Free Lean Manufacturing Tools And Techniques Essay Example
The Lean tools and manufacturing system is believed to have been developed in Japan and was first applied in Toyota manufacturing systems. Currently, the lean tools are being utilized in most production and manufacturing environments and have been proven to be effective in reducing costs and maximizing profits. From Japan, experts in lean manufacturing principles, most especially Toyota employees who are experienced in the lean manufacturing systems have been imparting their knowledge about lean and how it is applied in a manufacturing environment. One particular example of this exchange in knowledge is the partnership between the University of Kentucky and a mentoring team of former Toyota management executives with a mission of “sharing true lean knowledge applicable to any organization”. Among the outcomes of the partnership program between the University of Kentucky and it partnering Toyota former executives are the training and certification of lean on the participants as well as the implementation and coaching of executives in the lean processes. This paper will discuss the major points discussed in the lean systems program of the University of Kentucky and to discuss on how these lean concepts can be applied to actual manufacturing environments. Among the major discussion points in this report are the lean manufacturing tools as discussed in the program which are the 5S, visual management, work standardization, pull systems, Just-in-time principles and production leveling. Each of these lean tools has their own merits and each tool complement one another towards a true lean approach. Since each of these lean tools is equally important, it is imperative that anyone who wishes to incorporate the lean manufacturing systems into their manufacturing environment should be well-versed on the meaning and applicability of these lean tools in the manufacturing process.
The Lean System
The basic principle behind the lean manufacturing system is to identify and eliminate waste through continues improvement until perfection is arrived. However, underlying this major principle are ways or tools that would help individuals and organizations realize this primary objective. Prior to the introduction of the lean systems, it is quite typical for manufacturing environments to operate in clutter and waste. Among the common wastes in a non-lean production environment are time, effort, and excess materials that do not add value to the final product. In the early 1900’s, for example, the theories that dominate the production systems are those that were developed by Henry Ford, which is the mass-production system combined with the principles of scientific management as developed by Frederick Taylor. However, Henry Ford’s mass-production system focused only on making high volumes of products while Taylor, on the other hand, focused primarily on work standardization without emphasis on elimination of waste and perfection of the manufacturing flow. In 1940’s, Toyota executives led by Taiichi Ohno developed a manufacturing system that is somehow related to the mass production system of Ford with work standardization signature of Taylor. However, in terms of the use of resources as well as the flow of how things are done, the Toyota manufacturing system is the exact opposite of what is being practiced in the traditional non-lean manufacturing systems. While mass production systems in the west employ unskilled workers, the lean production system in Toyota develops multi-skilled workers for more work flexibility. While mass production system in the west are employing expensive machines that can only serve limited purpose, the lean manufacturing system in Toyota develops machines that can be utilized for various purpose. Also, while the mass production systems of the west are producing excessive volume of product output, Toyota’s lean system only allows production level based on customer demand. Perhaps the term ‘lean’ suggests a concept that is based on the principle of not using any resources that is not needed, which is also tantamount to eliminating waste. The success of the lean system became evident when Japanese manufacturers overtook Western manufacturers in almost all aspect of production, sales and profit margin.
The lean manufacturing strategy is modeled as a house with two pillars. In this model, ‘kaizen’, the Japanese word for ‘continuous improvement’ sits on top of two pillars namely ‘jidoka’ or commonly known as ‘automation with a human touch’ and ‘just-in-time (JIT)’ or the not too soon, not too late principle of ordering materials for production. These three lean principles sit on ‘standardization’, which is pictured as the foundation of the lean model structure as shown below:
Figure 1. Lean system model is based on a structure with ‘kaizen’, ‘jidoka’, ‘just-in-time’ and ‘standardization’ as its major components.
Evidently, as based on the model of the Toyota Production System of the lean system, ‘kaizen’ or ‘continuous improvement’ is the ultimate focus. But for continuous improvement to occur another important concept is introduced into the lean system and that is problem identification.
The Seven Wastes
According to the lean systems program of Kentucky University, there are seven types of waste identified in a work environment and these are:
Waiting or delay. Evidently, waiting consumes time, which is a valuable aspect in manufacturing operations. Waiting includes waiting for raw materials, information, equipment and other necessities that further delays the work. It can also refer to the idleness of equipment or employee. Equipment downtime and unscheduled maintenance are examples of delays. In the lean system, waiting is considered as waste and is greatly discouraged.
Over processing. Another waste common in most non-lean manufacturing systems is the over processing of materials especially if it does not add value to the final outcome of the product. Among the most common examples of over processing that happens in manufacturing environments are activities such as over painting, polishing or any activities that are not necessary.
Rework. Manufacturing defects that could have been identified during the initial phase of production represents waste in the lean systems perspective. Reworking a defective product drains the manufacturer the needed time and resources that otherwise could have been spent to produce more product of value.
