I encountered many strange situations as I worked with many Single Minutes Exchange of Dies (SMED).
Please understand. SMED is not a problem-hiding tool. Don’t use SMED to cover your problems…
SMED doesn’t cover poor Quality of material
SMED doesn’t cover lousy Supply chain
SMED doesn’t cover horrible Management
1. SMED doesn’t cover poor Quality of material
Once in a while, I ran into a " strange changeover.” It is strange because, in most changeovers, current materials come out. And then, the following materials and fixtures come in. In the strange changeover, none of such things happen. There’s no “pattern.” The entire process of changeover is an adjustment.
When I dig deeper into these cases, the material's quality is the root cause. The quality of the material is so poor that the machine requires additional adjustments. This does not mean that incoming materials were out of tolerance. Those are actually within the tolerance. And who defined tolerance? Unfortunately, the supplier is the usual answer when I ask who determines the tolerance. Or an engineer who has no understanding of the process capabilities. As a result, the material contains far more significant variation than what the machine can handle. The people who conduct the changeover guess what variables could impact the results through experience. Yet, it is guesswork. It is not engineering or science. Therefore, the time is almost impossible to standardize. The quality of output also varies.
I name this condition “Push of quality,” which is unacceptable. Typically, the customer has the right to determine the tolerance. Here, the decision was made without the internal customer the process. The scary part is that some organizations are getting used to adjusting material quality at production. Every time there is an increase in defects or loss of efficiencies due to more extended adjustment, they blame the production. Yet, incoming materials have high variations, and production can’t sustain quality. In many cases, these changeovers do not have a “datum.” And SMED is not a solution to make up for lousy engineering or product design.
2. SMED doesn’t cover lousy Supply chain
Sometimes I entered discussions with senior management that SMED was ineffective. I checked why they said that and saw he only looked at “total changeover time.” It is a problem. So, I submitted another data that showed each changeover time was significantly below what it used to be. Yet, we change over more frequently. Therefore, the total changeover has not changed. Then I mentioned that we are changing over more frequently, not because we have reduced the lot, but because of an unstable supply chain. Materials are not arriving on time. Immediately, the manager started screaming and yelling.
After such a meeting, the production and plant manager apologized to me. They said that since the senior manager also sees the supply chain, they cannot say that materials are not arriving on time. The reason why senior management wanted to use SMED was to cover the poor performance of the supply chain. The top wanted the production to change over quickly when they found the material was short.
There is some confusion between flexibility and chaos. SMED increases flexibility but should not operate under chaos. There are so many plants changing over according to material availability. And, when they stopped for material shortage, the production was blamed, not the one who made a mistake. I also would be careful about blaming the suppliers. Every time I talk with the supplier, they will show us the data on our orders' instability. Production & supplier are two easy targets of blame in operations. And SMED is not a fire-fighting tool for production to cover material shortages.
3. SMED doesn’t cover horrible management
“Again!?” I thought of seeing a presentation at a factory.
The factory presented the same changeover for the third consecutive year—precisely the same results.
So, I asked questions.
The plant manager explained that they look at the average change over time. And they have not seen a change. Therefore, they worked on this topic.
That was the problem. The plant management only sees numbers on the computer. They never come to the floor. They never check if external work was done correctly. They never came and saw what was happening. They don’t even care if the standardized work was followed or not.
That night, the senior manager and I returned to the shop floor. We saw what was really happening during the “changeover.” Some were having smokes. We saw a football game. The cafeteria was busy while the computer was counting as changeover time.
To be clear, we did not fire anyone after this finding. The senior manager said that it was his mistake that he did not randomly come to the shop floor frequently.
So please use SMED under proper conditions. It is an excellent tool.