DMAIC’s Improve

Improve is the fourth step of the Six Sigma five step process DMAIC. The objective of Improve is to develop and implement the best plan for improvement of the opportunities (Root Causes) identified in the analyze step. It is not to develop only one plan because to get the “best” you need to have several approaches to work through with your sponsor to find the best mix of solutions that is acceptable to all. I often tell my black belts to develop several options and pick one to really sell to management and the sponsor. If you do not do this then management (your project sponsor) only have the ability to accept what you have or reject the team efforts and shut down the project.  You have to understand that the team is focused on improving the process. Management is focus on the whole business and the plan you really want may have a bigger negative impact some where else. That can happen and you need other options that will. Here are a series of questions that you will want to answer before moving on to control:

n      What options do you have?

n      What options will we go ahead and do?

n      What is the plan to implement the new process (options)?

n      What additional resources are needed?

n      How does your new process work?

n      Are you sub-optimizing?

n      What are your measures that show improvement?

n      What went different than planned?

n      Does this solution support company’s goals?

It is very important that you get all of these answered. Some that stand out are “Are you sub-optimizing” and “Does this solution support company Goals?”  Sub-optimization is when you make improvements in your process only to have a negative impact further down stream in the company or organization. This is best address as I mentioned earlier buy making sure you understand all the options to improve. Once you have a plan make sure again that you are making an impact on your company goals. Some times we get to this stage and do not make sure that the options we want to implement really do impact the company goals.

To answer the question above it may take several tools and techniques to collect the “facts and data.” So here in Improve, there are several good tool and techniques that can help get you that data.

• Constraint Management – A Constraint (bottleneck) is any resource with fewer throughputs than the demand placed on it. Usually constraints regulate the output of the process so you need to use techniques that optimize the constraint and keep it running/ working all the time.
• Pull Systems – These are method of controlling the flow and quantity of resources by only replacing what has been consumed. It is a system of signals to refill/ replenish right when you take the last item to work.

• Setup Reduction – Setup is the time required for the process or activity to changeover from producing the last good piece of the prior item (part) to the first good piece of the next item. Setup Reduction is a set of techniques used to reduce that time.
• Lot Size Reduction – Lot Size is defined as “The amount of a particular item that is ordered from the plant or a supplier or issued as a standard quantity to the production process – (APICS). Lot sizes larger than 1 adds wait time to every piece in the lot. Waiting is considered a waste[1]. So in Lot Size Reduction we try to decrease the lot size to one.
• 5 S’s – The 5 S’s are a waste elimination process that is applied to any process. There are a lot of methods to doing this and worksheets to help but in short the 5S’s stand for:
  • Sort through and Sort out
  • Set everything in order
  • Shine everything
  • Standardize processes
  • Sustain the gains

• Design of Experiments – This is simply when you design an experiment to determine when you change something how a process reacts to that change. Many times we do this by hold all input variables constant except one and  observe the response as you vary the single input. This is called OFAT (one factor at time) which is not the best way to do a designed experiment. Problems with this approach are:

1. It usually isn’t possible to hold all other variables constant.
2. There is no way to account for the effect of joint variation of independent variables, such as interaction.
3. There is no way to account for experimental error, including measurement variation.

Most that do Design of Experiments (DOE) vary two or more variables simultaneously and make multiple measurements under the same experimental conditions. This eliminates all three of the above problems. This is the best way to run an experiment to get the most for your efforts.

• Simple Business Analysis – This analysis takes all the approaches to improvement and evaluates them on at least in these three areas; effectiveness, costs to do and time it will take to implement. Below is a simple chart I use to do this analysis.

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The above are seven tools I have not talked about before, other useful Improve tools that I have talked about are:

Brainstorming, LCS, Affinity Diagramming, Multi-voting and 5 Whys from my article The First step of DMAIC – Define.

Plus  DE & UDE, Gauge R&R, Basic Summary Stats and Pareto Charts from my article The Second step of DMAIC – Measure.

Cause & Effect Diagrams,  The Third step of DMAIC – Analyze.

Well there you have it, a little more understanding of the Improve step of the Six Sigma 5 step DMAIC process. I hope that this gives you a better understanding of what questions to answer and what tools to uses to get those answers in Improve.

Peter Bersbach
Six Sigma Master Black Belt
Bersbach Consulting
From Process to Profits

1.520.829.0090

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[1] The Seven Types of Waste a Summary

Tags: DMAIC, DMAIC Improve, Method

This entry was posted on Monday, November 23rd, 2009 at 2:46 pm and is filed under Introduction to Six Sigma, Six Sigma Tools. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.