An engineering drawing, a type of technical drawing, is used to fully and clearly define requirements for engineered items.
Engineering drawings: common features:
Drawings convey the following critical information:
- Geometry – the shape of the object; represented as views; how the object will look when it is viewed from various angles, such as front, top, side, etc.
- Dimensions – the size of the object is captured in accepted units.
- tolerances – the allowable variations for each dimension.
- Material – represents what the item is made of.
- Finish – specifies the surface quality of the item, functional or cosmetic. For example, a mass-marketed product usually requires a much higher surface quality than, say, a component that goes inside industrial machinery.
Line styles and types
A variety of line styles graphically represent physical objects. Types of lines include the following:
- visible – are continuous lines used to depict edges directly visible from a particular angle.
- hidden – are short-dashed lines that may be used to represent edges that are not directly visible.
- center – are alternately long- and short-dashed lines that may be used to represent the axes of circular features.
- cutting plane – are thin, medium-dashed lines, or thick alternately long- and double short-dashed that may be used to define sections for section views.
- section – are thin lines in a pattern (pattern determined by the material being "cut" or "sectioned") used to indicate surfaces in section views resulting from "cutting." Section lines are commonly referred to as "cross-hatching."
- phantom - (not shown) are alternately long- and double short-dashed thin lines used to represent a feature or component that is not part of the specified part or assembly. E.g. billet ends that may be used for testing, or the machined product that is the focus of a tooling drawing.