Wasted motion. The lean system is very particular with work flow. Any unnecessary action that does not add to the improvement of the system or the product is considered as waste. Wasted motion is common in a chaotic working environment. Examples of such are the searching of employees for tools and materials that could already have been easily visible and accessible if lean systems have been employed.
Over production. Mass production concepts of the past advocates over production in anticipation of increased demand. Over production is a result of producing an item before there is demand or before it is needed. Before the lean systems became popular, mass production methods operate on excessive production, which results to excessive inventory. In non-lean systems, the quantity of the items produces are based on sales projections of so-called experts that sometimes end up to over production. The problem is what happens to the excess product if actual sales do not meet expectations? Evidently, excessive production is a waste of time and material and increases the risk of future losses.
Inventory. This concept is closely related with over production. Since stocks are excessive due to over production, the items are stacked for safekeeping in a warehouse or any additional facility that constitute additional space and labor. Evidently, keeping an inventory of items represents additional costs, which could have been avoided with the lean systems.
Transportation. If a material, equipment or labor needs to be constantly transported from one place to another instead of keeping them in one place, then waste is accumulated. Also, materials should be delivered directly on where it would be used instead of being shipped from several points in the supply chain. A complicated transportation set up increases delays, which also adds to the underlying wastes in that particular system.
In order to eliminate waste and pursue ‘kaizen’ or continuous improvement, the lean system employs powerful tools that have been proven effective in manufacturing environments. Among the primary tools for lean are:
5S is a lean tool that reinforces the principle of eliminating waste in manufacturing. The adaptation of the 5S, according to the lean program of the University of Kentucky, was the American version of the original 4S that was taught in Toyota lean systems. The original 4S represents ‘seiri’ or sift, ‘seiton’ or sort, ‘seiso’ or sweep and ‘seiketsu’ or sanitize. In the American version, a fifth ‘S’ was added to represent ‘sustain’. Currently, the Americanized version of the S’s in the lean system is simplified as sort, straighten, shine, standardize and sustain. In a manufacturing environment such as in automotive production, it is easy to get lost and confused by the many materials and tools that are used. However, with the use of the 5S, the work environment is kept in order in such a way that every object such as materials and tools are sorted according to their usefulness and arranged in a logical and orderly manner. Anything that is not of use in the work environment is set aside or discarded while those that are often used are placed in a strategic location where it can be easily accessed and used. Evidently, aside from eliminating the unnecessary things in the production area, one of the advantages that 5S offers are the unimpeded work flow. An organized work area also allows for easy detection of problems, which is consistent with the lean concept of ‘kaizen’ or continuous improvement. Apparently, housekeeping is the major emphasis of 5S. In sorting, it is advised that necessary and unnecessary things should be identified and placed on where they should belong as suggested by the flowchart below:
Figure 2. Sorting flow chart.
After sorting, each item should be straightened or arranged in such a way that they occupy the least space and do not block the work flow. Most often, shelves are use with each item conspicuously placed and each item is labeled for easy identification. Aside from a properly arranged work area, ‘shine’ or the concept of cleanliness and neatness is an important consideration in the lean system. An unclean equipment or tool, for example, is more prone to damage than the equipment that is often cleaned and maintained. An unclean workplace is also an indication of poor inspection. As a result, some minor abnormalities, which could have been corrected if observed promptly, may become a major trouble and may lead to equipment failure. This scenario could have been avoided if cleaning is adopted as a scheduled routine whether daily, weekly or as determined by the need. In order to maintain the level of cleanliness that has been achieve, the fourth S, which stands for ‘Seiketsu’ or standardized clean-up provides a measure to maintain the level of cleanliness that was achieved. Lastly, the fifth S-sustain, implies continuous cleanliness in the workplace. This means that cleanliness should become habitual. A lot of benefits can be realized by applying 5S in manufacturing environments. Among the benefits include less downtime of equipment because of early detection of defects; eliminate wastes of time and effort due to searching and transporting of materials and equipment; better utilization of space and improves the flow of work thereby improving the over-all efficiency of the manufacturing processes.
