Lean Manufacturing and Environment
Lean and Environment Toolkit
Appendix A: Lean Methods
- Value stream mapping;
- Kaizen events; and
- 6S (5S+Safety).
Overview of Value Stream Mapping (VSM)
Value Stream Mapping (VSM) is a process mapping method used to document the current and future states of the information and material flows in a value stream from customer to supplier. A value stream is the set of specific actions (value-added and non-value added) required to bring a specific product through three critical management tasks of any business: problem solving, information management, and physical transformation. VSM is used as a communication tool, a business planning tool, and a management tool.
Through VSM, a business process is examined from beginning to end. Each step in the process is included in a drawing that acts as a visual representation of the material and information flows. In other words, an end-to-end system map is created; this is called the current state map. A future state map shows how things should work in order to gain the best competitive advantage. The opportunities for improvement at each step that would have a significant impact on the overall production system are highlighted on the future state map and then implemented, creating a leaner production process.
The key to VSM is to see the big picture as a sum of the parts. Rather than optimizing one part of one step or “fixing something broken,” you see how that step fits into the overall production process and how changing it will affect the overall process. This provides the opportunity to visualize how different types of changes, or a combination of changes at multiple places in the process, will affect the entire system. The change, or set of changes, that will result in the most efficient production overall can then be chosen.
The Three Steps to Value Stream Mapping
The current production system is drawn by first conducting a walkthrough of the entire system from beginning to end. During the walkthrough gather information on the shop floor and analyze the current production system. Then draw a basic overview map with process and material flows represented by different symbols on the map. A set of existing symbols can be used or a new set created, but the method of mapping should always be kept consistent within the company to gain better staff understanding and awareness. After the basic production process is understood, more detail is added to the map at each process step creating a comprehensive picture of the current system.
2. Future State Drawing
Future state ideas will likely arise while gathering information in the first step. You can either keep a running list of these ideas and turn them into a future state map after you have completed the current state map, or draw the future state map alongside the current state map. A key to creating a more Lean future state is identifying areas of overproduction and root causes of waste in the current production system, and finding ways to reduce or eliminate them in the future system. The idea behind creating a Lean value stream is to create only what is needed when it is needed. A few ways to help accomplish this are to use takt time (the rate of customer demand) to synchronize the pace of production with the pace of sales, develop a continuous flow, and level the production mix. More details on how to Lean the value stream can be found in the resources below.
3. Work Plan and Implementation
In this step, a work plan is prepared based on the future state value stream map that describes specific ways in which the future state map will be achieved. VSM is a tool to identify areas that need improvement in the value stream. By itself, VSM will not produce the desired change; implementation is key to achieving results. Implementation is usually best done in stages since the entire system is affected. One way of doing this is to break the future state map into segments or loops, and implement changes within one loop at a time. The work plan should also include measurable goals and checkpoints. Once the work plan is implemented a new, more efficient current state is formed. To keep continuous improvement happening in your business, once a future state becomes a new current state, a new future state map should be drawn, and the cycle continued. An annual value-stream review is a good way to keep things moving.
Rother, Mike and John Shook. Learning to See: Value-Stream Mapping to Create Value and Eliminate Muda. Brookline, MA: Lean Enterprise Institute, Inc., 2003.
Tapping, Don, Tom Luyster, and Tom Shuker. Value Stream Management: Eight Steps to Planning, Mapping, and Sustaining Lean Improvements. New York, NY: Productivity Press, 2002.
Common Icons Used in Value Stream Maps
Here is a key to Lean symbols used in the value stream maps in this toolkit.
Overview of Kaizen Events
Kaizen means continual improvement and is taken from the Japanese words kai, meaning “to take apart” and zen, meaning “to make good.” Kaizen is based on the fundamentals of taking something apart and understanding how it works so that it can be made better. There is a focus on eliminating waste, improving productivity, and achieving sustained continual improvement in targeted activities and processes of an organization. Kaizen is built on the philosophy that small, incremental changes routinely applied and sustained over a long period result in significant improvements overall.
Kaizen events, also known as rapid process improvement events, are a team activity designed to eliminate waste and make rapid changes in the workplace through the targeted use of Lean methods. The strategy aims to involve workers from multiple functions and levels in the organization in working together to address a problem or improve a process. The team uses process improvement methods, such as cellular manufacturing and Total Productive Maintenance, to identify opportunities quickly to eliminate waste in a targeted process or production area. The team also works to implement chosen improvements rapidly (often within 72 hours of initiating the kaizen event), typically focusing on solutions that do not involve large capital outlays.
The philosophy of kaizen is often is considered to be the “building block” of all Lean production methods. Kaizen’s impressive results often stem from:
- Kaizen’s focus on moving rapidly from planning to implementation;
- Kaizen’s focus on making continued progress rather than waiting to find the perfect solution;
- Kaizen’s focus on worker involvement and team work;
- Kaizen’s focus on addressing the root causes of problems; and
- Kaizen’s focus on process improvement from a systems perspective.
The Three Phases of a Kaizen Event
Kaizen events typically require an organization to foster a culture where employees are empowered to identify and solve problems. Most organizations implementing kaizen-type improvement processes have established methods and ground rules that are well communicated in the organization and reinforced through training. Kaizen events generally have three main phases, although organizations can adapt and sequence these activities to work effectively in their unique circumstances.
Phase 1: Planning
To prepare for a kaizen event, a target area and problem are selected. Such areas might include: areas with substantial work-in-progress (WIP); an administrative process or production area where significant bottlenecks or delays occur; and/or areas that have significant market or financial impact (i.e., the most “value added” activities). A more specific “waste elimination” problem within that area is then chosen for the focus of the kaizen event. Baseline information is collected for the process area and improvement targets and measures are established. An event leader and a team are carefully selected and trained, making sure to tap a range of expertise, including shop floor workers who are intimately familiar with the targeted process.
