Unfolding and blanking of ventilation pipe processing: in ventilation engineering, the shapes of pipes and parts made of metal and non-metallic sheet materials are various, and some parts must be processed and fabricated by the basic method of unfolding and blanking. The so-called unfolding is to lay the surface of pipe fittings on the sheet material according to the actual size according to the requirements of the pipe fitting construction drawing (or setting out drawing), Directly affects the quality and material efficiency of spiral ducts and components.
Steps for unfolding cutting: The basic steps for unfolding cutting include familiarizing oneself with graphics, analyzing shapes, finding the true length of a straight line or the true shape of a plane, determining the unfolding method, and drawing an unfolding diagram.
Be familiar with the drawings. Before unfolding and blanking, first of all, be familiar with the construction drawings carefully, understand the contents of the pipe fittings or components to be unfolded, the position of the ventilation project, the pipe fittings to be connected with, the size of its size on the drawings, and the material to be used. For complex pipe fittings and components, it is necessary to carefully read and analyze the construction drawings repeatedly, and all U-shaped parts must be understood. If there are errors in the drawings, or the design is unreasonable, it should be reported to the relevant departments.
The ventilation pipes and components in ventilation and air conditioning engineering are all composed of geometric shapes. The purpose of analyzing shapes is to decompose complex geometric shapes into simple geometric shapes. Through decomposition, an appropriate unfolding method can be found. Generally, the components that need to be unfolded are mostly shells, which have flat shells and curved shells.
1) Flat shell: It is a shell formed by a set of planes, mainly consisting of two types: prism and pyramid. The former has parallel prisms, while the latter has more intersecting prisms. Usually, there are three prisms, four prisms, and three prisms and four pyramids according to the number of prisms. Regular prism shell: the bottom is a Regular polygon, and the edge is perpendicular to the bottom plane. Pyramid shell: the bottom is a polygon, and the cone projection coincides with the center of the bottom Regular polygon, otherwise it is a conical shell. After cutting, various types of cut bodies can appear on the shell. The characteristic of a prismatic shell (truncated body) is that the different projection surfaces of each pair of edges are parallel to each other or intersect at a point. The characteristic of a pyramid shaped shell (truncated body) is that the projections of each edge intersect at a point. A polyhedral shell with four extended edges that do not intersect at a point.
2) Curved shell: A shell with a curved surface or both surfaces is called a curved shell. Curved shells can be divided into two types: rotating or non rotating shells.