3 minute 5 why: Case1

The operators use a 5 Why investigation to understand why they lost time on their packaging line during the last shift.

They ask the question: Why did the machine shut down?

Answer: The overload protection switch opened.

They continue on with these questions and answers. The questions, answers and notes the operators use in their investigation could be recorded in a table like the following one.

Question	Answer	Notes
Why did the machine shut down?	The overload protection switch opened.
Why did the overload switch open?	High current draw by the conveyor particularly the box transporter.	The shift electrician checked the overload and reported that it was operating properly but the current draw seemed to occasionally increase on some machine cycles of the box transporter.
Why was there a high current draw on the box transporter?	Cardboard seems to be slightly damp and might have been preventing easy sliding in the box transporter.	The operators inspected the box transporter mechanism for jamming and recovered the cardboard on one of the cycles when the current draw was high.
Why was the cardboard damp?	Packaging of cardboard feed stock damaged.	The operators inspected incoming pallets of cardboard and found some with damage to the plastic wrapping an in some cases there were signs that some moisture had penetrated.
Why was the packaging damaged?	Packaging damaged by forklift during unloading.	The operators called in on the stores department. The forklift operators said that sometimes packing can be damaged if they are closely stacked and plastic catches on another pallet. They didn't realize it was a problem and changed their procedure to avoid this situation.

The operators felt that their investigation was successful and had led to the real cause of the problem. They decided to enter the findings into the RCA Rt software to communicate their observations to the other shifts and as a way to store the details in case the problem happens again in the future. A screen print of their RCA Rt record is shown below. They did a quick check of the Risk Matrix to confirm that they had completed the job in accordance with company policy.

Click here to see their check on the Risk Matrix.