Nicolas Tang's Blog

Six Sigma is a business management strategy, originally developed by Motorola, that today enjoys wide-spread application in many sectors of industry.

Six Sigma seeks to identify and remove the causes of defects and errors in manufacturing and business processes. It uses a set of quality management methods, including statistical methods, and creates a special infrastructure of people within the organization (“Black Belts” etc.) who are experts in these methods. Each Six Sigma project carried out within an organization follows a defined sequence of steps and has quantified financial targets (cost reduction or profit increase).

DMAIC is used to improve an existing business process; DMADV is used to create new product or process designs.

DMAIC

The basic methodology consists of the following five steps:

* Define process improvement goals that are consistent with customer demands and the enterprise strategy.
* Measure key aspects of the current process and collect relevant data.
* Analyze the data to verify cause-and-effect relationships. Determine what the relationships are, and attempt to ensure that all factors have been considered.
* Improve or optimize the process based upon data analysis using techniques like Design of Experiments.
* Control to ensure that any deviations from target are corrected before they result in defects. Set up pilot runs to establish process capability, move on to production, set up control mechanisms and continuously monitor the process.

DMADV

The basic methodology consists of the following five steps:

* Define design goals that are consistent with customer demands and the enterprise strategy.
* Measure and identify CTQs (characteristics that are Critical To Quality), product capabilities, production process capability, and risks.
* Analyze to develop and design alternatives, create a high-level design and evaluate design capability to select the best design.
* Design details, optimize the design, and plan for design verification. This phase may require simulations.
* Verify the design, set up pilot runs, implement the production process and hand it over to the process owners.

5S is a method for organizing a workplace, especially a shared workplace (like a shop floor or an office space), and keeping it organized. It’s sometimes referred to as a housekeeping methodology, however this characterization can be misleading because organizing a workplace goes beyond housekeeping (see discussion of “Seiton” below).

The key targets of 5S are workplace morale and efficiency. The assertion of 5S is, by assigning everything a location, time is not wasted by looking for things. Additionally, it is quickly obvious when something is missing from its designated location. 5S advocates believe the benefits of this methodology come from deciding what should be kept, where it should be kept, and how it should be stored. This decision making process usually comes from a dialog about standardization which builds a clear understanding, between employees, of how work should be done. It also instils ownership of the process in each employee.

In addition to the above, another key distinction between 5S and “standardized cleanup” is Seiton. Seiton is often misunderstood, perhaps due to efforts to translate into an English word beginning with “S” (such as “sort” or “straighten”). The key concept here is to order items or activities in a manner to promote work flow. For example, tools should be kept at the point of use, workers should not have to repetitively bend to access materials, flow paths can be altered to improve efficiency, etc.

The 5S’s are:

Seiri – Sorting. Refers to the practice of going through all the tools, materials, etc., in the work area and keeping only essential items. Everything else is stored or discarded. This leads to fewer hazards and less clutter to interfere with productive work.

Seiton : Set in Order. Focuses on the need for an orderly workplace. “Orderly” in this sense means arranging the tools and equipment in an order that promotes work flow. Tools and equipment should be kept where they will be used, and the process should be ordered in a manner that eliminates extra motion.

Seisp: Sweeping, Systematic Cleaning, or Shining. Indicates the need to keep the workplace clean as well as neat. Cleaning in Japanese companies is a daily activity. At the end of each shift, the work area is cleaned up and everything is restored to its place, making it easy to know what goes where and to know when everything is where it should be are essential here. The key point is that maintaining cleanliness should be part of the daily work – not an occasional activity initiated when things get too messy.

Seiketsu: Standardising. This refers to standardized work practices. It refers to more than standardized cleanliness (otherwise this would mean essentially the same as “systemized cleanliness”). This means operating in a consistent and standardized fashion. Everyone knows exactly what his or her responsibilities are. In part this follows from Seiton where the order of a workplace should reflect the process of work, these imply standardised work practice and workstation layout.

Shitsuke: Sustaining. Refers to maintaining and reviewing standards. Once the previous 4S’s have been established they become the new way to operate. Maintain the focus on this new way of operating, and do not allow a gradual decline back to the old ways of operating. However, when an issue arises such as a suggested improvement or a new way of working, or a new tool, or a new output requirement then a review of the first 4S’s is appropriate.