Tuesday, June 26, 2018

New Book Part 9

In my last post, we began our discussion on what I believe are the 4 best tools for problem solving.  I listed the four best tools as the Run Chart, the Pareto Chart, the Cause and Effect Diagram, and the Causal Chain.  I completed the last post by giving a brief description of the Run Chart and explained the basics of how to create one and how it can be used.  In today’s post we will look at more of these problem solving tools.
The 4 Best Tools for Problem Solving (con’t)
The Pareto Chart
While the run chart answers the questions of if and when a change has occurred, the Pareto chart is more of a comparative tool.  That is, if we suspect differences in performance between things like machines, people, or even days of the week, then we can visualize these differences with a Pareto chart.  The genesis of Pareto charts came from a most unlikely source.  An Italian economist, Vilfredo Pareto, was studying the distribution of wealth in Italy in the 19th century.  When he assembled his data, he discovered that approximately 80 % of the wealth in Italy was controlled by only 20 % of the population.  Later Dr. Joseph Juran, a noted American quality authority, further developed Pareto’s inadvertent discovery and so named this phenomenon the Pareto principle in Pareto’s honor.  Juran found that the Pareto principle applied to many different things like absenteeism, defects, accidents, etc. He found that many things typically align themselves and follow the principle that 80 % of problems are manifested in 20 % of the items with the problem. Let’s look at an example of this tool.

Suppose that a machine is experiencing faults and we have been asked to look into the problem.  We assemble the data and notice that the frequency of the faults is not the same every day. If we were to arrange the data as a Pareto chart, by day of the week, as in Figure 2.4, we see that the chart of this data validates what we believed was true.  The Pareto chart gives a picture of the days of the week and clearly shows us that we have a severe problem with faults on Monday and then the faults gradually decrease as the week progresses until Friday when they cease to exist. By knowing that Monday is the worst day for faults, we can focus our efforts on comparing what is unique or different on Monday compared to the best day of the week, Friday.

Pareto charts are really quite simple to create.  Along the horizontal or x-axis we simply place what we are comparing (e.g. operators, machines, etc.), and then place whatever we are measuring along the vertical or y-axis.  Now what could be more straightforward than that?

In my next post, we continue our discussion on these four important tools.  As you go through my postings, if you have any questions for me, send me an email to ras8202@live.com.
Bob Sproull

Friday, June 1, 2018

New Book Part 8

In my last post, we looked at the 4C’s of problem solving which were contain the problem, find the root cause of the problem, correct the problem, and control the problem.  I explained that if you correctly implement the 4C’s, you will be in control of the problem.   In today’s post, I will talk about what I believe are the four best tools for solving problems.
The 4 Best Tools for Problem Solving
In my travels, one thing that has become very apparent and evident to me is that there are so many people who have no grasp of basic analysis tools and techniques.  One of the prerequisites for solving problems is having at least a basic understanding of which tools to use and when to use them.  It is remarkable to me that even after all of the many initiatives and programs like TQM and Six Sigma, so many people and companies haven’t embraced or begun to understand the basic tools and concepts.

In this post we will consider four basic tools that a problem solving team must make use of, if the team is to successfully determine the root cause of the problem they are addressing.  You may be wondering if there are other tools available besides these four and the answer is yes.  But having said this, it is my belief that if you can master and make use of these four simple and uncomplicated tools, you will be able to solve the majority of problems facing you.  So what are these four tools?

The four tools are the Run Chart, the Pareto Chart, the Cause and Effect Diagram, and the Causal Chain.  The run chart will answer the question of when the problem started, when it has occurred since it started, and will then help identify whether or not it is a change or launch-related problem.  The Pareto chart will help the team determine things like where the problem is, which machine is creating the problem and who has the problem.  The Cause and Effect Diagram will facilitate the creation of a list of potential causes, while the Causal Chain will help the team formulate the chain of events that led to the problem (i.e. the hypothesis).  Although there are other tools that can be used by the team, I firmly believe that teams will be much more successful by using just these four simple tools.  Now let’s look at each tool and some examples.

The Run Chart
One of the keys to solving problems is knowing when the problem began and when it has occurred since its inception.  In addition, the team needs to be able to measure the impact of any changes made to the process.  The Run Chart will provide the answer to all of these questions.  The Run Chart or Trend Chart, as it is also termed, is a graphical representation of the problem being tracked as a function of time, with time being any unit like hours, days, etc.  Time is placed along the horizontal axis (x-axis) and whatever you are measuring is placed along the vertical axis (y-axis). Let’s look at an example.

Suppose we suspect that temperature is a key factor in the creation of a defect and we are interested in knowing what happens to the temperature throughout the day.  We measure the temperature each hour and record it as follows:

                        Time                                                               Temperature
                        6:00 am                                                                 60
                        7:00 am                                                                 62
                        8:00 am                                                                 63
                        9:00 am                                                                 65
                      10:00 am                                                                 70
                      11:00 am                                                                 75
                      12:00 pm                                                                 80
                        1:00 pm                                                                 81
                        2:00 pm                                                                 82
                        3:00 pm                                                                 80
                        4:00 pm                                                                 79
                        5:00 pm                                                                 75
                        6:00 pm                                                                 72

Although we are able to view the temperatures as recorded above and see the general trend, it is sometimes difficult to see other subtleties of how the data is trending, so creating a Run Chart facilitates this.  The figure below is the Run Chart created from the data we collected and as you can see, the temperature begins at 60 degrees at 6:00 AM and begins to rise until the maximum value of roughly 82 degrees is reached at 2:00 PM.  If you have suspected that temperature is an important factor in the problem you are attempting to solve, the Run Chart tells you what you need to know in terms of correlating temperature to the defect.

In my next post, we continue our discussion on these four important tools.  As you go through my postings, if you have any questions for me, send me an email to ras8202@live.com.
Bob Sproull