Lean manufacturing concepts have been implemented in thousands of companies as a continuous improvement program. Some of the implementations serve the foundation of the continuous improvement program, while others are combined with various initiatives such as six sigma.
When lean manufacturing and six sigma concepts are combined within a continuous improvement program, it is often called “lean six sigma”. It simply means the company is employing both lean manufacturing and six sigma techniques to obtain improvement.
A common question is whether one or the other, or both lean and six sigma should be utilized for a specific type of facility. The simple answer is that every business can use both lean manufacturing and six sigma tools for improvement.
However, some businesses make each type of tool more conducive to obtaining improvement. For example, a simple job shop manufacturer may be able to use six sigma, but many lean manufacturing tools can be used. On the other hand, a telemarketing firm can use a few lean tools, but six sigma can surely be utilized in a big way.
For the trained lean six sigma practitioner, it isn’t very difficult to choose which tools would be effective. The difficult part is determining which tools to use to provide the return on investment of the initiative.
To illustrate a little more clearly, consider both the job shop and the telemarketer. The job shop can always use the 5S system of lean. The system of organizing the workplace helps to reduce motion waste and setup time and improves overall equipment effectiveness. Standard work sustains 5S, helps the SMED (single minute exchange of die) project reduce setup time, and improves quality. Standard work is finding the best known way of doing a job and ensuring it is done the same way every time. Simple kaizen events can be used to reduce all of the 7 wastes such as scrap and rework, inventory, transportation, etc. Simple OEE analysis will help reduce the 6 big losses such as breakdowns, setup loss, small stops, speed, and quality losses. Once the lean tools have captured some low hanging fruit in terms of improvement, some six sigma tools can be used to capture additional gains. These tools might include a few of the hundreds of tools available to a six sigma black belt, such as cause and effect diagrams, statistical analysis, and design of experiments.
The telemarketer that has a large call center producing thousands of calls per day all over the world may use six sigma for large gains. For example, if the firm has available 3000 man hours per day of calling, simple statistical analysis might show that rather than having 600 people working 5 hours per day, it is more effective to have 800 people working about 4 hours per day. In addition, rather than making the calls between 10 a.m. and 2 p.m., it might be shown to be more effective between 8 a.m. and noon. Normally, major improvements can be made very quickly. However, advanced design of experiments with trials conducted of a few factors at a couple levels will lead the team to the best result at the least cost. Simple control charts would help the group stay in control, making not too few nor too many calls per hour. The time spent on calls might also be pinpointed as a cause of low sales. The six sigma DMAIC (Define-Measure-Analyze-Improve-Control) methodology led by a six sigma black belt in this environment would utilize tools such as FMEA, hypothesis testing, analysis of variance, regression analysis, and many of the simple tools for root cause problem solving.
The most important part of any program is to determine the challenge and then decide on which tools need to be used to solve it. The best use of any tool to solve the wrong problem is not a good return on investment.
