What is 4M Change?

What is 4M Change?

What is 4M?

4M refers to a method of thinking about things in terms of four elements: Man, Machine, Material, and Method.
It is called 4M after the first letter of each of the four alphabets.


People = workers and staff on site.
In order to maintain a certain level of quality, it is essential to maintain and control the competence of workers and staff on site.
The manufacturing process requires skilled and disciplined techniques and skills to control and maneuver machines, select and secure materials, and implement accurate and rapid methods.
To this end, the skills and aptitude of each worker/staff member must be analyzed and understood, and after careful management, the appropriate worker/staff member must be assigned to each task.
Machines, materials, and methods are all made by human hands, and “people” are the foundation and most important aspect of the 4Ms.


Various machines and equipment have been installed and are in operation at manufacturing production sites.
In order to maintain consistent product quality, the following management of these machines and facilities is necessary.
・Introduction and development of state-of-the-art machinery and equipment
・Maintenance and inspections
・Accurate layout (arrangement) of machinery and equipment
・Deployment of personnel who can effectively use machinery and equipment


To manufacture products, it is essential to procure a variety of raw materials, components, and other materials.
And in quality control of products, the following materials should be controlled for stable manufacturing.
・Amount of materials procured (preventing lost opportunities and overstocking)
・Means of procurement of materials (selection of suppliers, method of distribution from place of purchase, purchase price)
・Inspection of materials (checking for defects or shortages)


A method is a way of manufacturing a product.

In quality control, standardization (defined procedures and methods) of each manufacturing process is essential.
For this purpose, manuals should be developed and manuals should be reviewed.

What is 5M+E?

Measurement and Environment are often added to the above 4Ms.
It is said that the degree of variation in the quality of these elements is combined to determine the quality of the product.

What is 4M Change?

In general industry, the definition of 4M change is
Man”: Change of workers
Machine: Changes in manufacturing equipment, jigs and tools, etc.
Material: Change in raw materials, parts, etc.
Method: Changes in work methods, processes, measurement methods, etc.
The first is.
However, process changes (design changes) in medical device regulationsThe key elements in the process change are Machine, Material, Method and Measurement. and does not include Man. .
In medical device regulations, design changes must be strictly implemented and documented without affecting the quality of the finished device or the safety of patients and users. There must be no deviation from user requirements, regulatory requirements, international standards, etc.
In general, Man (person) is not subject to change in medical device design.
However, special processes(A process that involves destructive testing and therefore only sampling inspection can be performed. Soldering, sterilization, caulking, gluing, welding, crimping, etc.), man (human) change management is important.
For special processes, you are required to process validation and process validation must be performed This is because it must be carried out by someone with competence (someone with training and experience).

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