People
People, and the proper handling of people—including training, career planning, and the commitment to a job—are forever are at the heart of the TPS. The culture of Toyota is built on the people, and the company makes few compromises in this area. Some of the basic needs to execute the TPS are covered in the following subsections.
Multiskilled Workers Multiskilled workers are required to staff the production facilities, for two major reasons. First, to achieve process improvements it is often necessary to reduce or change the elements of the work. This in turn often requires a redistribution of the work. In addition, work cells are often designed so they can be operated by one, two, three, four, or five people, for example, depending on changes in demand. If the workers are not multiskilled, the dynamics of Lean are lost. Multiskilled workers are at the heart of flexibility in Lean Manufacturing.
Problem Solving by All Problem solving by all has been a hallmark of the TPS since its inception. Workers are expected to solve simple problems, and the TPS incorporates a time trigger regarding the escalation of problems and the involvement of others. Here we have the very revolutionary concept of line shutdowns initiated by the line worker himself. To really give justice to allowing the operator to shut down the production line is a book in itself. But just for fun, let’s touch on one of the topics here—that is, how problems are perceived within the TPS is much different than the typical attitude toward problems. In a normal Western plant, problems are seen as a nuisance and even a sign of failure of management, engineering, or even the worker himself. Hence, prob- lems become a thing to hide and shrink away from. No one wants to accept the resul- tant blame handed out, and so many problems go unresolved even though they are obvious to many. This is commonplace, even today, in most facilities where we work.
However, within the TPS, problems are viewed as a weakness in the system and an opportunity to improve the system and make it more robust. Guilt and finger-pointing are avoided and problems are addressed and solved.
Now, let’s do a little exercise in imagination. First envision several problems within your organization. Think of a production problem that has persisted for a while, maybe one that people feel a little uncomfortable talking about. No one else is around, so be honest!
Now ask yourself, “What must we do as a company to remove the root cause of this problem?” Do not be surprised if myriad answers come to mind, few of which are really doable.
Next, ask yourself, “What must we change in our company so this problem will never appear again?” and you will get an idea of the deep cultural change needed to alter the attitude toward problems in your company.
Understanding of Variation An understanding of variation is a topic almost skipped in Ohno’s book. Yet this topic is the topic of problem solving, process improvement, and inventory reduction, to name just a few. So why is it missing form Ohno’s writings?
Well, after some thought I’ve concluded that he had both a deep understanding of, and an ability to manage, variation reduction to such a level that it was simply obvious, it was second nature, to him. And Ohno—if he has a weakness—sometimes does not state the obvious. Do not slight this topic. It is at the heart of your company’s survival and
nearly all the 20 Lean tools require an understanding of, and reduction of, variation to work.
Stability
OEE OEE stands for Overall Equipment Effectiveness and is the primary measure of production effectiveness. It can be used for value stream or individual work station performance evaluation. Good value stream OEE is one of the key precursors to the implementation of Lean and is the product of three important operational parameters.
These are:
• Equipment availability
• Quality yield
• Cycle-time performance
To calculate OEE, you will need five parameters. First is the planned production time for the line. Second is the unplanned line downtime. Third is the line cycle time, or cycle time, of the bottleneck. Fourth is the total production including scrap, and fifth is the total amount of salable product. Let’s say we have the following data:
• Planned production time is 20.5 hours. It is 24 hours less 1 hour per shift for lunch and breaks, and less one-half hour for planned preventive maintenance.
• Unscheduled downtime was 1.5 hours.
• Design cycle time is 30 seconds per piece.
• Actual total production was 2020 pieces with 50 rejects, yielding 1970 pieces of salable product. This then allows us to calculate:
• Availability= Total uptime divided by total planned uptime = A = (20.5 – 1.5)/
20.5= 0.927
• Quality Yield = The total of salable production units divided by the total production = Q = 1970/2020 = 0.975
• C/T Performance= Total units produced, good and bad, divided by the volume, which should have been produced during the actual uptime at the design cycle time = P = 2020/[(20.5 – 1.5) × (3600/30)] = 0.886
• OEE= A × Q × P = 0.801
This is a way to express how our production facility is performing, and then priori- tize our problems and allocate our resources. In this example, OEE is 80 percent. The losses can be stated as about 2.5 percent due to quality issues, 7.3 percent losses due to availability issues, either materials delivery or machinery downtime, and we are losing 11.4 percent due to the line not performing at the design cycle time. It is a very good picture of plant performance and allows management to focus on the appropriate goals for improvement.
MSA MSA stands for measurement system analysis. It is the statistical calculation of the variation in the measurement system and applies to both attribute and vari- ables data. MSA must be done on all measurement systems. The most common use of MSA is as a precursor to doing a capability study on a product characteristic or a
process parameter. It is crucial to understand the variation in the measurement system since it detracts from the capability performance of the process. Frequently, process performance can be improved simply by working on the variation in the measurement system.
