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Waste in Lean production has always been a well-known problem; however, many people don’t fully understand it. First, let’s discuss what the seven types of waste in Lean production are So-called waste in lean production refers to production activities or management processes that do not add any value to high-quality products and good services. Such waste increases a company’s costs, consumes time, and reduces efficiency and profitability. 1. The waste of overproduction – Among the seven wastes of lean production, overproduction is a method of mass manufacturing used to cope with uncertainty. Due to differences in the manufacturing capabilities of various processes, and because the equipment must keep running during mass production, the manufacturing speed in earlier stages is faster than that in later stages, and this manufacturing speed is again faster than the sales pace; as a result, large amounts of inventory often accumulate. In mass-production systems, in an uncertain world where various fluctuations occur continuously, overproduction can cushion or prevent the production sector from being fully affected by demand swings, thus avoiding chaos throughout the entire system. Traditional methods compensate for this contradiction by increasing inventory investment rather than improving the ability to address real-world problems. The cost of inventory materials throughout the manufacturing process is exceptionally high, although it is difficult to quantify. 2. Waste caused by waiting: Waiting time or queue time is another problem that arises in mass production. Large processing batches are one of the reasons for the delays. Allowing mass production and establishing a queued supply system is a response to concerns about disruptions that might arise in the original order. Frequent changes in product types can reduce batch sizes, but it is generally believed that such frequent changes lead to long mold change times, which results in significant waste; therefore, manufacturing costs can be reduced by increasing batch sizes. This is related to people’s way of thinking rather than to technical systems. 3. Waste from transportation: While transport seems to create value systemically as a means of eliminating regional disparities, from the customer’s perspective, it brings us no benefits at all. Consumers are concerned about what kind of reactions this will cause and what quality issues it might lead to, rather than transportation itself. Knowing when, where, and what to move, as well as how to prevent loss and damage, through materials, handling equipment, indirect labor, and command and control systems – all of this indeed incurs costs. 4. Waste in inventory: Inventory serves as a buffer to prevent abnormalities and helps to balance external conditions, but it remains unused and merely waits there. Traditional calculation methods treat inventory as part of a company’s current assets, but in reality it only becomes an asset after it is sold. Companies spend a great deal of money simply to keep hold of it until consumers purchase it. 5. Waste in processing: Waste in processing may be an inherent flaw in the production process itself. Their existence is actually predictable and can be gradually eliminated through continuous improvement. Advanced processing techniques and tooling can effectively limit and eliminate these wastes. 6. Eliminating wasted movements: Workers are experts in the work process, and they should be helped to continuously improve their working methods, so that they can work more intelligently rather than harder. In the workplace, work efficiency science and behavioral economics have been in use for twenty years; in repetitive production processes, a detailed analysis of avoidable, combined, reorganized, and rearranged actions can improve efficiency by eliminating tension and unnecessary movements. 7. The generation of defective products during the waste process is not only a form of waste but also an extremely dangerous situation in that process. Efforts must be made to improve the working conditions during the design phase, and preventive measures should be considered to ensure that as few defective products as possible are produced; some defects can be eliminated through methods that prevent errors from occurring. Seven strategies to address waste in lean production. Strategy 1: Waste due to waiting. Waiting means being idle, awaiting the next action to take place; this type of waste is undeniable. The common causes of waiting include: unbalanced workload, poor job scheduling, downtime due to lack of materials, and poor quality, etc. Take the case of the Performance Testing Section in the Manufacturing Department waiting for an electrical control panel: since the panel cannot be delivered on time as required, there is a risk of failing to meet the delivery deadline. Once the panel arrives, efforts must be made to catch up on the schedule, which may lead to overtime work and quality issues. Another example is the waste associated with “monitoring machines”. Some factories purchase fast and expensive automated machines; however, for these machines to function properly or for other reasons—such as fixing minor malfunctions or replenishing materials—personnel are usually assigned to stand by and monitor them. Therefore, although it is an automated device, it still requires human supervision, which is