Introduction to Lean Six Sigma technique
Lean and Six sigma are two effective process improvement techniques. This article introduces you to “Lean Six sigma” a combination of both the techniques.
Lean six sigma brings the best from both the world.
Before we look into the technique, let’s first understand what a process is.
Process is a series of actions or steps taken in order to complete a particular task.
Why do we need Process Improvement?
Process improvement focuses more on prevention than cure. It helps to understand process flow properly to identify factors causing variations.
Better process means increased Customer satisfaction, reduced response time and zero defects.
Improving process also leads to better process quality.
Designing a process includes a set of assumptions followed under ideal conditions. In real time situations, those assumptions might go wrong and re-starting from scratch may not be feasible for every organization.
Models are designed considering all possible variables which are modified at specific intervals to generate customer specified outputs.
Designing also includes removal of activities that add no value to the final product.
Process improvement focuses on reducing Lead time.
Lead time is defined as the ratio of "Total no. of activities to be executed" to "Average completion time of activity"
Increase in lead time beyond certain limit leads to increased customer response time, non-value add cost to the project and over utilization of resources.
How can we Increase average completion rate of activity?
We can try re-defining execution scope with respect to new requirements.
Try to minimize number of activities to be executed by selecting from a set of permutation combinations representing maximum coverage.
One last option is to add more resources to the project.
Lean Management Concept
Lean means “Poor or Not Producing Much”.
It focuses on management of 7 kinds of waste also known as “Mudas”, which contribute non-value add to the product.
- Over Production
- Over Processing
- Non- Right First Time or Rework
Lean Management - Process flow
As shown in the image, Lean management starts with identification of activities, determination of sequence, elimination of unwanted activities, final product and improvement of the new process.
Here’s a list of commonly used Lean tools:
- 5S (Sort, Set in Order, Shine, Standardize and Sustain)
- Bottleneck Analysis
- Ishikawa Diagram
- KPI (Key Performance Indicator)
- Poke Yoke (Error Proofing)
- Smart Goals
- Standardized Work
- Value Stream Mapping
Benefits of Lean Management:
- Enhances process efficiency.
- Enhances speed.
- Reduces muda (waste).
- Reduces re-work.
Six Sigma - Concept:
Sigma means Standard Deviation i.e. variation from average/ expected value.
Six sigma technique is a statistical measure of a process capability, targeting 3.4 DPMO (defects per million opportunity). It means 99.9997 % probability of passing non defective products to customer.
As Six sigma focuses on high quality, it helps to understand and manage customer requirements.
It also help to align key business processes to achieve customer specific requirements.
Six Sigma Approaches:
For designing new process – DMADV
For improving existing process - DMAIC
Six sigma technique starts with definition of activities, measurement of the results and analyzing the results.
In case of a new process, analysis is continued with design of the new process and then verifying the new process.
In case of existing processes, based on the analysis results, process are improved and controlled.
Six Sigma Tools:
Following are some of the commonly used Six sigma tools:
- Cause and effect Diagram
- Control Charts
- Pareto Analysis
- Scatter Diagram
- Check sheets
Benefits of Six sigma technique:
- Improves process by eliminating defect and process variations.
- Maintains acceptable level of performance quality.
What is Lean Six Sigma?
Lean Six Sigma = Lean + Six Sigma (6σ)
As the name indicates Lean six sigma is the combination of Lean and Six sigma techniques.
Lean Six Sigma Concept:
Lean Six Sigma obviously facilitates organization with benefits of both Lean and Six Sigma.
Here, Lean focuses on elimination of wastes and subsequently increases the speed of process by focusing on customer’s quality definition.
Six Sigma takes care of process variations using quality statistical tools.
Lean + Six Sigma
Focuses on resource utilization and removal of waste.
Focuses on statistics and response optimization.
Value Stream Mapping that involves identification of customer requirements, sequencing of process flow, establishing value-add steps, and reworking of process so that value-add steps flow without any interruption.
DMAIC process that involves defining the problem, measuring its current situation, analyzing for root cause, improving the process effectively and finally controlling to maintain the consistency.
Both problems and solutions are known prior to improvement implementation process.
Root cause of the problem is unknown.
Implemented using simple concepts. E.g. 5S, Kaizen etc…
Implemented using statistical tools. E.g. Pareto Analysis, Ishikawa Diagram etc…
100% of team can be involved and trained for its implementation.
Only 25% (specific group) of team can be involved and trained for its implementation.
Preferred in case organization(s) is/ are targeting for short term gains.
Preferred in case organization(s) is/ are targeting for long term gains.