The Lean definition of flow goes something like this, the accomplishment of steps within a value stream so that a product or service proceeds from the beginning of the value stream to the customer without waste. Most Lean transformations first step is thinking and improving flow. They start many times with 5S (Sort, Straighten, Shine, Standardize, Sustain) and then utilize Lean tools such as Value Stream Mapping, One-Piece Flow Cells, Reduce Inventory and Work in Progress (WIP) and create Standard Work. Flow is a lifetime journey and to become proficient at the before mentioned tools can take just that. We will go over 5S and the Seven Wastes next week in Standard Work.
Shigeo Shingo in the, A Study of the Toyota Production System, defines five distinct process elements that are critical in the flow of raw materials into products:
- Processing—the processing element is used to represent a physical change in the material or the quality of a work item
- Inspection—the inspection element is used to make a comparison to a standard
- Transportation—the transportation element is used when a work item is moved from one location to another
- Process delay—the process delay element is used to represent the delay of an entire production lot while the previous lot is processed, inspected,
or moved (the three previous process elements) - Lot delay—the lot delay element is used to represent the situation where one piece is processed while the other pieces of the lot wait to be
inspected or transported.
These 5 steps and the symbols that represent them are very often your initial guidelines in the mapping process. We typically analyze these processes and arrange them sequentially before beginning with a Value Stream Map.
The subject of flow was taken to a different level in the book, The Goal: A Process of Ongoing Improvement by Eliyahu M. Goldratt. The Theory of Constraints (TOC) methodologies developed from this book and helped make both Lean and TOC the topically discussion during the 1990s and early part of this century. Lean used the reduction of waste as its ally and TOC used the recognition and management of the bottleneck as its ally.
A simple process, paraphrasing both methodologies can be used to get started.
- Create a Value Stream Map based on a defined process (a starting and ending point).
- Analyze each part of the process and start asking these questions until you have eliminated all waste from the process:
- Why are we doing this process?
- What value/purpose does it serve the customer?
- How can we eliminate all waste from this process?
- Map new simplified process
- Now determine the constraint in your process.
- Identify the system’s constraint.
- Exploit the system’s constraint.
- Subordinate everything else to the above decision.
- Elevate the system’s constraint.
- If a constraint is broken (that is, relieved or improved), go back to Step 1. However, don’t allow inertia to become a constraint.
- Implement and Test new process using the Plan, Do, Check, Act cycle.
- Simplify your process:
- Eliminate all wasted activities that the customer sees little value in.
- Create dashboard with input/output measurements showing daily, weekly, monthly and yearly progress
- Find the Value Stream ROI and Resource Allocation
- Create the Future Value Stream Map
- Feedback by developing visual metrics showing progress of this lean continuous improvement program.
Start looking at flow in more simple ways. With limited training, you can take a simple process (home or business, use one that happens frequently) map the process. It should be as simple as taking the trash out. Use the process to walk through the six steps above. How do you view that process now? Did you find waste? Did you find a limiting process step, a bottleneck? What did you do?
I have quite a bit of information on the Theory of Constraints on my website and if your looking for a particular area it might be best to ask. One particular podcast that can be particularly helpful is John A. Ricketts, a distinguished engineer at IBM Corporate Headquarters podcast on using TOC in Services.
All Business901 Podcast are available at the Business901 iTunes Store or view the Mobile Version of Business901 Podcast