What are the types of stamping and stretching mechanical manufacturing processes?

Stamping and stretching forming is the use of molds to form flat blanks into open hollow parts of the process method. Stamping and stretching process should be combined with equipment, personnel and other actual conditions, select and design a technologically advanced, economically rational, safe and reliable use of the process program. Stretching as one of the main stamping process, with the stretching process can be made into cylindrical, rectangular, stepped, spherical, conical, parabolic and other irregular shapes of thin-walled parts, if with other stamping and forming process, but also to create a more complex shape of the parts. The following is a brief introduction to the types of stamping and stretching process:

I. Types of press molding process

(1) according to the workpiece to be divided. Stamping process according to the workpiece can be broadly divided into two categories of separation process and molding process (also divided into bending, deep drawing, forming).

(2) according to the temperature at the time of stamping to be divided. There are two types of cold stamping and hot stamping according to the temperature at the time of stamping. This depends on the strength, plasticity, thickness, degree of deformation, and equipment capacity of the material, etc., and should also take into account the original heat treatment state of the material and the end-use conditions.

(2) Divided according to the structure of the die. Punching die is to make the sheet material to produce separation or deformation of the tool, which consists of two parts of the upper die and lower die, according to the die structure to divide the process can be divided into simple stamping, continuous stamping and composite stamping three kinds.

Types of stretching process

(1) panel stretching process

Panel is a complex surface shape of the plate stamping parts, in the stretching process in the blank deformation is complex, the nature of its molding is not a simple stretch forming, but the composite molding of the existence of the deep-drawing and expansion at the same time.

(2) curved surface forming process

Curved surface stretch forming, so that the metal plate blank outside the flange part of the flange part of the narrowing of the inner flange part of the elongation, to become a non-straight wall of non-flat bottom of the curved surface of the shape of the hollow of the stamping molding method.

(3) edge stretching process

The flange part of the previous process stretching products for the angular re-stretching, this process requires good plasticity of the material.

(4) depth stretching process

The stretching workpiece which exceeds the stretching limit needs to be stretched more than two times before it can be completed. After stretching in the depth direction of the previous station, the re-stretching process is carried out in the depth direction.

(5) Thinning and stretching process

Different from ordinary stretching, thinning and stretching is mainly to change the thickness of the cylinder wall of the stretched parts in the stretching process. The gap between the convex and concave molds is smaller than the thickness of the blank, the blank straight wall part is under large uniform compressive stress when passing through the gap, the wall thickness is thinned in the stretching process at the same time, eliminating the deviation of the wall thickness of the container, increasing the smoothness of the surface of the container, and improving the precision and strength.

(6) reverse stretching process

Reverse stretching of the workpiece stretched in the previous process is a kind of re-stretching. Reverse stretching method can increase the radial tensile stress, for the prevention of wrinkles can receive a better effect, but also has the potential to improve the stretching coefficient of re-stretching.

Three, the selection of stamping and stretching equipment

(1) the selection of stamping equipment according to the nature of the stamping process to be completed and a variety of stamping equipment, force and energy characteristics, taking into account the stamping of the required deformation force, deformation work and die closure height and the size of the profile size of the main factors, combined with the existing equipment to a reasonable selection of the type of equipment and tonnage.

(2) Commonly used stamping equipment are crank presses, hydraulic presses, etc., of which crank presses are the most widely used. Stamping type stamping process in the crank press, generally do not use hydraulic press; and forming type stamping process can be in the crank press or hydraulic press.

Four, precision stamping and stretching oil selection

Stamping and stretching oil in the stamping and stretching process plays a key role, good cooling performance and extreme pressure and anti-wear properties for the service life of the mold and workpiece precision enhancement has been a qualitative leap. According to the different materials of the workpiece, stamping and drawing oil in the selection of performance focus is not the same, usually according to the difficulty of the stamping process and the method of oil and degreasing conditions to decide.

(1) The materials which are easier to be punched and cut, generally for the sake of the easy cleaning of the finished workpieces, low viscosity stamping and drawing oil will be chosen under the premise of preventing the generation of punching burrs.

(2) the material is easy to produce hardening, requires the use of high film strength, good anti-sintering stamping and drawing oil. General use of stamping and drawing oil containing sulfur and chlorine complex additives, in order to ensure extreme pressure performance at the same time, to avoid the workpiece burrs, rupture and other problems.