Tip:
Highlight text to annotate it
X
Hi there. My name is Ron Pereira and I'd like to officially welcome
you to this first overview module of the Gemba Academy 7 QC tools course.
By the end of this module you'll know what quality control is, you'll
understand the benefits of quality control, and you'll know what the
7 QC tools are. You'll also begin to see how the
7 QC tools can help your organization improve no matter what type of work you do.
To be sure, you don't have to manufacture widgets to practice quality control as we'll
learn throughout the rest of this course. Okay. Well let's get things started by offering
a definition of quality control. And to do so we're going to hear from one
of the giants of quality control, Dr. Kaoru Ishikawa, the person credited with
defining what we call the 7 QC Tools today. Well when asked to define what quality control
was, Dr. Ishikawa said, "...that it consists of developing,
designing, producing, marketing, and servicing products and services with optimum
cost-effectiveness and usefulness which customers will purchase with
satisfaction." Now from this definition it's clear that Dr.
Ishikawa felt quality control was far more than visually inspecting parts
at the end of the assembly line. In fact, Dr. Ishikawa often spoke of Total
Quality Control or TQC which saw quality control spread to all facets of
the organization including front office tasks. So that's what
it is. Now let's now turn our focus to the benefits of quality
control. First, when quality control becomes a way
of life the number of defective products will decrease and as such, over time customer satisfaction
will increase leading to enhanced trust and loyalty.
And from an internal perspective, consistent quality control lowers costs for
the company since people aren't wasting time reworking parts and waiting
for good parts to be
produced and, as such, profits increase year over year.
So you see, done correctly, quality control reaches all aspects of our
business which results in happy and loyal customers.
Now then, the tools most often used for problem solving by organizations
well versed in quality control are called the Seven QC Tools.
Now for the rest of this module, we'll take some time to introduce them
and then throughout the rest of this course we're going to be taking a deep dive into
each tool explaining how they can be applied in both
manufacturing and transactional environments. But before we get into the tools,
I'd like to provide a little background on how these concepts developed.
And as it turns out, the Japanese began applying quality control during the
1930's and 1940's after Dr. Walter Shewhart and Dr. W Edwards Deming
introduced the concepts. Dr. Kaoru Ishikawa, the then head of the Japanese Union
of Scientists and Engineers decided to expand the use of these tools
in the 1960's with the introduction of what we now call the Seven
Quality Control Tools. Dr. Ishikawa chose these 7 tools as
a way to make the use of quality control accessible to anyone,
no matter their experience with statistics. Well the first of the 7 QC tools is the graph.
Now most of us have seen or used graphs at one time or another.
With graphs, data are expressed to easily compare quantities or quantity changes.
They're also used for arranging data, sharing information with others,
and making judgments. Now in our next module, we'll not only explore several
different types of graphs, but we'll also explain how to
choose the correct graph to use. The second QC tool is the Check
Sheet which are tables used to arrange data by type.
Now we also use these simple, but powerful tools, for checking if
jobs are completed without problems and for preventing
mistakes from happening at all. The third QC tool is the Pareto Chart.
Now Pareto Charts classifies problems and defects by type in the order
of quantities and shows the cumulative total. Now Pareto Charts are often used for checking
a problem or defect to be highlighted for solution.
In other words, Pareto Charts often help us identify where the problem
is as we learned about in the Gemba Academy Practical Problem Solving course.
Again as a reminder, Pareto charts get their name from Wilfredo Pareto,
the Italian economist who was the first to identify the so called 80-20 rule. Well the
fourth tool invented by the aforementioned Dr. Ishikawa is
the Cause & Effect diagram, sometimes called the fishbone.
Now the cause and effect diagram systematically arranges the results
of effects and the factors that influence them. With this
information, we're able to classify causes and their potential influence
on the problem at hand. The fifth QC tool is called the
Scatter Diagram which is a graph used to examine the correlation between
variables by plotting corresponding data. In other words, Scatter Diagrams
help us examine the relationships between two variables and whether
or not they're associated, or correlated, with one another.
Now, we'll get into different variations of the Scatter Diagram including
regression later in the course, but I do want to mention an extremely
important aspect of studying correlation. Namely that correlation does not
automatically mean there is causation. Now an example of this is how in some cases it
can be statistically shown that as the number of liquor stores in a
town increases so do the number of churches built. So one could
conclude that if a town hoped to have more churches all they need
to do is build more liquor stores, right? Well of course this is complete nonsense
since the two, liquor stores and churches, aren't correlated at all.
Now a better explanation for this situation is that as a town grows in population
, there'll be some who like to visit liquor stores and some who
like to attend church. Next, we come to the Histogram which
is a graphical display of numerical data in the form of upright bars.
With histograms, we're able to learn many things including how much variation,
or spread, a data set contains. Now when we add in customer specification
limits, which we'll learn more about later in the course, we're able to calculate
something called Cp and Cpk which basically tells us how well our
process meets customer requirements. And last but certainly not least,
we come to the Control Chart which is a tool used for judging the situation of quality
values against control limits in order to check the stability of a process.
Now Control charts also help us to understand whether we're dealing with common
cause or special cause variation which is an extremely important information
to know as we work to control quality across all levels of the organization.
Now we first learned about common cause and special cause variation in our
Practical Problem Solving course, but as a quick refresher common cause variation could
be likened to the normal everyday traffic we experience on
our commute each day to work. And special cause variation could be
likened to when there's an accident and traffic comes to a complete stand still.
Alright. Those are the 7 QC tools. As promised throughout the rest of
this course, we're going to take a deep dive into each one separately explaining how
the tool can be applied in both manufacturing and transactional environments. Additionally,
throughout the rest of this cours,e we're going to learn how
to create each of these tools using Microsoft Excel and Sigma XL
statistical software. Alright, well this wraps up this overview
module. In our next lesson, we're going to dive right into
things as we gain a deeper understanding of the many different kinds
of graphs available to us. So we'll speak to you soon.