What is the appropriate production flowchart? It is therefore more than logical not to include this information in the process flow diagram. In the end, all this would overload the value stream chart document. transport lengths, means of transport, path widths, and transport lot sizes). Further parameters are necessary for the layout design (e.g. Logistics only emerges when the process has to be implemented in a production layout. The design goal in value stream considerations is an ideal process, the target value stream. This is modeled in the One-Piece-Flow, which allows consideration of lead time, Process Cycle Efficiency (PCE), and line balancing. This is because value stream representations focus on the throughput of quantity 1. However, one aspect is not modeled in the value stream: The logistics. This means that only a few symbols are required for value stream mapping, which are arranged linearly from left to right following the process flow. These can be realized with less control effort if processes follow the flow principle. To this end, this kind of PFD focuses on its purpose: It is about production processes that are as lean as possible. So we reduce complexity and thus keep the whole thing simple. In value stream diagrams, therefore, we intentionally forgo opportunities. Why run through an activity twice or three times? Why does it not succeed on the first run? Why rework?įlowchart loops hide the need to rework steps So why should it be possible to model loops in a value stream chart simply? It is not purposeful and therefore not intended.Įspecially since each loop can also be represented in a chain of similar steps, which illustrates their waste potential. They create the need for buffers and control. Loops in the process lead to eddies and bring unrest. This may also be due to the flow principle, which the value stream design declares as its goal. The value stream example shows that production processes can be modeled in a simple and understandable way. ![]() This advantage should not be underestimated. Without loops, however, no conditions need to be formulated at the branches or merges. Necessary feedback steps can be understood quite intuitively in the form of a loop, which is why most flowcharts allow loops in some form. This is because the value stream process maps are simple in that the symbols used and their arrangement are in many cases self-explanatory.ĭifferent templates to model loops in process flow diagrams Perhaps this is why value stream sketching, extracted from the Toyota Production System by Rother and Shook around the turn of the millennium, gained such popularity in the practice of many manufacturing companies. And understanding was the motivation mentioned at the beginning to deal with process diagrams. Therefore, specialized manufacturing flow charts are to be preferred to universal ones if they are to be easy to understand. A small number of symbols logically reduces the range of applications. Understandable flowcharts are therefore characterized by a small, preferably self-referential symbol range. Or to put it another way: No flowchart contributes to understanding until those involved have learned to interpret the symbols used in it in a uniform manner. But does this solve the problem? No.īecause the fact remains: Every type of diagram requires interpretation. Only one thing is clear: There are countless ways to create such diagrams professionally. In addition to the above list, there are countless software tools, each of which has its own focus or, on the contrary, sees itself as a universal tool, e.g. It’s easy to lose interest in the topic, isn’t it? Now let’s go one step further.
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