specifically referred to as the waste of \"idle watching\". Apart from the waiting that occurs during the direct production process, does this kind of waste—waiting—not happen in other management activities? When the manufacturing department encounters some problems in producing new products, can the technical department and the quality assurance department resolve them immediately, without the on-site staff having to wait for a long time? How can this waiting be reduced? Countermeasure 2: Waste caused by handling. Most people would agree that handling is an ineffective activity. However, some also believe it to be a necessary step; after all, without handling, how can the next step be carried out? Many people have this idea. For this very reason, most people assume its existence without trying to eliminate it. Some people think of using conveyor belts as a solution. This approach can only be described as spending a lot of money to reduce physical exertion; however, the waste associated with the handling process isn’t eliminated at all—it merely gets concealed. If the waste associated with handling is broken down, it includes wastes from actions such as placing, stacking, moving, and organizing. For example, the transportation time between the two factories remains high; in particular, the time spent transporting raw materials from Factory 2 to Factory 1 accounts for the majority of this time. How to overcome it? To reduce handling, the large-scale department at Sony in Japan merged four workshops into two; the processing of some components was moved from other locations to be carried out right next to the production lines, thereby reducing handling. When it is impossible to completely eliminate handling, the production layout should be readjusted to minimize the distance of handling. Everyone should consider how the company’s production layout should be changed How to minimize handling? Strategy 3: Waste of defective products. During the product manufacturing process, the occurrence of any defective products results in waste of materials, machinery, labor, and other resources. Any repairs represent additional cost expenses. The lean production method enables the early detection of defective products, makes it easy to identify the source of defects, thereby reducing the occurrence of such defects. This one is relatively easy to understand; the key is to get it right on the first try, but it’s very difficult to implement. Everyone might want to think carefully: apart from product production, are there similar forms of waste in management work as well? One of the principles of lean production is to use every means possible to eliminate or reduce all non-value-added activities, such as the waste caused by inspections, handling, and waiting. The approach to this is to achieve a \"zero rework rate\" – ensuring that each part is qualified from the first attempt. More importantly, it is necessary to prevent defective parts and raw materials from reaching later stages of production at the source, thereby striving for a zero-defect rate. Strategy 4: Waste in movements To achieve the same goal for a task, there are various movements involved; which of these movements are unnecessary? Do we need to pick it up and put it down so frequently? Is it necessary to have reversal motions, walking motions, bending motions, aiming motions, right-angle turning motions, etc.? If designed well, many actions can be eliminated! In management theory, there is a specific approach known as \"time study,\" but it is quite complex to implement. We can simply use the basic ideas mentioned above to consider which actions in our daily work are unreasonable How to improve? Strategy 5: Waste in processing. In the manufacturing process, in order to achieve the desired outcomes, some processing steps can be omitted, replaced, reorganized, or combined. If a careful examination is carried out, it will become apparent that there is still plenty of waste that can be improved. During the visit to the production line for household air conditioners at Sony in Japan, the Japanese supervisor took us to the heat exchanger assembly line and showed us examples of how waste could be eliminated through reorganization and integration: in the original heat exchanger assembly process, one worker would pack the heat exchangers with the tubes already installed inside them, then transport them to the tube-expanding equipment using a cart; another worker would operate the equipment to expand the tubes, and finally a third worker would move the heat exchangers with the expanded tubes to another conveyor belt. As a result of these improvements, they extended the conveyor belt on the heat exchange assembly line next to the tube expansion equipment, which allowed for the reduction of one shipping worker. In the future, they plan to move the tube expansion equipment next to the cantilevered line, so that the workers responsible for tube expansion can directly deliver the heat exchanges to the cantilevers, thereby saving another handling worker. Through two reorganizations and mergers of the processes, the number of operators was reduced from 3 to 1. How many such areas that need improvement exist within our company? Is it turning a blind eye? Are they unwilling to make improvements? Do you still have the will but lack the capacity? How can we make improvements within our capabilities first, and then scale them up? Strategy 6: Eliminating