Cp and Cpk Cp and Cpk are the industrially accepted measures of process perfor- mance. They are both called process capability indices. Several good books describe how to calculate Cp and Cpk, but one major point of understanding must be accepted—
specifically, Cp and Cpk have no meaning if the process does not exhibit process stability—that is, process predictability. Process stability is best evaluated using a con- trol chart and is absolutely necessary for Lean initiatives to be implemented. Nothing is more basic to successful Lean implementation than process stability.
Availability Availability is the concept that the production process shall be capable to produce product, when it is scheduled to do so. High process availability is a necessary characteristic of a process ready to be Leaned out. Low process availability is almost always a sign of an unstable process. Usually, low availability is associated with machin- ery downtime or the inability to deliver on-spec raw materials to the production line.
Cycle-Time Reductions Cycle-time reductions are very important to Lean implementa- tions. It is best to work hard on cycle-time reductions prior to implementation of a Lean initiative. This helps stabilize the process and then the quantity control issues are more easily managed. However, often during a Lean implementation, cycle-time reductions will be found and they usually translate directly into higher production rates. These cycle-time reductions are truly the “low hanging fruit” of Lean implementations. Any time a cycle-time reduction can be achieved, the resultant extra production is the lowest cost product you can make. Basically, you are transforming the cost of raw materials into the value of the finished product.
Standard Work Standard work, as defined by Ohno, has three elements:
• The cycle time
• The work sequence
• The standard inventory
However, it is a much misunderstood concept. In his book, Ohno says, “…I want to discuss the standard work sheet as a means of visual control, which is how the Toyota production system is managed.”
Notice he uses two interesting terms. First, he uses the term “visual control,” and second he says it is how the TPS is “managed.” He does not say, “this is how the TPS is operated.” He is very specific, so do not be confused. This explains why, when you enter a Toyota facility and see the standard work sheet at a work cell, it is not facing the operator. Rather, it is facing the aisle so it is available to the supervisor, the engi- neer, and the manager. Standard work is not used by the line operator but by the team leader, engineer, or manager so they can audit the work, understand the status of the process, and provide assistance if the process is not performing as designed. The stan- dard work chart is part of the concept of transparency and is there for visual control by the management team. It is a myth that the Standard Work Chart is made for the operator.
Transparency Transparency is the concept that the performance of the process or the entire line is able to be “seen” simply by being on the floor. It is not generally a set of charts that will allow this—to the contrary, it is a set of visual controls such as andons, heijunka boards, and space markings that make the process performance “transparent.”
Where transparency is implemented properly, a manager can determine within one or two minutes if his process is performing as designed—and if the process is deficient, the manager can quickly discern the problem areas. For more on transparency, see Chap. 10.
5S 5S is a set of techniques, all beginning with the letter “S.” They are used to improve workplace practices that facilitate visual control and Lean implementation. The 5Ss in Japanese and English are:
• Seiri. . . .Separate
• Seiton. . . . .Set to order
• Seiso. . . .Shine
• Seiketsu. . .Standardize
• Shitsuke. . .Sustain
TPM TPM are the initials for Total Productive (not preventive) Maintenance. It is a revolutionary approach to the management of machinery. It consists of activities that are designed to prevent breakdowns, minimize equipment adjustments which cause lost production, and make the machinery safer, more easily operated, and run in a cost-effective manner. In most plants, wishing to implement a Lean Initiative, we find that equipment availability is a large source of the process losses. Frequently, the largest of the three losses in the OEE metric. TPM is therefore a powerful tool to improve overall performance of the plant. It is generally defined as having five pil- lars, which are:
• Improvement activities, designed to reduce the six equipment-related losses of:
• Breakdown losses
• Setup and adjustment losses
• Minor stoppage losses
• Speed losses
• Quality defects and rework
• Startup yield losses
• Autonomous maintenance, which is an effort to have many routine activities performed by the operator rather than the maintenance department.
• A planned maintenance system, which is based on failure history. This is not timed maintenance. Instead, it is based on historical evidence.
• Training of operators and maintenance personnel to improve operations and maintenance skills.
• A system for early equipment maintenance to avoid the loss that occurs upon new equipment startup.
Process Simplification Process simplification is a basic concept, but is frequently over- looked by most. It is the idea of eliminating and simplifying steps in the production process. This is one of the most powerful variation reduction techniques you can employ.
Sustaining the Gains Sustaining gains is the concept that once a process improvement is achieved, the next step is to standardize it. Thus, we want to institutionalize the gains so they will be there forever. We then want to build on this gain. It is curious that almost everyone knows this, but almost no one does it, not even modestly. In my work with over 200 companies, I can’t give you one example of any company that does this well.