The word Heijunka is often used in the manufacturing industry, and it means sequencing, or smoothing of production. The idea behind this term is to help absorb sudden fluctuations or changes in the demand of the market. This is often done by producing several different models of a product, in smaller production batches.
In practice, this helps to eliminate waste in a variety of ways. It helps to make the work which is done more standardized, and can also reduce the amount of inventory which must be kept on hand. This is all done without causing customers to have to wait for their products, even for unexpectedly large orders.
Heijunka helps to ensure a facility is able to get better amortization of the resources they have, including factories, the machinery, and the shop floor itself. These things must operate more efficiently so that more can be produced with the existing resources. Of course, this isn’t necessarily an easy task, but using Heijunka, it is possible.
The main way this can be accomplished is by moving away from lines in a facility which are focused exclusively on one product. These lines are far too susceptible to sales variations, meaning when there is a slowdown in orders, the line sits unused, and when there is a spike in orders, it has to run much harder than normal to keep up.
The solution is to make production lines more flexible, so they can run multiple different products with minimal adjustments. By creating several other products on the same line, the spikes and drops of orders will have a far smaller impact on the overall efficiency of that line. It is possible to keep it running at a standard level regardless of market conditions.
For example, if your facility is creating a single product on a line, and orders on that line drop by 50%, the entire line has 50% less work to do. If, however, the same line runs 4 different products on it, the drop in orders by 50% for a single product affects the line by only 12.5% (.25 * 50% = .125). This is because the other products on the line are still running at their normal rates. Another possible benefit in some industries could be that other products being made may actually go up in orders when one goes down.
Essentially, a facility can use Heijunka to spread out the risk of reduced orders on a particular line. Similar to mutual funds which spread out risk by investing in many different companies at once, Heijunka can help reduce the risk for variations in product orders in a particular facility. The more a facility can diversify what is being made on a particular machine, or even in the facility as a whole, the less waste they will experience.
Each facility will need to look at their unique situation and see how Heijunka can best fit into their processes. The bottom line, however, is that by reducing the impact of a reduction in orders, a facility can keep up and running efficiently at all times.
- Changeover – Creating Flow and Eliminating Waste
- Kanban Systems
- Using Kanban to Reduce Waste and Inventory
- Mass Production & Lean: What’s the difference?
- The Toyota Production System House
- Understanding Lean Principles