Visual management is an important concept in lean marketing, which relates to the utilization of visual tools and signals in order to measure performance. Lean management is influenced primarily by visual management since primary among the objective of lean is to detect errors. To do so, visual tools such as systematic labeling of work areas, flowcharts, ‘kanban’ cards and other visual signals that provide clear picture of the status or condition of the working environment is encouraged. One of the objectives of visual management is to design a work system that can be always and easily visualized. In creating a visual image of the manufacturing process, team leaders can easily observe the work flow and identify wastes in the process. In Toyota, for example, ‘kanban’ or visual cards were utilized to signal the steps in the manufacturing process. With the use of these visual tools, even the simple color coding to indicate a particular tool or operation can get a long way in making work communication and the manufacturing process more efficient. Visual management is very important in the analysis of data and in identifying possible trouble spots in the entire manufacturing process. With the use of workflows and floor plans, troubleshooting of defects can be efficiently accomplished. Graphs and charts are also important aspects of visual management that helps in evaluating performance of the standards being employed in the lean systems. As much as possible, every activity in the lean system is represented by a visual chart or any visual performance monitoring tools that are visible to each participant in the manufacturing process. Doing so promotes easy identification of abnormalities; still for the purpose of continued improvement or ‘kaizen.’
Standardized work has been defined as “the written, current best method for safe and efficient work that meets the required quality and provides the standard for continuous improvement”. In the lean systems, work standardization is a dynamic activity since it tends to change over time. Work standardization seeks to eliminate variations on how a particular activity is done by setting as standard the best and most efficient method available. The standardization process starts with the team leader who writes the standardized work and instructs it to his members. While work is in progress using the initially established standard procedure, the team members are tasked to identify any abnormalities with the current procedure and are encouraged to voice out their opinion. The team leader performs observations as well and takes note of any issues and abnormalities identified by his team members. He then evaluates the abnormalities that has been discovered and troubleshoots on what particular practices could eliminate the identified problems. As a result, a new standard procedure is produced with an improved output. The standardization process is an ongoing activity in the lean system until such time that perfection is achieved as pictured in the figure below.
Figure 3. A graphic representation of how standardization is achieved in the lean systems.
The pull system is closely related with the ‘just-in-time’ (JIT) principle of the lean manufacturing system, which is understood as “what is needed, when it is needed, in the quantity needed”. Among its primary goals is to control production in order to produce only what is sold as based on customer demand. Traditional manufacturers operate using the push system wherein products are being forced into the market because of excessive inventory and supply. In the lean system, however, production is based on demand. It is believed that the pull system of lean manufacturing has been inspired by supermarket retailers. Accordingly, when Toyota executives visited the west, the found that in the supermarkets, the shelves only got replenished when customers removed the stocks; “this ensured that the supermarket only had to purchase what the customers were buying and could minimize their stocks”. Evidently, the lesser stocks to handle, the lesser space is required for stacking and inventory purposes. In order to determine whether manufacturing should start ordering materials and produce, kanbans or visual signals are used. Most often, kanbans are in the form of color coded floors or lightings, which indicates signals such as replenishment of raw material, stepping up of production volume and other production signals that a particular kanban indicates. In the pull system, the buyer influences the flow of the manufacturing process, which can be pictured as being a pulling stimulus that signals the production of goods. Because of this single stimulus, scheduling in pull systems is simple as shown in the figure below.
Figure 4. In the pull system, the buyer directly influences the production of goods, which makes the flow of production simple and the scheduling of work uncomplicated.
On the other hand, in a push system, productions are influenced by complex factors without direct connection with the buyer or consumer. Most often, the objective is to fill the warehouse with stocks based on what is projected by the sales department. As a result, work scheduling becomes complicated as it is influenced by a lot of considerations as shown in the figure below.
Figure 5. Push systems scheduling are complicated with no direct connection with buyer.
Production Leveling (Heijunka)
Production leveling is closely related with pull systems as it aims to optimize production operations while meeting customer demands although it is more complicated since it considers all production aspects such as quantity, variety and capacity. Actual customer demand is fluctuating and lean system requires that production should be based only on customer demand. Apparently, rigidly following the inconsistent and fluctuating demands of consumers is impractical and would strain the manufacturing process. In order to address the fluctuating demands of consumers, production leveling techniques are employed in the lean manufacturing system. In order to create an effective production leveling technique, it is necessary that manufacturing maintains a close communication with sales in order to achieve predictable patterns from previous sales experiences. Production leveling ensures a continuous supply without the need for bulk resources or raw material. In an actual work environment, it could not be avoided that some equipment and workers have uneven capacity and skills. These uneven capacity and skill results to uneven processing that also results to uneven outputs and increasing inventory buildup between work stations. In implementing production leveling, emphasis on obtaining the right equipment that can perform varied tasks is crucial. In lean systems, individuals are trained to be cross-skilled so that work can be easily realigned when necessary. If one machinery or work station processes much faster than the following work station, then it experiences a fluctuating activity as characterized by overproduction then idle time afterwards. In the pull system, it is desired to have all equipment and labor synchronized so that there will be no idle time, therefore no waste is accumulated. In the figure below, notice how work-in-progress (WIP) accumulates as each process takes longer time than its predecessor.
Figure 6. Work-in-progress (WIP) accumulates between stations because of unbalanced work capacity.
