Title : Methods And Analysis Of Lean Manufacturing Process
Author :Sanjeevakumar mayachari
Dept of Mech Engg.
University: Visvesvaraya Technological University, Belgaum,
ISSN :
Volume: 01 Issue: 01
Publication Year: June 2026
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ABSTRACT
Lean manufacturing is a performance-based process used in manufacturing organizations to increase competitive advantage. The basics of lean manufacturing employ continuous Improvement processes to focus on the elimination of waste or no value added steps within an organization. The challenge to organizations utilizing lean manufacturing is to create a culture that will create and sustain long-term commitment from top management through the entire workforce. Lean manufacturing techniques are based on the application of five principles to guide management’s actions toward success.
INTRODUCTION
What is Lean Manufacturing?
Lean Manufacturing, also called Lean Production, is a set of tools and methodologies that aims for the continuous elimination of all waste in the production process. The main benefits of this are lower production costs; increased output and shorter production lead times.
More specifically, some of the goals or objectives include:
• Defects and wastage - Reduce defects and unnecessary physical wastage, including excess use of raw material inputs, preventable defects, and costs associated with reprocessing defective items and unnecessary product characteristics which are not required by customers.
• Cycle Times - Reduce manufacturing lead times and production cycle times by reducing waiting times between processing stages, as well as process preparation times and product/model conversion times.
• Inventory levels - Minimize inventory levels at all stages of production, particularly works-in-progress between production stages. Lower inventories also mean lower working capital requirements.
• Labor productivity - Improve labor productivity, both by reducing the idle time of workers and ensuring that when workers are working, they are using their effort as productively as possible (including not doing unnecessary tasks or unnecessary motions).
• Utilization of equipment and space - Use equipment and manufacturing space more efficiently by eliminating bottlenecks and maximizing the rate of production though existing equipment, while minimizing machine downtime.
• Flexibility - Have the ability to produce a more flexible range of products with minimum changeover costs and changeover time.
• Output – Insofar as reduced cycle times, increased labor productivity and elimination of bottlenecks and machine downtime can be achieved, companies can generally significantly increased output from their existing facilities.
Most of these benefits lead to lower unit production costs – for example, more effective use of equipment and space leads to lower depreciation costs per unit produced, more effective use of labor results in lower labor costs per unit produced and lower defects lead to lower cost of goods sold.
In a 2004 survey by Industry Week Magazine, U.S. companies implementing lean manufacturing reported a median savings of 7% of Cost of Goods Sold (COGS) as a result of implementing lean [1]. We believe that the savings many actually are higher for companies in Vietnam considering the higher levels of waste which they typically have compared to U.S. based manufacturers.
Another way of looking at Lean Manufacturing is that it aims to achieve the same output with less input – less time, less space, less human effort, less machinery, less material, less cost.
When a U.S. equipment manufacturing company, Lantech, completed the implementation of lean in 1995, they reported the following improvements compared to their batch-based system in 1991[2].
• Manufacturing space per machine was reduced by 45%.
• Defects were reduced by 90%.
• Production cycle time was reduced from 16 weeks to 14 hours - 5 days; and
• Product delivery lead time was reduced from 4-20 weeks to 1-4 weeks.
History of Lean Manufacturing:
Many of the concepts in Lean Manufacturing originate from the Toyota Production System (TPS) and have been implemented gradually throughout Toyota’s operations beginning in the 1950's. By the 1980’s Toyota had increasingly become known for the effectiveness with which it had implemented Just-In-Time (JIT) manufacturing systems. Today, Toyota is often considered one of the most efficient manufacturing companies in the world and the company that sets the standard for best practices in Lean Manufacturing. The term “Lean Manufacturing” or “Lean Production” first appeared in the 1990 book The Machine that Changed the World.
Lean Manufacturing has increasingly been applied by leading manufacturing companies throughout the world, lead by the major automobile manufactures and their equipment suppliers. Lean Manufacturing is becoming an increasingly important topic for manufacturing companies in developed countries as they try to find ways to compete more effectively against competition from Asia.
