Process Description of Heijunka
Introduction
Heijunka is a tool used in lean manufacturing which focuses on eliminating waste without losing productivity through a manufacturing technique that relies on leveling production. Popularized by Toyota, lean manufacturing is often seen as an alternative and more effective manufacturing process than mass production that is commonly used in America (Friddle n.d.). Whereas mass production relies on production in large batches to obtain the lowest cost per part possible, lean production instead focuses on the flow of production, adjusting flow as demand changes. One of the primary problems heijunka serves to solve: how do you produce the correct amount of product when demand is always changing? The traditional mass production approach would rely on large inventory levels to handle high numbers of orders. But when orders are scarce, inventory is then built up. Unfortunately, this method is wasteful due to large overhead costs including handling and damages. Heijunka, on the other hand, allows manufacturers to produce at an even pace-- minimizing machine downtime and reducing lead time (the amount of time from order to shipment) (Jones 2006). Heijunka relies on three important principles: predictability, flexibility, and stability, and the steps to implement it follow these (Bisk n.d.). The first step is to calculate the average demand of the given product. The next step is to determine the takt time, or the rate of production needed to fill demand. Using the takt time one can level production with demand. And finally, the last step is to level output of a mixture of products. Discussion Figure out average demand The first step with implementing heijunka is to figure out the average output of the manufacturing facility. Ideally, one should look at the past 12-24 months to see the peaks and dips of the production throughout a long period of time. The average demand is needed to figure out the takt time in the second part. The average demand should be in units per week. Takt Time Takt time is the rate a finished product needs to be completed to meet customer demand. A formula can be used to figure out the takt time. That formula is: Takt time = Available time / required units of …show more content…
For example, let's assume that the average demand is 12 units a week, which would be 2.4 units per day. The takt time would then be .41 days per unit (1 day divided by 2.4 units). If the manufacturing pace is currently set up to have .50 days per unit then the facility knows that they need to increase the pace to ensure they meet customer demand. The production pace and takt time need to be the same for heijunka to be fully implemented, in other words, level the production with demand.
Level output by product mix
Most manufacturing facilities make a wide range of products, not just one. So the last step in implementing heijunka is to level the output by product mix. Before lean manufacturing concepts emerged, the idea was to batch build that wide range of products. Under the heijunka idea, this is incorrect. The idea of heijunka is to not only level the volume of output, but also by the product mix. Assume a company is creating products A, B, C, and D. Batch building would create a production schedule like this:
AAAA BBBB CC DD A manufacturing facility, with heijunka implemented, would follow a production schedule
Introduction
Heijunka is a tool used in lean manufacturing which focuses on eliminating waste without losing productivity through a manufacturing technique that relies on leveling production. Popularized by Toyota, lean manufacturing is often seen as an alternative and more effective manufacturing process than mass production that is commonly used in America (Friddle n.d.). Whereas mass production relies on production in large batches to obtain the lowest cost per part possible, lean production instead focuses on the flow of production, adjusting flow as demand changes. One of the primary problems heijunka serves to solve: how do you produce the correct amount of product when demand is always changing? The traditional mass production approach would rely on large inventory levels to handle high numbers of orders. But when orders are scarce, inventory is then built up. Unfortunately, this method is wasteful due to large overhead costs including handling and damages. Heijunka, on the other hand, allows manufacturers to produce at an even pace-- minimizing machine downtime and reducing lead time (the amount of time from order to shipment) (Jones 2006). Heijunka relies on three important principles: predictability, flexibility, and stability, and the steps to implement it follow these (Bisk n.d.). The first step is to calculate the average demand of the given product. The next step is to determine the takt time, or the rate of production needed to fill demand. Using the takt time one can level production with demand. And finally, the last step is to level output of a mixture of products. Discussion Figure out average demand The first step with implementing heijunka is to figure out the average output of the manufacturing facility. Ideally, one should look at the past 12-24 months to see the peaks and dips of the production throughout a long period of time. The average demand is needed to figure out the takt time in the second part. The average demand should be in units per week. Takt Time Takt time is the rate a finished product needs to be completed to meet customer demand. A formula can be used to figure out the takt time. That formula is: Takt time = Available time / required units of …show more content…
For example, let's assume that the average demand is 12 units a week, which would be 2.4 units per day. The takt time would then be .41 days per unit (1 day divided by 2.4 units). If the manufacturing pace is currently set up to have .50 days per unit then the facility knows that they need to increase the pace to ensure they meet customer demand. The production pace and takt time need to be the same for heijunka to be fully implemented, in other words, level the production with demand.
Level output by product mix
Most manufacturing facilities make a wide range of products, not just one. So the last step in implementing heijunka is to level the output by product mix. Before lean manufacturing concepts emerged, the idea was to batch build that wide range of products. Under the heijunka idea, this is incorrect. The idea of heijunka is to not only level the volume of output, but also by the product mix. Assume a company is creating products A, B, C, and D. Batch building would create a production schedule like this:
AAAA BBBB CC DD A manufacturing facility, with heijunka implemented, would follow a production schedule