Some characteristics of rectangular box-shaped stamping and deep drawing parts

Rectangular box-shaped deep-drawn parts are a relatively common type of deep-drawn parts in daily metal stamping processing. Because the rectangular box-shaped stamping and drawing part has four rounded corners, it has the characteristics different from the round drawing part. Rectangular box-shaped parts can be considered to be composed of rounded corners and straight side parts, and the drawing deformation can be approximated as: the rounded corners are equivalent to the drawing of cylindrical parts; and the straight side parts are equivalent to simple bending. However, since the straight edge part and the rounded corner part are not completely separated, they are connected as a whole. Therefore, it is necessary to observe and analyze through experiments. If the rectangular box blank is drawn on the upper grid, the vertical spacing is n, the horizontal spacing is b, and au003db. After drawing, the square grid changes (as shown in Figure 3-61): the horizontal spacing decreases, and the closer it is to the corners, the more it shrinks; the vertical spacing increases, and the higher the upward, the more the spacing increases. The edge part is not simply curved, because the material in the corner of the garden has to flow to the straight edge part, so the straight edge part is still squeezed. Similarly, the rounded part is not exactly the same as the drawing of the cylindrical part. Due to the presence of the straight edge part, the material of the rounded part can flow to the straight edge part, which reduces the degree of material deformation of the rounded part (same as Straight cylindrical parts with fillet radii). From the point of view of drawing force, due to the internal connection between the straight side part and the rounded corner part, the straight side part bears the bending resistance, but also bears the compression deformation resistance; while the rounded corner part is reduced due to the degree of deformation (with the corresponding round Compared with cylindrical parts), the deformation resistance that needs to be overcome is reduced. It can be considered that because the straight side part shares the drawing deformation resistance of the rounded corner part, the drawing force of the rounded corner part is smaller than the drawing force of the corresponding cylindrical part. The characteristics of the rectangular box-shaped stamping and drawing parts are as follows. (1) The distribution of radial tensile stress along the periphery of the box is uneven, with the largest at the rounded corners and the smallest at the straight side, and the distribution of a3 is also the same. Secondly, as for the corners, due to the uneven stress distribution, the average tensile stress is much smaller than that of the corresponding cylindrical parts (the latter's tensile stress is evenly distributed). Therefore, in terms of the load at the dangerous section, the box-shaped part is much smaller. Therefore, for the same material, the drawing coefficient of the box-shaped piece can be small. (2) Since the compression (extrusion) stress is the largest at the corners and gradually decreases toward the straight side, compared with the corresponding cylindrical parts at the corners, the stability of the material is strengthened and the tendency to wrinkle is reduced, The straight side part rarely wrinkles. (3) The magnitude of the mutual influence of straight edges and rounded corners varies with the shape of the box-shaped piece. If the relative rounded semicircle rffi/B and the relative height H/B (B is the short side of the rectangular part) are different, there are big differences in the methods of rough calculation and process calculation. Previous post: Furniture hardware stamping parts are the cornerstone of the development of the furniture industry