• Journal paper on Lean Manufacturing
European Journal of Scientific Research
ISSN 1450-216X Vol.38 No.4 (2009), pp 521-535
© EuroJournals Publishing, Inc. 2009 http://www.eurojournals.com/ejsr.htm
• Abstract of Journal paper on Lean Manufacturing:
The purpose of this study is to investigate the adoption of lean manufacturing in the electrical and electronics industry in Malaysia. A questionnaire survey was used to explore 14 key areas of lean manufacturing namely, scheduling, inventory, material handling, equipment, work processes, quality, employees, layout, suppliers, customers, safety and ergonomics, product design, management and culture, and tools and techniques. The respondents were asked to rate the extent of implementation for each of these areas. The average mean score for each area was calculated and some statistical analyses were then performed. In addition, the survey also examined various issues associated with lean manufacturing such as its understanding among the respondent companies, its benefits and obstacles, the tools and techniques used etc. The survey results show that many companies in the electrical and electronics industry are committed to implement lean manufacturing. Generally, most of them are “moderate–to–extensive” implementers. All the 14 key areas investigated serve as a useful guide for organizations when they are adopting lean manufacturing. In essence, this is perhaps the first study that investigates the actual implementation of lean manufacturing in the Malaysian electrical and electronics industry
[3].
METHODOLOGIES
Standard Work:
Standard work (also called “standardized work” or “standard process”) means that production processes and guidelines are very clearly defined and communicated, in a high level of detail, so as to eliminate variation and incorrect assumptions in the way that work is performed. The goal is that production operations should be performed the same way every time, except insofar as the production process is intentionally modified. When production procedures are not highly standardized, workers may have different ideas of what the correct operating procedure are and easily make incorrect assumptions. A high level of process standardization also makes it easier for the company to expand capacity without disruption.
The standard work guidelines used in Lean Manufacturing are typically defined in significantly greater detail than the minimum required for conformity with 7.5.1. Of ISO9001:2000 on “Control of Production and Service Provision”, particularly in terms of standardizing the movements and work sequences of particular workers.
In Lean Manufacturing, standard work has several main elements:
• Standard work sequence - This is the order in which a worker must perform tasks, including motions and processes. This is clearly specified to ensure that all workers perform the tasks in the most similar ways possible so as to minimize variation and therefore defects. Ideally this is so detailed as to clearly describe every single hand movement by a worker. For example, in wood cutting, the standard work sequence would describe every specific cut and operating step from machine setup to materials handling, cutter adjustment, manual movements and processing time. In an assembly process, it would describe the exact sequential step-by step motions by which the item is assembled.
• Standard timing – Takt time is the frequency with which a single piece is produced. Takt time is used to clearly specify and monitor the rate at which a process should be occurring at various production stages. For lean manufacturers, the Takt time of each production process is actively managed and monitored so that a continuous flow can occur. (Takt time different from cycle time which is the time it takes one particular piece to complete a process. For example, a furniture manufacturer may produce one sofa every 10 minutes (takt time) but it takes 3 days of work to actually produce the sofa (cycle time)).
• Standard in-process inventory – This is the minimum unit of materials, consisting primarily of units undergoing processing, which are required to keep a cell or process moving at the desired rate. This should be clearly determined since it is necessary to maintain this minimum amount of in-process inventory in order to not cause unnecessary downtime. This is used to calculate the volume and frequency of orders, or Kanban, to upstream suppliers.
Communication of Standard Work to employees:
Standard work guidelines shouldn’t only be textual manuals but should include pictures, visual displays and even samples. Employees are unlikely to read boring textual production manuals so visual displays and actual samples, including pictures, should be used as much as possible. The guidelines should be clear and detailed, but at the same time be presented in such a way that is as easy as possible for employees to understand and relevant to what they need to know. This is particularly true in Vietnam since many of the workers may have low education levels and will find visual displays easier to understand than written materials. Some companies even apply video training for tasks which are more complicated or safety-related.
Standard work and flexibility:
Some companies in Vietnam have expressed concern that having highly standardized/defined production procedures will lead to inflexibility. Although standard work requires a high level of detail, in Lean Manufacturing the standard work guidelines
should be updated as frequently as necessary to incorporate ongoing process improvements. In fact, companies are encouraged to maximize the rate of process improvement which means that the standard work guidelines are likely to change frequently. Also, standard work typically includes clear guidelines for workers to handle unusual situations, thereby empowering them to respond in flexible ways to unusual situations.
