- Is Standardization Coercive?
- Standardized Work or Work Standards?
- Objective of Standardization
- Strategies to Establish Standardized Processes and Procedures
- Types of Standardization
- Quality, Safety, and Environmental Standards
- Standard Specifications
- Standard Procedures
- Myths of Standardized Work
- Standardized Work
- Standardized Work Documents
- Some Challenges of Developing Standardized Work
- Auditing the Standardized Work
- Standardized Work as a Baseline for Continuous Improvement
- Takt Time as a Design Parameter
- Importance of Visual Controls
- Standardization Is a Waste Elimination Tool
Is Standardization Coercive?
Standardized work evokes images of industrial engineers with stopwatches terrorizing the workforce by squeezing out every second of productivity. It brings to mind a highly regimented existence in which “big brother” is watching to make sure you follow each and every rule. It is bureaucracy run rampant where human will and creativity are wiped out and people become automatons.
But there are other views of standardization. Masaki Imai in his seminal work says he learned that there can be no kaizen without standardization.1 Standardization is actually the starting point for continuous improvement. As discussed in The Toyota Way, Paul Adler took an organizational theory perspective and looked in depth at the Toyota Production System (TPS).
He discovered that much of what had been written on the unintended negative consequences of bureaucracy were avoided by Toyota, which used the standardization of bureaucracy along with employee empowerment to create an “enabling” bureaucracy. We think of bureaucracy as “coercive”—limiting the ability of people to be flexible and improve. Yet Toyota’s enabling bureaucracy has the opposite effect—allowing for flexibility and true innovation that makes a lasting impact.
The establishment of standardized processes and procedures is the greatest key to creating consistent performance. It is only when the process is stable that 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 of standardized processes is based on defining, clarifying (making visual), and consistently utilizing the methods that will ensure the best possible results.
As such, standardization is not applied as a stand-alone element at specific intervals. Rather, it is part of the ongoing activity of identifying problems, establishing effective methods, and defining the way those methods are to be performed. And it is driven by people, not done to people. People doing the work understand it in sufficient detail to make the biggest contributions to standardization.
We have stated throughout that our objective is to teach the core philosophies and concepts of the Toyota Way. Again, this is not intended to be another “how to” lean tools book. The process Toyota refers to as “standardized work” is so important to the overall production system that one third of Toyota’s internal TPS Handbook is devoted to it.3 Quite simply, standardized work and other work standards are the baseline for continuous improvement.
This is another one of those misunderstood points about TPS. Until standards are defined in any operation, it is not possible to truly make improvements. Think about it this way: If a process is not standardized (it is random and chaotic), and improvements are made, what was improved? Did you improve the randomness? Or did you just add one more version of how the work can be done to further increase the chaos? If a person creatively improves the work but it does not become a standard, then the work is only improved while that particular person is doing it. And nobody else will build on that improvement. If the improvement was to create standardization, then you created a platform from which to enable teams to continuously improve the process. You have the foundation for a learning organization.
Unfortunately, it is not uncommon in our work with companies that are implementing lean processes to be asked to “do standardized work” as if it were a stand-alone tool to be applied according to an implementation schedule (“Our road map says we need to do standardized work now”). One such request went something like this: “We need to get standardized work done by October.” To which was replied: “We can certainly do that, but standardized work is a tool, and like any tool, it has specific uses and is used to accomplish specific objectives.”
In one company, standardized work was behind schedule according to the lean implementation plan. The solution: Hire a schoolteacher over the summer to write out the standardized work for all jobs. The result: very nice looking, posted standardized work that no one followed. If you just want to fill out sheets, laminate and hang them in the work area and create no real value, you can do that. If you are interested in using standardized work to reduce waste, define a better work process, and continually improve process, you can do that as well. Which would you prefer?
We are introducing standardization as one of the “phases,” but in reality this concept is applied throughout the journey and is the one concept that should be considered during the development of any work method. As with most elements of TPS, the concept is key, and an understanding of the concept will improve your ability to apply it. Standardization is not a set of documents that are prepared and carefully controlled. It is a means of creating the most consistent performance possible. It is the basis for process stability. Without it, tools like Six Sigma and other advanced variation reduction methods are worthless.
Standardized Work or Work Standards?
Standardization may be the most misunderstood and most often misapplied of all lean concepts. The root of this problem may extend back as far as the early studies by Frederic Taylor and the desire to maximize profits by carefully defining the work elements and holding employees accountable for achieving them. Work standards have a long embattled history in some industries (particularly the automotive industry), and the objective has been to “beat up” employees for nonperformance.
This has created certain recognizable “games” and ways to beat the system.Most of all it’s created an antagonistic relationship between workers and management, instead of a mutual objective of creating the best possible product for the customer, we find an environment of one-upsmanship. This is a game in which management more carefully defines the work method in order to determine costing standards and to ensure that each employee is putting forth the required effort.
Employees know this game and intentionally change work methods when observed, in order to create artificially low requirements that are easy to achieve. Management then utilizes the “standards” to make manufacturing decisions based on “earned hours” or “absorption” or a similar measure based on the work standards, with the goal of making sure that manufacturing employees “earn” the correct amount of hours for the amount of product produced. If this occurs, the overhead cost of employees is “absorbed,” the correct standard cost is achieved (or exceeded), and the desired profit is theoretically generated.
Employees view work standards as a measure of how “hard” they have to work, or the amount of effort that will be exerted. In addition, they inherently understand that everyone has different capabilities and the system is based on the lowest capability. In this way low performers can be successful and high performers can exceed performance, or if they choose, work faster to create extra “free time.”
In this model, a work standard is established based on the wrong objective. It is based on creating a cost standard rather than creating the best possible work method, with the least amount of waste, producing the best quality product at the lowest cost. This work standard is then used as either a club to beat employees for nonperformance or as a carrot to entice them to exceed the standard (as in payfor-performance derivatives of this method).
Since these ideas are so ingrained in the minds of management and employees, the establishment of standardized work as defined by Toyota can be one of the greatest challenges during lean implementation. It is extremely difficult for all parties to let go of the current process because everyone has learned how to survive or thrive under that system. Managers fear that the Toyota Way will allow employees to run amuck, deciding their own work methods and therefore not working hard enough. They also fear the loss of a measurement system that they have learned how to manipulate and control to achieve success. Everyone is familiar with this conversation:
Production manager (to supervisor): “The earned hours are down in your department. What are you going to do to get them back up?”
