a foundation for creating flow and establishing standardization. In essence, this isolation of variation is a basic application of heijunka, or leveling. By grouping similar products, we were able to level the workload for the majority of the process. The highly variable work is still difficult to standardize, but in this case 80 percent of the total is possible. This is an important aspect of creating stability. Some basic applications of leveling can be done in the stability phase, and there are advanced applications of heijunka as well, that will incrementally tighten the timing and pressure on the system in later phases. (We will discuss this in detail in Chapter 7.) One common mistake is to attempt to establish flow or standardization too soon. As we will go into in the next chapter, creating flow between operations is designed to surface any issues quickly and to make them critical in nature (ignoring them would be disastrous). If this step is taken before eliminating major obstacles, the result will be too many problems and a consequent retreat to the “old way.” Likewise, an attempt to standardize a chaotic process with a high level of variability will most certainly cause frustration, since it is not pos- sible to standardize variation. If we liken the creation of lean processes to building a house, we understand that in order to support the roof, we will need walls and trusses. Foundations and subfloors, in turn, support the walls. This is easy to see and understand because a house is a real, visible, tangible object with common elements (they all have roofs of some type). A lean system, on the other hand, is not so clear. If you focus your effort on developing an understanding of the intent of each phase, rather than the application of lean tools, this process will be more successful. Understand the what before trying to apply the how. The lean tools are applied to address specific needs, and should not be applied simply because they are in the toolbox. THE TOYOTA WAY FIELDBOOK78 Figure 4-9. Process stability after variation of welding time is isolated Throughput Time (Days) 0 5 10 15 20 25 Nov-02 Dec-02 Jan-03 Feb-03 Mar-03 Apr-03 May-03 Jun-03 Jul-03 Aug-03 Sep-03 Oct-03 Nov-03 Dec-03 Jan-04 Feb-04 Mar-04 Apr-04 May-04 Jun-04 Jul-04 Days Chapter 4. Create Initial Process Stability 79 Reflect and Learn from the Process 1. Develop a current state map of your operation. The primary purpose is not to complete a map, but to see what is actually happening in your organization. a. List at least 50 examples of waste that you observed while developing the map. At this time do not be concerned with “fixing” the problems you see. Simply look and notice the opportunities. b. If you cannot identify at least 50 examples, walk through the process again, taking more time to stop and observe (repeat as necessary). 2. Identify one specific operation from your current state map where you believe the greatest need for improvement exists. a. Complete the “stand in the circle” activity at this opera- tion for at least two hours or more (longer is better). b. List at least 50 examples of waste within this single oper- ation. This should be a simple task. If you have trouble identifying 50 items, you’re overlooking many examples of waste. Take time away from the process; then return with a fresh mind. Begin with the most obvious examples (big waste), and then become more focused on smaller and smaller examples of waste. If 50 examples is a simple task, keep adding to the list until you are challenged to find additional examples. This is when you will develop your powers of observation. 3 Identify indicators of instability in this one operation (chaos, variation, firefighting, inconsistent performance). Do not think about why these conditions exist or how to correct them. The purpose is simply to observe the current condition. a. Make a list of the indicators of instability that you observed. b. Separate the list into two categories based on whether the instability is caused by external issues (customer demand and product variation) or by internal issues (changes made that are within your control). c. Review the suggestions in this chapter and determine the strategies and lean tools needed to address the issues. Chapter 5 One-Piece Flow Is the Ideal Taiichi Ohno taught us that one-piece flow is the ideal. In school when you have the right answer for the test you get an A. The right answer is one-piece flow. So just go out and implement one-piece flow and you are doing lean. What could be easier? In fact, Ohno also taught that achieving one-piece flow is extremely difficult and, in fact, not always even practical; he said: In 1947 we arranged machines in parallel lines or in an L-shape and tried hav- ing one worker operate three or four machines along the processing route. We encountered strong resistance among the production workers, however, even though there was no increase in work or hours. Our craftsmen did not like the new arrangement requiring them to function as multiskilled operators. . . . Furthermore, our efforts revealed various problems. As these problems became clearer, they showed me the direction to continue moving in. Although young and eager to push, I decided not to press for quick, drastic changes, but to be patient. Ohno learned to be patient and deliberate about reducing waste while moving in the direction of one-piece flow, also called “continuous flow.” Products that move continuously through the processing steps with minimal waiting time in between, and the shortest distance traveled, will be produced with the highest efficiency. Flowing reduces