Typically when you first start improving a process or conduct a kaizen, there are four improvement cycles or phases that one goes through. It’s helpful to know what they are so you can quickly address the issues that cause them, or even better, avoid them in the first place!
The first step before any kaizen or continuous improvement (CI) is to ensure that standard work is being followed and that the process is within standards. Often it is not, so the first thing that needs to be done is to either put them back in place, or if they didn’t exist, create and put them in. The lack of standard work and standards is generally the cause of the high variation that is experienced in the process. In this stage, if adherence to standard work has not been a priority, it is common to find that operators over time have created their own standard work with each one maybe doing it slightly or totally differently. This is what often causes the high variation. If you do not address this variation before CI, you will likely create higher levels of variation and your process will not provide a predictable result. It can easily become complicated and frustrating trying to figure out why sometimes you achieve the desired results after the CI, but not always. Once the standard work and standards are in place, you should see the variation in the results dramatically decrease and the process will become stable. Even if the process is not delivering to the desired target, it is critical to make the process stable and therefore predictable. Now you are ready to kaizen or CI the process.
Phase #2 comes after a kaizen when the process is now consistently achieving the desired target. The process and the results are stable and predictable. Everything is going well and the team starts to think about what’s next. This is the happy phase when the team is feeling good about the results and their accomplishments. Document the changes clearly, revise the standard work, make any new standards permanent (until the next kaizen), and provide the operators and the process time to operate and stabilize. If you are aware of Phase #3, then phase #2 is a good time to implement mitigation so that you can avoid phase #3!
If you are experienced at CI, phase #3 can be prevented, but far too often there is a phase #3. Phase #3 is a result of a weak or missing sustainment step or mechanism. After the CI the operators and the leaders get comfortable. They either stop or change the frequency of a key success attribute that was put in place during the original CI. An example is training. During the CI all the operators were trained on the new standard work and everyone does the process steps in the same order and same way. However, if the training materials weren’t revised, or the trainers were not informed, the result can be below target conditions with higher rates of variation. Or perhaps, the leaders didn’t add a key check or confirmation to their standard work and after a period of time missed a check here or there and perhaps eventually even stopped doing it. Again, this can lead to high variation and below target results. However, since all the CI changes and actions are fresh, typically you can recover from this situation very quickly and return to target and stability. Lessons are learned and mechanisms put in place to maintain stable target results. Until phase #4, that is!
After a period of stability, it is not uncommon for a sudden and unexpected short term unfavourable to target result. This is the result of an abnormality in the process. The abnormality may be one of the 4M’s – Man, Machine, Material, Method. With the focus and controls put in place by this point in the CI, the abnormality is usually quickly identified and corrected almost immediately. These abnormalities can also point you in the direction of your next kaizen or CI activity.
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