How to perform effective root cause analysis

To run an effective manufacturing floor, you must give your manufacturing teams the right tools and empower them to use them properly. The following three components are key to getting this right:

• Real-time, accurate data: Real-time visibility of how the manufacturing floor is performing is crucial. Without it, you are flying blind and cannot make quick decisions throughout the shift. Whether it is tracking output to plan, monitoring defect levels, addressing unplanned downtime issues quickly or measuring the overall effectiveness of the operation (see OEE article), data is king. As W. Edwards Deming once said, “without data, you are just another person with an opinion”.
• A Good meeting structure: Whether it’s a quick huddle at the start of a shift between the supervisor and production operators or a top level review with the operations management team, manufacturing meetings can be effective in just 5 minutes. But they need to have a clear agenda, where everybody leaves the meeting knowing what the priority actions are for the day (see Meetings article).
• A structured approach to solving problems: Sometimes a problem is well defined and the root cause is obvious. Other times it is not. Regardless, a consistent approach to looking at and solving problems brings many benefits to a manufacturing company and increases the likelihood that old problems won’t re-emerge in the future.

What is structured problem solving and root cause analysis?

Structured problem solving is a methodology for solving problems in a systematic way in order to prevent them from reoccurring. It is a widely used approach in many industries but has gained a lot of traction in the manufacturing sector under lean manufacturing and sig sigma umbrellas. Although there are many different methods, they all have the same principles; understand the problem properly, find the root cause and put a solution in place that will prevent a problem from reoccurring

The benefits of effective root cause analysis

1. It stops issues from reoccurring

Firefighting is the practice of reacting to problems with quick fixes. It is about focusing on addressing the symptoms of a problem without fully understanding the problem or its root cause. For example, a common problem that Kyzentree’s clients have is that the output target for the first hour of the shift is not hit. Overtime is a common fix to address the shortfall, which does nothing to address the root cause of the problem. Very often the root cause is that production operators are waiting for materials, paperwork or tech support to get their process up and running properly. Using Kyzentree’s software, Kt-Pulse, clients can quantify exactly what is happening at the start of shift and how much time is lost. Once the root cause is understood, a solution can be put in place to prevent it from happening in the future.

2. A well-defined problem is often 50% solved

If a problem is well defined it very often makes the practice of finding a root cause and implementing a solution much easier. Using data rather than opinions to define the problem is a must. Avoid statements such as “this problem is always happening” or “we never see that happening”. Once the problem is defined based on data, it generally makes it far easier to find the root cause and solution.

For example, let’s say we are producing a product where some parts have scratches on the surface that must be discarded. The problem could be defined as…

“We are always producing parts with scratches on the surface and we have to throw lots of parts away”

Or the team could go further and generate more facts…

“5% of products that are produced on the ABC line have scratches on the surface. 90% of the scratches are on the top surface of the handle component. The problem only affects the large product size. The small and medium parts are unaffected by this issue. The problem started happening on the 4-May-2020”

The more prescriptive the problem statement, the more clues you have to find the root cause. Kt-Pulse provides more in-depth analysis on defects and is widely used in the root cause analysis process.

3. A boost to team morale

A core principle of structured problem solving is that it is a team-based activity; the responsibility is shared among the whole team. A problem shared is a problem halved, which avoids the issue becoming overwhelming for any one individual. Furthermore, there is a great sense of achievement when the root cause of a problem is discovered and a robust solution is implemented. Acknowledging the successes is also important, giving the team a sense that their efforts are recognised and worthwhile

4. A reduction in costs

Spending time “fixing” the same problem multiple times has many cost implications; material costs if it is a scrap problem, labour if it is a downtime problem and a drop in morale if the same team keeps encountering the problem over and over. Solving a problem once is clearly the most favourable outcome. Structured problem solving and root cause analysis is a skill your teams will become better and better at whilst continually improving the processes they work on.

Root Cause Analysis (RCA) methodologies

There are numerous methodologies used to determine the root cause of problems in the manufacturing industry. From the basic 5 Whys approach to the more complex 8D methodology, here is a snapshot of a few popular methods

4-step Problem Solving Roadmap

The 4-step problem solving roadmap is both simple and powerful. It concentrates on the four critical steps in problem solving. It works very well for more complex problems when the problem and root cause are not well understood.

Step 1 Define the problem

This step involves finding out as much about the problem as possible. It also means finding out what the problem is not (e.g. the problem is affecting large product sizes but is not affecting small product sizes). Every fact that is gathered about the problem could be the vital clue in determining the root cause. The following tools are popular for defining a problem…

• Is/Is-Not Charts
• Checksheets
• Process Mapping

Step 2 Implement containment action

This step gives the team a chance to step back from the problem and see what, if anything, can be done to contain the issue in the short term. It offers the possibility to put a temporary solution in place while the team works on step 3 in parallel. Typical containment actions include…

• Implementing additional inspections to screen out defective products
• Replacing a part on a tool or piece of equipment that keeps breaking
• Removing a suspect batch of material, tool or piece of equipment
• Putting suspect batches on hold for further investigation
• If there is no obvious containment action, the manufacturing process may need to be shut down for a period of time, which is usually the last resort

Any action taken at this point should be seen as a short term fix (containment) rather than a long term solution. However, on occasion, a really good containment action may become a really good permanent solution.

Step 3 Identify root cause

This is very often the most difficult step in a structured problem solving investigation. The more well defined a problem is, the easier it is to find a root cause. During this step it is useful to pull a wider team together to brainstorm potential causes of the problem. This includes everybody from production operators through to senior engineers and management. The collective brain power of the whole team can create a more comprehensive list of potential causes.

Once the list of potential causes are identified, they are usually prioritised as low, medium and high for investigation, based on the team’s experience. From here the process involves a mixture of investigative work (e.g. digging through historical paperwork) and experimentation (e.g. running experiments to recreate the root cause)

Finding the root cause of a problem is often a pivotal moment in the process and a welcome relief for all involved. Useful tools during this step include…

• Brainstorming (yes, it’s a tool in itself!)
• Cause & Effect Chart (Fishbone Diagram)
• Fault Tree Analysis
• Design of Experiments (for more complex problems)
• An inquisitive mind

Step 4 Implement solution

Very often, once the root cause is found, the solution is obvious. However, that doesn’t mean that the solution is easy to implement. The danger at this stage of the process is that the solution is not followed through fully. This is especially true if the containment action is doing a reasonable job of containing the issue. Focus on planning out the solution and track it as a project in itself. Useful tools include…

• PDCA (Plan-Do-Check-Act)
• Gannt Chart (if it is a complex solution)

Process validation and documentation may also need to be created in order to complete the solution, depending on the industry.

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Request a free demo: Solving problems is part of the everyday fabric of the manufacturing floor. And access to good data is fundamental to doing it effectively. Kt-Pulse is the first app-based product that accurately captures output, quality and downtime data in real-time from any manual or semi-automated process. The data has been instrumental in helping to solve many problems on the manufacturing floor. If you’d like to see for yourself how Kyzentree’s software, Kt-Pulse, can help you to carry out more effective root cause analysis, book a one-to-one, no obligation consultation today and we’ll showcase the benefits to you

About Kyzentree: We are a recognised leader in improving productivity by making it easy to visualise and manage manufacturing operations. We specialise in operator-driven processes. We have brought together a team of manufacturing, lean-sigma and technology experts to bring you our flagship product Kt-Pulse™. Kt-Pulse is an app-based software solution built exclusively for monitoring any type of manual assembly, inspection or packaging process.