Waste refers to anything that not only lacks value but also consumes time and resources. In the realm of Lean Management systems, the three primary types of waste, collectively known as the "3 Ms" (Muda, Muri, Mura), must be avoided to attain an optimal process and enhance overall quality.
- MUDA
The waste of value can manifest in forms such as the production of defective pieces or unnecessary movements of material and human resources. Muda is the most common and, sometimes, least visible form of waste for companies that struggle to identify the problem: removing waste necessitates a meticulous analysis. Below are proposed the seven specific types of the most common Muda and some lean tools to prevent or address emerging issues.
1.1 Waitings
This form of waste arises when issues occur due to an imbalance among different production phases, leading to delays caused by equipment breakdowns, inadequate staff organization, lack of standardized processes, or simply resource shortages. When faced with these challenges, monitoring the time spent in each production phase can prove beneficial to prevent imbalances causing delays and promote a continuous flow. To mitigate such wastes, it is advisable to monitor key metrics like the O.E.E. (Overall Equipment Effectiveness) index, implement SMED (Single-Minute Exchange of Die) practices, and adopt TPM (Total Productive Maintenance) measures.
1.2 Transportation
This category of waste is more prevalent in sizable enterprises, which frequently deal with substantial movements of materials, finished or semi-finished products, or personnel. Various methods can be employed to diminish waiting periods and minimize waste resulting from transportation, such as opting for swifter modes of transport or implementing tools like the Milk Run System or the Spaghetti Chart.
1.3 Overproduction
If production volumes do not align with demand or if the production pace surpasses the absorption rate of products, there is a potential for tying up material and human resources without generating value. To avert this form of waste, strategies like Just in Time and Kanban can be employed.
1.4 Stock
Inventory pertains to items that remain inactive, anticipating the next action, movement, or processing, resulting in no value creation and the immobilization of capital. This form of waste may stem from a flawed procurement policy or misjudgment of requirements. Employing tools like Cross Analysis can enhance inventory management practices.
1.5 Motion
Any unnecessary movements by operators, which not only lack genuine necessity but also carry a potential risk of injury or harm to the worker, need focused intervention to decrease the chances of accidents and improve the quality of the operator's work. Introducing tools like the Spaghetti Chart, POUS, and 5S can be effective in minimizing unproductive and unnecessary movements.
1.6 Defects
Defects contribute to an extended lead time, resulting in material waste for rejected products and a deceleration in production when additional work is necessary on defective items. To prevent this form of waste, it is crucial to conduct a comprehensive analysis of both the production process and customer demand, as the product may be rejected if it fails to meet specifications. Without effective analysis tools, there is a risk of delayed defect identification, leading to the processing of a product destined for rejection and the consumption of resources without value creation. Tools for defect identification include Failure Mode and Effects Analysis, 5P (problem, why, process, people, place), and 5M (method, machinery, material, manpower, environment).
1.7 Inefficient processes
Excessive use of resources occurs when production processes are overly complex, production facilities perform suboptimally, setup times are prolonged, etc. To pinpoint these inefficiencies, an analysis will be conducted to identify factors that consume time and resources without adding value. This analysis can be facilitated through tools such as the Value Stream Map and Makigami.
1.9 Understimating Creativity
Recognizing the underappreciation of individual creativity as a form of waste is a relatively recent development. From a Lean perspective, it is essential that everyone is empowered to participate and contribute ideas or critiques to drive continuous improvement. - MURI
Alongside the types of waste proposed above, we also find "muri," or wastes due to irrationality, as identified by Sutherland (2021), highlighting potential adverse effects when applied excessively.
2.1 Absurdity
Setting unrealistic goals might boost ambition and morale, but an excess of absurd objectives can yield the opposite effect.
2.2 Unreasonable Expectations
Believing it's possible to recover delays through luck can cloud the mind and worsen the situation.
2.3 Excessive Load
Unsustainable goals lead to lead time extensions and connections with other types of Muri, generating stressful situations.
2.4 "Emotional Muri"
Connected to ineffective managers who struggle to engage with team members in a constructive manner, resulting in emotional strain for employees. - MURA
This form of waste is associated with disruptions caused by fluctuations in demand, leading to instability in operations due to abrupt increases or decreases in demand. Such fluctuations can disrupt production and inventory planning.
The Lean Management System serves as a pathway to operational excellence, empowering organizations to pursue the maximization of customer value, reduction of waste, and the establishment of an efficient and sustainable long-term working environment. Strategic management of the seven types of Muda, coupled with an understanding of Muri and Mura, provides a comprehensive framework for optimizing business processes.
The implementation of specific tools, such as Just in Time, Kanban, Value Stream Map, and Makigami, offers a structured approach to address various types of waste. Additionally, recognizing individual creativity and managing emotional aspects, identified as Mura, are crucial elements for fostering a collaborative and motivated work environment.