Supervisor: “We had some tough jobs coming through the shop, which hurt our hours. We are going to come in Saturday to work on some of the easy jobs to get them out. That will help.”
Production Manager: “Okay. I have to report to the plant manager on this, so I’m going to tell him that the product mix has not been good and that it should get better after this week.”
Clearly this is a misguided focus on the measurement and not a focus on creating a truly efficient process that will consistently deliver performance results. Notice that the supervisor will work on “easy jobs” to get the numbers up. A part is a part according to the numbers. But are the easy jobs the parts that the customer wants? That seems secondary. It is a shame how much time and effort is wasted trying to “make the numbers” rather than trying to create the best possible process. Management is caught in a vicious cycle and can’t seem to break free because their own performance is measured on their ability to deliver the desired numbers.
Objective of Standardization
The traditional manufacturing model has an initial focus on achieving the lowest possible unit cost and then creating work method standards to achieve the cost objective (Figure 6-1). This model considers individual efforts and “cost per piece,” while the Toyota Way seeks to maximize the entire system and considers “total cost” via waste reduction as the primary indicator of success. The traditional method utilizes time and motion studies to determine the most “efficient” work procedure, and a “standard” time is allotted for the designated task. Typically, an operator is observed and the work elements and times are recorded. This is not necessarily the best method; it is just the method that the operator happens to be using when being observed. This process creates a “false standard” that is then utilized to determine “efficiency.”
Figure 6-1. Traditional unit-cost-focused manufacturing
The Toyota Way seeks the same objective in terms of low cost; however, the primary focus is on reducing the waste within the system (Figure 6-2). As such, Toyota considers the development of standardization to be a baseline for continuous improvement, meaning that future results are expected to improve from the standard. The traditional method considers standards as the objective to achieve, as if the standard were the ultimate level of performance, which precludes the possibility of improvement. This fundamental difference in thinking is the basis for many of the paradoxical elements of a lean system. The objectives are the same; namely, to provide the highest quality product at the lowest possible cost within the shortest time possible; however, the thought process to achieve these results is opposite the one used by mass manufacturers for the past 100 years. And the mass production approach limits the ability to achieve these objectives.
Figure 6-2. Lean waste reduction results in lower total cost, improved delivery, and quality
The lean waste reduction model begins with a philosophy focused on waste reduction. In most organizations there is a substantial amount of waste that is caused by random activities and inconsistent methods. To eliminate waste, we must reduce or eliminate variation within processes. Variation is the antithesis of standardization.
By definition, variation implies the inability to standardize. As discussed in Create Initial Process Stability and Create Connected Process Flow, the isolation of variation is a key to the establishment of standardized work methods and procedures. This will also establish a baseline and the ability to distinguish the (normal) standard method from (abnormal) nonstandard methods. Visual control methods and other lean tools are utilized to provide instant recognition of performance, and adjustments can be made in real time so performance objectives are achieved consistently.
Strategies to Establish Standardized Processes and Procedures
The primary tools in establishing standardized processes and procedures are standardized work documents and many of the lean tools that were used during the previous phases are also used in the development of workplace standards (Table 6-1).
Traditional policies and procedures often work against standardization. Consider attendance policies. With standardized work processes it’s mandatory that every work position be filled at all times. This means that when a person is absent, he or she must be replaced in order for the process to function correctly. It can’t function correctly when there are no contingencies as to how the position will be filled in the event of absence. Yet, in traditional systems absenteeism is rarely a top management focus and supervisors scramble around to fill positions due to absences each day without a standardized approach.
Create a Structure to Support Standardized Work Toyota has a system of group leaders and team leaders. The team leaders are hourly and are responsible for supporting about five to seven associates. They audit the work procedures of employees to detect deviations from standard work (see Chapter 11 here and page 191 of The Toyota Way) and provide the necessary structure to fill in for absences. They are often involved in developing stan- dard work for new models. They are a key to turning standard work from good looking wall hangings to true tools for continuous improvement. Interestingly, the team leader role is exactly what is missing in most companies.
|Strategies||Primary Lean Tools||Secondary Lean Tools|
|• Create a repeatable work method that becomes the foundation for kaizen
• Establish clearly defined expectations
• Develop processes to insure consistency for all elements of the work
• Labor needs
• Work Methods
|• Standardized work documents
• Standardized work chart
• Production capacity sheet
• Work Combination Table
|• Visual controls
• Policies and procedures
• Boundary samples
• Process check sheets
• Job Instruction Training
Table 6-1. Stategies and Tools for Standardized Processes and Procedures
Types of Standardization
There’s often confusion regarding the establishment of the process Toyota broadly refers to as “standardized work.” This seemingly simple method is deceivingly difficult for other companies to mimic. Since the intent of standardized work is different from the traditional process of creating work standards, it is not possible to make a direct correlation. Companies have methods they call “standards,” but it’s not what Toyota means by using the term “standardized work” to define the method used to perform work tasks with the least amount of waste. In fact there are many types of standards that are consolidated into one overriding method used to dictate the best work procedure. Within Toyota, the primary tool that dictates the work method is standardized work, which defines who, what, when, and where work is to be performed.
Figure 6-3 uses a house model to show the relationship of the different types of standards and how they support the primary objectives of providing a defined method to perform the work with the least waste, as well as to provide detailed information to the employees about developing the highest knowledge and skill level possible.
Notice that each standard serves a separate function, but they all must be incorporated into the standardized work method. This does not mean that the standardized work document includes all the standards. It simply includes the work steps that will produce the desired result (achievement of other standards). The details of other standards are included in operator instruction and training, as can be seen in Figure 6-4.
Quality, Safety, and Environmental Standards
Quality standards are based on customer expectations that have to do with items such as fit and finish, and establish the cosmetic requirements of a product. Examples include:
- General appearance
- Color matching
- Deformities, abnormalities (rounded edges, depressions, )
- Gaps or tolerances
- Surface quality
- Limitations of defect size and quantity
TIP: Store Your Valuables for Safekeeping
Boundary samples are very important items and must be treated with a degree of care. They should be stored in a safe place, and possibly locked, with access limited to a supervisor. They are not used frequently once operators develop judgment ability. Boundary samples must be signed and dated by the authorized quality representative, and it is manufacturing’s responsibility to request and maintain them. Treat them like an investment!
