First, the blanking process Blanking is the use of a die to separate the material of a stamping process, including blanking, punching, cutting, cutting and trimming processes, but under normal circumstances often refers to blanking and punching. This process can be directly made of materials into parts, but also for bending, deep drawing and forming processes. Punching down a part or blank of a desired shape from a material is called blanking. Punching a hole of a desired shape on the workpiece is called punching.
1, punching process (1) elastic deformation. (2) plastic deformation. (3) fracture separation.
2. Blanking Die Clearance (1) Blanking Die Clearance Value Determination (2) Punching Die Clearance Impact on Punching
3, convex and concave die edge size calculation Die edge size accuracy is the impact of the size of the blanking part of the first factor, the mold clearance is also due to the die edge size and tolerance to ensure.
4. Punching force and its reducing method (1) Calculation of punching force (2) Method of reducing punching force
5, precision blanking (1) fine red (2) semi-precision
6. Renovation (1) Rim Renovation (2) Interior Renovation
Second, the bending process
1, bending deformation process (1) elastic bending stage. (2) plastic bending stage.
2. Characteristics of the bending deformation process (1) The deformation zone is mainly located in the rounded part of the bending part, but no deformation occurs in the two sections far from the fillet area.
(2) In the bending deformation zone, the tangential metal in the outer zone is stretched, and the tangential metal in the inner zone is compressed short. In these two deformation zones, there is a layer of metal with the same length, ie a strain-neutral layer.
3, the minimum bending radius (1) the position of the strained neutral layer. When stamping the sheet material, the position of the strain-neutral layer must be determined in order to determine the minimum fillet radius of the punch and the blank size of the bent part.
(2) Determination of the minimum bending radius. During the bending process, the fiber of the outer layer of the material is subjected to tensile stress. When the thickness of the material is constant, the smaller the bending radius, the greater the tensile stress.
4, bending rebound phenomenon (1) Calculation of the rebound value. When the bending deformation is not affected by the external force, it is always accompanied by elastic deformation, so that the bending center angle and the bending radius become the same as the size of the mold, which is called rebound.
(2) Factors affecting the rebound amount 1 Mechanical properties of the material 2 Bending deformation degree 3 Bending center angle 4 Bending method 5 Workpiece shape 6 Mold structure (3) Measures to reduce rebound
5. The processability between the bending of the bending part refers to the requirement of the shape, size, and precision of the bending work piece, and whether the material selection and technical requirements are in compliance with the bending process requirements.
(1) Bending radius of the bending piece (2) Shape of the bending piece (3) Distance between holes of the bending piece (4) Straight edge height of the bending piece (5) Design process
Third, the deep drawing process
The flat blank is passed through a drawing die to form an open cylindrical or other cross-sectional shaped part, or a tubular or other cross-sectional shaped blank is reworked into a cylindrical or other cross-sectional shaped part, and this process becomes deep drawing (or drawing) ).
1, deep drawing deformation process (1) concave mouth flange part.
(2) The corner radius of the die is in addition to the radial tensile stress and the tangential compression stress in the above-mentioned area, and it also bears the compressive stress resulting from the pressure, friction, and bending at the corners of the die. A transition zone.
(3) The wall portion.
(4) Punch rounded corners.
(5) The bottom part of the cylinder.
2. Mechanical analysis of deep drawing process (1) Stress distribution in flange deformation area (2) Analysis of wrinkling phenomenon (3) Analysis of cracking problem (4) Main measures to overcome cracking and wrinkling
3ã€Drawing coefficient and drawing times When drawing the drawing process and designing drawing dies, it is necessary to determine in advance whether the parts can be deepened with a drawing process or with multiple processes.
(1) Drawing factor (2) Factors affecting drawing factor (3) Drawing times (4) Drawing methods after drawing for the first time
4. Calculation of processability and drawing process of drawing parts (1) Technological requirements of drawing parts (2) Calculation of drawing process