In the mid 1990s I had the opportunity to visit the Toyota Motor Corporation in the town of Toyota between Tokyo and Kyoto to see my car being built and to talk to various personnel about their engineering and production methods.
Having previously worked part time as a engineering student at an automotive plant in Australia, there were many differences between Toyota and the Australian car maker. Today many of the methods and techniques used by Toyota in their Toyota Production System have been copied, but at that time the differences were eye opening! What impressed me most was not the techniques such as JIT-Kanban, Poka Yokes, 5S and statistical process control charts (impressive as they are!), but rather how the corporate culture allowed the teams to act to solve problems and the use of Keiretsu. Each workstation (called a workcell in Lean) in the assembly halls had a large red light and 'stop' button to activate it. When the workstation team encountered a problem, they could halt the assembly line, form a quality circle to solve the problem and provide rapid feedback/improvements. I was lucky enough to see such an event occur. This people aspect of the Toyota Production System (see the People-Process-Product model for more on holistic approaches to quality and improvement) has been a key differentiator to how many companies implement Lean Manufacturing. This ability of the workers at Toyota to stop production to solve problems was in stark contrast to my earlier visit at a large commercial aircraft manufacturer, where problems were regularly passed from workstation to workstation and eventually had to be solved by the airline inspection teams on the delivery tarmac. Toyota involved suppliers in their production approach, forming true partnerships in a Keiretsu, rather than using pure cost driven purchasing and contracting. The aim is reduce waste and share improvement and profit.
The empowerment of the people doing the work is emphasized in Lean, but the reality is that production schedules and organization hierarchies still have a tendency to work against this critical principle. This situation has improved in several automotive manufacturers in Germany that I have seen in the past decade. Sometimes this lean culture has flowed down to first tier suppliers and their suppliers, but it is not always apparent due to myopic purchasing people who do not understand the benefits of lean methods and stick to cost based purchasing. There is still room for much improvement.
Lean is one form of quality management (for more on quality management, readers should visit the Quality Management knol I created or my similar work on the topic in Wikipedia).
It is a growing set of disciplines and has grown to embrace several components:
- Lean Manufacturing
- Lean Thinking
- Lean Engineering
Lean Manufacturing is the original translation of the Toyota Production System. It embodies most of the major aspects of TPS with an emphasis on optimizing process flow, pull orientation and reducing waste. The original seven types of waste are:
- Inventory, whether work-in-progress, waiting components and finished product not being processed
- Moving products when not required to perform the processing
- Movement of people or equipment more than required
- Waiting for the next production step (a large waste item)
- Overproduction leading to inventory
- Over or extra processing due to poor design or tools
There are many techniques in Lean, including:
- Just In Time (JIT): is an inventory strategy implemented to reduce in-process inventory by means of a Pull system (Kanban or similar).
- Kaizen is a Japanese philosophy that focuses on continual improvement.
- 5S - Seiri (Sorting): Sort all tools, materials, etc., to keep only essential items. Sotre or discard the rest as appropraite. Seiton (Set in Order): Arrange the tools, equipment and parts to optimize work flow. Seisō: Systematically keep the workplace clean and neat so that other waste is obvious. Seiketsu (Standardizing): Standardized work practices. Shitsuke (Sustaining): Maintain and review standards to maintain the focus on this new way of operating.
- Poka-yoke is a Japanese term that means mistake-proofing to avoid inadvertent errors. This can be a physical (e.g. the floppy disc) or behaviour shaping constraint so that an operation can only be performed correctly.
- Autonomation describes a feature of machine design to implement automation with a human touch. This type of automation implements some supervisory functions rather than production functions.
- Single Minute Exchange of Die (SMED) focuses on providing a rapid and efficient way to convert a manufacturing process from the current product to the next product.
- Fixed Repeating Schedule is a production schedule which is repeated perhaps daily or over a longer period such as a fortnight.
- Genchi Genbutsu means to go and see for yourself. The aim is to see a process in action so that problems are seen in full context and improvements are simpler and more appropraite.
- The "5 Whys?" a question-asking method to determine the cause/effect relationships underlying a particular problem by asking why to create deeper levels of understanding.
- Gemba - visiting the actual place of work (or scene of the crime :-)
Lean Thinking is in essence a distillation of how Lean Manufacturing was created. Readers may wish to look at the Thinking stage in STARS for more on thinking and the process optimisation page. One of the techniques used is Value Stream Mapping (based upon earlier work with Value Chains). This looks not just at the processes but also aspects such as waiting to determine waste in a value stream with the aim to eliminate it. One of the more recent extensions to this is Value Networks, although this is not yet a mainstream Lean technique (and encompasses more than just value streams, building upon aspects such as knowledge frameworks and social networking analysis). For software engineering and systems engineering, Practical Process Profiles methodology provides a Lean Thinking application to process optimization.
Lean Engineering is the application of Lean thinking into the engineering and design disciplines. Much work on lean engineering has occurred in the lean aerospace initiative (and the Lean Advancement Initiative). There is also a relatively new initiative in systems engineering being promoted through INCOSE in the Lean Enablers working group.
The following links are to sites that match my own interest and work-oriented profile.
Lean Advancement Initiative (MIT)
INCOSE Lean Systems Engineering work group.