Chaku-Chaku Load-and-Go Work Sequence

Why it matters

In this lesson, chaku-chaku is used in the sense of a load-and-go working arrangement. The worker loads a part into a machine, completes the safe start and moves on to the next machine while the automatic work continues. When processing is complete, the part is ejected from the machine automatically; at the next visit the worker expects the machine to be empty and ready for a new load. The benefit of this arrangement is not keeping the person at the same point for the whole automatic time. But using the name does not prove automatic unloading. If the existing machine requires removing the part by hand, the work sequence and the human load change. First the real hardware and the safe working condition are determined, then the cycle is calculated.

That the machine works automatically does not mean all the movements around it are automatic too. Taking the ejected part from the safe transfer position, orienting it and carrying it to the next station can be human work. These must be included explicitly in the loading or transport elements. Automatic unloading covers only the removal of the part from the processing zone; it is not assumed that no human work remains. Where the unloaded part goes, whether it gets mixed with the previous part and whether accumulation blocks the movement are observed. If a new operation cannot continue while the part waits at the exit position, an invisible machine wait can arise. This boundary cannot be left outside the cycle calculation.

The human cycle and the machine's part occupation time are not the same quantity. The worker's return to the same point can consist of loadings and walks. The machine, on the other hand, is occupied during loading, then completes automatic processing and automatic unloading. If the next arrival at the same machine happens before this occupation ends, the worker waits. If the occupation ends earlier, the machine can stand idle for a while. Adding the automatic times on top of the human work loses the concurrency; ignoring the automatic times completely plans loading into a machine that is not ready. The right solution is to show every resource on a shared time axis. Taking only the longest time without knowing the start moments is also not enough.

The work sequence must be understandable not only in steady state but also at start-up and after a stop. Filling an empty cell for the first time and receiving a finished product every cycle are not the same situation. Because of the sequence, there can be work in process waiting at the start; their positions are defined. At a stop, the flow is not restarted without checking the state of the part left in automatic processing. Disabling safety functions or changing hand access for the sake of speed is not a work sequence improvement. The basic decision of this lesson is to show that a load-and-walk cycle can be set up once automatic unloading and safe leaving conditions are verified, and that the calculation will be redone when these conditions change.

Formula