requirements for each step to guarantee that each step produces only good output (correct and complete). There are a variety of ways to establish those requirements, but a good starting point is with overall process output requirements. If we examine each requirement and consider the potential impact that each process step has on that requirement, we can identify those steps that contribute to achieving each requirement.

This can be conveniently summarized graphically in a process planning chart, using “Os” to identify links between process step and overall output requirements (Figure 2).

We can see at a glance that, if we wish to guarantee there is no damage, then we need to address five process steps (1 through 4 and 6), while two steps do not contribute to damage.

Next, we look more closely at each of the contributing process steps and identify specifically how that step contributes to the requirement. Sometimes, it is easier to identify how that step can fail to meet the requirement. For step 1 (Receive Cartons), failure conditions might include:

• Cartons damaged upon receipt;

• Cartons missing label or incorrectly labeled;

• Cartons in wrong orientation (will jam in palletizing equipment).

The first two items may not be within our direct control but are often within our influence. Just as we seek to ensure that the outputs of our processes are correct, we have the right to insist that what we receive is correct. What we receive is, in fact, the output of a previous process. If we can convince the owners of that previous process to eliminate those failures, then both their process and ours will be improved.