Paul Bunyan with Six-Sigma Tools
Powerful Six-Sigma Tools for a Job Shop
I’m not a big fan of force-fitting lean and six-sigma tools into applications that just don’t make sense. I believe that there are enough real-need applications in the lean/sigma toolbox such that force-fits aren’t needed. Additionally, force-fitting continuous improvement tools just tends to discredit the methodologies.
On the other hand, overlooking truly value-adding applications is a big mistake too. I think manufacturing job shops are often quick to dismiss lean and six-sigma methods. Both methodologies get dismissed to some degree in job shops, but six-sigma much more so. In doing so however, job shops are missing significant improvement opportunities.
Let’s explore one six-sigma opportunity that is available and extremely effective in improving quality and costs for most manufacturing plants, including job-shops across the globe. That is Gage R&R Studies.
Gage R&R Studies (Continuous Data): A problem for every manufacturing company is the establishment of accurate measurement methods. So many manufacturers don’t even recognize the problem, or the cost created by product measurement inconsistency. The variability comes from the operators and the inspectors and how they measure products. Frequently, manufacturing employees are using different tools and different methods to measure the same parts.
For example, an operator is operating a process and making process adjustments based on their own measurement methods, then a QA inspector can measure the same parts and get different results. The result of this discrepancy is product getting placed on quality hold for being potentially out of spec. Now whether it is the operator or the inspector who is measuring incorrectly is irrelevant. The product is still questionable because of inconsistent measurement .
A key point to make here is that process output is always more consistent than what is actually measured and that is because the measurement process itself increases the data variability. So the actual process contains less variability than the measure process.
Solving this problem isn’t all that complex. First, complete a benchmark Gage R&R study. The second step is to bring together a small team of subject-matter-experts and have them define and document the best method of measurement. This should include the ideal gage-type and detailed procedures that outline the step-by-step measurement technique. Once documented, then employees need to be trained and certified on the procedure. Finally, another Gage R&R should be conducted to capture the improved result.
New employees, need to get trained and certified on the procedure and their measurement results need to fall within the results of your second Gage R&R, otherwise measurement results will drift over time. You want to make sure everyone follows the measurement procedure to the letter. Sometimes, unfortunately, employees think they know better and hence they fail to comply. You need to monitor compliance to ensure long-term success. But know that it’s less costly to prevent defects than to scrap product.
Gage R&R Studies (Discrete Data): A KAPPA Study is a Gage R&R study, but it is used to capture measurement discrepancies in the form of product attribute or discrete data instead of continuous data. Product attributes are features that are important to customers but are not measured in a fractional way. These are usually visual attributes like scratches, dents and colors, but they can also be defined by our other senses such as taste or smell.
I think KAPPA studies have great application in job shops, especially whereas customers are expecting an artisan level of quality. Improving product quality using a KAPPA Study follows the same process steps as a continuous data Gage R&R do. These steps are:
- Complete a benchmark KAPPA
- Form a team of subject-matter-experts to define the best method
- Document the best method
- Train operators and inspectors on the new procedure
- Complete a second KAPPA to establish your improvement
- Train all new hires that will be assessing the product
- Compare new hire measurement performance to the latest KAPPA results
- Enforce compliance for sustained results.
Summary: The moral of the story here is to always remain open to exploring tools that can help you improve. Remember that Paul Bunyan, with his axe, lost a tree cutting challenge to salesman who used a chain saw. Was the salesman a better man than Paul Bunyan? Of course not. He just had a better tool. Wouldn’t optimal productivity result from the combined effects of Paul Bunyan using a better tool, aka a chain saw?
Be Paul Bunyan with a chain saw. Be the best you and use the best tools.
Stay connected with news and updates!
If you want some weekly T4T wisdom coming straight to your inbox for your reading pleasure - look no further! Join our mailing list to receive the latest blogs and updates.
Don't worry, your information will not be shared.
We hate SPAM. We will never sell your information, for any reason.
