Cycle time

Takt time follows from demand: available working time divided by the number of units needed in that time. With 450 minutes of net working time and 300 parts per shift it is 90 seconds. It is a requirement placed on the workstation.

Cycle time is the time the operation actually takes. If it exceeds takt, the line backs up. For handling, what counts is therefore not how fast a unit lifts but whether the whole handling operation fits into the share that takt leaves for it.

A cycle consists of more than lifting and lowering. Comparing lifting speeds alone compares the smallest item.

The large shares are almost always gripping and positioning. A gripper that centres itself on the part saves more than a faster hoist. A balancer on which the load floats and is guided by hand positions faster than a hoist that has to be inched into place with push buttons.

The return counts as well. A heavy gripper makes every empty run slow; a unit that returns to its home position by itself takes a step off the operator.

A lifting aid does not compete with another lifting aid but with handling the part without one. If it is noticeably slower, it will be bypassed as soon as takt presses – and the investment in ergonomics has no effect.

The enquiry should therefore state the takt time, the share available for handling and the number of lifts per shift. The number of lifts also determines the loading of the unit and thus its classification.