Development Drawings(展开图)

The process of spreading out the surfaces of a solid continuously and true-shapely onto a plane is called the development of the surfaces of the solid, as shown in Fig.10-1. The drawing created by development is called a development drawing.  Development drawing is widely used in shipbuilding, mechanical engineering,electronic engineering, chemical engineering, architecture, packaging design, fashion design and so on.

将立体表面按其实际大小,依次连续地摊平在同一平面上,称为立体表面的展开,如图10-1所示。展开后所得到的图形,称为展开图。展开图在造船、机械、电子、化工、建筑、包装设计、服装设计等工业部门中都得到广泛的应用。

In terms of industrial demands, parts like shields, pipes, funnelsand so on are usually made of sheet metal. As shown in Fig.10-2, a segregator consists of a cylinder, a taper tube, a siphon and a deformed joint. Before being manufactured, the surfaces of these components are developed to a plane by a process called lofting. According to the developed plane drawings, sheet materials can be cut and bended, and finally welded together into a complete shape.

在工业生产中,常常有一些零件或设备是由金属板材加工制成,如防护罩、管道、漏斗等。如图10-2所示的分离器,它是由圆柱、圆台、弯管和变形接头所组成。在制造时,首先要把它们的表面展开(俗称放样),画成平面图形,然后按图下料,弯曲成形,再将接缝焊接而成。

There are two methods to create a development drawing,i.e.,graphic method and calculation method. This section focuses on the graphic method as it is simple as well asintuitive. 

画展开图的方法有两种,即图解法和计算法。由于图解法具有作图简捷、直观等优点,故本章重点介绍这种方法。