专注通风管道加工·排烟罩

Unfolding and blanking of ventilation pipe processing: In ventilation engineering, the shapes of pipes and parts made of metal and non-metallic sheets are various, and some parts must be processed and fabricated by the basic method of unfolding and blanking. The so-called unfolding refers to laying the surface of pipe fittings on the sheet according to the actual size according to the requirements of the pipe fitting construction drawing (or setting out drawing). The drawn figure is the unfolding drawing, and the quality of the unfolding drawing is good or bad, It directly affects the quality of spiral air duct and components and the use efficiency of materials.

展开下料的步骤：展开下料的基本步骤是：熟悉图形，形体分析，求直线的实长或平面的实形，确定展开方法和画展开图等。

Steps of unfolding blanking: the basic steps of unfolding blanking are: getting familiar with graphics, shape analysis, finding the real length of a straight line or the real shape of a plane, determining the unfolding method and drawing the unfolding diagram.

熟悉图纸展开下料前，要认真熟悉施工图纸，了解需要展开的管件或部件的内容，它在通风工程的部位、与何种管件相连接，它在图纸上尺寸的大小，用哪种材料制作等。对于复杂的管件和部件需要反复仔细地对施工图进行阅读和分析，必U型全部看懂，如果图纸有错误或看不懂或设计不合理，应向有关部门提出。

Be familiar with the drawings. Before spreading and blanking, first of all, be familiar with the construction drawings carefully, understand the contents of the pipe fittings or components to be spread, the position of the ventilation project, the pipe fittings to be connected, the size of its dimensions on the drawings, and the material to be used. For complex pipe fittings and components, it is necessary to read and analyze the construction drawings repeatedly and carefully. All U-shapes must be understood. If the drawings are wrong or cannot be understood or the design is unreasonable, it should be reported to the relevant departments.

形体分析通风和空调工程中的通风管件和部件都是由几何图形构成的，对形体的分析的目的就是把复杂的几何形体分解成简单的几何形体，通过分解，便能找到恰当的展开方法，一般需要展开的部件多为壳体，壳体有平面壳体和曲面壳体。

Shape analysis The ventilation pipe fittings and components in ventilation and air conditioning engineering are all composed of geometric figures. The purpose of shape analysis is to decompose complex geometric figures into simple geometric figures. Through decomposition, you can find the appropriate expansion method. Generally, the parts to be expanded are shells, which include plane shells and curved shells.

1)、平面壳体：它是由一组平面形成的壳体，主要有棱柱形和棱锥形两种。前者棱形相互平行，后者棱形丰交一点，通常按棱线的多少有三棱、四棱柱形及三棱、四棱锥形。正棱柱壳体：底部为正多边形，棱与底平面相垂直。正棱锥壳体：底部为多边形，而锥项投影与底部正多边形相重合，不重合者为锥形壳体。经过剖切，壳体可出现各种截体。棱柱形壳体（截体）的特点是：各棱对不同投影面相互平行或分别交于一点。棱锥形壳体（截体）的特点是：各棱的投影相交于一点。多面壳体，它的四棱延长线不相交于一点。

1) Plane shell: it is a shell formed by a group of planes, mainly including prismatic and pyramidal shells. The former is parallel to each other, while the latter is rich in intersection. Generally, according to the number of prisms, there are three prism, four prism and three prism, four pyramid. Regular prism shell: the bottom is regular polygon, and the edge is perpendicular to the bottom plane. Regular pyramid shell: the bottom is a polygon, and the projection of the cone is coincident with the center of the regular polygon at the bottom, otherwise it is a conical shell. After sectioning, various sections of the shell can appear. The characteristics of prismatic shells (truncated bodies) are that the edges of different projection planes are parallel to each other or intersect at a point respectively. The feature of pyramid shaped shell (truncated body) is that the projection of each edge intersects at a point. The extended lines of the four edges of a polyhedral shell do not intersect at a point.

2)、曲面壳体：表面为曲面，或曲面、平面兼有的壳体称为曲面壳体。曲面壳体可分为：旋转或非旋转两种壳体。

2) Curved shells: shells with curved surfaces or both are called curved shells. Curved shells can be divided into rotating or non rotating shells.