In order to implement this successfully, responsibility should be clearly delegated for preparing and distributing the necessary documentation and visual aids, as well as ensuring that any changes are clearly communicated to employees by their supervisors. As long as this responsibility is clearly delegated, the standard work procedures can be modified frequently. In fact, lean manufacturing companies such as Toyota are known for their flexibility, both in terms of product mix and their ability to make rapid improvements to their production processes, which also leads to quicker responses to customer’s changing demands.
Visual Management:
Visual Management systems enable factory workers to be well informed about production procedures, status and other important information for them to do their jobs as effectively as possible. Large visual displays are generally much more effective means of communication to workers on the factory floor than written reports and guidelines and therefore should be used as much as possible. When it comes to improving compliance with a process, visual presentation helps the team better understand a complicated process including the correct sequence of events, the correct way to perform each action, internal and external relationships between actions, and other factors. These visual tools may include the following:
• Visual Displays - Charts, metrics, procedures and process documentation which are reference information for production workers. For example, trend chart of yield performance, % variation of defect rate, month-to-date shipping volume status, etc.
• Visual Controls – Indicators intended to control or signal actions to group members. This may include production status information, quality tracking information, etc. For example, color-coded panel for temperature or speed setting control limits that help an operator quickly identify process is out of the control range. Kanban cards are another example of visual controls.
• Visual process indicators – These communicate the correct production processes or flow of materials. For example, this would include the use of painted floor areas for non-defective stock and scrap or indicators for the correct flow of materials on the factory floor.
Quality at the Source (or “Do It Right the First Time”):
Quality at the Source, also called “Do It Right the First Time”, means that quality should be built into the production process in such a way that defects are unlikely to occur in the first place – or insofar as they do occur, they will be immediately detected. Lean Manufacturing systems often refer to the Japanese word “Jidoka” which means that problems should be identified and eliminated at the source.
Some of the key implications of this:
• In-line inspection – The main responsibility for quality inspection is done in-line by workers, not by separate quality inspectors who inspect sample lots. Although some independent QC inspectors are often still used in lean companies, their role is minimized (ideally there are no QC inspectors because they also are considered a waste in Lean Manufacturing).
• Source inspections – In source inspections, the quality inspectors don’t inspect for defects themselves, but inspect for the causes of defects. For example, they may inspect if standard processes are being done correctly by workers, or in a case where defects have occurred, they may be responsible for identifying what was the source of those defects. From this perspective, the primary job of a quality control team is to troubleshoot the root cause of defects, implement preventive measures and provide training to workers to ensure the defects do not reoccur.
• Clear accountability among workers – In Lean Manufacturing, unless there is an intentional inventory of semi-finished products, there is a direct handoff between each upstream stage and downstream stage, meaning that the workers at each upstream stage are fully responsible for the quality of the materials they deliver to the downstream stage and will be held personally accountable for any defects. On the other hand, if there is a large buffer of inventory between two production stages, the workers at the upstream process are less likely to feel personally accountable for any defects.
• Poka Yoke – Simple methods for in-line quality testing (not just visual inspection), sometimes referred to as “Poka Yoke”, are implemented so that defective materials do not get passed through the production process. In Poka-Yoke, 100% of the units are tested as part of the production process. These measures are performed in-line by the production workers (not the quality control team).
• Intentional shutdowns – When defects are generated, production is shut down until the source of the defect can be solved. This helps ensure a culture of zero tolerance for defects and also prevents defective items from working their way downstream and causing bigger problems downstream. For example, at Toyota any worker can shut down the production line. This also helps ensure accountability by upstream workers.
Value Stream Mapping:
Value stream mapping is a set of methods to visually display the flow of materials and information through the production process. The objective of value stream mapping is to identify value-added activities and non value-added activities. Value stream maps should reflect what actually happens rather than what is supposed to happen so that opportunities for improvement can be identified.