Quality standards are generally incorporated into operator instruction sheets for detailed description of what type of condition to look for, where specifically to look, and how to make a judgment determination of good/no good. Operations people use the feedback from quality audits to determine the primary conditions to look for, as well as the most common areas of occurrence. This provides the ability to create a specific inspection method that can be incorporated into the work to ensure that key areas are checked for the most common problems. It promotes a higher level of quality at the source. The inspection step is not spelled out in detail in the standardized work documents but is shown as a single element (inspect the part).
Written quality standards that require a visual disposition of a product are subject to interpretation and are somewhat subjective. For example, the interpretation of “acceptable surface appearance” depends on the subjective opinion of “acceptable.” In these situations it is essential that the quality department provide tangible examples of the desired quality levels. These are referred to as “boundary samples,” and they represent the limit of acceptability for a particular issue.
The company generally establishes safety and environmental standards to follow state and federal regulations. These standards are usually created by the specific engineering departments and are not modifiable by other employees or management without approval from that engineering department. However, these requirements are provided to the employees who will develop standardized work methods to achieve the necessary operator and environmental safety. The work team or management for that area may develop safety requirements specific to a particular job. Examples would include specific injury risk, such as lacerations, or equipment pinch points. These potential safety concerns are noted by the safety cross on the standardized work document.
These specifications provide the technical information on the correct operation of equipment and certain process specifications required for producing a product. Examples include:
- Dimensions and tolerances
- Processing method (welding method, finishing method, )
- Equipment operation parameters (time, temperature, pressure, )
- Equipment operation sequence
- Corrective action information
Standard specifications are not detailed on the standardized work documents. They are included in the operator instruction documents only if not previously specified on other documents such as blueprints (there is no need to document standards previously specified).
Equipment operation parameters are used to develop equipment verification processes that become a task assignment for a specific individual and a routine standardized process. In Toyota’s case, the team leader most often does this. The equipment verification process is completed at various intervals during the day to ensure correct operating conditions. In many cases it is completed prior to the start of the shift, and again during the shift, depending on the critical nature of the equipment. The intent of the “preshift” verification is to ensure that all process parameters are in the correct operating range and that equipment is operational and ready for production.
Corrective action information is handled similarly to the specifications for equipment verification. It provides detailed step-by-step actions to be taken in the event of equipment failure or process problems and includes contingency plans such as alternative equipment that may be used or the manual operation of equipment.
Standard specifications are typically provided by industrial or manufacturing engineering, and manufacturing uses the information to develop standard procedures and operator instruction sheets, as necessary. Some companies confuse these specifications with standard work for the operator, but the standard specifications do not tell the operator anything about work steps, timing, or how to optimally perform the job.
These are developed by the manufacturing group and are used to define operating rules. The procedures may be necessitated by the other sources of standards or may be the sole responsibility of manufacturing. Examples include:
- Standard work in process
- Kanban rules and parameters (inventory levels, number of cards, )
- Material flow routes within the facility
- Defined 5S requirements
- Production result boards
- Color coding
These standard procedures should be visually defined in the work area and, thus, are self-explanatory and need not be documented in the standard work. For example, a kanban card includes all the information related to its use, and the standards are defined within the content of the card. Likewise, the defined agreements between operations will be visually apparent in the work area. Note that the items mentioned here are likely to change often as process improvements are made. It would become a paperwork nightmare to attempt to document these standards and constantly update them as conditions in the work area change. Develop a visual system to convey the standards, and maintain the visual awareness.
Myths of Standardized Work
There are many myths regarding standardized work in the world outside of Toyota. It is frustrating to see the amount of time and effort wasted by companies that fall into one or more of these myth traps and attempt to create a system based on them. We will attempt to debunk as many of these myths as possible in the hope that your efforts can be directed effectively toward the goal of process improvement.
Myth 1: If we have standardized work, anyone can learn everything about the job by looking at the documents.
We’re not sure how this myth originated, but it is probably caused by Toyota’s description of standardized work. During Toyota plant tours, standardized work is touted as the process used by operators to define their work method, and of course it is documented and posted. Perhaps this is misinterpreted as a fully detailed description of the work and associated standards. Anyone who has read the sheets would see that the work description explains the work elements in basic terms—not nearly enough information to read and fully understand the job.
Within Toyota, the job instruction method (explained in Chapter 11) is used to transfer complete knowledge of a job to a team member. This is a lengthy process, since there is much to learn to become an exceptionally qualified associate. Anyone who believes that a job is simple enough to distill down to a few sheets of paper underestimates the competency level necessary of their employees. We have never been in any work environment where the work is so simple that “everything you need to know” is on a few sheets of paper.
Myth 2: If we have standardized work, we can bring anyone off the street and train them to do the job in a few minutes.
Refer to Myth 1. This may be possible for a small portion of a job or for a specific task, but to become a “complete” employee with a full understanding of the work takes considerable effort. We often hear this myth in conjunction with a reference to bringing “monkeys” off the street that could be trained quickly.
Not only does this reference display a complete lack of respect for employees and their abilities, it mistakenly assumes the simplicity of the work done by employees. This mind-set will need to be adjusted in order to create the right culture for developing a lean operation.
Myth 3: We can incorporate all details of the work and standards into the standardized work sheet.
This is a classic case of trying to make a Swiss army knife out of a specific tool. Standardized work is not an all-inclusive tool. It is specifically used as a tool to identify and eliminate waste. After the most effective work method is established, the documented process is used as a visual reference to ensure adherence to the standard.
Myth 4: We will post the document so operators can look at the sheet each day to remember how to do the job.
This is a complete misunderstanding of the purpose of a visual standard. In this case, after the operator has been trained—a carefully controlled process that ensures the employee’s capability before he or she is fully released to the job— and after the first few hundred repetitions, a reminder of the proper method is not necessary. The visual reference is utilized by management for adherence to the standard, which we’ll discuss later when we describe “auditing the standardized work.”
Myth 5: Employees develop their own standardized work.
