What is a path diagram?
Although a process flow diagram gives us a lot of information about the production process, it does not clearly show the process flow. If a process analysis is performed, this information is useful for improving the production process.
We record operations, inspections, shipments, delays and storage in the same order in which they occur in the flow chart. The movement path is indicated by lines, each activity is identified and placed on the diagram with its corresponding symbol, and operations and controls are numbered according to the process diagram.
The path diagram can be of two types:
De tipo humano: analiza los movimientos y actividades de la persona que realiza la operación.
Tipo de material: donde se analizan los movimientos y transformaciones que le ocurren al material y, como en el caso anterior, se «sigue o persigue» al material paso a paso.
Si es necesario visualizar o analizar el movimiento de más de un material o persona que interviene en un proceso, cada uno de ellos puede identificarse con líneas de distintos colores o trazos diferentes.
The route diagram complements the information contained in the process diagrams; it consists of a plan (which may or may not be to scale) of the plant or section where the investigated process takes place. This diagram records all the different material movements, identifying by means of symbols and numbering the different activities and the place where they are carried out.
The route diagram allows to visualize the transport, the advance and withdrawal of the units, the bottlenecks, the points of the highest concentration, etc., in order to analyze the work and see what can be improved (eliminate, combine, reorder, simplify).
PROCESS DIAGRAM TYPES.
According to its form:
- Vertical format: In this format, the flow or sequence of operations goes from top to bottom. It is an ordered list of the operations of a process with all the information considered necessary according to its purpose.
- Horizontal format: In this format, the flow or sequence of operations goes from left to right.
- Panoramic format: the entire process is shown in a single graphic and can be seen at a glance much faster than reading the text, which facilitates understanding even for the ignorant. It records not only vertically, but also horizontally, several simultaneous actions and the participation of more than one position or department that the vertical format does not record.
- Architectural format: describes the path of a shape or person in the architectural plan of a work area. The first diagram is very descriptive, while the second is mainly representative.
By purpose:
- From the form: deals mainly with the form with little or no description of the operations. It indicates the sequence of operations or steps through which the form passes in different copies, through different locations and departments, from its origin to its submission. It shows the distribution of multiple copies of forms to several different people or units in the organization.
Shapes may be represented by symbols, scale drawings or photographs, or descriptive words. A horizontal format is used. The form is illustrated or labeled on the left side of the chart, followed by a horizontal progression, crossing each column assigned to organizational units or individuals.
- Work: These abbreviated diagrams represent only the operations involved in the individual activities or tasks into which the procedure is divided and the department or unit performing them. The term work includes all types of physical or mental effort. A vertical format is used.
- Methods: are useful for training and also represent how the various operations of a procedure are performed, by the person who is to perform them and in the specified order and by the person who performs them, but also analyze the purpose of the various operations within the procedure. If the data is important, the time used, distance traveled or some additional data is recorded. A vertical format is used.
- Analytical: represents not only the individual operations of the procedure in the specified order and the person performing them, but also analyzes the purpose of the individual operations within the procedure. If the data are relevant, the time used, distance traveled or any additional observations are recorded. A vertical format is used.
- Space: represents the path and distance traveled by the shape or person during the various operations of the procedure or part of it, and indicates the space through which it moves. If this is important, it represents the time spent on the route. The architectural format will be used.
- Combined: represents a combination of two or more diagrams of the previous classes. The vertical diagram format is used to combine tasks, methods and analysis (what is done, how it is done, what it is done for). The panoramic format is used to combine different forms and tasks from different positions or departments.
Regarding presentation:
- Block: is presented in general terms to highlight certain aspects. It presents a routine through a sequence of blocks, each with its own meaning and interconnected. It uses a much richer and more varied symbology than the previous diagrams and is not limited to predetermined lines and columns in the chart.
It is widely used by systems analysts to represent systems, i.e., to indicate the inputs, operations, connections, decisions, archiving, etc., that constitute the flow or sequence of activities of a system.
- Detailed: Represent activities in their most detailed form.
What is the function of the path diagram?
A route diagram is a diagram or model, more or less to scale, that shows where certain activities are performed and where workers, materials or equipment move as they are carried out.
In organizations that manufacture goods and/or services, there are five critical factors related to the facilities, since it is in them where many of the problems that arise during the process or activity that is developed can be attacked, so it is there where there is a great opportunity to increase productivity.
These five factors are as follows:
| Plant expansion | The physical layout of the plant. |
| Material handling. | Means of transporting materials. |
| Communication. | Information transmission systems. |
| Services. | Arrangement of elements such as electricity, gas, etc. |
| – Buildings. | Buildings in which the facilities are located |
It is important to consider that the above factors are closely related, as they all interact and are part of the system in the facility.
In the case of material handling and plant layout, the problem that arises is that if there is no proper plant layout or proper material handling system, no matter how hard we try to increase plant efficiency, we will not achieve optimal results because the material and workers usually make a long and complicated journey during the production process with loss of time and energy and no added value for the product.
In terms of efficient plant layout, the objective is to develop a production system that allows the necessary number of products to be manufactured with the required quality and at the lowest possible cost.
If one wants to analyze the routing of materials in a plant, it is necessary to first recall the systems that are commonly used in the industry for production. The four main plant layout systems are 16:
- Fixed arrangement of major components, in which the manufactured product does not move in the factory, but remains in one place and therefore the necessary machinery, labor and other equipment are brought there.
- Disposition by processes or functions in which all operations of the same nature are grouped together.
- Disposition by product, in series or in batches, in which case the machinery and equipment required to manufacture a given product are grouped in the same area and arranged according to the production process.
- Group layout or work cell layout, which allows the use of group production methods, i.e., a team of operators working on the same product and having all the machines and accessories necessary to complete their work within their reach.
In somecompanies it is common to find combinations of two or more systems or parts of the plant with one of these types of layout.
Once these layout systems are known, it is possible to move on to an analysis of the routing of materials in the factory.
Although the analytical flowchart provides most of the relevant information about the manufacturing process, it is not an objective representation of the workflow. Sometimes this information is used to develop a new method. For example, before sizing a conveyor, it is necessary to determine or imagine where equipment or facilities could be added to shorten the distance. It is also useful to consider possible temporary or permanent storage areas, control stations and workstations.
Por ello, la mejor manera de obtener esta información es realizar un plano de la distribución existente de las áreas consideradas en la planta y dibujar líneas de flujo que indiquen el movimiento de material de una actividad a otra. Se denomina diagrama de recorrido de actividades a la representación objetiva o topográfica de la disposición de zonas y edificios, que muestra la ubicación de todas las actividades registradas en el diagrama de recorrido de procesos.
Clearly, the path diagram is a valuable complement to the analytical path diagram, as it can be used to plot the inverse of the path and find areas of potential congestion, facilitating better plant layout.