06 March 2019 The meaning of “poka yoke”: why it is becoming increasingly functional in Lean production processes
POKA-YOKE is a Japanese term. But which is its real meaning? It is used to indicate a design choice or apparatus that imposes restrictions on how an operation can be carried out to force the user to do so correctly. This composite word literally means “avoid (yokeru) careless mistakes (poka)”.
Examples of poka-yoke are commonly found in the IT and audio/video sectors, for example in many electronic connectors.
There are three kinds of poka-yoke:
- Contact method: the physical characteristics of an object (shape, colour, etc.) highlight the correct position and prevent malfunctions due to incorrect contact;
- Fixed-value method: checks that a specific number of steps have been completed;
- Motion-step method: checks that all the steps in a specific process have been carried out in the correct order.
Meaning and benefits of Poka-Yoke systems
“Poka-yoke” systems bring many benefits to industrial assembly processes because:
- they check that a specific number of steps have been completed (fixed-value method);
- they check that all the steps in a specific process have been carried out in the correct order (motion-step method).
Therefore, these systems relieve operators from the constraint of continuously controlling the machine during operation so that they can oversee the whole process, offering considerable benefits to final product quality.
In line with the principles of Lean Production, Fiam has therefore developed several devices that follow the Poka-Yoke concepts, precisely because they serve to achieve the following key objectives:
- make the processes more efficient;
- support the operator during the various work stages.
A Poka-Yoke solution in tightening processes: FIAM TOM
Fiam TOM, or “Tightening Operation Monitor”, is also a “poka-yoke” unit.
In fact, it is a monitoring unit that can be used with screwdrivers to speed up working performance and check the progress of tightening processes in real time, all through a display that provides information about the production cycle with light and sound feedback.
A unit of this kind can bring numerous benefits to industrial assembly processes:
- It immediately intercepts an error before a product is irreparably transformed into a reject;
- It supports the operator during assembly;
- It stops the production line to prevent a reject from reaching the end, which would waste the accumulated manufacturing costs;
- It reduces errors and allows them to be corrected promptly;
- It considerably reduces costly post-process checks on the final product.
It is therefore a practical and concrete example of how Poka-Yoke systems can be applied in the industrial field to guarantee high working continuity, resulting in faster working cycles.
To find out more on how to support operators, eliminate waste and increase finished product quality within tightening processes, take a look at TOM: https://bit.ly/2EJd4V4