throughput time, which shortens the cost to cash cycle and can lead to quality improvements. But Ohno learned that one-pi ece flow is fragile. Create Connected Process Flow Copyright © 2006 by The McGraw-Hill Companies, Inc. Click here for terms of use. Sustaining continuous flow also serves to surface any problem that would inhibit that flow. In essence, the creation of flow forces the correction of problems, resulting in reduced waste. We often use the analogy of a ship on a sea filled with dangerous rocks. As long as the rocks, like problems, are covered with water, like inventory, it’s smooth sailing. But if the water level is lowered, the ship can quickly be demolished by running into the rocks. In most operations there are boulders hovering just under the surface, so naturally we keep enough invento- ry to hide the problems. Ohno discovered that if he reduced the inventory, the problems surfaced, and people were forced to solve them or the system was forced to stop producing. This was a good th ing, as long as the damage was not too severe and the people had the capability to improve the process so that the problems did not recur. He also learned that the system needed some minimal level of stability, or the reduction of inventory would just result in a loss of production, as we saw in Chapter 4. Connecting two or more processes into a continuous flow will increase the severity of any problems and necessitate their elimination. Connected flow across the enterprise means that production in the entire facility—and perhaps across multiple facilities—will be shut down if the problems are not corrected effec- tively. Imagine the importance of equipment readiness, manpower ava ilability, and material supply when thousands of people all stop working if there is a failure! At Toyota this occurs from time to time. The entire operation is connected, and so within a few hours a problem with a main component will halt the entire facility. Many organizations believe that this type of production stoppage is unaccept- able. Stopping production is a sure ticket to the unemployment office. But Toyota sees it as an opportunity to identify a weakness within the system, to attack the weakness, and to strengthen the overall system. It is this counteri ntuitive think- ing that perplexes bottom-line thinkers. The Toyota Way suggests that “failing” and correcting the shortcoming is a way to improve results for the long term. Traditional thinking, in contrast, is that success is achieved by never allowing “failure” to affect the short-term result. That said, the objective is not to entirely jeopardize performance. It is wise to prepare for flow by eliminating major issues, and to move with careful intent and understanding, beginning w ith planning, and developing the discipline for solving problems. As the process improves, and develops capability, the control parameters are compressed during the leveling phase to surface the next layer of issues in an ongoing cycle of continuous improvement. Why Flow? Most often the failure of implementation stems from a misguided belief that suc- cess is rooted in the application of lean tools (such as setting up the cell). We often tour clients through lean plants, in some cases Toyota plants, and it’s interesting Chapter 5. Create Connected Process Flow 81 to hear what they get out of the tour. They have overall impressions of cleanliness, orderliness, precision, and people engaged by their work. But their eyes light up when they see something they can directly apply in their plants. One time, someone noted how a lean plant kept small cabinets of expendable materials by each work cell and the cell leader signed out materials as needed. A kanban system was used to replenish things like plastic gloves. The “industrial tourist” was excited about going back and setting up a similar system for expend- able materials in his plant. Unfortunately, he had noticed only one specific tool, and failed to see the interconnectedness and i nterdependence of all the various elements. Successful creation of lean processes is derived from a deep under- standing of how each tool is utilized to accomplish an end objective. A trained mechanic does not bring a wrench to the car and then find a nut to loosen. He first determines the nature of the problem, what will need to be done to correct it, and then selects the appropriate tools to complete the job. Yet we often see organizations place the tool before the understanding. “We are going to implement visual control,” managers say, as if it were an individual piece of a jigsaw puzzle to be added. A key to long-term success is a combined effort that includes understanding the pr imary philosophy or concept, an effective strategy that necessitates the concept (it must become mandatory), a methodology for applying the concept, lean tools that support the method, and an effective way to measure the overall result. We find it helpful to think about the relationship between one-piece flow and waste reduction in the context of a broader model as shown in Figure 5-1. Rather than leap into implementing tools for flow and pull, step back and understand the purpose. This model emphasizes the relationship between the primary prin- ciple of lean—the identification and elimination of waste—and the method for achieving that objective—reducing batch size to move toward continuous flow. The creation of cont inuous flow is often thought to be a primary objective when creating a lean process, but in reality, the creation of continuous flow is designed to drive waste from any operation: Waste elimination is the primary objective. When