About TLS - Theory of Constraints Lean Six Sigma
Less than a quarter of all
companies reported achieving significant progress towards world
class.*
*Industry Week Magazine, “2007 Survey of
Manufacturers”
Many organizations struggle with their continuous improvement (CI) efforts. Achieving real bottom line improvements whether in real cost savings or rising revenues has proven to be difficult. In spite of the widespread implementation of Lean and Six Sigma principles, poor results persist. That’s not to say there are pockets of success; some implementations do deliver a competitive edge. It’s just that these projects are the exception, not the rule.
Theory of Constraints Lean Six Sigma – TLS – has, in double blind studies, been shown to deliver 15 times more results than Lean alone and 23 times the results with Six Sigma alone. TLS blends the Theory of Constraints (ToC), Lean and Six Sigma principles to deliver significant bottom line returns FAST; ROI is typically 10 to 1.
The TLS Process
TLS combines the processes of each of the major improvement initiatives to create synergy in improvement. ToC (Theory of Constraints) helps us focus on the right things - to create improvement outcomes that matter to shareholders and customers. Lean helps us eliminate waste from the process and Six Sigma helps us reduce variation. It does no good to focus on creating a perfect process, if that process is not the constraint of the business. Alternatively, what is one to do with the constraint once you find it? When the constraint is in a process, clearly, you should employ the best tools available to either remove or elevate it.
- Set the stage for your implementation by evaluating the
measurement system to eliminate any reinforcements for behaviors
that allow for local improvement but do not contribute to global
improvement.
Commission your continuous improvement initiative by senior management and provide accountability for local process ownership of improvement teams.
- Apply the Theory of Constraints to investigate the problem at hand from a global
perspective; (the overall firm’s performance) to identify the
constraint of the enterprise. The constraint is your leverage
point to get results quickly from your improvement initiatives.
- Stabilize the process of managing the constraint using
buffers and buffer management to ensure that the constraint is
not wasted and promises to customers can be met consistently.
Use customer pull and level load the resources.
- Using the feedback from buffer management, create a
problem/objective definition for your improvement team that
addresses the organization’s constraint. (The most significant
payback will be created when elevating the system's constraint,
but targeting non-constraint resources and processes to prevent
interference with the constraint may also prove beneficial.)
- Once the leverage point is found, employ the appropriate tools of Lean to drive out the waste in the process.
The organization's value-add would be identified through a behavior oriented value-stream-mapping process. A waste-less, aligned value stream would be created by streamlining the process activities and behaviors so that queues, unnecessary inventories, and work-in-process would be minimized.
- After eliminating or minimizing the waste, apply Six Sigma tools to identify and isolate the source(s) of process variation and systematically remove or minimize those variations. At this stage, the process must perform consistently and repeatedly with minimal variability (scrap, rework, etc).
When the source(s) of process variation have been identified using Six Sigma’s analytical tools the critical few factors are identified for process control. During this stage it may be necessary to perform design of experiments (DOE) to establish the best process design. Upon establishing the best design, it is necessary to establish the control mechanisms to ensure that the critical process factors will remain in statistical control. Application of Poka-Yoke and statistical process control is essential to sustain the process gains and provide an early warning system to prevent process variability.
- If in any of the prior steps, the constraint moves, go back to the identification step and start the process over.
TLS Process Summary
- Create the right structure for continuous improvement
- Stabilize the overall process before implementing process changes
- Apply the Theory of Constraints to focus on what needs to be fixed
- Apply Lean tools to eliminate waste
- Apply Six Sigma tools to reduce process variability
- When the constraint is eliminated, go back to the beginning.