inventory waste – The lean production approach holds that “inventory is the root of all evils.” This is where Toyota’s view on waste differs the most from traditional views, and it is also the driving force behind the significant benefits Toyota can bring to businesses. Almost all improvement actions in lean production are directly or indirectly related to eliminating inventory. Why does the lean production approach consider inventory to be the root of all evils, and why does it strive to reduce it at all costs? Because inventory leads to the following wastes: 1. Unnecessary wastes such as handling, stacking, placement, protection measures, and searching. When inventory levels rise, the volume of handling increases; more storage and stacking areas are required, additional protective measures must be implemented, and extra time is needed for daily management and item retrieval. Even the time required for inventory counts increases. All these constitute waste. 2. It makes first-in-first-out processing difficult. When inventory increases, taking copper pipes as an example, the newly arrived pipes are stacked on top of the existing ones; those that were stored there first must be moved separately in order to be used first. And if, for the sake of convenience, the newly arrived copper pipes are used first, the original copper pipes, when left unused for a long time, can lead to a range of problems related to quality. 3. Lost interest and administrative fees. As inventory levels increase, a large amount of funds intended for production and business operations get tied up in inventory. This not only increases the total amount of capital required but also raises interest costs and storage management expenses. And these are often embedded in the company’s administrative expenses; only by listing them separately can one realize the severity of the problem, address it properly, and strive to solve it. 4. The value of the items will decrease, turning them into obsolete goods. When inventory increases, the amount of stock will exceed the amount used, which can even lead to long-term accumulation of stock. This problem tends to become more severe, especially when there are changes in product models. During the process of localization and the transition from Type C machines to Type G machines, our company faced a large backlog of materials due to excessive inventory previously held. Moreover, to dispose of these accumulated materials, additional investments were required. Furthermore, due to the long period of time that has passed, the goods that were originally purchased in bulk to take advantage of lower prices can now be acquired at a 40% discount for a new model, which results in a decrease in their actual value, an increase in costs, and reduced profits. Think about the excess inventory – at what price it was purchased originally and what its current price is, and then you’ll understand. 5. It occupies factory space, resulting in wasted investment in the construction of additional workshops and warehouses. When inventory increases, additional storage space is needed. In recent years, due to the increase in steel and other materials, a new material storage area has been added on the north side of our second factory. Additional investment was made, but it did not yield any benefits. Furthermore, the intangible losses caused by inventory are no less significant than the tangible losses mentioned above. The lean production approach believes that inventory hides problems, and in lean production, \"problems\" are considered to be treasures; by continuously identifying and resolving these problems, benefits can be generated repeatedly. Inventory hides problem areas, leading to the following consequences: there is no sense of urgency in management, which hinders improvement. When inventory levels are high, the negative effects caused by mechanical failures or defective products do not become apparent immediately, so no countermeasures are taken. Thanks to sufficient inventory, when problems arise, it can be covered up with that inventory, allowing the issues to be resolved gradually or even not at all; at the very least, they are concealed, so there is no urgency, and no one from higher up will hold anyone accountable. As a result, the department’s performance improves. 6. Misjudgment of equipment capacity and personnel requirements: Due to the existence of inventory, imbalances in equipment capacity are not apparent (the more inventory there is, the less likely such imbalances will be detected). It is also impossible to determine whether there is an overabundance of staff. Due to the large inventory levels, the supply department needs to hire more staff, and the production lines require additional workers to manufacture products to replenish the inventory. More equipment is also needed to meet the capacity requirements for producing this inventory, which in turn leads to another round of waste. The main reason for having inventory levels is the fear of problems occurring – what if something breaks? Could problems with some equipment affect the production of the entire production line or the whole factory? Thus, in order to prevent the impact from spreading, inventory became necessary; numerous problems were thus concealed, and naturally, the pace of progress and profit-making (identifying and solving problems is how one makes money) slowed down. No wonder the Lean production method