Form and painting in mechanical system

Mechanical drawing is a subject that accurately expresses the structural shape, size, working principle and technical requirements of machinery with drawings. Drawings are composed of figures, symbols, words and numbers. They are technical documents that express design intentions and manufacturing requirements and exchange experiences. They are often called engineering languages.

The items specified in the mechanical drawing standard include: drawing width and format, scale, font and drawing lines, etc. In the drawing format and format, the size of the standard drawing format and the corresponding frame size are specified. Proportion refers to the ratio of the dimension length in the drawing to the actual dimension of the machine parts. Except drawing with the scale of 1: 1, only the reduction scale and enlargement scale specified in the standard are allowed.

China stipulates that Chinese characters must be written in long imitation of Song Dynasty, and letters and numbers must be written in a prescribed structure. There are eight specifications for drawing lines. Thick solid lines draw visible outlines, dashed lines draw invisible outlines, thin dashed lines draw axes and symmetrical centerlines, and thin solid lines draw dimension line and section lines.

Mechanical drawing mainly includes part drawing and assembly drawing, as well as layout drawing, schematic drawing and axis drawing. Part drawings show the shape and size of parts and the technical requirements for manufacturing and inspecting parts; Assembly drawing expresses the assembly relationship and working principle between parts in machinery; The layout shows the position of mechanical equipment in the factory building; The schematic diagram shows the working principle of machinery, such as the mechanism movement diagram showing the mechanical transmission principle and the pipeline diagram showing the liquid or gas conveying line. All mechanical components in the schematic diagram are represented by symbols. Axonometric drawing is a kind of stereoscopic drawing, which is intuitive and often used as an auxiliary drawing.