This myth is partially true. Toyota does not want individual employees to “own” their standardized work, and uses job rotation so no one employee owns any one job. The initial standard work is developed by engineers working with representative operators who are part of a “pilot team,” and this team assists in the launch of the next new model. Group leaders and team leaders then have responsibility for training employees on the standard work and soliciting their input. Once the process is operating at some level of stability, employees are challenged to develop better methods, but the methods are always reviewed by others, including management. So it is the work team with their team leader and group leader that collectively “own” the tasks to be accomplished.
This myth is often combined with a misguided attempt to institute “employee empowerment,” whereby employees are free to develop their own work methods. It’s this notion that creates fear in the hearts of managers who envision employees creating work that is inefficient and who worry that employees will take advantage of the situation.
Nothing could be further from the truth. If everyone is in agreement that the objective is to create a work method that meets the needs of the customer with the least amount of waste possible, it does not mean that employees have free will to create the work any way they would like. They still have to follow specific rules and guidelines. It is analogous to a sports team. Players at specific positions know their jobs in detail, but the coach does not simply say to players, “Do your own thing—you are empowered.”
The coach has specific ideas about the team’s strategy and how specific individuals need to fulfill their roles. On the other hand, a coach who simply dictates how each player should play generally ends up with a player revolt and also does not capitalize on the unique talents and knowledge of each player. Similarly at Toyota, the work methods are not created in a vacuum. Everyone is looking at the work with the same intent. There are many possible alternatives. The idea is to find a method that is better than the current one. (Note that "better" is not subjective. It must be quantifiable and measurable.) Management has the responsibility to set the objectives for the employees and to provide the tools and resources necessary to achieve them. These objectives are most realistic if management has a deep understanding of the process, and of the lean philosophy, and is acting as an effective coach.
Myth 6: If we have standardized work, operators will do the job properly and will not deviate from the standard.
This may be the most preposterous myth. Defining work and documenting it on paper is still a great distance from good performance. There is nothing in standardized work that will prevent deviation by the operator except the visual awareness of others. To ensure compliance to the standard, it’s necessary to remove options from the work area and to remove the “clouds.” If any deviation from standard is immediately recognizable, and there is a negative consequence, the standard will be followed.
At Toyota work is so carefully defined and requirements for performance so stringent that a deviation from the standard will generally produce immediate recognition. Suppose an operator elects to perform a task out of sequence, and as a result the time required increases. This operator would likely exceed the takt time and need to “stop the line” using the andon cord. If this happened several times it would attract immediate attention, and when investigating the condition, the team leader or supervisor would verify adherence to the standard.
Toyota says that the purpose of standardized work is as a “foundation for kaizen.” If the work is not standardized and it is different each time, there is “no basis for evaluation,” meaning no reference point from which to compare. Many companies are dismayed to discover that sometime after “improvements” are made, the work has returned to the “old way” and there has been no sustained improvement. Doing kaizen before standardizing would be analogous to building a house on quicksand. You may get it built, but it will be sinking fast!
You may ask, “If standardized work is the foundation for continuous improvement, why don’t we do it first?” This is a good question. Toyota points out that there are some prerequisites to developing standardized work. They are typically dealt with during the stability phase, and bear repeating here in case you’re tempted to skip the appetizer and head to the main course. Putting standardized work ahead of stability will surely create a condition similar to a dog chasing its tail—you will go round and round but never get the result you want.
Prerequisites of Standardized Work
A degree of stability is needed in each of the three areas listed below before moving on to standardized work. Unfortunately, there are no definitive measures that say, “Now you are ready for standardized work.” The best advice we can give is that if you feel like the dog chasing its tail, the process is not stabilized enough for standardized work.
- The work task must be If the work is described in “If . . . then” terms, it will not be possible to standardize. For example, if the task is described by saying, “If A happens, then do B, but if C happens, do D,” and so on, it is not possible to standardize unless these are just a few very simple rules.
- The line and equipment must be reliable, and downtime should be It is not possible to standardize if the work is constantly interrupted and the worker is sidetracked.
- Quality issues must be minimal. The product must have minimal defects and be consistent in its key If the worker is constantly correcting defects or struggling with the effects of poor product uniformity— such as size variation that affects the fit of the part, and thus the time required—it is not possible to see the true picture of the work.
A frequent mistake when implementing an “improvement” to the work is to leave an operator with a new process and with- draw support too soon, or worse—not to be present when the new process is tried for the first time! The operator feels dumped on, is not confident in what to do with the new procedure, and will view “process improvements” as negative, stressful events.
Standardized Work Documents
There are three primary documents used for developing standardized work, and many other related or supporting documents. It is not the purpose of this book to go in to detail on how to use each of these tools but it is worth saying a bit about each of the following:
- Standardized Work Chart
- Standardized Work Combination Table
- Production Capacity Sheet
Standardized Work Chart
Originally the document that Toyota used for the Standardized Work Chart was primarily a diagram of the work area and worker flow. There was no verbal description of the work method and no element times associated with each step. The detailed element times were a separate document, such as the Standardized Work Combination Table. Somewhere along the line in many operations the Standardized Work Chart and the Standardized Work Combination Table were blended into one simplified document that is often referred to (outside of Toyota at least) as a “Standardized Work Sheet,” or “Standardized Work Chart.”
The Standardized Work Sheet is used initially as a tool to identify and eliminate waste. After improvements are made, the new method becomes the baseline for improvement. Then it is posted in the work area as a method of visual control for management to verify adherence to the standard.
As with any tool, its use is dependent upon the circumstances. What is the skill of the user? What condition is being corrected? Do not worry about trying to achieve a perfect result or using the sheet “correctly.” During the initial application of standardized work in a process, the first step is to create a baseline for improvement. The steps of the process are:
- Record the sequence of the job (the work steps)
- Diagram the work
- Identify waste
- Determine improvements needed to achieve desired results (meeting the takt time is an objective that is explained below)
- Incorporate material usage and flow (standard in-process stock)
- Document improved method
Figure 6-5, below, provides an example of a Standardized Work Sheet. The main elements are the work sequence and the diagram of the work movement. Once the steps and diagram of the work flow are completed we ask the question, “What do you see?” Look at the diagram and describe your initial impression.
