countermeasure? Yes, you can add it to the Training Time Table so that it is not overlooked in the future.
If you ask why again, will it take you to another problem? Yes, you would
◾
be asking how the purge process was left off the list of required trainings.
If you implement a countermeasure that addresses the root cause, will it
◾
prevent the problem from recurring? Yes, by adding the purge process to the Training Time Table, the Team Leader will not overlook the training next time a new person is trained on the process.
If you are able to answer yes to all three questions, you will have a higher likeli-hood of successfully achieving your target. If addressing what you believe is the root cause(s) will not allow you to achieve or bring you closer to your target, you will need to continue with the Cause Analysis process until you identify the real root cause(s).
One of the benefits of the A3 is that the information can be shared easily with other departments and even sister companies. In the years that I have been teaching A3 Problem Solving, I often find that leaders in different depart-ments experience problems that stem from similar root causes. Many of these problems could be avoided by sharing the findings of A3 Problem Solving throughout the organization, thus allowing leaders to learn from one another.
Therefore Test
Before moving on to the countermeasure portion of the A3 Problem-Solving process, you must test the logic of your Cause Analysis. To do this you will use the word “therefore” in place of the word “why” and read the chain of events in reverse. This is referred to as the “Therefore Test” and helps identify information that might be missing from your analysis, making it difficult for someone with little or no knowledge of the problem to understand.
Start by reading aloud the statement of the root cause followed by the word
“therefore.” Then read the statement previous to the root cause and say “there-fore.” Continue this process until you have read the statement of the problem at the beginning of the 5-Why causal chain.
At any point in the process, if you are not able to insert the word “therefore”
and make sense of the analysis, you have a gap in your logic. If there are gaps, you will need to fill in the gaps with additional facts. Figure 7.7 shows how using the “Therefore test” can help you detect an incomplete 5-Why chain.
Read the following cause-and-effect 5-Why chain to see if there are any gaps:
To those with maintenance experience, the following analysis may seem complete because they can make intuitive leaps based on their experience and knowledge that close the gaps. However, to those with little or no maintenance experience, it may be a little difficult to make the leap from the associate not purging the ink
Cause Analysis ◾ 57
from the printer to the printer nozzle being clogged. Figure 7.8 is based on the same situation but with additional information that makes it flow more logically.
As with most rules, there is an exception to the 5-Why process. There will be times when you will not be able to confirm potential causes due to the inability to get accurate information. You will begin the process just as described earlier.
However, at some point in the process, you may not be able to answer why something is happening.
This may be due to the inability to see what is going on. If you are having a problem with painted parts that are coming out of an oven, you may need to brainstorm potential causes regarding how the oven contributes to the problem.
However, because you cannot go inside the oven while it is running, you may need to brainstorm a broad spectrum of countermeasures and stagger the imple-mentation to determine what actually caused the problem.
This process is more time consuming than cause-and-effect analysis. Cause-and-effect analysis is like firing a scoped rifle that has been sighted in to a hit a bull’s-eye at 100 yards. You are very likely to hit the target dead center provided your scope is dialed in properly. Conversely, the trial-and-error approach is much more like firing a shotgun at the same target, where you will have lots of holes in the target, but only a few will actually hit the bull’s-eye.
Now that you have identified the problem and analyzed to root cause, you will need to generate possible countermeasures and select the countermeasure(s) that will allow you to achieve your stated targets.
20 minutes downtime due to packing line #2 label printer not printing Therefore
Therefore
Therefore Root Cause:
Printer nozzle clogged
Worker did not purge ink from printer
Purge process not identified on training time table
Figure 7.7 incomplete 5-Why chain.
20 minutes downtime due to packing line #2 label printer not printing Printer nozzle clogged
Dry ink in printer nozzle
Ink left in printer over weekend dries Worker did not purge ink from printer
Worker not trained on purging process
Purge process not identified on training time table Root Cause:
Figure 7.8 Complete 5-Why chain.
Production 5-Why Exercise
Read the following examples and number them in the correct sequence to create a logical 5-Why chain leading from the problem to the root cause. To ensure that you have each statement in the correct order, use the “Therefore” test to check your logic. See Appendix H for answers to this exercise.
example 7.1
Problem: 25% of fabricated fireproof storage boxes do not fit in home location.
Fireproof storage boxes are ¼ inch too tall, wide, and deep.
Associate #3’s tape measure is off by ¼ inch.
Associate #3’s tape measure is not documented by Quality department.
Associate #3’s tape measure is not calibrated.
Associate #3 is using his personal tape measure.
example 7.2
Problem: 10% of runners on plastic molded parts do not fall onto regrind chute.
Robotic arm not aligned with regrind chute.
Regrind chute is too narrow.
Runner sways back and forth before dropping.
example 7.3
Problem: 30% of refrigerator water filter cartridges strip out on second shift.
Associate thinks cartridges are too loose.
Torque set too high on cartridge air tool.
Associate does not understand torque requirements for part.
Associate increases air pressure.
Torque specification not specified on Job Breakdown sheet.
Associate not provided specifications during Job Instruction.
example 7.4
Problem: 18% of inserts damaged when pressed into part.
Neck on press blocks assembler’s view.
Insert not aligned flush with part opening.
Assembler cannot see insert in relation to part opening.
Cause Analysis ◾ 59
Office 5-Why Exercise
Read the following examples and number them in the correct sequence to create a logical 5-Why chain leading from the problem to the root cause. To ensure that you have each statement in the correct order, use the “Therefore Test” to check your logic. See Appendix I for answers to this exercise.
example 7.5
Problem: Picnic tables have trash stuffed into gaps between boards.
Associates do not want to walk 150 feet to dumpster.
Associates do not put trash in dumpsters.
Associates think it takes too much of their breaks and lunchtime.
example 7.6
Problem: Interoffice mail not delivered at 9:00 a.m., thus delaying payroll process.
Security was asked to transport associate to Urgent Treatment.
Security did not pick up mail until 8:30 a.m.
Night shift supervisor did not want to take the Team Member to Urgent Treatment.
Mail not sorted until 9:00 a.m. by office staff.
Supervisor did not want to stay late to complete production reports.
example 7.7
Problem: Network copier jammed.
Paper curls around roller.
Paper is too large.
Paper is feeding at the wrong angle.
Too many pages are feeding at the same time.
example 7.8
Problem: Supply room ran out of blue ink pens.
Supply room replacement not specified when office supply staff went on vacation.
Supply room staff did not notify office manager.
Office manager did not know that blue ink pens were needed.
Purchasing did not receive a purchase order for blue ink pens.
Purchasing did not order blue ink pens.