To understand what a mechanical drawing is, we must first consider each term that makes up the expression separately. A drawing is a line or a delineation that allows to represent a figure. The mechanical, on the other hand, can be linked to a machine, a device or a mechanism.
A mechanical drawing, therefore, is a graphic representation of machinery, part of it, or its parts. These are plans or diagrams that show the layout or operation of these devices.
Mechanical drawings are part of the set of technical drawings: those that, by representing an object, provide data that enable its design, manufacture, operation and/or maintenance. Electrical drawings and architectural drawings are also considered technical drawings.
A mechanical drawing allows to represent a machine, or part of it, through a graphic.
Origin of mechanical drawing
The importance of drawing to convey ideas through graphics and lines has been considerable over many millennia. Let’s not forget that long before human beings invented and developed writing systems, they relied solely on art to express themselves and record their ideas and experiences.
When writing finally appeared, drawing became an activity of certain specialists, both artists and people with needs that the written language could not cover, as is the case today with engineers and designers who need to draw up plans, sketches and sketches for your work activities.
Like the rest of the technical drawings, the mechanical drawings must exhibit those details that are required to execute a project. They generally use different symbols to represent cuts, lines and other elements. Standardization allows the same symbology to be used globally, favoring understanding among specialists.
The use of symbols has another objective in addition to making it possible for people from all over the world to read a plan: to simplify the drawing and minimize the chances of error. If engineers did not have a series of conventions at their fingertips to easily represent certain concepts, they would be forced to design devices and parts with the greatest possible degree of realism, and that would entail very hard work, which would not always reflect accurately. total precision the less obvious characteristics of the products.
Mechanical drawings often appeal to symbols. See Abbreviation Finder for acronyms related to mechanical drawings.
Standardization and symbology of the mechanical drawing
According to the International Organization for Standardization (whose name in English is Organization for Standardization and its acronym, ISO), two representation systems are currently used, the American and the European, also known as the third quadrant and the first quadrant, respectively. Trends indicate that American will be used in almost all cases in the future.
Regarding the symbology of each one, it is important to point out that the user must know in advance to which the mechanical drawing corresponds in order to understand it correctly, since the same symbol can mean different things in one and in another. For example:
* for ISO(E), the European representation system, P, Q and R are used to symbolize front, top and side views, respectively;
* the American system, ISO(A), instead, uses the P, the Q and the R to represent the top view, the front view and the side view, respectively.
Use of computing resources
It should be noted that a mechanical drawing can be developed by hand on a flat surface (such as paper) or carried out virtually with the help of a computer program (software). In this way, 3D representations can be generated and different perspectives can be obtained.
An example of a mechanical drawing is the graphic that shows all the parts of an engine. Thanks to this representation, it is possible to understand how the different gears are formed and how the whole works.