Value Stream Mapping is often used in process cycle-time improvement projects since it demonstrates exactly how a process operates with detailed timing of step-by-step activities. It is also used for process analysis and improvement by identifying and eliminating time spent on non value-added activities.
The Five S’s:
The Five S’s are some rules for workplace organization which aim to organize each worker’s work area for maximum efficiency.
• Sort – Sort what is needed and what is not needed so that the things that are frequently needed are available nearby and as easy to find as possible. Things which are less often used or not needed should be relocated or discarded.
• Straighten (or “Set in order”) – Arrange essential things in order for easy access. The objective is to minimize the amount of motion required in order for workers to do their jobs. For example, a tool box can be used by an operator or a maintenance staff who must use various tools. In the tool box, every tool is placed at a fixed spot that the user can quickly pick it up without spending time looking for it. This way of arrangement can also help the user be immediately aware of any missing tools.
• Scrub (or “Shine”) – Keep machines and work areas clean so as to eliminate problems associated with un-cleanliness. In some industries, airborne dust is among the causes of poor product surface or color contamination. To be more aware of dust,
some companies paint their working places in light colors and use a high level of lighting.
• Stabilize (or “Standardize”) – Make the first 3 S’s a routine practice by implementing clear procedures for sorting, straightening and scrubbing.
• Sustain – Promote, communicate and train in the 5 S’s to ensure that it is part of the company’s corporate culture. This might include assigning a team to be responsible for supervising compliance with the 5 S’s.
Preventative Maintenance:
Preventative Maintenance is a series of routines, procedures and steps that are taken in order to try to identify and resolve potential problems before they happen. In Lean Manufacturing, there is a strong emphasis on preventative maintenance which is essential for minimizing machine downtime due to breakdowns and unavailability of spare parts. When equipment reliability is low, manufacturers are forced to maintain high inventories of works-in-progress as a buffer. However, high inventories are considered a major source of waste and defects in Lean Manufacturing.
Total Productive Maintenance:
Total Productive Maintenance (TPM) assigns basic preventative maintenance work including inspection, cleaning, lubricating, tightening and calibration to the production workers who operate the equipment. TPM clearly assigns responsibility to workers to proactively identify, monitor and correct the causes of problems leading to unnecessary machine downtime. By allocating this responsibility to the machine operators, maintenance problems are less likely to occur and therefore machine downtime can be reduced. This also requires the operators to frequently update to the maintenance team about the machine condition so that potential technical problems could be discovered on a timely basis and prevented.
In TPM, the maintenance team is responsible for the higher value-added maintenance activities such as improving the equipment, performing overhauls and improvements, fixing problems and providing training.
Changeover/setup time:
Lean Manufacturing aims to reduce unnecessary downtime due to machine setup or product changeovers since machine downtime is a significant source of unnecessary waste. This requires a culture of continuous improvement in which the company is continuously trying to find ways to reduce changeover and setup times.
Often quicker changeover times can be achieved to some degree by having very standardized (and well-documented) configuration settings for the production of particular products so that there is no uncertainty about how to reconfigure the equipment during a changeover. Companies with a wide range of product mix, color and specifications often underestimate the conversion cost every time the production process is halted to replace molds, clean leftover materials with a different color or specification, adjust machine settings, etc.
Other ways to minimize the changeover/setup time include changing the physical layout of a process, having all materials and tools needed available, and using dual/spare storage bin to eliminate cleaning downtime.
Batch Size Reduction:
Lean Manufacturing aims for materials to flow on the factory floor in the smallest batch sizes possible, with the ideal being one piece flow, so that works-in-progress between processing stages can be minimized. The smaller the batch size, the more likely that each
upstream workstation will produce exactly what its customer needs, exactly when its customer needs it.
Therefore, instead a few large production lines with large batch sizes, Lean Manufacturing usually favors a larger number of small production lines with small batch sizes, with the cellular layout being one version of this. The main benefits of smaller production lines are:
• Smaller batch sizes mean less works-in-progress between processing stages and brings the company closer to the ideal of continuous flow.
• A larger number of production lines with smaller batch sizes allows for a bigger range of products to be made concurrently, therefore reducing downtime and disruptions due to changeovers.
