In our everyday lives, we stumble across multiple problems or concerns that need solving. This can be a relatively small problem with a simple solution or a large problem requiring more in-depth thought. We rarely think about how we got to the solution, however as an engineer this journey is critical to solving the problem. Within the engineering field there are multiple problem-solving techniques and tools that can be used to support us in creating the best solution. Throughout this blog we hope to give an overview of these tools and techniques, which will provide you with great knowledge you can bring with you into interviews and the first few months of your new job.
What is problem solving?
When problem solving is spoke about within engineering, the phrase “root cause” is almost always used. Simply put, this is the exact reason why a problem has occurred, and it is sometimes buried under layers of other information. The idea behind utilising problem-solving techniques is to help engineers find this root cause, rather than jumping directly to a solution. A very simple example could be a machine that has started to produce more rejects than it typically does. Upon investigation, the engineers find that a pulley is worn and needs replacing. This is where most non-engineers would stop. However, someone trained in problem solving would dig deeper here. They might review the internal maintenance schedule and find that the pulley is supposed to be changed once per year, but upon speaking with the machine vendor, they recommend changing the pulley every 6 months. This is now a root cause. The internal maintenance schedule of the machine did not follow the vendor recommendations and the machine stopped working correctly. Had the engineers resumed normal work after replacing the pulley, they would run into more issues 6 months later wasting valuable time on solving the problem again.
The Root Cause Analysis Stages
So now that you see what a root cause is, lets run through the key steps to finding one. First, the problem must be clearly defined. If too broad of a problem statement is generated it can lead to diffuse solutions or difficulty knowing exactly where to focus on during the initial problem-solving stages. In the above example, it is straightforward. The problem statement could be that the machine is producing 20% more rejects than typically seen. A more difficult problem to define would be if you were approached by a manager regarding a production line that is only delivering 70% yield and you must undertake a project to improve it. A production line could have any number of different reasons for parts failing so this would be much too broad for you to start the problem-solving process on. A great tool to use in this instance is a Pareto chart.
The Pareto Chart promotes confidence that you are directing your attention and energy into the highest priority issue, which if solved, will have the largest positive impact on the process. A Pareto, as seen above, is essentially a bar chart which is arranged by height in descending order. The order of the bars allows you to rank and prioritize the problems. This allows you to have a starting point for your problem-solving actions.
You may have heard of the term the 80 20 rule or also known as the Pareto Principle. This term states that for many outcomes 80% of the consequences come from 20% of the causes. This is a term that you will encounter and have a deep understanding of from working within engineering. Pareto charts are an excellent visual aid to demonstrate your data in a clear and concise manner, they are simple to read and understand which will support you when presenting your approach to the wider team, allowing you to provide justification for why you are pursuing one issue initially.
Once the problem is defined, it is important to outline the end goal. This can be done by highlighting the current condition which is currently unacceptable and then providing a target or goal, of where the process/part should perform at, the target condition. We then need to approach the problem with an open mind. A common mistake is jumping straight into the solution without having the correct evidence to support your decision. This is where we need to understand the problem and utilise an appropriate methodology for solving it. We need to investigate the issue and highlight potential root causes to create a foundation for the investigation. A great tool for this is the Cause-and-Effect diagram (sometimes referred to as a Fishbone Diagram).
A Cause-and-Effect diagram is a modified brainstorming tool which allows you to group potential variation under different characteristics. This is an excellent tool to be used in a team environment, as it allows every individual to have input. This tool allows you to then concentrate on the potential root cause and is an excellent visual aid to support the problem-solving process. It gives the team the opportunity to explore potential causes of a specific problem, and more importantly allows you to understand the relationship between these causes. Sometimes you may see the same potential cause appear under more than one heading, which may suggest it is worth investigating further.
The six headings that the potential causes are characterized under are shown below. We also provided a few examples of what may fall under each heading. These are very general, and it will vary from problem to problem massively with what causes you evaluate.
a. Measurement – How are things inspected? What equipment used? How accurate? Etc.
b. Environment – Where did the issue occur? Was it very humid? Was the manufacturing area controlled? Etc.
c. Man – Who was working on the parts? Using the machine? Etc.
d. Material – What lots effected? Different vendors? Age? Etc.
e. Method – How is the part manufactured, inspected, handled? Etc.
f. Machine – What machine is the issue with? What machine was used to make the parts? Etc.
Each one of your potential causes will be populated under one of the above headings, this then creates a relationship between each of the sources. Once completed, it is then time to prioritize your potential causes. Label each cause with a number from 1 to 3 (1 meaning there is a high possibility and 3 meaning there is a low possibility). This then allows you to prioritize testing the most likely causes first making more effective use of your time.
An action plan can be created following this that describes the trials and areas intended for further investigation. This may involve creating a timeline to map out your experiments, along with describing an interim measure for preventing the reoccurrence of the problem while root cause work is ongoing.
As the root cause work is ongoing, it is best to constantly challenge your current thought process to ensure you are finding the true root cause. The 5 Why’s is a simple tool developed for this which can be used several times during a problem-solving exercise. It is a tool that allows you to dissect a cause into sub compartments allowing you to evaluate each section in simple terms. Each why is evaluated as its own unique problem to allow you to ask the question again - “Why?”. This tool allows you to breakdown complex problems into manageable subsections with a clear emphasis on driving you towards the root cause.
An example of a “5 whys” is below in relation to a car not starting.
1. The battery is dead
2. The alternator is not working
3. The alternator belt is damaged
4. The belt was not replaced during maintenance
5. The correct maintenance schedule was not followed
Finally, when we have identified our solution and have tested it out through experiments and the 5 Why’s, we introduce, implement and monitor to ensure the problem has been resolved for good.
The above information is a brief overview of problem-solving techniques and tools to support you on your career path and set yourself up for success. If you desire to learn more, please read though our other posts where we will be continually developing more content and advice for up-and-coming engineers.
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