Stretch forming is a stamping process that uses moulds to form blank blanks into open hollow parts. Many metal stamping manufacturers in China are using stretch forming. As one of the main stamping processes, it is widely used. With the stretching process can be made into cylindrical, rectangular, ladder, spherical, conical, parabolic shape and other irregular shape of thin wall parts, if with other stamping forming process, but also can make more complex shape parts.
Use stamping equipment to carry out tensile forming processing of products, including: stretching processing, redrawing processing, reverse drawing and thinning drawing processing, etc. Drawing processing: using the pressing plate device, the punch pressure is used to pull part or all of the flat plate into the concave model cavity, so that it is formed into a container with a bottom. The processing of the side wall of the container and the drawing direction parallel is a simple drawing process, and the drawing processing of the conical (or angular cone) shaped container, hemispherical container and parabolic surface container, which also includes the expansion processing.
Redrawing processing: that is, for the deep drawing products that cannot be completed by a drawing processing, it is necessary to draw the forming products again to increase the depth of the forming container.
Reverse drawing processing: reverse drawing of the workpiece before the process, the inside of the workpiece into the outside, and make its diameter smaller processing.
Thinning stretch processing: the punch will have formed the container squeezed into the concave model cavity slightly smaller than the outer diameter of the container, so that the outer diameter of the container with the bottom becomes smaller, and the wall thickness becomes thinner, not only eliminating the wall thickness deviation, but also making the surface of the container smooth.