• Smaller production lines have fewer workers and therefore lead to greater accountability among the workers at each line.
Production Layout and Point of Use Storage:
Lean Manufacturing aims for the minimum amount of transportation and handling between any two processing stages. Likewise, works-in-progress should be stored as close as physically possible to the place where they will next be used. This is to reduce material handling requirements, reduce misplaced or inaccessible inventory, reduce damage to materials in transit, and to require the discipline of adhering to a pull based production system.
Kanban:
“Kanban” is a pull-based material replenishment system that uses visual signals, such as color-coded cards, to signal to upstream workstations when inputs are required at
a downstream workstation. In effect, Kanban is a communication tool for pull-based production. A Kanban could be an empty bin, a card, an electronic display or any suitable visual prompt.
Typically there are two main kinds of Kanban:
• Production Kanban – A signal from the internal customer to the internal supplier that something is required from the internal supplier.
• Withdrawal Kanban – A signal from the internal supplier to the internal customer that the supplier has produced something which is available to be withdrawn by the internal customer. In such case the internal supplier doesn’t produce more until the withdrawal is made by the internal customer.
There are many variations on the Kanban system and in fact there are many books dedicated to the topic of how to best apply Kanban.
Production Leveling:
Production leveling, also called production smoothing, aims to distribute production volumes and product mix evenly over time so as to minimize peaks and valleys in the workload. Any changes to volumes should be smoothed so that they occur gradually and therefore in the most non-disruptive way possible. This will also allow the company to operate at higher average capacity utilization while also minimizing changeovers.
A key element of production leveling is that the person(s) responsible for placing orders to the factory floor should have a system for automatically smoothing out the orders so that any increases or decreases are gradual and not disruptive. This makes it easier to correctly allocate the necessary equipment and people. In order to apply this methodology, a company needs to know its true capacity as well as the rate of production at each production stage.
Pacemaker:
In order to ensure the smooth functioning of continuous flow production in lean manufacturing, each workstation has to produce its product at the correct rate which is not too much or too little compared to what downstream workstations require. In order to achieve this, one workstation is often designated as the “pacemaker”. The pacemaker sets the pace of production for the whole production line and the production rates at other workstations are increased or decreased so as to match the rate of the pacemaker.
In a Replenishment Pull system, the pacemaker is usually the final workstation such as final assembly. In a Sequential Pull system, the pacemaker is often a workstation near the beginning of the value stream.
Overall Equipment Effectiveness:
Overall Equipment Effectiveness (OEE) is a measure of the overall capacity utilization of particular pieces of equipment. OEE can be broken down into:
• Availability - how much time the equipment can be potentially operational after considering downtime;
• Performance efficiency - the machine’s actual throughput when it is operating compared to its designed maximum capacity or the maximum it could produce based on continuous processing.
If, for example, availability is 80% and performance efficiency is 75%, then the OEE would be:
Availability x Performance Efficiency = OEE 80% x 75% = 60%
(OEE=Sometimes quality yield percentages are also included in this equation.)
When analyzing OEE, many companies may be surprised to find that there is significant room to increase the output of certain pieces of equipment. For example, they may be able to minimize:
• Unnecessary equipment breakdowns.
• Downtime due to set-up and adjustment.
• Idling and minor stoppages due to lack of raw materials to process due to bottlenecks or Poor production planning.
• Operation below maximum designed speed due to poor operator efficiency, maintenance constraints or other factors.
• Defects that require re-processing.
Tracking OEE is helpful for identifying the sources of bottlenecks, for making capital spending decisions and for monitoring the effectiveness of programs to increase machine productivity.
However, Lean Manufacturing typically prioritizes the maximum utilization of people instead of the maximum utilization of machines. One reason for this is that factories that produce multiple products will not be able to use all machines at all times since the requirements may differ depending on the product being produced.Fig 3.1 Lean manufacturing tool cycle
IMPLEMENTING LEAN
Senior Management Involvement:
As for any significant process improvement project, the total commitment and support of the most senior management is essential. Problems will almost certainly arise during the implementation of lean production systems and those problems will likely only be solved if the senior management is fully committed to the successful implementation of lean.
