Lean Six Sigma For Dummies. Brenig-Jones MartinЧитать онлайн книгу.
Toyota chairperson Fujio Cho provides a clue as to what’s also needed:
The key to the Toyota way is not any of the individual elements but all the elements together as a system. It must be practised every day in a very consistent manner – not in spurts. We place the highest value on taking action and implementation. By improvement based on action, one can rise to the higher level of practice and knowledge.
Figure 1-1 shows that people are at the heart of TPS. The system focuses on training to develop exceptional people and teams that follow the company’s philosophy to gain exceptional results. Consider the following:
✔ Toyota creates a strong and stable culture wherein values and beliefs are widely shared and lived out over many years.
✔ Toyota works constantly to reinforce that culture.
✔ Toyota involves cross-functional teams to solve problems.
✔ Toyota keeps teaching individuals how to work together.
Being Lean means involving people in the process, equipping them to be able, and feel able, to challenge and improve their processes and the way they work. Never waste the creative potential of people!
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:
✔ Heijunka provides the foundation. It encompasses the idea of smoothing processing and production by considering levelling, sequencing and standardising:
● Levelling involves smoothing the volume of production in order to reduce variation, that is, the ups and downs and peaks and troughs that can make planning difficult. Amongst other things, levelling 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 week, making things even worse for the customer and the business.
● Standardising is the third strand of Heijunka. It seeks to reduce variation in the way the work is carried out, highlighting the importance of ‘standard work’, of following a standard process and procedure. It links well to the concept of process management, where the process owner continuously seeks to find and consistently deploy best practice. Remember, however, that you need to standardise your processes before you can improve them. Once they’re standardised, you can work on stabilising them, and now that you fully understand how the processes work, you can improve them, creating a ‘one best way’ of doing them.
In the spirit of continuous improvement, of course, the ‘one best way’ of carrying out the process will keep changing, as the people in the process identify better ways of doing the work. You need to ensure the new ‘one best way’ is implemented and fully deployed.
✔ Jidoka concerns prevention; it links closely with techniques such as failure mode effects analysis (FMEA), which are covered in Chapter 10. Jidoka has two main elements, and both seek to prevent work continuing when something goes wrong:
● Autonomation allows machines 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 he spots 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 7).
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 each person performs an operation and makes a quick quality check before moving his 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.
Traditionally, large batches of individual cases are processed at each step and are passed along the process only after an entire batch has been completed. The delays are increased when the batches travel around the organisation, both in terms of the transport time and the length of time they sit waiting in the internal mail system. At any given time, most of the cases in a batch are sitting idle, waiting to be processed. In manufacturing, this is seen as costly excess inventory. 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.
● 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 ‘seven wastes’ identified by Ohno and covered in Chapter 9.
● 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 a precise interval of time, such as a musical meter. It serves as the rhythm or beat of the process – the frequency at which a product or service must be completed in order to meet customer needs. Takt time is a bit like the beat of the drum on the old Roman galleys for synchronising the rowers.