Phase 2: Implementation—The Event
Implementation focuses on the actual kaizen event, lasting from two to five days, depending on their scope. The facilitated events emphasize worker participation. The first part of an event includes a kick-off and an assessment of the current state of the targeted process and problem so that all team members have a similar understanding of the problem they are working to solve. This part frequently involves process observation, data collection, and process mapping. Team members are assigned specific roles for research and analysis. As more information is gathered, team members add detail to value stream maps of the process and conduct time studies of relevant operations (e.g., cycle time, lead time). The next part focuses on developing, selecting, implementing, and testing improvement ideas. Team members identify and record all observed waste, by asking what the goal of the process is and whether each step or element adds value towards meeting this goal. Once non-value added activity is identified and measured, team members then brainstorm improvement options. Ideas are often tested on the shop floor or in process mock-ups. The most promising ideas are selected and implemented.
Phase 3: Presentation and Follow-up
Wrap-up and follow-up activities ensure that the results of a kaizen event are communicated and sustained in the organization. Improvements made during an event must be shared with others in the organization, particularly with those affected by changes to standard work. Celebration is also important to recognize team member contributions and to cultivate a culture of worker involvement. Follow-up activities to measure process performance, make adjustments, and ensure that unresolved actions are completed are critical to prevent backsliding.
Productivity Press Development Team. Kaizen for the Shopfloor (Portland, Oregon: Productivity Press, 2002).
Overview of 6S (5S+Safety)
6S is modeled after the 5S process improvement system designed to reduce waste and optimize productivity through maintaining an orderly workplace and using visual cues to achieve more consistent operational results. It derives from the belief that, in the daily work of a company, routines that maintain organization and orderliness are essential to a smooth and efficient flow of activities. Implementation of this method “cleans up” and organizes the workplace basically in its existing configuration. It is typically the starting point for shop-floor transformation. The 5S pillars, Sort, Set In Order, Shine, Standardize, and Sustain, provide a methodology for organizing, cleaning, developing, and sustaining a productive work environment. 6S uses these five pillars plus an added pillar for Safety. 6S encourages workers to improve the physical setting of their work and teaches them to reduce waste, unplanned downtime, and in-process inventory.
The 6S Pillars
Sort. The first pillar focuses on eliminating unnecessary items from the workplace that are not needed for current production operations. An effective visual method to identify these unneeded items is called "red tagging," which involves evaluating the necessity of each item in a work area and dealing with it appropriately. Organizations often find that sorting enables them to reclaim valuable floor space and eliminate such things as broken tools, scrap, and excess raw material.
Set in Order. This pillar focuses on creating efficient and effective storage methods to arrange items so that they are easy to use and to label them so that they are easy to find and put away. Set In Order can only be implemented once the first pillar, Sort, has cleared the work area of unneeded items. Strategies for effective Set in Order include affixing labels and placards to designate proper storage locations and methods, outlining work areas and locations, and installing modular shelving and cabinets.
Shine. Once the clutter that has been clogging the work areas is eliminated and remaining items are organized, the next step is to thoroughly clean the work area. Daily follow-up cleaning is necessary to sustain this improvement. Working in a clean environment enables workers to notice malfunctions in equipment such as leaks, vibrations, breakages, and misalignments that could lead to loss of production. Organizations often establish Shine targets, assignments, methods, and tools before beginning the Shine pillar.
Safety. This pillar focuses on eliminating hazards and creating a safe environment to work in. Once the workplace has been organized and cleaned, potential dangers become easier to recognize. A separate “safety sweep” should be performed to identify, label, and deal with hazards; however, safety measures can also be implemented in conjunction with strategies in the other five pillars (for example, yellow (safety) tagging can be done at the same time red tagging takes place).
Standardize. This pillar is used to maintain the first three pillars, creating a consistent approach with which tasks and procedures are performed. The first steps are to assign 6S (Sort, Set in Order, Shine) job responsibilities and integrate 6S duties into regular work duties. Some of the tools used to accomplish this are: job cycle charts, visual cues (e.g., signs, placards, display scoreboards), and check lists. The second part of Standardize is prevention—preventing accumulation of unneeded items, preventing procedures from breaking down, and preventing equipment and materials from getting dirty.
Sustain. This pillar makes a habit of properly maintaining correct procedures and is often the most difficult pillar to implement and achieve because changing entrenched behaviors can be difficult. Sustain focuses on defining a new status quo and standard of work place organization. Without the Sustain pillar the achievements of the other pillars will not last long. Tools for sustaining 6S include signs and posters, newsletters, pocket manuals, team and management check-ins, performance reviews, and department tours.
When the six pillars have been implemented and organizational and safety procedures are maintained, the workplace becomes a safer and more efficient place to work leading to increased productivity and worker confidence. Although other Lean methods can be used without using 6S, the 6S method creates a streamlined workplace and a good base which can often times enhance the results from other Lean processes.
Hirano, Hiroyuki. 5 Pillars of the Visual Workplace (Portland, Oregon: Productivity Press, 1995).
Peterson, Jim, Roland Smith, Ph.D. The 5S Pocket Guide (Portland, Oregon: Productivity Press, 1998).
Productivity Press Development Team. 5S for Operators: 5 Pillars of the Visual Workplace (Portland, Oregon: Productivity Press, 1996).
Productivity Press Development Team. 5S for Safety Implementation Toolkit: Creating Safe Conditions Using the 5S System (Portland, Oregon: Productivity Press, 2000).
Productivity Press Development Team. 5S for Safety: New Eyes for the Shop Floor (Portland, Oregon: Productivity Press, 1999).