Figure 6-5. Standardized Work Sheet
Your initial impression is of the waste! If we ask the question regarding the job depicted in the figure we might get the answers: “It is a mess,” and “Look at the long distance between operations,” or “The operator has to crisscross his work pattern.” These are observations of the waste. Once the waste is understood we can ask: “Is there a better method?”
As you progress through the improvement cycle your use of the Standardized Work Chart will change. The initial effort to achieve standardization and eliminate waste within a single operation shifts to creating operations that are aligned and balanced with other operations in the flow. This alignment is achieved by designing jobs that are aligned to a common pace known as takt time (explained below).
TIP: Focus on the Work, Not the Operator
One advantage of documenting the work flow and showing it to operators is that it removes the “fault” for a poor method from the operator. If you see waste and point it out to operators, they will likely explain why it is necessary (defending the method, which they own). If you diagram the work and show operators the diagram, they are likely to respond, “Look at the poor work pattern. We should change that!”
Standardized Work Combination Table
As the name implies, this table (also called the Standardized Work Combination Sheet) is used for analyzing jobs that have combined work. The intent is to show the relationship in terms of time of two or more activities that occur simultaneously. It is used primarily for operations that have a combination of manual operations and automatic equipment, but it can also be used for operations where two or more operators work together on the same product at the same time.
For example, a good application for this tool would be if an operator loads a robotic welding station and pushes the start button, and the robot welds while the operator unloads and loads another station. We have seen many people attempt to use the Standardized Work Combination Table for all jobs, but using it to analyze a single operator who does not utilize automatic equipment is a waste of time and effort. You will not learn anything from this analysis except how to fill out the form.
Figure 6-5, above, depicts an operation with an automatic cycle robot. The shortcoming of using a simple Standardized Work Sheet analysis in this case is that it does not show what happens after the robot cycle is started. There will likely be the waste of waiting by the operator. The operator may perform miscellaneous tasks to “keep busy,” such as getting the next parts ready or “organizing” the work area (we observed one operator neatly restacking every part in the bin, which looked nice but was of no value). It is not clear what the cycle time of the robot is. The Standardized Work Combination Table (Figure 6-6) is useful for this situation.
TIP: The Operator Is Your Most Important Resource
The Toyota Way philosophy is that the operator, not the machine, is the most important asset. The machine serves the person, not the other way around. Toyota believes that it is disrespectful to the individual to waste his or her value by waiting for a machine to complete its cycle. The Standardized Work Combination Table is used to gain an understanding of the man/machine relationship and to effectively utilize the human asset.
Figure 6-6 shows the same job depicted on a Standardized Work Combination Table. Read it by following the work elements one by one from left to right, and you can see where in the cycle the operator walks to perform the next work element. In this example the operator picks up Bracket A in one second, walks to the machine in two seconds, loads Bracket A in six seconds, walks to get the next part in two seconds, and so on. By Step 11 all of the parts are loaded into the robotic welder, and you see by the dotted line that the machine cycles for 23 seconds.
Figure 6-6. Standardized Work Combination Table with one robot
This is a fairly simple job in terms of the operator-machine interface. More complex jobs may have an operator who moves within a cell and operates three or four machines. Like the Standardized Work Chart, the Standardized Work Combination Table converts the work into a visual format so the work/walk/wait time relationships can clearly be seen (the waiting time on this job should be the first improvement target!). The waiting time occurs after the operator starts the robot cycle. This time should be utilized for additional value-adding activity.
Figure 6-7, below, shows the same job with the addition of a secondary task by adding loading and unloading of a second automatic operation. Notice that the operation time “wraps around,” meaning the machine operates beyond the takt time relative to the start time of the operation. The important thing to note is that the second robot completes its cycle before the operator is ready to return to reload it (the robots have an automatic unload feature, which is common in Toyota). In Toyota’s view, it is acceptable to allow a machine to wait for the operator, but it is not acceptable to allow the operator to wait for the machine. Remember, the operator comes first.
Figure 6-7. Standardized Work Combination Table with two robots
Production Capacity Sheet
The Production Capacity Sheet (not shown here) indicates the capacity of machinery in the process. You must consider the cycle time of the equipment, that is, how long it takes to process each piece, but also factor in planned downtime during tool changes and changeover times. It is most applicable to machining operations that involve tooling wear and tool changes, but applies to operations such as injection molding and stamping, where changeover times must be considered. It is a useful tool for identifying bottleneck operations.
The document used is very similar to capacity planning processes used by most manufacturing engineers to specify equipment for purchase. The primary purpose is to determine if the machinery has capacity for the production requirement. Calculations are based on the available run time, the cycle time per piece, and time lost due to tool changes or other changeover requirements.
Some Challenges of Developing Standardized Work
Aside from an attempt to develop standardized work based on the myths mentioned earlier, other challenges include attempts to standardize an entire “job,” versus task elements of the job, and attempting to standardize a task that has variation built in. Much of the work we see in companies today includes a variety of tasks that are performed by a single individual.
For example, an employee may have a task to build a certain product. In addition he or she will also retrieve the materials necessary and deliver the finished goods to the next operation. The task of building the product is fairly consistent and easy enough to document, but what about the other tasks? They occur randomly, or once every so many cycles. How would you weave these two distinctly different tasks together into one Standardized Work Sheet? The answer is that generally you don’t. The work elements needed to build the product constitute the primary task (and the value-adding operation), and it should be standardized creating the most efficient, repeatable method. Within Toyota, operators do not typically retrieve their own materials nor transport finished product because these activities take away from the value-adding activities. The transportation of materials would be standardized for the person responsible for them, such as a material handler.
In Chapters 4 and 5 we discussed the need to isolate variation so that standardization may be achieved. The following case example illustrates the challenge of standardizing a task with built-in variation. In these cases, before the task can be standardized the variation must be separated or isolated from the remaining portion, which can then be standardized.
Case Example: One Job, Three Different Tasks
The “job” in this case example is to operate two automatic screw machines, which cut and machine long bars of steel into discrete metal parts. The operator’s work includes three distinctly different tasks. The variation inherent in the three tasks makes the job nearly impossible to standardize.
The first task is to perform in-station quality checks and serve the machine (removing metal chips and moving finished product). The operator is required to perform a specific number of part inspections each hour. The inspections are repeatable in nature, and the task is repeated within a one-hour time frame (a standard cycle time).
