3M – that is, muda, mura and muri

3M – muda, mura, muri

What can an overload involve?

Overload, or muri, in a manufacturing company usually affects:

• people – the company’s employees,
• machines – the equipment, machinery or devices used.

Human overload

Let’s start with people. Human capital in an organization is one of the main factors determining the success or failure of a company. “Human” overload can occur at any stage of the process. However, in a manufacturing company, it usually affects direct production employees, who, with their daily work, add real value to the products for which the customer pays. It is not uncommon for machine operators to work beyond their strength, spending many hours performing heavy or monotonous tasks. All this causes overload.

Overload can also affect those supporting the process and management.

In summary, human overload can affect all employees in an organization, regardless of their location in the organizational structure.

The consequence of overloading human resources is to work inconsistently with the company’s standards, “looking for shortcuts,” which can consequently cause quality deterioration or other types of waste. Substandard work can also create safety hazards for the employee and the risk of workplace accidents. An additional effect of overloading people is lowering their morale, which in the future may translate into layoffs, unwillingness to change or lack of commitment to continuous improvement.

Machinery overload

The second type of muri is overloading of machinery, equipment and facilities. This type of overloading most often occurs due to poor work planning. In a complex production system, overloading of machinery is particularly noticeable while the production plan changes dynamically, as a result of changing customer orders. The customer has the right to change his order or demand forecast really from day to day. This requires an extremely flexible production system.

In a situation where we in the organization do not have the ability to freeze the production plan for a week or a month, and the customer may change his order despite previous declarations and forecasts, this will translate directly into overloading both people and machines. Changing orders will result, for example, in overtime, the need to run an additional production shift, an additional machine, or an entire production line.

The consequence of overloading machinery will be faster wear and tear of equipment, machinery and its parts. It is worth noting that the duration of preventive maintenance of machinery will result mostly not from man-hours but from the time period. For example, replacement will occur – once a month, once a year, etc. This approach will result in increased failure rate, micro downtime, or production line stoppage.

Another consequence of machine overloading is the quality problems that arise, related to machine malfunctions (for example, exceeding maximum throughput). Quality problems are most often detected after the defective workpieces, parts or semi-finished products have already left the machine, process or production line. If we do not have solutions in the production system that allow us to react to deviations immediately (lack of quality built into the process), then we have to prepare for considerable financial losses. Defective parts, details or semi-finished products will either have to be corrected (reawork) or produced again. The situation will become even more complicated if we fail to meet customer delivery deadlines and are forced to pay penalty fees.

How to prevent the occurrence of muri?

The answer to this question is not obvious and simple. First of all, one must learn to recognize this loss. It is worth noting that muri can be perceived by any employee in the organization. Here, it will be extremely important to properly train staff on the types of waste in processes. Such training should take place in the initial phase of implementing lean principles in the organization.

Correctly identifying the overload is the first, very important step to success. The next step is to find the cause of the muri and then focus on eliminating it.

In any organization, sooner or later there will be a situation where people or machines are overloaded. However, it should be remembered that these situations should be rare, sudden and requiring concentration over a short period of time. Under no circumstances should they become the standard.