The 7 Essential Tools for Quality Engineers

Do you ever look at something so long it becomes completely meaningless? Sometimes that’s what quality engineers feel like. Our job is to take a bunch of seemingly random numbers, organize them, and explain that data with neat and tidy stories.

Stories, after all, are how we understand things (it’s why we all get excited for the next season of our favorite show!). Knowing the story of a process—how a product comes together—is half the battle for a quality engineer. If something goes wrong, but you understand the process, it’s a lot easier to fix.

At Treetown Tech, that’s what our quality engineers do every day—using these seven essential tools allows one to identify and resolve quality related issues as quickly and efficiently as possible. After all, time is money!

Credit: www.effectivedatastorytelling.com

What Is Quality Engineering?

Quality engineering ensures that products and processes meet specifications. This involves identifying risks, mitigating those risks, and preventing defects so that products are reliable and safe. Remember kids—plan, do, check, act!

The mantra of the quality engineer is “Don’t ship garbage.” (Yes, we made that G-rated!) Ensuring quality throughout the development and manufacturing process is critical because reworking often means investing additional time and money that you may not have.

Getting things right the first time is what quality engineering is all about. But to do that, every quality engineer will reach into their toolbox for at least one of these seven tools.

7 Essential Tools for Quality Engineers

Every quality engineer depends on a variety of tools to make their job easier—here are our seven go-tos.

1. Fishbone Diagram

The fishbone or Ishikawa diagram (a visual cause-and-effect map, invented by Kaoru Ishikawa) is useful when pinpointing a root-cause problem. The “fish head” (at the right) is the problem that needs solving, and the “fishbones” (to the left) are the potential causes. The most common are:

  • Manpower (personnel)
  • Machine (equipment)
  • Method (process)
  • Material (raw material)
  • Measurement (inspection)
  • Mother Nature (environment)
Credit: ASQ.org

2. Check Sheets

With check sheets, we collect quantitative or qualitative data. These sheets help us identify how many times an error has occurred in a process or product, helping with detecting defect patterns. This data can be used in several different ways, such as to improve a design for the manufacturing process or predict when your tooling needs to be replaced before parts are made out of spec. 

3. Pareto Chart

A Pareto chart (named after Vilfredo Pareto) is a column chart that shows the relative importance of different issues so we can prioritize defects that most impact quality. Under the Pareto Principle (also known as the 80/20 rule), 80% of problems are caused by 20% of the major factors. We prioritize the root cause and resolution of these “vital few”.

Credit: ASQ.org

4. Distributions

Managing quality means understanding the behavior of your data, i.e., how it’s distributed. We use histograms, box plots, dot plots, Anderson-Darling normality test, Individual Distribution Identification, and other tools to see the shape of the data before we start making assumptions. You wouldn’t want to use parametric statistics on non-normal data, would you?

Credit: Minitab

5. Scatter Plots

Scatter plots help us identify cause and effect by depicting the relationship between two variables. Analyzing the scatter plot determines if there’s a correlation, such as Y = mX + b in a linear regression. Remember, correlation only shows if a relationship is present—it does not establish causation!

Credit: www.tylervigen.com/spurious-correlations

6. Control Charts

Control charts (invented by Walter A. Shewhart) display how a process behaves over time. With reference lines in place, we can determine if a given process is in statistical control. If not, it can help us identify special-cause (unanticipated) events that are resulting in increased defect occurrence or process variation.

Credit: Minitab

7. Flow Charts

Flow charts are a terrific snapshot of a process, showing organizational structures and how the process flows. We can easily see what’s getting done, and by whom, as well as where the most important quality gates are. Creating a visual map of a process helps identify and eliminate inefficiencies.

Credit: Lucidchart

Keeping Quality High at Treetown Tech

Want to learn more about what makes quality an integral part of the design process—even when you’re working with low-quantity prototypes or proofs of concept? Reach out to our team of experts today!

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