An example of categories might be:
- Check - preparations or quality controls operations that must be performed before starting with our job
- Transport - tasks of moving people / work in progress from one part of the work area to another
- Operate - value-added activities
- Wait - waiting for any reason
- Store - tasks that you perform on finished parts (e.g. put parts on a pallet, put a paper chart in a box) or on inputs / materials maybe because they are not delivered in a proper form.
To start the analysis, prepare a table of this form shown in Table1:
Table 1: Form for Process Analysis
In the first column list all the tasks you need to perform. Since this method is used for the analysis of micro-processes, remember to do a detailed analysis and to list all the tasks. If you don't focus in this way and look at the aggregate process you'll lose opportunities for improvement.
As you can see, I decided to assign a numerical value to the tasks of my example; in your real-world exercise you should use real name for your tasks to avoid forgetting what you listed.
As a second step, you must measure the time it takes to perform all the tasks. This part is the most important because it will help you focus on the non-value-added tasks; these are the tasks that will give you the greatest results from improvement.
Table 2 - Process Analysis Time Allocation
The third step is to assign a label to each one of your tasks, by putting a DOT on each single cell. Link each dot with the dot of the preceding task and with the one of the following task.
Table 3 - Process Analysis
We now have all data we need. Now it is time to complete the matrix, filling the cells on the bottom!
For our example, we have a global process of 10 tasks, 1 of which is a check, 2 are transport, 3 are operation, 2 are waiting, 2 are storing.
As you can see just 3 out of 10 tasks are value-adding (e.g. Operation) . Now let’s look at the times:
Table 4 - Process Analysis
We can see that just 38 seconds out of 200 (19.0%) are value-adding. So in a 200-second process, there are 162 seconds of waste. We can also see that the category that increases waste the most is storing with 65 seconds, followed by transport. So maybe we have some problems with logistics.
After this analysis we surely have ideas about waste reduction in our process, and most important now, we know which waste is the one that is more profitable to reduce.
For more from Matteo, visit his blog.