material and information flow continuously, there is less waste in the operation. This is true by definition. If there were a lot of waste, material and information would not be flowing. However, there is something more profound happening here. Maintain ing continuous flow between processes will create a linkage, making each process dependent on the other. This interdependency and the relatively small amount of buffering make any condition that interrupts the flow more critical. Anyone who has attempted to implement one-piece flow (a difficult task indeed!) understands that heightening the level of problems can be of great ben- efit . . . or of great harm. If effective systems are not in place to support the oper- ation, the severity of problems will surely spell doom. This is the time when lean THE TOYOTA WAY FIELDBOOK82 Less Is More: Reduce Waste by Controlling Overproduction In a true one-piece flow, each operation only builds what the next operation needs. If the next operation gets backed up for some reason, then preceding Chapter 5. Create Connected Process Flow 83 Figure 5-1. Waste reduction model Philosophy Waste Elimination Performance Measure Reduced Lead Time Principle Create Continuous Process Flow Strategy Create Interdependent "Connected" Processes Reason Problems Are Surfaced Quickly and Are Critical Effect Problems Must Be Corrected Quickly Result Waste Is Reduced! Method Pull System Lean Tools Kanban, Supermarkets, Defined FIFO Lanes Control Method Utilize Visual Controls So That No Problems Are Hidden tools must be applied to provide the necessary structure to ensure success rather than failure. The lean tools can help by providing both support systems and con- trol methods to react appropriately to the problems that surface. operations actually stop. It seems that nothing can be more uncomfortable in a traditional manufacturing operation than stopping. Yet the alternative to stop- ping is overproducing—producing more, sooner, or in greater quantity than the next operation requires. Toyota considers overproduction to be the worst of the seven types of waste because it leads to the other six types of waste (inventory, movement, handling, hidden defects, etc.). This is the key to understanding how less can be more (less means fewer parts produced in some individual steps in the process, more means getting more value-added activity done from the overall process). The case example below explains a typical situation of overproduction that reduced the ability to meet the customer requirement. Case Example: Control Overproduction to Improve Operational Availability While standing in the circle and observing a fabrication line, it was clear that overproduction was rampant. The line was filled with product, much of it stacked two and three layers deep. The workers were all busy, but we could see that the operators overproducing were engaged in “busy work” such as stacking and positioning the excess product. Operators typically reached a point when no additional work would fit on the line, and then excess time was spent care-tending the overpro- duction (inventory). Cycle time comparisons to takt time revealed— no surprise—that these operations were below the takt time and had extra time available. Since they were not provided with additional value- adding tasks, the operators filled their extra time by overproducing and care tending. Observation also showed that the process downstream of the over- production (the customer) had to spend additional time moving and unstacking the product that was poorly presented in large batches. The cycle time of this operation was at takt time, but with the additional work required to move and unstack product, the total time actually exceeded the takt time. It could not achieve customer demand during scheduled work hours. In this case, the supplier process created the excess waste, but the negative effect was realized at the customer process. We asked the operators at the initial operations to stop, and to stand doing nothing, rather than to continue producing when the next process had more than enough material to work with. It is, of course, very uncom- fortable for operators to do nothing because they’ve been conditioned by management to “keep busy.” Toyota stresses the importance of this concept because it allows everyone to see and understand the amount of opportunity available. Everyone can see the idle time because it is not being clouded by busy work (overproduction). THE TOYOTA WAY FIELDBOOK84 By having these operators do less (make fewer parts), the customer operations also had less wasted time and were able to convert that time to more production. The total output of the entire operation increased significantly by simply controlling overproduction. Of course, we were not satisfied to have operators standing around with idle time—the waste of waiting. The next step was to determine how to eliminate additional waste from these operations, and to combine operations and achieve “full work.” For this task standardized work analysis similar to the example described in Chapter 4 was used. Case Example: Making Aircraft Repair Flow at Jacksonville Naval Air Depot Repair operations have even more variability than manufacturing. Until you break into the equipment, you don’t exactly know what the problem is or how long it will take. So repair is often treated as a craft process: Get a team of expert repair persons to work on each piece of equipment. It is a return to the old days of the Model T, when a team of craftsmen stood around a stand and built the car in place. The U.S. Department of Defense does a