Hydraulic press,Stretch forming is a stamping process in which let the flat sheet is formed into an open hollow portion using a processing method. Stretching is one of the main processes for stamping and has been widely used. The drawing process can be used to manufacture irregularly shaped thin wall stampings such as cylindrical, rectangular, trapezoidal, spherical, conical, and parabolic. If combined with other stamping processes, more complicated parts can be produced.
The metal stamping system is used for deep drawing of the product, including deep drawing, re deep drawing, reverse deep drawing and fine deep drawing. Deep drawing is the use of a stamping device that uses the pressure of the punch to pull some or all of the flat plate into the concave mold cavity to form a container with a bottom. The processing of the side walls of the container parallel to the drawing direction is a simple drawing process, and the drawing process of the conical container, the hemispherical container and the parabolic container also includes the unwinding process.
Simple hydraulic press,Re-stretching method: In order to increase the depth of the molding container, it is necessary to process a shaped product that cannot be completed by one drawing to increase the depth of the molding container.
Reverse stretching method: The drawn workpiece in the previous step is reversely stretched so that the inside of the workpiece becomes the outer side and the outer diameter thereof becomes small.
Simple hydraulic press,Thinning stretching method: the forming container is extruded into a concave cavity slightly smaller than the outer diameter of the container by a punch, so that the outer diameter of the bottom container is small and the wall thickness is thin, thereby eliminating the deviation of the wall thickness and making the container The surface container is smooth.
When using metal stamping die for metal stamping and drawing, there are usually the following:
1 Panel stretching method
The panel products are all flat stamping parts with complex surface shapes. In the drawing process, the rough deformation is complicated, and the forming property is not only stretch forming but also deep drawing and expansion composite forming.
2 Elliptical stretching method
Simple hydraulic press,The deformation of the blank on the flange is tensile deformation, but the amount of deformation and the deformation rate vary correspondingly along the contour shape. The greater the curvature, the greater the amount of plastic deformation of the billet; conversely, the smaller the curvature, the smaller the plastic deformation of the billet.
3 Step stretching method
Re-stretch the initial drawing product on the left to form the bottom of the ladder on the right. The deeper part is deformed at the beginning of the drawing, and the lighter part is deformed at the later stage of the drawing. The side wall of the stepped portion is liable to cause shear stress deformation.
4 Cylinder stretching method
The flanged cylindrical stamping part is stretched, the flange and the bottom are in a planar shape, the side walls of the cylinder are axisymmetric, the deformation is evenly distributed on the same circumference, and the blank on the flange is subjected to deep drawing deformation.
5 Rectangular drawing:
A low rectangular part formed by one-time drawing. When stretching, the tensile resistance at the rounded corner of the flange deformation zone is greater than the tensile resistance at the straight edge, and the degree of deformation at the rounded corner is greater than the deformation at the straight edge.
6 Hill drawing:
Simple hydraulic press,When the side wall of the stamping part is a beveled surface, the side wall is suspended during the stamping process, and is not pasted until the forming is completed. The deformation characteristics of different parts of the side wall during forming are not completely the same.
7 Flange drawing:
Simple hydraulic press,The flange part of the product drawn in the previous process is processed by angular re drawing, which requires the material to have good plasticity.