Manufacturing Process Improvement: Fixing Errors and Abnormalities Quickly

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TBM Consulting
Contributing Writer

In this blog, we discuss how to address errors in manufacturing by using manufacturing process improvement problem-solving methods for effective manufacturing risk management.

Resiliency, the ability to overcome challenges, is a defining factor in whether we “make it or break it” as individuals, teams, or enterprises. This is a particularly crucial trait in manufacturing risk management, and it’s a skill that can be honed through manufacturing process improvements.

In this two-part e-guide series, Boosting Existing Systems & Resources to Maximize Production, we provide in-depth, step-by-step guides for enhancing your existing Operational Management System (OMS). Part one of the guide, Developing the Framework & Tools for Effective Operational Management, provides changes manufacturing leaders can make to set themselves up for success. Part two of the guide, Addressing Errors & Abnormalities: Proven Methods, is all about troubleshooting common challenges manufacturing operations managers often face.

In part one of this blog series, we provided approaches manufacturing leaders can implement for increased production efficiency in your OMS. In this blog, we’ll review problem-solving strategies for how to address errors in manufacturing to help address errors and abnormalities quickly and effectively.

Topics include:

  1. Investigative Problem-Solving Strategies

  2. How To Make More Effective Manufacturing Process Improvements

Investigative Problem-solving Strategies

When faced with errors and abnormalities, manufacturers have two choices depending on the scope and complexity of the situation: apply a quick fix, or take a calculated, investigative approach. When problems are multifaceted, difficult to resolve, or recurring, leadership needs to take care to swiftly fix the issue at its core so it solves the problem once and for all. Four problem-solving tools can help leadership get organized and set up for success when it comes to how to address errors in manufacturing:

  • The Five Whys

  • Pareto analysis

  • Fishbone diagrams

  • A3 methodology

The 5 Whys

Previous SafetyChain blogs have discussed the Toyota Production System (TPS) and how it kickstarted lean manufacturing. Another product of the TPS to aid in manufacturing process improvement is a problem-solving strategy called the 5 Whys. The general premise of the 5 Whys is to continuously ask the question “Why?” until you reach the true root cause of the error that occurred.

The classic example provided by the TPS concerns a malfunctioning welding robot:

Begin with the most basic form of your issue, such as the error that occurred. Now, ask yourself, why did that error occur? Chances are, your response to this question will not be the root cause, and it’s going to take several more whys to move from symptoms of the error, to the actual root cause itself. The actual number of whys is arbitrary, as long as you get to the root cause. You will know when you’ve gotten to the root cause because it’s actionable, and you can generally trace multiple, higher levels of whys back to a particular root cause.

For example, missing a production deadline because the materials weren’t ready, because there wasn’t enough time to produce them, because workers had to prioritize other projects, because there weren’t enough workers for the total number of projects, all points to a labor shortage problem. Identifying the core problem is the first step to improving manufacturing risk management.

Pareto Analysis

You may not have heard of the Italian researcher Vilfredo Pareto, but perhaps you’re familiar with a theory based on his work: the 80/20 rule.

The 80/20 rule is a widely applicable interdisciplinary theory that postulates that roughly 20% of external factors are the causes of 80% of all outputs.

The 80/20 rule was popularized by Joseph M. Juran in 1937, based on his studies of Vilfredo Pareto’s 1906 publication. Pareto discovered that approximately 20% of Italy’s population owned 80% of the country’s land, and similar distributions held across other countries he surveyed. Juran wondered if this same rule, that only a few factors impact the larger picture, could be applied to other areas of economics as well, and in fact, it could.

The 80/20 rule has since been applied to a wide variety of fields with success, such as engineering, computer science, occupational safety, and more. Pareto Analysis is now considered to be an interdisciplinary method for optimizing decision-making processes. As applied to problem-solving in manufacturing, 80% of problems can be traced to 20% of root causes or defects.

A Pareto Chart can be used to help narrow down where your biggest problem areas are so you can implement manufacturing process improvement changes.

To make your own Pareto chart, follow these steps:

  • First, list the problems you’re having.

  • Then, for each problem, determine what the error was that caused the problem.

  • Finally, create your Pareto chart — typically displayed as a bar graph — to determine which errors are most affecting your business.

The ASQ provides a free, downloadable template to help you get started with creating your own Pareto chart.

Fishbone Diagrams

Fishbone diagrams, also known as Ishikawa diagrams for the engineering professor at the University of Tokyo who first created the diagrams in the 1960s, Kaoru Ishikawa, are a useful tool to pair with the 5 Whys when relationships between problems may not be straightforward.

In a fishbone diagram, the problem is the fish’s head and other bones are the causes. Major causes (which can also be thought of as categories; see discussion in the next paragraph) are identified as ribs that directly branch out from the fish’s backbone, and root causes are eventually identified as bones that branch out from the ribs. Once the root causes are identified, leadership can move to implement manufacturing risk management measures.

Fishbone diagrams typically follow the so-called 6Ps of manufacturing to serve as categories to identify potential causes, an update to the 6Ms of manufacturing to support important changes within the industry. The categories are helpful in narrowing down whether the root cause of a problem is stemming from a process-related issue or a product-related issue, for example:

The ASQ provides a free, downloadable template to help you get started with creating your own fishbone diagram.

A3 Methodology

It’s just a piece of paper. But, it’s one of the most effective lean tools available to manufacturing engineers.

Austin Weber / AssemblyMag

Yet another brainchild of the Toyota lean manufacturing system, A3 is a tool for breaking problems and projects down to their core. The name “A3” refers to the international paper size A3 that was originally used for this strategy because it was the largest, faxable size of paper, so the information could easily be distributed and collaborated on throughout multiple departments and offices. That’s it though — that’s all you get: just one sheet of paper on which to condense your objective down to its most fundamental components.

Interesting fact:

Paper sizes are geometrically related to the zeroth size within their series (e.g., A series, B series, etc.). Within the A series, each successive paper size is almost exactly half of the area of the previous paper size. So a single A0 page — the largest within the series — can fit two A1 pages within the same area; a single A1 page can fit two A2 pages within the same area; a single A2 paper can fit two A3 pages within the same area, and so forth.

An A3 can technically contain information in any format, but it’s often paired with visual tools like the 5 Whys, Pareto Analysis, and Fishbone Diagrams to help narrow down the root of the issue when problem-solving. The rule of thumb is to use visuals and hard data in the form of tables, graphs, and charts as much as possible in place of text to give teams an at-a-glance understanding of the situation and solution.

How to Make More Effective Manufacturing Process Improvements

Manufacturing risk management starts with having a plan to respond to errors and abnormalities as they occur, so you can take them in stride and implement resolutions fast. By understanding the strategies behind how to respond to challenges effectively, leadership can choose the correct approach to make manufacturing process improvements.

Learn more about how to address errors in manufacturing in our eGuide, Addressing Errors & Abnormalities: Proven Methods.

About the author: TBM is a global operations consulting firm with an emphasis on operations, lean, and supply chain consulting for manufacturers and distributors.

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