The second task involves loading raw material as needed. This task is also repeatable in nature, but the cycle time varies, based on the part being produced and the cycle time of each part produced. The time variation is between one and two hours.
The third task is to set up and change tooling when worn and between product changes. This portion of the job is not repeatable within several hours, and the frequency of this event is highly variable.
The tasks range from fairly repeatable and consistent to very variable and inconsistent. When blended into one job, it is not possible to determine a repeatable pattern that can be standardized. To complicate matters, each operator is responsible for two machines. If one machine is in setup and the other needs material, the machine in setup will wait. If both machines are in setup simultaneously, one machine will wait for attention. In many cases this lost time exceeded several days. If both machines were operating normally, the first task was not enough to fully occupy the operators’ time and they had considerable waiting time. This scenario created waiting time for both the operator and the machine.
To isolate variation, the work tasks were reassigned. The first task was assigned to one person who was now responsible for servicing 10 machines and performing the quality checks. The loading of material was assigned to one operator who was responsible for 10 machines, and the setup responsibility was assigned to two people for all 10 machines. This reassignment “freed up” an operator, and the team leader role was created to provide additional support to the line.
The reassignment also provided additional advantages, such as two people working simultaneously on setup activities, thus reducing the overall setup times. This reduction facilitated the reduction of batch sizes, increased the run frequency, and reduced the overall inventory. The team leader position ensured that each position would be filled every day and the output would be consistent. Andon signals were added to the machines to notify the material feeder before the machine ran out. The andon also included notification of impending setup and tool changes. These signals allowed the operators to prepare for upcoming tasks, verifying the readiness of tools and material before the actual need. These changes increased the overall output of the operation by 30 percent.
Is Standardized Work an ISO-Controlled Operator Instruction?
Many companies today have pursued ISO certification. As organizations struggle with defining ISO requirements, this question will undoubtedly be raised when we begin to use standardized work: “Is standardized work a controlled document per the ISO requirement?” While we are not ISO experts, we have seen the result as companies struggle with the paperwork nightmare often associated with ISO. Many companies opt to refrain from posting any documents out of fear of getting “dinged” on an ISO audit or because every change to the process will require a laborious effort to update the paperwork. One company we observed removes all standardized work documents prior to an ISO audit and replaces them afterward (to appease the lean auditors). Whether standardized work is in fact a controlled document per ISO requirements depends upon interpretation.
Remember that standardized work is used as an analysis tool and establishes a baseline for continuous improvement. It is not an operator instruction, and it is not provided to the operator as a training tool (see myths, above). Management uses it to audit and verify the general steps of the job, and as such, it should be up to date. If you do make standardized work a controlled document, create a simple system that allows it to be “a living document” and makes it easy to change (e.g., one level approval process).
Auditing the Standardized Work
As mentioned, it’s a common myth that standardized work is posted so the operator can refer to it while doing the job. At Toyota operations, standardized work faces out toward the aisle, where the operator cannot easily see it. It is for the benefit of the team leader and group leader who are responsible for auditing the standard work.
Isn’t auditing a coercive type of management practice that reinforces the view of standardized work as the framework of a rigid bureaucracy? In an adversarial environment, auditing anything is the basis for conflict and tension. But in an environment where the focus is on eliminating waste to better serve the customer, auditing standard work is a way to maintain stability of the process. It is a cooperative venture between management and the worker. Operators often deviate from the standardized work because of a problem (creating a “work around”). Management audits uncover the root problems and ensure that they are corrected quickly and standardized work is re-established.
TIP: Allow Time for Adjustment to the New Method
A change in the work method (standardized work) will require an adjustment period. The body becomes “habituated” and will tend to return to the familiar pattern. For example, if you change from a standard-shift car to an automatic shift, you will reach for the shift lever unconsciously (and it will not be there!). It is necessary to pro- vide continued support as the operator adjusts to the new method.
Two things trigger an audit at Toyota. First, a problem: What caused a defect? What is causing an operator to repeatedly get behind? Often, observing the operator through several cycles compared to the standard work will reveal the source of the problem. Second, it may simply be time for the audit. Toyota has a standard work auditing schedule, much as they have a schedule for preventive maintenance. You don’t need to wait for the machine to break down before you maintain it at Toyota. Similarly, you don’t need to wait for an operator error to audit the standard work.
Auditing allows for the discovery of deviation from the standard method. We often erroneously conclude that the operator is at fault when a deviation occurs. Upon investigation, we may find that the deviation is due to a malfunctioning piece of equipment or a problem with the product. The reason for the audit is to find the cause of the problem and to correct it.
In many Toyota operations there’s a visual system set up for auditing the standard work. Each work group may have a visual board with cards called a kamishibai board (story book). At NUMMI, group leaders check one process each day for compliance to standardized work, watching work cycles. This brings them to each job at least once per month. The cards contain questions they complete on the performance of standardized work and the accuracy of the standardized work document.
Discrepancies are noted and countermeasures described on the card. There is a card slot for every process in a team. The cards are moved to a corresponding adjacent vacant slot once the check has been performed. When a problem is noted, the card is turned with the dark side facing out, indicating that something needs correction. Assistant managers check the boards each day to verify that the checks are being made properly. They randomly select a card from the board, obtain the standardized work and conduct a check of a process with the group leader. There are approximately 90 boards throughout the shop.
Now compare this to many companies that “have” standard work. A standard work sheet is filled out and posted, perhaps by an industrial engineer. If they get really fancy, it may have photos of the work steps. It is posted so the operator can see it. No one does anything with it, but it looks good to visitors, who can say, “They look lean.”
Standardized Work as a Baseline for Continuous Improvement
After the initial standardization of tasks the real fun begins. We should now ask, “Where is the next level of opportunity?” This is where the answer becomes more complex. We must reconsider our primary objective—to get more valueadded activity with less cost, or in other words, to make more parts with fewer resources. Before running off and making improvements, however, we should first understand what will be done with the gain. It is important to always make improvement based on need, rather than because improvement is possible. Improvement will always be possible!