Start with a Partial Implementation of Lean:
Some companies may initially implement only some of lean manufacturing and gradually shift towards a more complete implementation. In a 2004 survey of manufacturing companies in the U.S. by Industry Week Magazine, among companies which had commenced lean manufacturing programs, 39.1% reported implementing some aspects of lean, 55.0% reported implementing most aspects of lean and only 5.9% reported complete implementation of lean.
Some simple first steps may include:
• Measuring and monitoring machine capacity and output.
• Creating more clearly defined production procedures.
• Implementing the 5S system for shop floor housekeeping.
• Streamlining the production layout.
Start Small:
We recommend that companies try to implement lean as a test case at a small part of their operations before applying it through their entire operations, especially for the shift from a push-based to a pull-based system since this can potentially be disruptive. For example, the test case may be a single production line or a small series of processes. This
will help to minimize the risk of disruption, help educate the staff on the principles of lean while also serving to convince others of the benefits of lean.
Use an Expert:
We recommend that for most private Vietnamese companies, it would be best to use the services of a lean manufacturing expert to help them implement lean manufacturing systems. In particular, the shift from a push-based to a pull-based production system can potentially be quite disruptive so it is best to be guided by someone who has significant experience in this.
Develop a plan:
The company should develop a detailed and clear implementation plan before proceeding with the conversion to lean manufacturing [9].
RECONCILING LEAN WITH OTHER SYSTEM
Toyota Production System:
Although Lean Manufacturing originated with the Toyota Production System (TPS), Lean Manufacturing has been adopted by many companies and has therefore become broader than what TPS encompasses. TPS can be seen as the way one particular company has implemented lean in a very pure form. In TPS, several key themes are emphasized:
• Standard Work – All production process are highly specified in terms of work content, sequence of events, timing and outcome. The objective is to eliminate any variation in the way that workers perform their responsibilities.
• Direct handoffs – Every customer/supplier connection must be direct, and there always must be an unambiguous yes-or-no way to communicate production requests between suppliers and customers. This ensures maximum accountability by suppliers and ensures optimal communication flow.
• Production flow - The pathway for every product and service must be simple and direct, with a predetermined flow. This means that goods do not flow to the next available person or machine but to a specific person or machine and that this person or machine is as close as possible to its supplier.
• Worker empowerment for process improvement - All improvements must be made in accordance with the scientific method, under the supervision of an expert, but should originate at the lowest possible level in the organization. Toyota encourages workers to propose improvements to the production process which can be implemented on a trial basis, but any changes to the production process must be defined in detail in accordance with Toyota’s standards for Standard Work, as described above.
Lean Six Sigma:
Six Sigma is a systematic methodology for breakthrough improvement of business processes by identifying the causes of variation in the production process which lead to defects and then eliminating that variation to minimize defects. Since a key objective of Lean Manufacturing is also to eliminate defects, statistical and problem-solving tools of Six Sigma can be used in the implementation of Lean Manufacturing. Often they are implemented concurrently in what is referred to as “Lean Six Sigma”.
5.3 Lean and ERP:
Enterprise Resource Planning (ERP) has its roots in Material Requirement Planning (MRP) systems for which production is typically scheduled based on a push-based production plan. The schedules are updated based on information on production status which is fed from the factory floor back into the MRP system. A frequent problem that emerges with MRP systems is that the data from the factory floor on production status and inventory levels may be inaccurate or not entered on a timely basis, causing the MRP system’s production plan to use some incorrect assumptions which cause bottlenecks and/or cause the MRP system to intentionally produce more buffer inventory as a precaution. Most ERP packages are designed for push-based, centrally-planned production. More recently some ERP systems have been optimized to support lean manufacturing. Companies should consider this carefully when selecting an ERP system. For more information on evaluating the suitability of ERP systems for Lean Manufacturing, please see Brian Nakashima’s article Can Lean and ERP Work Together? From Advanced Manufacturing Magazine.
It should also be noted that ERP systems typically include a number of modules that don’t specifically relate to production planning – such as accounting, financial analysis, human resource management, sales management, etc. These can often be very beneficial for the company and have no direct impact on the company’s ability to implement lean manufacturing.
