5 Whys

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来自 University System of Georgia 的课程

Six Sigma Tools for Analyze

186 个评分

University System of Georgia

Six Sigma Tools for Analyze

186 个评分

课程 3（共 4 门，Specialization Six Sigma Yellow Belt）

This course will cover the Measure phase and portions of the Analyze phase of the Six Sigma DMAIC (Define, Measure, Analyze, Improve, and Control) process. You will learn about lean tools for process analysis, failure mode and effects analysis (FMEA), measurement system analysis (MSA) and gauge repeatability and reproducibility (GR&R), and you will be introduced to basic statistics. This course will outline useful measure and analysis phase tools and will give you an overview of statistics as they are related to the Six Sigma process. The statistics module will provide you with an overview of the concepts and you will be given multiple example problems to see how to apply these concepts. Every module will include readings, discussions, lecture videos, and quizzes to help make sure you understand the material and concepts that are studied. Our applied curriculum is built around the latest handbook The Certified Six Sigma Handbook (2nd edition) and students will develop /learn the fundamentals of Six Sigma. Registration includes online access to course content, projects, and resources but does not include the companion text The Certified Six Sigma Handbook (2nd edition). The companion text is not required to complete the assignments. However, the text is a recognized handbook used by professionals in the field. Also, it is a highly recommended text for those wishing to move forward in Six Sigma and eventually gain certification from professional agencies such as American Society for Quality (ASQ).

从本节课中

Root Cause Analysis

Root cause analysis is a common problem solving step. Determining the root cause of something is an important aspect of uncovering the causes of a problem. In this module you will review the different tools used in determining root cause including 5-whys, process mapping, force-field analysis, and matrix charts.

Root Cause Analysis1:23

Process Mapping3:55

Force Field Analysis4:07

Matrix Charts7:08

与讲师见面

Christina Scherrer, PhD
Professor of Industrial Engineering
Department of Systems and Industrial Engineering
David Cook, PhD
Assistant Professor of Mechanical Engineering Technology
Department of Mechanical Engineering Technology
Gregory Wiles, PhD
Interim Chair and Assistant Professor
Department of Systems and Industrial Engineering
Bill Bailey, PhD
Assistant Professor of Industrial Engineering
Department of Systems and Industrial Engineering

Five Whys is a simple brainstorming tool to get to root cause.

It's usually done within a group.

The technique was developed by Sakichi Toyoda.

Often, when we have a problem and we try to fix it, we're only addressing symptoms.

We have to dig deeper to get to root cause by asking why.

We have to peel back the layers.

There's nothing magical about five; you might reach root cause with three whys,

or it might take more than five,

but the idea is to keep digging until you can't go any deeper.

Here is an example.

Our problem is that we've been getting a large number of defects from one supplier.

Why are we getting so many defects?

An initial investigation revealed that parts are being damaged in shipping.

Why are they damaged in shipping?

Because the packaging does not protect them adequately.

Why is the packaging inadequate?

Because the supplier received no guidance on packaging.

Why did we not advise the supplier about packaging?

Because our packaging specifications are incomplete,

so they have not been available to the supplier.

So the lack of specifications was the root cause.

Here's another example; this is an automotive problem.

Started to go to work in the morning, and my car wouldn't start.

Why?

Because the battery is dead.

It would be easy to stop right there and go buy a battery,

but we need to dig a little deeper.

Why is the battery dead?

Because the alternator was not charging it.

Why was the alternator not charging?

Because the belt is broken.

Why did the belt break?

Because I did not do the necessary preventative maintenance.

That is the root cause.

If we had stopped anywhere short of that, it's likely the problem would have recurred.

Here is a manufacturing example.

We have a machining center that requires cooling,

but the coolant suddenly stopped flowing.

Why?

A quick investigation revealed that a circuit breaker had tripped.

Why did the circuit breaker trip?

Because the pump had overloaded.

Why did the pump overload?

Because metal chips got into the pump.

Why did metal chips get into the pump?

Because a metal screen meant to keep them out was missing.

Why was it missing?

Because preventative maintenance was done incorrectly and the screen was left off.

Why was preventative maintenance done incorrectly?

Because we did not do proper training and documentation.

That is the root cause.

I don't know how much truth there is in this old story,

but it's a good illustration all the same.

It seems that the Washington Monument was deteriorating

and it seemed to be happening rapidly.

Why was this happening?

Well, we've been using harsh chemicals and cleaning it frequently.

Why was it cleaned so frequently?

Because there are a lot of bird droppings and they accumulate quickly.

But why are there so much bird droppings?

Birds are attracted to the monument to eat the spiders

that seem to live there in great numbers.

Why are there so many spiders?

Because they eat other insects that gather at the monument at dusk.

Why are insects attracted to the monument at dusk?

Because the lighting attracts them.

The solution, or at least part of it, was to turn the lights on later.

These examples are meant to illustrate just some of the ways

that the Five Whys can be used to find root cause.

Remember, this usually works best with a group

and there's nothing magical about the number five.

Sometimes it will take more than that; sometimes it will take less.

You just need to keep digging until you cannot go any further.

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