If you continue to reduce setup time, for example, what will you do with the additional time? Is it important to drive down batch sizes, to increase flexibility, or do you need the volume? Too often we see companies “do setup reduction” and reduce the time significantly, but there is no plan for using the freed up time, and the setup times slowly creep back to the original level. This same phenomenon applies to other “improvements.” When improvements are made, you must change the process so that sustaining the improvements is necessary for continued success. The improved level must become the new standard, and the excess removed. If there is no need to sustain, any gains will not be maintained.
Takt Time as a Design Parameter
Many people get confused about the difference between takt time and cycle time. Takt time is not a tool. It is a concept that is used to design work, and it measures the pace of customer demand. In terms of calculation, it is the available time to produce parts within a specified time interval divided by the number of parts demanded in that time interval. The number you get tells you, for instance, that a part needs to be produced every three minutes to satisfy customer demand. Seem straightforward? Yet takt time is often misunderstood.
And determining it for lines that produce a variety of products with varying demands, becomes a tricky issue. Here’s an example: If the available operation time for one shift is 400 minutes, and the demand for the product is 400 per shift, the time allotted per piece (takt time) is one minute for each part. The cycle time of each operation needs to be one minute or less on average to meet the demand. If the cycle time (actual time to complete the tasks in a single job) is greater than takt, the operation will be a bottleneck and additional time will be necessary to meet the production schedule. If the cycle time is less than takt, there will be overproduction or waiting time. A major challenge that arises is determining the customer demand. In most cases (unless you are a supplier to Toyota) the demand varies significantly. How can takt time be determined when the demand varies? You must understand that takt time is a “reference point” for designing the work, and consider what the effect of an incorrect reference point will be.
The first thing to recognize is that cycle times—the time necessary to complete the task—do not vary significantly if they are standardized. Using our example above, the machine cycle time is 23 seconds and the operator work and walk time is 56 seconds. The combined cycle time is 75 seconds and varies only to the extent that the operator can load the robot faster now and then. This means that the output from this process will be fairly consistent provided there are no losses due to equipment downtime. If the demand varies significantly, what effect does this have on the operation? None. The operation cycle time will not vary more than a few seconds. If demand increases, how will the requirement be met? The operation time can be increased (e.g., using overtime if the demand does not increase too much). The utilization of takt time will not change this reality.
So how do we determine the demand and takt time? Select a demand number that will be sufficiently high enough to meet the need most of the time. For example, suppose the demand varies from 10,000 to 20,000 per month but the average is 16,000 per month. Which number should you choose? It depends on the situation, but generally we advise a higher number. Here’s why. Let’s suppose we use the maximum: 20,000. If we calculate a takt time, we will get a lower number (less time allotted per piece). We compare the takt time to the cycle time to determine the discrepancy. Selecting a higher demand number will create a larger discrepancy. The relevance of the discrepancy is only related to the amount of improvement necessary to achieve the takt rate, and the improvement potential is based on the waste that exists in the operation.
When presented with this dilemma, a Toyota sensei would respond, “No problem,” meaning that the pool of waste is large and the needed improvement can assuredly be made. The only risk of setting a demand level too large is that the amount of effort needed to achieve the takt time will be greater. You do not want to waste effort by falsely inflating the demand number (driving takt down), but it is not a major problem. If a process is improved beyond the actual need, the resources can be reduced or additional sales can be pursued.
The takt time serves as a common “beat” for all operations in the value stream. An operation balance chart is a powerful visual tool for seeing how cycle times compare to takt. In some cases it can be used for answering “What if?” questions about the capability of the process. Figure 6-8 shows an operation balance chart that was used to compare cycle times in a value stream to takt time. In this case the company wanted to increase production in order to meet possible increased demand that was only roughly estimated. They wanted to know how much of a change would be needed to meet a hypothetical takt of 90 seconds per part. We see that two operations are currently over that estimated takt time.
Figure 6-8. Operation balance chart to compare cycle times
If these two operations were improved, how much improvement would be necessary before the next balance “plateau” is reached? Figure 6-9 shows the next plateau. Several other jobs have a cycle time of approximately 60 seconds. Reducing the two jobs to 60 seconds would allow the entire value stream to flow at a rate of one part every 60 seconds. Does that mean we should immediately pursue this goal? In fact if we do this and the takt time based on actual demand is greater than 60 second we will be over producing—the fundamental waste.
After reducing the time it took for the two operations, it was determined that the actual takt rate necessary to meet the demand was 80 seconds. This allowed for “rebalancing” the operations and reducing their total number. In this case, after reducing the time it took to grind and buff, the total amount of work across all operations added to 645 seconds. If we divide 645 seconds of work by the takt of 80 seconds, we get a total of 8 operations at the takt time, compared to the original 12. Thus, we could reduce one-third of the operations by rebalancing to the 80-second takt. If this were manual processes, it would equate to 4 fewer operators (note: these “extra” operators could be used to develop a team leader structure as outlined in Chapter 10). It is interesting to note that if we balanced to the faster takt of 60 seconds, 11 operators would be needed (645/60 = 10.75). Thus, going faster can cost more (provided it was not necessary to go faster).
Use takt time to help make decisions about how the work will be designed and which improvements need to be made to meet the need. If you select a takt time that is too high, you will not meet the production need, which is worse than choosing a number that’s too low and exceeding the need (provided you did not add resources to meet the false need). It is always easier to stop production when the output is too high than it is to get more out if it’s too low. When in doubt, choose a higher demand and a lower takt time.
Figure 6-9. Cycle balance chart showing next level plateau
Importance of Visual Controls
The use of visual controls is the most important step in the process of developing standardization. Unfortunately, it is also the aspect of a lean process that is most often belittled. We frequently hear, “They are just doing 5S.” Perhaps this is due to the examples of visual control most often cited, namely, markings on the floor to indicate the location of trash containers and other items in the work area, which are viewed as “silly” and perhaps insulting to the intelligence of employees. Another example is signs that are used to identify the proper location of items or the type of material stored in a location. Managers and employees often respond with, “We all know what belongs there.” However, when asked to identify specific conditions such as the standard quantity, the minimum or maximum, or the supplying operation, the response is usually less certain.
Figure 6-10 demonstrates that the primary reason for visual control is to define the desired “normal” state (standard), and then to quickly recognize any deviation from that standard. As we have seen, there are many different specifications, procedures, and requirements within every work area. It is virtually impossible for every employee to remember all of these, and a written description of each in a notebook would be impractical for instant recognition.
