A Lean system consists of the ten operational components listed in Table 6.3. These components also have sets of tools and methods that are necessary to fully imple- ment a Lean system. A truly Lean organization will have each of these components and perhaps others more specific to the industry. Unfortunately, some organiza- tions implement just a few of the components. As a result, they do not obtain all the advantages of a fully implemented and integrated Lean enterprise. The first key component of a Lean system is system performance measurements. Key per- formance measurements are listed in Table 6.2. Performance measurements show an organization where to focus its Lean improvement efforts. Measurements are important because a Lean implementation may take several years. The second key
table 6.2 10 key benefits of a lean deployment
1. Higher customer on-time delivery (schedule attainment) 2. Higher value added time/total time
3. Higher throughput of materials or information
4. Faster machine or job changeover (especially at bottleneck resource) 5. Higher machine uptime (available time)
6. Higher quality of work (scrap/rework/warranty/returns) 7. Less floor space utilized
8. Lower system inventory
9. Higher supplier on-time delivery 10. Lower overall system cost
component of a Lean system is implementation of just-in-time (JIT) and a stan- dardized workflow. JIT implies that raw materials and components are delivered to the process just when they are needed for production. This increases system flexibil- ity, and raw material and work-in-process (WIP) inventory can be kept at very low levels. However, demand and lead time variation must also be decreased to imple- ment JIT and reduce system inventory. Variation reductions imply that work tasks have been standardized and demand is presented to the system at a constant rate with minimum variation. To achieve JIT, several of the other Lean system compo- nents listed in Table 6.3 must also be successfully implemented by an organization. As an example, Lean systems require that the work tasks be standardized or done the same way all the time. However, work tasks can be standardized only after they have been studied to the level of detail shown in Figure 5.16 and Figure 5.17. Important characteristics of work standardization include written work and inspec- tion instructions as well as employee training to use them effectively. Mistake- proofing is another important way to standardize work tasks. It begins early in the design of products or services using design for manufacturing (DFM) and other design tools and methods. If correctly implemented, only the simplest design is released for production based on DFM principles. Quality increases as the key components 3, 4, and 5 of Table 6.3 are implemented within a workflow.
As a Lean deployment evolves, the tools and methods associated with Total Productive Maintenance (TPM) and the Single Minute Exchange of Dies (SMED) are implemented within process workflows. These are the key components 6 and 7 of Table 6.3. TPM includes the study and deployment of preventive and correc- tive maintenance practices. These practices ensure machines will not unexpectedly break down, disrupting the workflow. SMED is a set of tools and methods that
table 6.3 10 key Components of a lean System
1. System performance measurements 2. JIT/stable system
3. Standardized work (5-S) 4. Mistake-proofing 5. High quality
6. Total Productive Maintenance (TPM) 7. Single Minute Exchange of Dies (SMED) 8. Visual workplace
9. Container design (packaging) 10. Supplier agreements
Making Value Flow through a Process n 171
study how jobs are set up. The goal is to reduce setup time and cost to increase the available number of setups for the system. This provides increased scheduling flex- ibility. In addition, the quality and reliability of job setups are increased by using SMED tools and methods. In SMED, a key concept is to separate a job setup into those operations that can be done externally or offline versus those that must be done internally or online. The concept is that if key work tasks associated with a setup can be done offline, then resources can be applied to complete these offline work tasks according to a schedule that has little impact on the actual online job setups. Also, modifications to online setup tooling and fixtures, as well as the appli- cation of mistake-proofing strategies, will help reduce the time required to com- plete online setups. SMED concepts will be discussed later in this chapter based on Table 6.7 and Table 6.8.
Integral to the communication process within and between workflows is deployment of visual controls in several formats. These are used to create a visual workplace. In a visual workplace, the status of a process workflow and its opera- tions and their work tasks can be seen at a glance, i.e., they are visible. Creation of a visual workplace within a Lean system allows the status of key workflow metrics to be readily seen and controlled by the local work team. The key steps necessary to implement a visual control system will be discussed later in this chapter based on the information contained in Figure 6.10. Additional supporting components of a Lean system include rules governing the flow of standardized amounts of material or information (service industries) based on the concept of Kanban containers and supplier agreements. The concept of Kanbans will be discussed in Chapter 12 under the topic of scheduling operations. Long-term supplier agreements are also an inte- gral component of Lean systems. Finally, long-term cooperative supplier agreements ensure suppliers have access to customer demand information and work jointly to improve the efficiency of process workflows between the two organizations.
Table 6.4 summarizes ten proven methods to improve operational efficiency. In fact, these methods are characteristic of any highly efficient system. The first method is maintenance of excess capacity within a system to maintain its schedul- ing flexibility to keep lead time low. This concept was discussed in Chapter 5 in the context of queuing analysis and is shown in Table 5.12. Also, improvements in quality, maintenance, and training reduce process breakdowns, which require that work be redone. The application of these methods will directly improve workflow efficiency. The creation of product family processes based on similar product or service design features or characteristics allows the design of similar workflows. This reduces the number of setups and increases scheduling efficiency. Additional benefits associated with fewer setups include higher yields and lower cycle times. Higher yields result from the fact that scrap and rework associated with starting up a job are eliminated through fewer setups. The use of multifunctional equipment also increases system flexibility. This is because equipment can be used to produce more than one type of job. As discussed above, the measurement of key process workflow metrics related to lead time, quality, and uptime is also important. The
sixth method, process simplification, is a major topic of this chapter using value stream mapping (VSM). The seventh method, multiskilled workers, has the effect of increasing system flexibility because direct labor can be matched more closely to production schedules. Method 8 suggests that an organization should only commit to orders it knows it can efficiently produce on time, rather than make promises that cannot be kept. Making such promises results in scheduling problems because other orders must be reprioritized for production. This wastes capacity and other system resources. Products should be made with no excess unless this is a strategic decision based on external or internal factors. Making an excessive amount of a product wastes capacity and resources. Finally, contractual obligations should also be standardized and consistent across the supply chain to ensure an uninterrupted supply of materials or services.