Appendix A. Lean Terminology
5S: A Lean methodology to create a productive and safe workplace. It consists of
• Sort: Keep only really necessary things.
• Set in order: Arrange and store everything to be easy to locate, access, and return to its storage place.
• Shine: Keep the entire work area clean and ready for production.
• Standardize: Create standard work documentation for tasks needed to keep work areas clean and orderly, with diagrams documenting where all tools and supplies are to be stored.
• Sustain: Ensure that workplaces are maintained as documented in standard work instructions through empowering operators to organize, maintain, and improve them; also include areas to be audited as a part of layered audit systems.
5 Whys: A method for identifying problem root causes by repetitively asking why, getting a response, and asking why again. The process continues until the identified cause can be linked back to the original problem and it is confirmed that removing or controlling the cause would eliminate the problem.
A3: Another Lean tool in common use; it is a persuasive one-page analysis and synthesis of a problem on A3-size paper (approximately 11 × 17 inches, hence the name), intended to get people involved and to act in ways they otherwise wouldn’t. A3 is used effectively for a number of purposes, including annual plan goal deployment, project management, and problem solving. The content should
• Provide the background, context, and importance of the problem
• Assess current performance and the gap versus standard and perfection
• Determine specific goals and objectives of the project
• Analyze the problem to identify its root causes
• Recommend countermeasures that will eliminate defined root causes
• Define an action plan to implement recommended countermeasures
• Establish a measurement, risk mitigation, and review process and standardization plan
There are many benefits of organization-wide A3 use, among them:
• A3’s standardized presentation format is understood across the organization so energy is focused on solving problems.
• There is increased speed of problem solving as repetitive use builds stronger problem-solving skills.
• A3s generate ideas from the entire organization as they are posted in areas accessible to everyone.
• They tell shop floor associates they are full team members with management.
Error-proofing—poka-yoke: A Lean set of practices intended to prevent the existence of conditions that can result in defects, or if it is not practical to prevent defects, to catch them as close to their source as possible.
Jidoka: Providing machines and operators with the ability to detect when abnormal conditions have occurred and immediately stop work. Jidoka is sometimes called “autonomation,” meaning automation with human intelligence.
Just-in-time (JIT) production: A production system of making and delivering just what is needed, just when it is needed, and in just the amount needed.
Kaizen: The continuous improvement of a value stream or an individual process to create more value with less waste. There are two levels of kaizen: System or flow kaizen focuses on the overall value stream, and process kaizen focuses on individual processes.
Kaizen events: A short-duration improvement project, normally one day to one week, completed by a team following a PDCA-based event methodology.
Kanban: A Japanese term for “sign” or “signboard.” In Lean it is a signaling device giving authorization and instructions for producing or withdrawing (conveyance) items in a pull system.
Layered audit system: A system of auditing work areas involving operators and all levels of leadership. Shop floor operators audit their areas every day, team leaders may audit their areas weekly, area managers monthly, and plant managers maybe semiannually. Its purpose is compliance with standard work, coaching, and identification of future opportunities to improve.
Lean production system: A business system for organizing and managing product development, operations, suppliers, and customer relations that requires less human effort, less space, less capital, and less time to make products with fewer defects to precise customer desires, compared with the previous system of mass production. The term was coined by John Krafcik, a research assistant at MIT with the International Motor Vehicle Program in the late 1980s.
Level scheduling: A scheduling method of minimizing the effects of mix and volume variability. Work is released to production by pitch, a volume of product defined based on an increment of time to standardize small lot production. It functions in combination with shortening process setup times so smaller lots can be run efficiently. Production volume flexibility is created by using cell design and standard work to be able to quickly flex crew sizes based on Takt time.
Management by fact (MBF): A tool used in a number of methodologies including Six Sigma and CMM. It also has many similarities to the A3 problem-solving process. It is a concise summary of quantified problem statement, performance history, prioritized root causes, and corresponding countermeasures for the purpose of data-driven problem analysis and management. MBF uses “4 Whats” to help quantify the problem statement and the gap between actual and desired performance, and “5 Whys” to determine root causes. (See Figure A.1.)
Obeya: Obeya in Japanese means simply “big room.” It is a major project management tool used to enhance effective, timely communication and ensure project success by shortening the PDCA cycle. Similar in concept to traditional “war rooms,” an obeya contains highly visual charts and graphs depicting program timing, milestones, and progress to date and countermeasures to existing timing or technical problems. Project leaders may have desks in the obeya to facilitate communication.