Figure 6-10. Lack of visual awareness leads to incorrect methods
One common condition is that people believe they “know” the standards, and any visual representation is redundant and unnecessary. Upon closer evaluation it is simple to determine the true awareness of standards. Ask different employees to explain the specific method to be followed. Is it possible for you to determine whether it’s happening as it’s supposed to be? The case example below on paint line loading illustrates that without the ability to quickly and easily verify adherence to standards, the abnormality will not be detected and will continue.
The following case example illustrates what happens when standards are “known” but are not visually displayed.
Case Example: Creating Visual Standards with a Paint Line Loading Pattern
This case example refers to a paint line that has three different color paint booths. The main line branches into three lines to supply all three booths. Given this branching from one main line, it is critical to the flow of product for the correct mix of product color and model to be loaded on the line to prevent overloading any booth and clogging the line.
Observation of the paint line (standing in the circle) revealed that product flow to one or two paint booths was often blocked by an overload at the other. This caused the entire loading process to stop, and the total line stoppage time was substantiated by the system data. This issue was especially critical since the paint system was the constraint operation for the entire facility (it is the only operation in the plant through which all product passes), and the system was above maximum capacity.
The paint department manager and the loading employees agreed that the product had to be mixed properly on the line and even agreed on what the mix was supposed to be. Each person noted, however, that “they” don’t always follow the rules. (The mysterious “they.” Who are “they”?) A closer review of the agreed-upon mix revealed that the desired method (not a defined standard yet) was vague and general. It included descriptions such as, “No more than two of this type per hour,” and “This product is supposed to follow one of these three models,” and “No more than six of this color per hour.” It was clear that trying to memorize this proposed sequence would be nearly impossible (there were many variables). If it were possible to memorize, it’s likely that the only people who could accomplish that would be those who do it every day. This is a problem if a regular employee is absent, and it’s impossible for anyone outside of that group to easily understand.
A team of three people who knew the process was assembled to develop a loading pattern that would meet all of the required constraints regarding color and model mix. It took this team nearly three days to finally determine a pattern that met all parameters and conditions. With this level of complexity, imagine the difficulty in memorizing such a pattern! Is it any wonder that the operators were not “following the rules” when the rules were so difficult to define?
The team developed an ingenious visual loading board that depicted the pattern, requiring the operators to move a color-coded magnet indicating the completion of the task. The operators responded favorably because the requirement was defined and clear and they did not get yelled at for not “following the rules.” The line stoppage was reduced considerably, and the number of completed units (each unit included several subcomponents) painted per day rose from 80 to over 110. As the operators gained a deeper understanding of visual standards, they made several enhancements to the board, further clarifying the requirement and incrementally leveling the mix (detailed in the next chapter).
Standardization Is a Waste Elimination Tool
Developing standardized work is the first step. It not only provides a standard way of doing the task, but the process of doing the analysis will reveal waste that should be eliminated as part of developing the standardized work. When standard work is developed and operators are properly trained, regular audits are needed to check on whether the standards are being followed, and if not, why. Operators should be encouraged to suggest changes that will improve the process and be reflected in revisions to the standardized work.
Once standards are developed, the standard condition should be visually displayed so deviations from the standard will be obvious. The paint case example illustrates the power of making a visual standard that was visible and understandable to everyone. Visual indicators by themselves become powerful tools only when used for visual control, showing the contrast between the standard and the actual situation (Figure 6-11). Following the standard as defined “clears the clouds” and improves flow and overall performance. Toyota places a high importance on the use of visual controls to support the adherence to standards. We cannot stress enough the need to “make it visual.”
- Clear and Understandable
- Correct Deviation
- Report Deviation
- Discover Deviation
- Make Standard Visible
- Able to verify adherence to Standard
Figure 6-11. Visual standards support adherence to correct methods
Reflect and Learn from the Process
As always, begin these exercises by “walking the flow” with your current state map in hand. If you’ve begun implementing improvements and have established some defined connections, you have created standards as well. Begin to envision the future state and to draw the defined connections on a future state map.
1. Has customer demand been determined and takt time calculated?
a. Identify the method currently used to monitor achievement of the takt rate at each operation.
b. Is it possible to see and understand this standard? If not, identify a corrective action necessary to create a visual standard of takt time and add these items to your action plan.
c. Is performance to the takt-rate standard being measured and recorded? If not, add this item to your action plan.
d. Inability to consistently achieve the takt rate is an indicator of instability. Identify the causes and necessary corrections to reduce instability and to achieve the standard (takt rate) at least 85 percent of the time.
2. Defined, dedicated, and controlled connections between processes serve as agreed-upon expectations of performance (standards) between a supplier process and a customer process. Review your connections and answer these questions.
a. Is there visual awareness of the standards?
i. What is the expectation?
ii. When is it supposed to be done?
iii. Who is supposed to do it?
iv. How do you know if it has been successfully completed?
b. What is the current ability to achieve the standard (satisfy the customer)? If the performance is below 85 percent, identify necessary steps to improve performance, and make a plan to implement it.
3. Identify an operation that does not consistently achieve the standard. Stand in the circle, and observe the following conditions.
a. Is the work method repeatable? (If it’s difficult to document the work steps because of constant interruption, it is not repeatable.) If not, list the causes of variation and corrective actions necessary to stabilize the process.
b. Is the work process interrupted more than 10 percent of the time because of equipment issues or quality-related problems? (Don’t overlook small issues such as difficulty loading or unloading a fixture.) Make plans to correct the issues that interrupt the process.
4. After the major issues have been resolved and the process is reliable and stable, stand in the circle to study the job and identify waste.
a. Use a Standardized Work Sheet to document the steps of the job.
b. Draw a diagram of the work area and where each step is performed.
c. Note the waste, and develop plans to improve the work process to reduce the waste.
d. Use the Standardized Work Sheet to diagram the proposed changes and show the waste elimination as a reduction of total cycle time.
e. What effect did the reduction of waste (and a cycle time reduction) have on the overall work balance and flow?
5. In the reflection questions in Chapter 5, you measured the cycle times for each operation. Identify the processes in the value stream that inhibit flow (cycle times that are over takt, or that are higher than the others), and target them for waste reduction using standardized work as an analysis tool.