Читать книгу Lean Six Sigma For Dummies - Martin Brenig-Jones - Страница 15

You can see from Figure 1-1 that Lean thinking involves a certain amount of jargon — some of it Japanese. This section defines the various terms to help you get Lean thinking as soon as possible:

 Standardization seeks to reduce variation in the way the work is carried out, so that everyone operates the process in the “one best way.” This highlights the importance of following a standard operating process or procedure. In the spirit of Continuous Improvement, of course the “one best way” of carrying out the process will keep changing, as people in the process identify better ways of doing the work. You need to ensure the new “one best way” is understood and fully deployed.

 Heijunka encompasses the idea of smoothing processing and production by considering leveling and sequencing:Leveling involves smoothing the volume of production in the production period, in order to reduce the ups and downs and peaks and troughs that can make planning difficult. Among other things, leveling seeks to prevent “end-of-period” peaks, where production is initially slow at the beginning of the month, but then quickens in the last days of a sale or accounting period, for example.Sequencing may well involve mixing the types of work processed. So, for example, when setting up new loans in a bank, the type of loan being processed is mixed to better match customer demand, and help ensure applications are actioned in date order. So often, people are driven by internal efficiency targets, whereby they process the “simple tasks” first to get them out of the way and “hit their numbers,” leaving the more difficult cases to be processed later on. This means tasks are not processed in date order, and people are reluctant to get down and tackle a pile of difficult cases at the end of the production period, making things even worse for the customer and the business.

 Jidoka concerns prevention; it links closely with techniques such as the Failure Mode Effects Analysis (FMEA), which are covered in Chapter 13. Jidoka has two main elements, and both seek to prevent work continuing when something goes wrong:Autonomation allows machines or processes to operate autonomously, by shutting down if something goes wrong. This concept is also known as automation with human intelligence. The “no” in autonomation is often underlined to highlight the fact that no defects are allowed to pass to a follow-on process. An early example hails from 1902, when Sakichi Toyoda, the founder of the Toyota group, invented an automated loom that stopped whenever a thread broke. A simple example today is a printer stopping processing copy when the ink runs out.Without this concept, automation has the potential to allow a large number of defects to be created very quickly, especially if processing is in batches (see “Single piece flow” below).Stop at every abnormality is the second element of Jidoka. The employee can stop an automated or manual line if they spot an error. At Toyota, every employee is empowered to “stop the line,” perhaps following the identification of a special cause on a control chart (see Chapter 8).Forcing everything to stop and immediately focus on a problem can seem painful at first, but doing so is an effective way to quickly get at the root cause of issues. Again, this can be especially important if you’re processing in batches.

 Just in Time (JIT) provides the other pillar of the TPS house. JIT involves providing the customer with what’s needed, at the right time, in the right location and in the right quantity. The concept applies to both internal and external customers. JIT comprises three main elements:Single piece flow means allowing single units of product to flow through the process step by step. When processing in batches, batches (or bundles) of individual cases are processed at each step and are passed along the process only after an entire batch has been completed. Delays are increased when the batches travel around the organization, both in terms of the transport time and the length of time they sit waiting to be actioned. At any given time, most of the units or work items in a batch are sitting idle, waiting to be processed. This represents excess inventory and can be costly. What’s more, errors can neither be picked up nor addressed quickly; if they occur, they often occur in volume. And, of course, this also delays identifying the root cause. With single piece flow, we can get to the root cause analysis faster, which helps prevent a common error recurring throughout the process.In a single piece flow system each person performs an operation and makes a quick quality check before moving their output to the next person in the following process. Naturally this concept also applies to automated operations where inline checks can be carried out. If a defect is detected, Jidoka is enacted: the process is stopped, and immediate action is taken to correct the situation, taking countermeasures to prevent reoccurrence. This concept is a real change of thinking that moves us away from processing in batches.Pull production is the second element of JIT. Each process takes what it needs from the preceding process only when it needs it and in the exact quantity. The customer pulls the supply and helps avoid being swamped by items that aren’t needed at a particular time.Pull production reduces the need for potentially costly storage space. All too often, overproduction in one process, perhaps to meet local efficiency targets, results in problems downstream. This increases work in progress, and creates bottlenecks. Overproduction is one of the “eight wastes” covered in Chapter 10.Takt time is the third element of JIT, providing an important additional measure. It tells you how quickly to action things, given the volume of customer demand. Takt is German for “rate.” It helps to think about a metronome that musicians use to keep to a consistent tempo, so the takt time is the frequency at which a product or service must be completed in order to meet customer needs.