Find the Root Cause of Your Broken Parts with the Lightning Problem Solving Method

Originally published: January 30, 2018 | Updated: January 2026

Who Knew It Was This Easy?

Today, we’re tackling the always-frustrating issue of broken parts. If you’re putting out manufactured parts that break on a regular basis, it can cost you a whole lot more than just time. Frustration, money, and even your job could be on the line, unless you use the Lightning Problem Solving Method!  The road to problem-solving with broken parts can be a bit bumpy. In this video, we’ll learn how to avoid potholes on the journey to your root cause. It’s as easy as breaking it down into five simple steps.

Broken Parts, 5 Steps to Solve FAST!

⚡ Lightning Insight:
“In a manufacturing setting, if you’re putting out parts that are breaking on a regular basis, it can mess up a whole lot more than just your day.”

#1: You’ll need to collect ten parts: five broken parts, and five in good shape.

Most engineers start by looking at only the broken parts. What a slow way to solve problems! This method won’t help you find the root cause – it only develops a temporary solution. Parts will continue to break. You’ll keep wasting time and money.

⚡ Lightning Insight:
“Here’s where a lot of engineers go wrong: they look ONLY at the broken parts and ask, ‘how can I re-engineer this so we don’t get broken parts again?’”

(Pro-tip: If you’re guilty of “solution-hunting,” you can check out my video on root cause vs solution. The best problem solvers know the difference between a solution and a root cause!)

Your good parts should be some that have been in that assembly or a similar scenario for a long time that haven’t broken. If you can’t find parts like these, then just find five parts from the assembly line – work with whatever you have.

#2: Ask the right questions.

⚡ Lightning Insight:
“Instead of asking HOW can I re-engineer this so it doesn’t break, ask WHY 5 times.”

Finding the root of the problem is all about asking the right questions. Instead of asking, “How can I re-engineer this part so it doesn’t break?” ask “Why?” — five times in a row. (No need to shout into the sky; asking “Why?” repeatedly is usually enough!)

Doing this consistently often uncovers the true root cause. Here’s an example:

• Why do we have these scrap parts? Because the operator didn’t follow the work instructions.
• Why didn’t the operator follow the work instructions? It was because he wasn’t trained properly.
• Why wasn’t he trained properly? Well, because we don’t have somebody in charge of training.
• Why not? Because unfortunately there isn’t enough funding to hire a single employee for that one job.

And so on!

(Pro-tip #2: If you need more insight on asking the right questions, check out this video on everything you need to know about the five whys.)

#3: Check the specification of the parts.

Now that you have the big picture, it’s time to get technical. Think of yourself as the Goldilocks of manufacturing problem-solving: are the parts too small, too big, or just right? Check every detail — dimensions, color, tolerances — everything should meet specifications perfectly.

#4: Check your processes.

We’re all human, but you want your employees trained to follow processes to a T.

⚡ Lightning Insight:
"Remember, you want your employees trained to follow the process similar to the way a programmed robot would."

#5: Reproduce the event.

Finally, we get to the fun part: testing your theory (aka: breaking things!). This means breaking parts — but safely, in a controlled environment. By reproducing the failure after following the first four steps, you can confirm whether you’ve truly found the root cause.

After the first four steps, you should have a good idea of what your root cause could be. Now is your opportunity to test your theory. If you found mistakes in the processes or specifications, run new parts mimicking those mistakes. Then, run more new parts the correct way. If you see contrast (broken vs. unbroken), then you got it right!

⚡ Lightning Insight:
“If the three parts that you made the good way do not fail and the three parts that you made bad fail, then most likely you have the root cause.”

In conclusion, if you’re stuck with a broken part problem that you need to get under control fast, get in touch! I offer consultations for your worst manufacturing issues, on-site or online. In the meantime, check out my other videos on the Lightning Problem Solving Method, a lightning fast way to become a manufacturing problem solver!

*This post was originally published January 30, 2018 and has been updated for clarity and current practices in January, 2026.