MRO Today - The DMAIC path

The DMAIC path

You’ve got the plan; now ask the right questions

by S. “Mani” Manivannan

Editor’s note: Part one of this article, “Six Sigma in no time,” ran in the February/March issue of MRO Today.

In “Six Sigma in no time,” we discussed the key differences between Six Sigma and TQM and the argument for pursuing Six Sigma projects. In this article, we will go through each step of the DMAIC process to help you create the specific metrics that will ensure success for your project.

To review, properly defined Six Sigma projects meet certain criteria:
1. They have clearly defined deliverables
2. They have management approval
3. They are not so large that they’re unmanageable nor so small that they’re unimportant or uninteresting
4. They relate directly to the organization’s mission
Here, then, are some specific questions and metrics to apply as you implement your Six Sigma project and their places in the Define Measure Analyze Improve Control (DMAIC) process.

Define: D
Define is the first phase of the DMAIC model. The purpose of the Define phase is to refine the project team’s understanding of the problem to be addressed and define the customer’s expectations for the process.

In this phase, the project team defines what is needed for a successful Six Sigma project. This includes:
    • Identification of customers (Internal/External)
    • Identification of the customer’s needs (Internal/External)
    • Goals of the project
    • Scope of the project
These elements are analyzed to develop the Problem Statement. It is extremely important to identify the right problem.

The purpose of the Problem Statement is to:
    • Clearly define and quantify the problem
    • Identify the potential metrics and measurement sources
    • Identify the negative attributes and the current performance and their relationship to the customer

The Problem Statement includes:
    • A specific statement of the problem being addressed
    • Descriptive statements outlining locations and/or occurrences of problematic events
    • An initial “scope of the problem” statement

Consider these two Problem Statements:
1. “Our first run is too low.”
2. “In June, Zone A’s average first run of 60 percent was below our 80 percent target.”

You will notice that the first version oversimplifies the problem and does not contain the critical information of the location of the problem (Zone A), its rate of occurrence (June), or its scope (60 percent productivity versus 80 percent targeted).

Key questions to ask yourself to arrive at this Problem Statement include:
    • Who is my customer?
    • What matters (CTQs – Critical To Quality)?
    • What is the scope?
    • What defect am I trying to reduce?
    • By how much (goal)?
    • What is the current cost of the defects?

The tools you’ll use to create your Problem Statement:
    • Y=f(x)
    • Process map
    • Fishbone

What you’ll deliver is a Problem Statement that includes the following:
    • Who is the customer?
    • What is the problem being addressed?
    • What does the customer want (VOC/CTQ)
      (VOC – Voice Of Customer)?
    • Where is the problem?
    • When does the problem occur?
    • How big is the problem?

When you can answer these in a single statement, you can be sure your problem has been targeted and that you have identified the right problem to work on.

Measure: M
The purpose of the Measure phase is to establish techniques for collecting data about the current performance and how well it is meeting the customer requirements. Upon completing the Measure Phase, the project team will have:
    • A data collection plan
    • A valid measurement system that ensures accuracy and consistency in data collection
    • A baseline frequency for defects
    • Sufficient data for problem analysis

Questions to ask yourself during the Measure phase:
    • What is my process?
    • Which outputs affect the quality most?
    • Which inputs seem to affect the outputs the most?
    • Is my ability to measure/detect good enough?
    • How is my process doing today?
    • How good could my process be if everything were running smoothly?
    • What’s the best that my process was designed to do?

Tools you use:	What you’ll deliver:
Process map	Key metric (what it is that you’ll measure)
Fishbone	Rolled throughput yield
Graphs	Defects identified
Operational definitions	• Data collection plan • Baseline capability • Defect reduction goal

Analyze: A
The purpose of the Analyze phase is to allow the project team to target improvement opportunities by taking a closer look at the data. In the Analyze phase, the project team will:
    • Know why, when and where defects occur
    • Select the appropriate graphical analysis tools and apply them to the data collected
    • Be able to target a set of potential improvements for action in the Improve phase

Questions to ask yourself during the Analyze phase are:
    • Which Inputs actually affect my quality most?
    • By how much?
    • If I change an input do I really change the output?
    • How many observations do I need to draw conclusions?
    • What level of confidence do I have regarding my conclusions?

The tools you’ll use in the Analyze phase are:

Tools you use:	What you’ll deliver:
Graphs	• Detailed process map • Sources of variation identified and prioritized • QPS reviewed • Refined Problem Statement • Estimates of opportunities for defects

Improve: I
The purpose of the Improve phase is to allow the project team to develop, implement and validate improvement alternatives that will fix the process. The Improve phase consists of:
    • Brainstorming to generate improvement alternatives
    • Testing the proposed solutions using a pilot cell or location validates the improvement
    • Creation of a new process map to illustrate the new process flow and then conducting a cost/benefit analysis to ensure the potential improvement is viable and cost effective
    • Collecting and analyzing data on the new process, demonstrating the validity of the improvements

The questions to ask yourself in this phase include:
• Once I know ‘for sure’ which inputs most affect my output, how do I ‘implement’ changes
• How many trials do I need to run to find and confirm the best setting/procedure of these key inputs?

The tools you’ll use in the Improve phase include:

Tools you use:	What you’ll deliver:
Process map	Solutions to the problem
Trials	‘Should be’ process map
Simulations	• Cost/benefit analysis for the proposed solution • Solution validation • Implementation plan • Communication plan

Control: C
The purpose of the Control phase is to institutionalize process/product improvements and monitor ongoing performance in order to sustain the gains achieved in the Improve phase. During the Control phase the project team will develop:
    • A control strategy based upon the results of the previous four phases
    • A control plan that incorporates changes into the process in a timely way
    • An updated QPS and training plan to document the changes and improvements

Questions to ask yourself in the Control phase are:
    • Once I’ve reduced the defects, how do the functional team and I keep them there?
    • How does the functional team keep it going?
    • What do I set up to keep it going even when things change (people, technology and customers)?

Tools you use:	What you’ll deliver:
Control plan	Control plan completed
SPC (statistical process control)	Evidence that the process is in control
Error proofing (prevention vs detection)	Documentation of the project
Preventative maintenance	New estimate of the reduce defects per million opportunities identified

All Six Sigma projects are challenging, and they should be. There is also no guarantee of success, but using these tools in their proper order will dramatically increase your odds of a successful Six Sigma project. When the benefits you realize measure in multiples of the effort required to do the project, you will know you have done it right. Good luck!