Chaku chaku, literally meaning “load load,” is a Japanese term for a single-piece manufacturing process based on cell manufacturing. A worker in a cell loads machines by taking the output from one machine, and putting it into the next machine in the production process. One worker is responsible for the entire production process, from beginning to end.
Chaku Chaku Overview
The traditional approach is to have similar machines grouped together, performing each step of the manufacturing process in separate parts of the factory. Each type of machine makes parts in batches. When a batch is complete it either goes into a work-in-progress inventory, or is moved to the next stage of the manufacturing process. Parts and components move through the manufacturing process in batches, step-by-step.
With chaku chaku all of the machines needed to make a product are located together in a “cell.” Any part of the work that can be automated is automated. For example, loading a part into a machine may require getting the orientation correct, properly seating the part in a jig, and clamping it into place. This requires a human skill. However, when the machine finishes it can just release the clamp and eject the part in a fully automated process. That's how chaku chaku got its name. The worker only loads the machine, and never unloads it.
The benefits of chaku chaku are significant. They include the elimination of work in progress, defect free production, and very high utilization of labor and space.
In the past, using the "job shop" method, these machines were located in separate areas of the factory, and each required a separate machinist to operate it. They turned out hundreds of parts in batches that were then loaded into baskets for transporting to another area, or simply sat there in stacks waiting until they were needed or the whole batch was completed. By incorporating the fundamental principles of the Lean production preparation process and designing equipment specifically for the type and size of the parts being manufactured, we've reclaimed 2,076 square feet of factory space.
The keys to chaku chaku are one-piece flow and lean manufacturing cells. What are these?
Chaku Chaku – One-Piece Flow
One-piece flow is a system in which products (or parts) are moved through a manufacturing operation one-piece at a time, in a continuous flow, with no work in progress (WIP). One-piece flow was developed as a part of the Toyota Production System.
One-piece flow can be defined as making one complete part at a time, or passing completed part to the next machine, or manufacturing cell, when that manufacturing cell is ready for it.
The opposite of one-piece flow is the batch process, in which a batch of parts are worked on, and then passed on to the next work station.
One-piece flow has many benefits. For example, it keeps WIP at the lowest possible level; it encourages work balance; it results in high quality; and it uses worker's time more efficiently. However, one-piece flow is not suitable for all manufacturing processes. To be a good candidate for efficient one-piece flow, the following conditions must exist:
- Processes must be able to consistently produce defect-free output.
- Process times must not have significant variation.
- Equipment used in the process must have very high reliability.
- The production rate must be flexible and able to be adjusted to match customer demand.
One-piece flow can still be used when the above conditions exist, but it requires there be an inventory buffer built into some parts of the production process. An evaluation needs to be made as to whether the cost of the inventory buffer is justified by the advantages of one-piece flow.
Chaku Chaku – Lean Manufacturing Cells
One-piece flow works best with a cellular arrangement of the production equipment. A cell includes everything needed to make a part, or a group of similar parts. The needed machines are arranged to match the order they are needed to make the part, usually in a “U” shape cell. This results in a smooth flow of materials into one leg of the “U,” and smooth flow of parts coming out of the other leg of the “U.”
Traditional manufacturing has machines grouped together by type of machine. All of the lathes are together. The drill presses are grouped together. And the shears are in one location. This provides an arrangement that is more tolerant of machine breakdowns, as other machines can pick up the extra load when one goes out of service. However, with the high reliability machines that are now available, this is not as big of a concern as it used to be.
On the other hand, the advantages of cellular manufacturing are many. They include:
- Reduced work in process.
- Reduced distances materials are moved.
- Improved flow of materials.
- Reduced lead times.
- Workers can operate multiple process (greater flexibility).
- Work flow is self-balanced within a cell.
Chaku Chaku and Jidoka
An important lean method that is used to support chaku chaku is jikoda. Jidoka involves automating the detection of defects and problems. When a defect is detected, the operator is notified, and makes a decision about what needs to be done.
As jidoka systems have advanced, they are become more automated, and current systems are often able to make corrections on their own. This essentially makes the system mistake-proof. However, human operators are still involved in monitoring what the machines are doing.
The advantage of jidoka is that it allows individuals to operate and monitor larger numbers of machines.
Using methods such as jidoka, cellular manufacturing, and one-piece flow, the principles of chaku chaku can be implemented to improve flexibility, quality, and productivity – all of which adds value to the products you sell, and makes for happier customers.
Chaku Chaku and Visual Communication
With chaku chaku workers are independent and more likely to be working on their own. Reminders about safe work practices are important, as well as required by OSHA. Graphic Products offers a free guide called the “OSHA Safety Sign Best Practices Guide.” Use the link to request your free copy today.