Lean with ISO 9001:2000:
ISO 9001:2000 is a quality management system which aims to ensure that the company has basic systems in place to consistently meet the customer’s quality requirements. Relative to ISO 9001:2000, Lean Manufacturing may be seen as an efficiency management system which aims to reduce all waste and inefficiency from the production process. Although these goals are overlapping in some ways, particularly insofar as they both should result in minimizing the level of defective products delivered to customers, there are substantial differences. For example, a company could have 100% conformity with ISO9001:2000 but still have very high levels of waste and inefficiency. An important distinction is that ISO9001:2000 requires that the company’s processes meet certain minimum criteria, whereas Lean aims for continuous improvement in the company’s processes, and provides a set of methodologies to achieve that.
ADVANTAGES & DISADVANTAGES OF LEAN MANUFACTURING:
Advantages of Lean Manufacturing:
• Reduced Inventory
The key being that the business will still run as good or better than before if you implement lean manufacturing correctly with significantly less inventory.
• Increase Throughput
By eliminating excess steps and non value adding activities and by making sure that every tool to complete a job is in a known place near the work area you can easily increase your output.
• More pleasant work atmosphere
A place for everything and everything in its place seems like an annoying phrase until you have seen the true power that it holds. Especially in a work environment.
• Higher Quality
Better quality and less rework is a key tenet to lean manufacturing.
Some other benefits
• Less investment for same level of production.
• Increased production at constant investment.
• Ecological production, more compact plants.
• Improved quality.
• Low inventory.
• Less scrap.
• Safety of operations.
• Total manufacturing time saved.
Disadvantages of Lean Manufacturing:
• Supply Problems
Because only a small amount of inventory is kept on hand, lean manufacturing depends heavily on suppliers that can provide products for the manufacturing process dependably and without interruption. Problems like employee strikes, transportation delays and quality errors on the part of suppliers can create manufacturing holdups that can be fatal.
• High Cost of Implementation
Implementing lean manufacturing often means completely dismantling previous physical plant setups and systems. Training employees can be lengthy and acquiring managers experienced in lean manufacturing process can add considerably to companies’ payroll expenses.
• Lack of Acceptance by Employees
Lean manufacturing requires constant employee input on quality control, which some employees may feel disinclined or unqualified to do.
• Customer Dissatisfaction Problems
Because lean manufacturing processes are so dependent on supplier efficiency, any disruption in the supply chain and therefore, on production can be a problem that adversely affects customers. Delivery delays can cause long-lasting marketing problems that can be difficult to overcome.
CONCLUSION
Lean Manufacturing is a group of methods, which are being increasingly implemented around the world, that aim to eliminate waste and inefficiency from the manufacturing process, leading to lower costs and greater competitiveness for manufacturers. In a recent survey, approximately 36% of U.S. based manufacturing companies have implemented lean or are in the process of implementing lean. Some of the changes required by Lean Manufacturing can be disruptive if not implemented correctly and some aspects of Lean Manufacturing are not appropriate for all companies.
REFERENCES
[1] http://www.industryweek.com/CurrentArticles/asp/articles.asp?ArticleID=1589
[2] James P. Womack & Daniel T. Jones: Lean Thinking. Simon & Schuster, 1996. P. 121.
[3] James Womack, Daniel Jones and Daniel Roos: The Machine that Changed the World. Simon & Schuster, 1992.
[4] Process improvement at Toyota Ben Thanh, Hoang Ly: Co The Tang Nang Suat ma Khong Can Dau Tu (Improving Productivity without Capital Investment). Thoi Bao Kinh Te Saigon, 27 May 2004.
[5] http://www.techhelp.org/about_success_details.asp?ID=37
[6] http://www.sme.org/cgi-bin/get-newsletter.pl?LEAN&20040309&1&
[7] Steven Spear and H. Kent Bowen: Decoding the DNA of the Toyota Production System. Harvard Business Review, September-October 1999.
[8] Steven Spear: Learning to Lead at Toyota. Harvard Business Review, May 2004.
[9] http://www.advancedmanufacturing.com/pdfs/buildingthelean.