tremendous amount of repair and overhaul of ships, submarines, tanks, weapon systems, and aircraft. These are very large things. There is almost always urgency getting a plane out. A fighter plane being repaired in a hangar is one less plane available for combat. The largest employer in Jacksonville, Florida, is a Naval Air Depot where aircraft is repaired for the Navy. Aircraft need to be completely overhauled at periodic intervals, and some aircraft have serious weak- nesses that require specific repairs. Because of the urgency of getting planes overhauled, repaired, and back in service, when a plane comes in, it’s brought into a hanger, and skilled personnel attack it, taking it apart. Each plane sits in position and is dismantled, parts are repaired or replaced, everything is tested piece by piece, and it is finally reassembled and flown back into the field. Another motivation to get to work on the plane immediately is to get paid. The base gets paid based on charging hours for working on planes. While the base had decades of experience repairing aircraft, the pressure to reduce the time aircraft spend on the ground was intense. In some cases aircraft are discontinued, and there are then a limited number avail- able in service. If the planes spend too much time in the repair hangar, there won’t be enough to fly the scheduled missions. A program called Chapter 5. Create Connected Process Flow 85 “Air Speed” was started at headquarters to speed up the process of repairing aircraft at NAVAIR facilities. Two aircraft repaired at Jacksonville were the F18 and the P3 fighters, worked on in different hangers. Lean manufacturing experts were hired as consultants to lead internal lean teams and develop internal expertise. Independently, they analyzed the current situation for the P3 and F18. Their conclusions were the same: ◆ Each plane was treated as a unique project, with craftsmen working in place, in no particular standardized process. ◆ The work area around the plane was disorganized with tools and parts lying every which way. ◆ Repair people spent an inordinate amount of time walking to get tools and parts and indirect materials. ◆ When the plane was disassembled, parts were tossed into boxes that were sent to storage (e.g., an automated storage and retrieval system), and then when the parts were brought out for reassembly, much time was spent sorting through boxes, looking for parts. Parts were often missing because they were "robbed" to work on another plane. ◆ Many planes were being worked on at once, and when they got stuck on one for some reason (e.g., needed key parts), they shifted to work on another. ◆ There was a belief that the planes came in for repair unpredictably and that it was impossible to plan for a stable, leveled amount of work. Value stream mapping revealed a huge amount of waste in the current processes. Future state maps were developed and similar solutions were presented for all the aircraft: ◆ The process of disassembly, inspection, repair, and reassembly needed to be separated into distinct phases. ◆ A flow line needed to be set up with planes at different stations, and specific work done at each station. ◆ The line then needed to be balanced to a takt time. Analysis of actual data showed the arrival of planes was far more stable than previously believed. ◆ Standardized work needed to be developed at each station. ◆ 5S was needed to stabilize the process and reduce much of the non- value-added walking and getting stuff. ◆ A “hospital” position was needed so that if the workers got stuck on one of the planes (e.g., waiting for a long-lead-time part), the plane could be set aside in the hospital and the flow would not stop. THE TOYOTA WAY FIELDBOOK86 ◆ Management needed to be educated in the process and stop the practice of bringing in additional aircraft whenever one arrived. They needed to control the work in process limiting aircraft to the number of stations in the flow lines (discussed later). The work areas were laid out into workstations. There was a technical challenge in moving the plane from station to station. At some point the plane was taken apart and the center barrel and wings were removed, along with the wheels. The F18 was a new aircraft for the base, and they were able to purchase a system that held the plane together on a big fixture on wheels so it could be moved from position to position. This was not the case with the P3, so in its case a decision was made to use a “virtual flow line.” That is, teams of repair persons would come to each aircraft at fixed intervals of time to perform a stage of work. This meant they would have to bring in the tools and materials needed for each phase of the process. Kaizen workshops were used to set up each piece of the overall system. There were 5S workshops to lay out the area, find places for everything, and label standard positions. There were material flow workshops to take parts off the plane and put them into “shadow boxes” or kits, so when they were brought back for reassembly they were organized. Hazardous materials were set out on carts in kits. All the kits and parts and materials were set up on pull systems to be replenished as they were utilized. The slow and complex process of analyzing each procedure in detail to develop standardized work was started so that each station could be aligned with the takt time. The P3 is an older plane soon to be retired. The Navy decided to reduce the available planes in the fleet by over 50, from 200 to 150, yet wanted a constant number in the field (about 120). This required less time tied up in maintenance to keep the planes needed in the fleet available. Due to some fuel tank and structural integrity problems associated with aging, additional stress testing and repair requirements were added, increasing the pressure—doing more in less time. In short, from the Navy’s perspective this was a crisis, and from a lean perspective an ideal opportunity to show the value of waste elimination. Repairing these aircraft prior to the additional testing and repair requirements took 247 calendar days. To meet the 120 planes needed in the field at all times required a reduction in turnaround to 173 days, a 30 percent improvement. In April 2004 the lean activities formally started under the direction of an experienced lean consultant. 