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How to solve the scene problem with 5 “why”?

China Manufacturer of white anodized aluminum

One, what is 5Why (5 Whys)? China Manufacturer of white anodized aluminum

The so-called 5WHY method, also known as the “5 way”, which is a problem to point to 5 consecutive “why” from asked to investigate the root cause. Although the 5 why, but are not limited to use “5 why study”, mainly to find the root cause. Sometimes, sometimes may be as long as 3 times, 10 times, as the old saying says: give the third degree.

The key to 5WHY method to solve the problem: to encourage people to try to avoid the subjective or conceited assumption and logic trap, from the results to follow it along the chain of causation, the original, to find the root cause of the problem. China Manufacturer of white anodized aluminum

Two, 5Why classic story

Classical case 1: Ono Chi’s 5-Why analysis

Once, Mr. Ono Chi saw the machine on the production line always stop, although repaired many times, but still no improvement, then asked the staff on the scene

(1-Why) asked, “why did the machine stop?” answer: “because the load is exceeded, the fuse is broken.””

(2-Why) ask: “why overload?” answer: “because the bearing lubrication is not enough.”China Manufacturer of white anodized aluminum”

(3-Why) ask, “why isn’t the lubrication enough?” answer: “because the lubricating pump doesn’t get oil.””

(4-Why) ask, “why don’t you get oil?” answer: “because the oil pump shaft wears off, it’s loose. China Manufacturer of white anodized aluminum

(5-Why) asked: “why to wear?” answer: “because the filter is not installed, with iron and other impurities”

After five consecutive times kept asking “why”, find the real cause problems (in oil with impurities) and true solutions (filter installed in the pump shaft). From the phenomenon of pushing its essence, so find a solution to the problem of a permanent solution, which is 5-Why. China Manufacturer of white anodized aluminum

Classical case 2: 5-Why analysis of Jefferson Memorial Hall in Washington

In the 80s of last century, the U.S. government found that the Jefferson Memorial in Washington was seriously damaged by acid rain, so a consulting company was invited to investigate it. Here is a dialogue between consultants and building managers:

Q: why is the Jefferson Memorial affected by acid rain more severely than other buildings?

Answer: because cleaners often use cleaning agents for comprehensive cleaning

Q: why should we wash it regularly? China Manufacturer of white anodized aluminum

Answer: because there are many birds in this shit

Q: Why are there many birds shitting here?

Answer: because it is very suitable for insect breeding, these insects are a good meal for birds

Q: why is it so good for insect breeding here?

Answer: because the people inside the curtain closed all the year round, the sun can not shine, the balcony and windowsill dust formed suitable for insect breeding environment

The curtain was opened, and the problem of the Jefferson memorial hall was solved so easily

Three, the implementation of 5Why. China Manufacturer of white anodized aluminum

5WHY is implemented from three levels:

One, why does it happen? From the point of view of manufacturing

Two, why not found? From the perspective of “inspection”

Three, why not prevent accidents from the system, from the point of view of “system” or “process”?

Each layer of 5 consecutive or N times of the inquiry, draw the final conclusion. Only the above three levels of problems are explored, in order to find the fundamental problems, and seek solutions

Four, 5Why analysis of the basic steps to solve the problem

Part one: grasp the status quo

Step 1: identify the problem.

In the first step of the method, you begin to understand a problem that may be large, vague, or complex. You have some information, but you must not have the facts

Step 2: clarify the problem.

The next step in the method is to clarify the problem for a clearer understanding

Step 3: decomposition of. China Manufacturer of white anodized aluminum

In this step, if necessary, the need to investigate the relevant personnel, the problem is decomposed into small, independent elements

Step 4: find out the reasons. The main points (PoC)

Step 5: you tend to grasp the problem

To grasp the tendency of the question, ask:


Which one?

What time?

How many times?

How many?

It’s important to ask these questions before asking why

The second part: the cause investigation

Step 6: * direct reason to identify and confirm the abnormal phenomenon.

If the cause is visible, verify it. If the cause is not visible, consider the underlying cause and verify the most probable cause. Confirm the immediate cause based on the facts. China Manufacturer of white anodized aluminum

* step 7: use the “5 why” investigation method to establish a fundamental reason to cause / effect relationship chain.

* step 8: take specific measures to deal with the problem.

China Manufacturer of white anodized aluminum

China Manufacturer of white anodized aluminum


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