Pacemaker process: The production process nearest the customer, where products take on their definition. It sets the pace for a value stream. (The pacemaker process should not be confused with a bottleneck process, which necessarily constrains downstream processes because of a lack of capacity.)
PDCA (Plan, Do, Check, Act): An iterative four-step problem-solving process to:
• Identify the real problem, using the five whys, and define countermeasures to eliminate or control the root causes
• Implement the countermeasures
• Measure the new processes and compare against expected results
• Analyze the differences to determine their cause and repeat the problem-solving cycle if necessary
Process efficiency: The percent of total value stream lead time or throughput time that is value-added; it is calculated by dividing value-added time by total time from receipt of raw materials to shipment to customers.
Production lead time (throughput time and total product cycle time): The time required for a product to move all the way through a process from start to finish. At the plant level this is often termed door-to-door time. The concept can also be applied to the time required for a design to progress from start to finish in product development or for a product to proceed from raw materials all the way to the customer.
Source quality: A quality management approach to focus on defect prevention at it source or detection and correction as close to the generating process as possible. Defects are never allowed to be passed on to the next downstream process.
Supermarket: Lean term for an inventory buffer of raw materials, work in process, or finished goods, ensuring reliable supply to a downstream process; created to mitigate the consequences of supply variability, demand variability, and differences in the process times of two sequential processes. Withdrawal of material is authorized by a withdrawal kanban from the using process, and replenishment is authorized by a production kanban sent to the producing process.
Standard work for managers: Every team member has well-defined standardized work, which is critical to accountability, commitment, and achievement of results through waste elimination. Standardized work is defined for every level of management. Thus, managers must have structured time in their daily schedules for time on the shop floor. The daily schedule must be arranged so that managers review all operations over a defined period. The purposes are to
1. Audit standardized work
2. Coach team members in the Lean system and mentor continuous improvement
3. Follow up on previously identified deviations to ensure corrective action is being completed
4. Identify the next level of system improvement
This is a critical management activity required for sustaining Lean systems. A second standardized work activity for managers is leading policy deployment, or hoshin kanri, to ensure that operations are completely aligned with the annual business plan. The third manager’s standardized work activity is conducting regular Lean operational reviews. Regular reviews are required to assure organizational accountability to fulfill operational plan goals.
Takt time: The increment of time, in seconds or minutes, required to produce one unit of product. It is calculated by dividing available production time by customer demand. For example, if a widget factory operates 480 minutes per day and customers demand 240 widgets per day, Takt time is 2 minutes. The purpose of Takt time is to precisely match production with demand. It provides the heartbeat of a Lean production system. The term is German for a precise interval of time such as a musical meter.
Toyota Production System (TPS): The production system developed by Toyota Motor Corporation to provide best quality, lowest cost, and shortest lead time through the elimination of waste. Development of TPS is credited to Taiichi Ohno, Toyota’s chief of production in the post–World War II period.
TPM (total productive maintenance): A system for managing facility and machine maintenance focused on elimination of emergency maintenance through rigorous application of preventive and predictive maintenance practices.
Value stream: All of the actions, both value-creating and non-value-creating, required to bring a product from concept to launch and from order to delivery. These include actions to process information from the customer and actions to transform the product on its way to the customer.
Visual management: An important Lean principle and practice. As a principle it is the foundation of making the system transparent so that all can see and understand it, not just the experts. As a practice it means implementing practices, progress metric status, and project implementation status in simple standardized approaches that everyone in the organization can understand. For example, inventory in a supermarket should never fall outside defined minimum or maximum levels. Storage locations in supermarkets are designed to hold the maximum planned inventory. If inventory exceeds the maximum, it must be stored outside designated locations, creating a visible variation that will be caught during the daily audits. These obvious deviations are easily observed and demand immediate follow-up to understand root causes of system failures.
Work cell design: The process of organizing production process steps into logical groups, creating a layout to facilitate minimum materials handling and the most efficient use of operator time. The work at each workstation is balanced to minimize waste and improve flow, resulting in shorter cycle times and lower cost.
Waste: A resource-consuming activity that does not create customer value. In Lean there are seven specific types of waste: excess transportation, inventory, motion, waiting, overproduction, overprocessing, and defects.