1 After value stream mapping and Chapter 5. Create Connected Process Flow 87 1 The consultant was Ed Kemmerling, who was later joined by Sam Talerico, both with many years of experience applying lean methods at Ford Motor Company. [...]... accordance with the agreement and then dedicated The space is dedicated just as in the previous example The third element requires a method to control the production to satisfy the agreement (the standard) How is the production controlled? It is controlled the same way visually What is the difference? The only difference is in the agreement of “what the customer wants.” In this case, the quantity is the same,... another Model 2; and the next item on the schedule is Model 3 Since there is an open space between Operation A and Operation B, A has permission to produce the next item on the schedule The rules of pull are still followed in that Operation A would not produce if the space were full The rule states that an operation can complete the part in process if the customer space is full, but will not pass the. .. throughout the day, Toyota used a physical card as the kanban A kanban that has been returned from the customer represents the consumption of material, and as kanbans are accumulated at the supplier, they are a visual representation of the WIP agreement The kanbans represent an inverse of the WIP quantity More kanbans at the supplier equals less WIP at the customer We do not intend to completely explain the. .. (see Figure 5-10) All the seats were completely designed, including heated, not heated, bench, captain’s chairs, power, and so on Based on the designs, parts were ordered The parts arrived at various times from suppliers The prototype group waited as long as they could for all the parts they needed and then started building whatever seats they could with the parts they had Then they released lots of... “Always satisfy the customer,” or put another way, “Never short the customer.” This is Rule 1 Always follow Rule 1! (Note the paradox of this statement While it is the goal to always satisfy the customer we Chapter 5 Create Connected Process Flow 1 03 have stated previously that a process that never stops a customer operation is likely to have excessive waste built in.) Is the agreement defined? The first... Executive, 13: 4, November 1999, 36 -47 2 Copyright © 2006 by The McGraw-Hill Companies, Inc Click here for terms of use 112 THE TOYOTA WAY FIELDBOOK you can begin the creative progression of continuous improvement As we’ve shown in the previous chapters, the work of developing standards begins early in a lean implementation and is a common thread throughout the development of lean operations The creation... empty) If Operation B completes the part before the signal space for Operation C is empty, the operator will hold it in the workstation and wait for a signal from Operation C to replenish the space In a high model-mix environment, the level of flexibility is limited by the lead time from the point-of-schedule introduction to the completion of the product This is dictated by the number of operations that... system there is no defined agreement between the supplier and the customer regarding the quantity of work to be supplied and when The supplier works at his own pace and completes work according to his own schedule This material is then delivered to the customer whether the customer requested it or not Locations are not defined and dedicated, and material is placed where there is an opening Since there... managers often state, “They know what they’re supposed to do, but we can’t get them to do it.” Many managers make the mistake of blaming the operator for not following the rules, and in fact the operator is compensating for a problem that needs to be corrected Stop, and “stand in the circle” to identify what the operator is compensating for There are generally two reasons for this condition The first thing... shows the strategies that guide the creation of connected process flow, as well as the primary and secondary lean tools often utilized The same tools that were used during the stability phase may be used (continually refining the result), as well as additional tools, depending on the circumstances of the operation The objectives and strategies, however, always apply Single-Piece Flow This is the epitome . isolated Throughput Time (Days) 0 5 10 15 20 25 Nov-02 Dec-02 Jan- 03 Feb- 03 Mar- 03 Apr- 03 May- 03 Jun- 03 Jul- 03 Aug- 03 Sep- 03 Oct- 03 Nov- 03 Dec- 03 Jan-04 Feb-04 Mar-04 Apr-04 May-04 Jun-04 Jul-04 Days Chapter. that the agreement is defined based on the schedule. All processes are working to the “same” schedule. In fact they may be on the same schedule, but they are not on the same page. THE TOYOTA WAY. long-lead-time part), the plane could be set aside in the hospital and the flow would not stop. THE TOYOTA WAY FIELDBOOK8 6 ◆ Management needed to be educated in the process and stop the practice of