regards inventory as the root of all evil; it absolutely does not allow its existence. Even if inventory already exists, every possible measure must be taken to reduce it, with the goal of achieving zero inventory. (Note: The “zero” in zero inventory does not mean “completely none” in a mathematical sense; rather, it refers to reducing inventory to the lowest level necessary.) ) Strategy 7: Creating excessive (early) waste. As mentioned earlier, inventory is considered the root of all evils, while creating excess inventory or completing tasks ahead of time is regarded by Toyota as the greatest form of waste. Lean production emphasizes “just-in-time production,” that is, producing the necessary quantity of the necessary items at the necessary time. Furthermore, it’s all a waste. And by the so-called necessary things and times, it refers to the quantity and time that the customer has decided to purchase. Suppose the customer only wants 100 units, at a price of 1 yuan per unit. If 150 units are produced, the total revenue won’t be 150 yuan, because those extra 50 units remain unsold and simply become inventory. As a result, no profit is generated. In other words, producing more than necessary is a waste. Producing too early is also a waste, but why do so many factories produce excessively and too early from the start? The main reason is that they don’t realize it’s a waste; instead, they think that doing more will improve efficiency, and completing tasks earlier will reduce losses in production capacity (it’s better to do something than not, after all the machine will still be idle, right?) ), clearly this is a huge misunderstanding. The belief that producing more and earlier can improve efficiency or reduce losses in production capacity is a short-sighted view; true profits come from sales, not from efficiency or production capacity. In order to achieve greater efficiency and production capacity, producing too much and too early without an increase in sales only leads to higher inventory levels. Do you think that’s reasonable? Therefore, the lean production approach emphasizes that it is absolutely not allowed to produce too much (too early), because: 1. It merely wastes costs (material and labor costs) in advance, without bringing any benefits. 2. It also hides the \"waste of waiting,\" causing managers to ignore the occurrence and existence of waiting. 3. Work-in-progress will naturally accumulate, which not only prolongs the production cycle (in an invisible way), but also increases the space required at the work site; as a result, the distance between machines grows, necessitating larger factory spaces. In this way, our profits are gradually eroded without us even realizing it. 4. It also causes waste in handling and stacking, and makes first-in-first-out processing difficult. Since the increase in production capacity outpaced that of sales capacity, production was not controlled; all departments were \"striving\" to produce, and the worksite was filled with self-made components. Different departments argued constantly over where to store them, and it took departmental coordination to resolve the issue. It was against this backdrop that the concept of \"zero inventory\" production management was developed. Although there have been significant improvements in subsequent work, some issues still remain, which require everyone to work together to resolve them. Apart from work-in-progress items, an excessive production of finished products is even more concerning; the scenario of finished product inventory exceeding 100 units at the beginning of 1998 seems all too real: products have already begun to be placed on the green channel ； It has become almost impossible to transfer products; for a product to move from the final assembly stage to the helium testing stage, at least three other products must be lifted first in order to create space ； There is so little space between the products that a person cannot even get in sideways, and product collisions occur frequently during lifting. There is an increasing demand to find a warehouse capable of storing mainframe products. What is the cause of this terrible situation? The marketing department faces difficulties in shipping, but amid fierce market competition, it is hoped that all the main models available in the company will be in stock, so that shipments can be made as soon as contracts are signed. There is poor communication between the marketing department and the production department; delivery dates are not accurately determined. Production is carried out based on the contractually specified delivery dates rather than the actual delivery times, with production taking place in order to replenish inventory. The manufacturing department carries out batch processing and production in order to improve efficiency and equipment utilization. Although this situation has been largely reversed at present, there are still some products that are completed according to the delivery schedule and remain in stock for a long time before being shipped, resulting in waste. Therefore, firms should be required to take confirmation of delivery dates seriously; they must provide timely and accurate feedback one month before the contractually specified delivery date, so as to avoid notifying only after the start of the assembly process for the upper and lower cylinders. This will help prevent the production of excessive finished products.