Six Sigma DMAIC Process - Improve Phase - Screen Against Musts and Wants

LEAN SIX SIGMA PART…. 21MARATHON STUDY

‘’In my last article, we learned how to Refine Solution Criteria

Please read along as we attain another height in PART..21..

We progress by understanding Six Sigma DMAIC Process - Improve Phase - Screen Against Musts and Wants

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Six Sigma DMAIC Process - Improve Phase - Screen Against Musts and Wants

Once possible solutions are listed, we can begin the process of seeing how they perform against the solution criteria. We base our assessment on the best available information about each alternative. In addition to known facts, this information may take the form of our best projections or the opinion of experts. The criteria serve as the guide for our data gathering. For each criteria we

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must have complete information about all of the alternatives, so that we can make a reasonable judgment.

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Six Sigma DMAIC Process - Improve Phase - Conduct Cost-Benefit Analysis

Cost-benefit analysis weighs the real costs of a potential solution under consideration against the potential benefits of the solution. Consider all costs associated with getting the proposed solution up and running. Cost examples would be: Capital investment needed, Implementation costs (time of project team, process improvement costs, etc), Start-up costs (training, lost

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production during switch from the old to new process), Operation costs (additional cost of running new process compared to old process).

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The steps involved in doing a cost-benefit analysis for possible solutions are:

???????? Consider all costs associated with getting solution up and running

???????? Quantify benefits of a fully implemented solution

???????? Compare the real costs of solution against potential benefits

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Does the identified solution have any risk?

Risk can be mitigated for the proposed solution by Identifying potential problem if any with the solution, Ensuring that the solution attempts to reduce the opportunity for error if not eliminated, Is it an “All terrain” or a" Feather bed” solution – How robust is the solution and Understanding the Failure Modes and Effect Analysis.

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Six Sigma DMAIC Process - Improve Phase - Failure Mode Effect Analysis (FMEA)

FMEA identifies all the probable failure modes for the product or process. It prioritizes the failure modes for focused attention by using a scoring model based on Severity (S), Occurrence (O) and Detect ability (D).

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RPN = S*O*D

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Based on the above suitable action plans can be created to contain the risk. It is used as a living document and could be a good foundation for building robustness.

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Definition of Terms:

???????? Failure Mode – The way in which a specific process input fails

???????? Effect – The impact the failure has on the Critical Quality Parameter

???????? Cause – The source of variation that caused the process to fail

???????? Current controls – Systemized devices in place to prevent or detect the failure

???????? Severity – Importance of an effect on critical quality parameter (1-Not severe; 10 – very severe)

???????? Occurrence – Frequency with which a cause occurs (1- Not likely; 10-Very likely)

???????? Detection – Ability of current control to detect the cause before creating a failure mode (1-likely to detect; 10-not likely to detect)

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???????? RPN is an acronym for Risk Priority Number. It is calculated by multiplying the Severity, Occurrence and Detectability.

Failure Mode Effect Analysis (FMEA) - 2

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Failure Mode Effect Analysis (FMEA) - 1

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Six Sigma DMAIC Process - Improve Phase - Pilot Solution Implementation

In general, there is a way to pilot all or some part of every solution that you will want to implement. It is almost always worth the extra effort to pilot. You certainly need to pilot when the scope of the change is large, the change could cause far-reaching unintended consequences, implementing the change will be a costly process and the change implemented would be difficult

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to reverse.

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The key steps involved in conducting a pilot are strong leadership from top management, select a steering committee/pilot team, conduct briefings with the pilot team, pilot planning for issueless execution, sell to employees affected under pilot, employee training for pilot execution, pilot implementation on the shop-floor, debriefing after pilot implementation and extend to a second area, if required.

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Six Sigma DMAIC Process - Improve Phase - Validate Measurement System

For continuous data we use Gage R&R and we check for

% Tolerance, % Contribution and # of Distinct Categories and for discrete data we use Attribute R&R and we check for Accuracy, Repeatability and Reproducibility.

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Six Sigma DMAIC Process - Improve Phase - New Process Capability / Mapping

New Process Capability can be calculated using DPMO Method or Z value method as discussed in the Measure phase.

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New Team Targets: With the desired results coming from

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the pilot, the current process baselining needs to be revisited. The new process capability achieved should be made the basis of re-baselining exercise and we need to set new internal team targets accordingly for the staff.

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With the desired results coming from the pilot, the new improved process “should-be” needs to be mapped. While mapping the new process, we should consider the following workflow instructions:

???????? Establish a product orientation or customer orientation

???????? Establish one-at-a-time processing

???????? Balance flow through bottleneck

???????? Drive parallel processing

???????? Reduce handoffs

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Six Sigma DMAIC Process - Control Phase - Statistical Process Control

SPC was developed by Walter Shewhart in 1924. Traditionally SPC has been used to monitor and control the output parameters of the process (Y’s).

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SPC is used to analyze and control process performance, proactively control processes, distinguish between natural and assignable variation, identify and prevent process from Special causes and involves the use of Control Charts to determine if a process is operating “in control”.

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Six Sigma DMAIC Process - Control Phase - What is a Process Control?

A control mechanism that ensures that the process performance be maintained are at level that satisfies the customer’s need and drive the ongoing improvement of process performance. The key elements that constitute a process control system are

???????? Documentation of the process

???????? Develop process metrics

???????? Monitor the process based on the defined metrics

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When we talk of a process is operating "In-Control" it

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translates to a situation that only common cause variation is present, process is predictable and process is stable.

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Control limit Vs Specification Limit

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Control Limits: It is defined based on process performance. It help determine if the process is “in control”. It is plotted on control charts and it changes when there is a verified, significant change to the process.

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Specification Limits: It is provided by the customer part of SLA. It help determine if the process is producing defects. It is not plotted on control charts and it changes when requirement comes from the customer.

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Six Sigma DMAIC Process - Control Phase - What are Control Charts?

Control Chart is a graphical tool that helps determine if a process is “in control or not”. A control chart has three zones and is graphically represented as:

Six Sigma Control Chart Zones

Common Causes and Special Causes which result with Variations

Characteristics of Common Causes:

???????? Present all the time

???????? Have a small effect individually

???????? Result in random variation

???????? Effect can be tolerated

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Characteristics of Special Causes:

???????? Not always present

???????? Come from outside influences

???????? Typically have bigger influence than common causes

???????? Effect we want to hear about

Thanks For Learning With Maxwell Stay close for part ,,,,21,,,,,

Next we shall study Six Sigma DMAIC Process - Introduction to Define Phase.