The TPS: tools and techniques

The TPS house (Figure 2.1) is a symbol illustrating the various tools and techniques that have been developed and practiced for decades by Toyota. It has become one of the most recognisable symbols in modern manufacturing and was created initially by Toyotas past president, Fujio Cho, working closely with former Toyota engineer and executive Taiichi

Best Quality– Lowest Cost – Shortest Lead Time –

Best Safety– High Morale

Through shortening the production flow by eliminating waste

Just-in-Time

Right part, right amount, right time

•Takt time planning • Continuous flow • Pull system •Quick changeover •Integrated logistics Jidoka (In-station-quality) Make problems visable

•Automatic stops •Andon •Person-machine

Separation •Error proofing •In-station quality control

•Solve root cause of Problems (5 whys)

People & Teamwork

• Selection • Common goals • Ringi decision making • Cross-trained Waste Reduction • Genchi Genbutsu • 5 Whys

• Eyes for waste • Problem solving

Continuous Improvement

Leveled Production(heijunka)

Stable and Standardised Processes Visual Management

Toyota Way Philosophy

Best Quality– Lowest Cost – Shortest Lead Time –

Best Safety– High Morale

Through shortening the production flow by eliminating waste

Just-in-Time

Right part, right amount, right time

•Takt time planning • Continuous flow • Pull system •Quick changeover •Integrated logistics Jidoka (In-station-quality) Make problems visable

•Automatic stops •Andon •Person-machine

Separation •Error proofing •In-station quality control

•Solve root cause of Problems (5 whys)

People & Teamwork

• Selection • Common goals • Ringi decision making • Cross-trained Waste Reduction • Genchi Genbutsu • 5 Whys

• Eyes for waste • Problem solving

Continuous Improvement

Leveled Production(heijunka)

Stable and Standardised Processes Visual Management

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Ohno, to support the teaching of TPS to suppliers of the company. Different versions of the TPS house exist today but the core principles remain the same.

The roof of the TPS house represents the goals of an organisation: best quality, lowest cost, shortest lead-time. The two outside pillars represent the concepts of Just-In-Time (producing the right quantity and in time) and Jidoka (automatically recognising quality issues). Just-In- Time in turn can be achieved by applying a number of different tools:

 Takt-Time: is the rhythm of customer demand. It is an indicator of how much time is available to produce one part based on the operating time available and the customer demand.

 Kanban: is used to realise pull-production in small batches (Monden, 1998). It relays information (on cards) with the intention of influencing behaviour (only the specified quantity on the cards are delivered).

 Continuous Flow: enabling material and information to flow fast as well as to link processes and people together so that problems surface right away (Liker, 2004).

 Quick Changeover: reducing the amount of time it takes to set up a machine to produce the next part (Liker, 2004).

Jidoka can be achieved by applying (Liker, 2004):

 Automatic stops: a technique that allows machines to automatically stop when a problem is detected. It attracts attention when there is a problem and prevents further errors from happening by stopping the process.

 Poke-Yoke: a physical device that prevents mistakes or calls attention to them by stopping production (Liker, 2004). Its purpose is to eliminate product defects by preventing, correcting, or drawing attention to process errors as they occur (Robinson, 1997).

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 Andon: is a signalling system which uses lights or flags to indicate that equipment has shut down as a result of a quality problem (Liker, 2004).

 5 Whys: understanding the root of the problem by asking “why” 5 times.

The two pillars of the TPS, JIT and Jidoka, are focused on creating transparency in information so that the process participants have access to the important information that they need to answer the six fundamental questions in a workplace which is what, how many, who, when, how and where (Section 2.5.1; Galsworth, 2005, p.34-5).

The tools and techniques of the TPS are applied to help identify so-called “waste” in the process. Toyota defines waste as any activity that does not add value for the customer and identifies seven different types (Liker, 2004):

 Overproduction: producing more than there is a demand for. Ohno considered this to be the fundamental waste, since it contributes to most of the other wastes.

 Waiting (time on hand): waiting for a machine, for material or information.

 Unnecessary transport or conveyance: carrying work in process (WIP), moving material.

 Over processing: taking unneeded steps to process parts.

 Excess inventory: excess raw material, WIP or finished goods, causing longer lead times, obsolescence, damaged goods, transportation and storage costs.

 Unnecessary movement: any wasted motion that employees have to perform during the course of their work.

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A further waste added by Liker (2004) is unused employee creativity. Employees work in the process and have a deep understanding of the nature of the work and what the root causes of problems are.

Finally, the TPS house is supported by several foundational elements, which include the need for standardised, stable and transparent processes, the performance of which is measured. Imai (1986) explained in his book on continuous improvement called Kaizen, that it is impossible to improve any process until it is standardised. It is also important to measure performance and create feedback that will lead to higher levels of improvements (Marosszeky et al., 2004). Managers tend to view measurement as a tool for controlling people’s behaviour. Instead, measurement is a way of communicating goals, sharing responsibilities and learning in organisations (Formoso & Lantelme, 2000). The foundational elements of the TPS include a levelled schedule or heijunka which is necessary to keep the system stable and to allow for minimum inventory and Visual Management, which is applied to create transparency in the work environment and to easily identify problems.

The principle of transparency is key to the effective application of the TPS. Section 2.3 discusses the principle of transparency and presents some important points to consider in order to create it.