Thoughts on proper management of batch production
I searched “batch production.” There are many explanations of the meaning and calculation. But I thought about what is the proper management of batch production.
I summarized in Plan - Do - Check - Act.
And my conclusion is that if we seriously pursue batch production, we recognize the power of one-piece flow. One-piece flow is the ultimate batch production.
The planning of the “batch” should not be only the quantity calculation.
Once the calculation is done, we should do the following;
Compare the batch quantity among different processes
Compare the batch quantity of logistics
When we compare these quantities, there should be multiple and divisor relationships between the numbers. If not, some adjustments on the quantity are required, which is most of the time. Otherwise, the factory will suffer from fractions. Also, keeping random numbers will create a condition where it is challenging to see a problem. Each process might suffer of loss of efficiency due to this adjustment, but the total system will gain significantly. Some industry has such coordination for centuries that they use a dozen as the standard unit from ordering to production.
When we tackle this problem, we recognize the power of “1.” One is the only number that is flexible to anything. That is the value of one-piece flow.
Sometimes, I ran into processes with the batch quantity, which was a prime number. I get really frustrated with just calculating batch quantity without considering flow.
Once proper planning is done, we can produce in batches.
During production, there should be some mechanism to control the quantity. The control should not be counting, eye measurement, or feeling of operators. I am not saying we must install computers. The mechanism can be physical space or slots. Something simple that matches the batch quantity. The above planning becomes essential for such a simple physical mechanism to work. People should not worry about quantity. They should focus on quality and process improvements.
Any deviation from the batch quantity should be captured as a problem and lead to problem-solving. It doesn’t matter if that deviation is a single unit or X%. All deviations should be captured. This should not require additional auditing. The deviation should be instantly apparent with open spaces. A manager should go and see that deviation and capture it. Then immediately move to problem-solving.
Two types of problem-solving improvement need to happen.
Why could we not produce precisely to the defined batch size?
What is the obstacle that forces the process to produce in batches? Can we change that?
The first one is problem-solving. Even if we are practicing “traditional” thinking, such problem-solving “should” exist. Unfortunately or conveniently, such problem-solving hardly exists. If existing, then the problem of defects, material shortages, and fractions should be driving the factory nuts. And this is the psychological danger of batch production. Somehow, by surrounding themselves with large quantities, people feel fake comfort. “The order was 100, but we produced 99. So it’s okay.” It’s not. We missed it. And this question about the deviation should come from the management. Why did we miss the batch quantity? What needed to be assured so that we could precisely produce the batch? If the management doesn’t care about these details, the organization will require more costs and inventories.
The second one is the Kaizen of the presumption of batch production. This might sound like something to think about for a one-piece flow. But I believe this starts when we try to do proper batch production. As I have mentioned in the “Plan” section, batch among processes and logistics should have multiple and divisor relationships. If not, partially filled containers and stray components will flood the plant. And when I started coordinating the batch quantity, we shouldn’t just change the numbers. If you do that, you lose some efficiencies in batch production. Instead, challenge the presumptions, such as SMED, to reduce the batch size toward optimum coordination.
In other words, I think one-piece flow is the ultimate “batch” production. The more we perfect batch production, we will face some difficulties. The most significant difficulty will be the coordination with the market. And the more we look into that coordination, we will understand the power of “one.”