Based on the graphic above, it is clear that as materials pass on the grind with a 4-minute processing time, some of it would be stacked between the grind and drill because the drill can process each material one minute longer than the grind. This WIP accumulates further as production is continued, which means that at the end of the day, it is either some equipment are forced to stop to accommodate the lesser capacity equipment or an unfinished job is left in between stations. In order to minimize idle time and therefore minimize waste, batches are kept in minimum and at a smallest number as possible. This implies that the machines or work stations are not loaded to their maximum capacity and the operation becomes smoother with no pending WIPs. This implies that the smaller the batch number, the smoother the manufacturing operation becomes.
Effectiveness of Lean Manufacturing System: The Case of Harley Davidson
The effectiveness and applicability of lean manufacturing system is not only documented in the success story of Toyota but also in the journey of Harley Davidson, an American motorcycle company that manufactures specialized motorcycle in selected market segment. The company was founded by Arthur and Walter Davidson, and William Harley in 1903 . During the time, the motorcycle industry is at its infancy and there are no other major competitors in the United States except for Indian Motorcycle. The timing of Harley-Davidson’s entry into the American market could never have been better. America was experiencing a booming economy in the early 1900’s and its rapid industrialization is drawing in an influx of wealth for the country. With an abundant supply of cheap raw materials and a curious and financially capable market, the motorcycle industry experienced a phenomenal growth. Accordingly by 1918, Harley Davidson became the world’s leading motorcycle manufacturer. However, the entry of Japanese motorcycle manufacturers in America after the Second World War presented a troubling scenario for the company. Although the company still maintains a cultic following, the Japanese manufacturers with the lead of Honda are rapidly gaining the American market. Evidently, Harley Davidson, with its traditional manufacturing techniques could not compete with Japanese motorcycle companies that are already incorporating lean practices in their production systems. As observed by Teerlink, “Lead by Honda, the Japanese manufacturers were not only distinguished by their ability to create small engines but were skilled in mass-producing motorcycles efficiently”. For years, Harley Davidson struggled to regain its market share but they did little to counter the advance of the Japanese manufacturers. Harley Davidson’s manufacturing system is characterized by low-volume, low-variety while the Japanese offers high-volume, high variety motorcycles. In variety and pricing, the Japanese manufacturers have created a huge gap between them and Harley Davidson, pushing the company further down the losing curve. Several issues have plagued the company’s production system, which can be attributed to its gradual decline in those years. Among the company’s production problems are quality issues, less skilled workers and internal bureaucracy that crippled the company further. Finally, Harley Davidson sent their executives to learn from the Japanese the art of lean manufacturing. A group of senior managers from Harley visited the Honda plant in Japan and observed that the plant is controlled by JIT or just-in-time system. Also, they observed that motorcycles are “built to order” rather than for inventory purposes. In contrast, Harley Davidson manufacturing system invests millions of dollars in computerized inventory systems in order to keep track of their inventories and work-in-progress (WIP). As observed by one company executive, “The Japanese were just better managers and they understood how to do manufacturing a hell of a lot better, with less inventory and much higher quality”. They also observed that the quality of Honda motorcycles greatly surpasses theirs because the system that the Japanese follows pushes the responsibility and accountability for quality down the lower levels of the organization. This realization came as a shock to Harley Davidson executives that they decided to implement the lean concepts in their manufacturing system urgently. The company realized that their entire line of products does not stand a chance against the Japanese both in quality and in pricing and so they decided to overhaul their entire manufacturing system using the Japanese lean manufacturing system as a blue print. Among the lean tools that were employed is the empowerment of all levels of employees for continuous product improvement, which is similar with the concept of ‘kaizen.’ Also, materials-as-needed (MAN) was adopted, which is an adaptation of the JIT principle of lean management. Employees were also encouraged to measure quality and recommend changes if necessary and to detect problems regarding quality along the manufacturing process. Harley Davidson’s adoption of lean practices enabled the company to rapidly bounce back. As observed by Teerlink, “productivity went up by 50 percent; work-in-progress inventory was reduced by 75 percent; scrap and rework, a measure of quality improvement, was down by 68 percent”. As a result of its lean implementation, the company’s profit increased by $59 million and market share increased by 97 percent.
The lean manufacturing system is not only a sound theoretical principle but also a physical concept that is tangible and readily observable. In the lean system, the accountability for further improvement of production rests heavily on the workers themselves. For the same reason, identification of problems in the currently installed standardization is encouraged among ordinary employees in order to achieve a new and better standard. This implies that work standards in the lean system are flexible and largely dependent on the best practices and the problems observed by the workers, themselves. As a result, continued improvement is achieved until such time that production reaches its most efficient form.
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