At first, the six-horse management proposed by Motorola is mainly the improvement of six-horse, which can be divided into four stages: MAIC: (measurement, analysis, improvement and control). MAIC is sometimes called "magic without G", and "G" stands for "guessing work". The four stages of MAIC are the key to the six-sigma problem-solving method, which is actually the problem-solving method itself. After 2000, on the basis of MAIC, it developed into five stages of DMAIC (supplementary definition), making Six Sigma an effective management model-a problem-solving model. Compared with other methods, the biggest difference or advantage of DMAIC can be simplified as the following six aspects:

① Measurement problem

In DMAIC, you can't just assume that you know the problem, you must prove it with facts.

② Pay attention to customers.

External customers are always important, even if you just want to reduce the cost of a certain process. Starting from C (Customer) of SIPOC (Supplier, Input, Process, Output, customer), we pay attention to customers through process analysis.

③ Check the root of the problem.

In the past, if you agreed with a reason, it could be used as sufficient evidence. Now six sigma management requires that these reasons must be proved by facts and data.

(4) Break old habits

The DMAIC project's solution to the problem will not only be the solution to complete minor changes in the inherent old process, but also the real changes and achievements need innovative solutions.

⑤ Managing risks

It is an important part of the six-horse principle to test and improve the solution and find out its shortcomings.

⑥ Measurement results

Tracking any scheme is to prove its true effect, so it relies more on facts. No matter how good the solution found by the DMAIC team is, it will soon disappear if it is not stopped and supported. Therefore, continuous improvement is the last key point to solve the problem in this method.

The DMAIC process is repetitive to some extent, which means that it is not straight from the definition stage to the control stage, but repetitive, and it needs to constantly revise and supplement the previous assumptions and hasty handover. In a sense, six sigma management remains unchanged: it needs to cope with changing flexibility, need the ability to absorb and interpret information, and need to pay attention to the input of many stakeholders inside and outside the project. If we can do this, DMAIC will have unlimited potential in solving problems and improving business performance.

2. design for six sigma (DFSS)

Usually, DMAIC projects focus on several main reasons for eliminating process or product defects and high cost. However, these improvement projects cannot meet all the requirements of enterprise change. Some processes are like old broken cars: you can fix this or that annoying problem and get it back on the road, but it may cost more. Finally, you will realize that it is better to change a new car, which is both easy to use and reasonable. Then, for enterprises, it is time to re-establish or "design" a new process. Design for six sigma (DFSS) is one such method.

According to the principles and methods of quality economic management, there are two points in implementing quality economic management:

① Improve customer satisfaction;

② Reduce the cost of operating resources.

There are two ways to improve customer satisfaction: developing new products and improving existing products. There are also two ways to reduce the cost of operating resources: reducing compliance costs and non-compliance costs. DMAIC focuses on improving original products and reducing non-compliance costs, while DFSS (i.e. DMADV and IDDOV) focuses on developing new products and reducing compliance costs.

Among the two main formulas of Six Sigma (DFSS) design, DMADV originated from DMAIC, which is similar to the basic method of DMAIC and has five stages, but the specific content is obviously different. For the improvement of DMAIC, the need for initial design or redesign may not be obvious. At first, the project may only be prepared to find the root cause of the problem within 3-6 months. However, the emergence of the following problems can make this project rethink, that is, it must be "changed":

It is found that the current process performance is far from the customer's demand, so that it is impossible to solve the problem only by "repairing";

② There are too many reasons (key X) to make the process worse. It is best to replace the old process with a new one.

In these cases, the best way is to start over and design a new process. Six-sigma management method uses the improvement and design of Six Sigma to carry out quality management, and achieves the goal of Six Sigma by improving customer satisfaction and loyalty and reducing defects and inferior costs.