According to the theory of constraints, proposed by Eliyahu Moshe Goldratt, it is possible to allocate considerably short list of working centres. These centres are bottlenecks, which productivity limits overall productivity of the whole entreprise. In order to achieve maximum productivity of an enterprise these bottlenecks have to be widen, if possible. They have to be used in the most effective way. .
A method ‘Drum-Buffer-Rope’ of the Theory of constraints (TOC) by Eliyahu Moshe Goldratt: general description
Concrete steps that allow optimisation of an enterprise, taking into account its bottlenecks are united in a methodology, known as ‘Drum-Buffer-Rope’. Key steps to be taken to apply the methodology:
- To identify working centers, that are bottlenecks. These bottlenecks are called ‘drums’ in the give methodology;
- To ensure the most effective load of bottlenecks. In order to do it, it is necessary to carefully plan its work; to draw up a schedule of work of these drums, downtimes excluded;
- To subordinate work execution at other working centers to the drum work. Production time at working centres, standing in the process of production in front of a drum, is called ‘buffer’ in the given methodology. Work at buffers has to be started beforehand; before defined time to planned time of drump work start. Durability of buffer has to be chosen according to the next calculation: work of a buffer has to be accomplished till ‘drum’ work starts to be executed. This way, buffer has to secure the drum from downtimes.
To support methodology ‘Drum-Buffer-Rope’(DBR) in the IT systems the next order of work is proposed:
- The whole process of production is divided into stages. Stages allocation is not a consequence of DBR methodology, but it can be necessary to achieve other aims. For example, to allocate parts of an process of production, that are executed on different territories;
- At every stage a key working centre (its drum) of the given stage is defined. Precise information about productivity of a drum is indicated. An overall time of execution, is allocated for works, executed before and after it. The time during which the works will be executed with 100 % probability, is called a buffer;
- Schedule planning of a production process is executed on the basis of of information, derived from the stages of production. This way, detailed information on productivity of all working centres is not necessary for planning of production process. It is enough to know productivity of the key working centers and working time in buffers. In the process of production status of work in buffers in front of key working centers is controlled.
Pieces of advice on usage of ‘Drum-Buffer-Rope’ methodology
- One of the most effective approaches to search bottlenecks is to identify in front of which working centers blanks, waiting for processing, are being accumulated.
- Quality control can be appropriate to be allocated before the drum. In such a case a bottleneck will process only known quality blanks. Therefore, its inefficient work will be excluded.
- It is necessary to track the process of production and to control changes of bottleneck content. New bottlenecks can appear when optimisation of load of bottlenecks, found earlier, occurs.
- All possible measures have to be taken to make a ‘drum’ work continuously and works effectively.
- Whenever possible productivity of a ‘drum’ has to increase productivity, as this will lead to overall system productivity increase.
Literature on TOC Methodology:
- Eliyahu Goldratt::
- 'The goal'. 1,2,3
- 'The Critical Goal’ - TOC for Project Management
- Haystack Syndrome - TOC in the process of ERP implementation
- I knew that - TOC for retail trade
- ‘Goldratt’s Theory of Constraints. A Systems Approach to Continuous Improvement’ by William Dettmer:
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Written by Maksim Zosim
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translated by Julia Yuliya Korgunyk
- Контент-маркетолог TQM systems Nataliya Raevskaya
- 6/23/2020 10:14:21 AM
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