Basic Forming Technology of Metal Package Container

Basic Requirements: master general metal packaging container forming process on the basis
Teaching content: 1, blanking process ; 2 , bending ; 3 , stretching principle
Important and difficult: molding process principles of metal barrel production line
Hours Distribution : 2 hours
3.1 blanking process
Punching is the use of a separation of the material die stamping process , including blanking, punching, cutting , trimming and other processes , and cut , but in general often means blanking and punching . The process that can be directly material parts , but also for bending, deep drawing and forming processes to prepare. Washed down from the material parts or blanks of desired shape , called blanking, the desired shape out of the workpiece hole , called punching .
1 , blanking process

( 1 ) elastic deformation . Began punching the punch pressure on the material , because bending moment , elastic compression material not only produce , but also bending and slightly pressed into the material to the die cavity mouth . This stage of the stress state does not meet the conditions of plastic , in the elastic deformation stage .


( 2 ) plastic deformation. Continue pressing punch the material when the material meets the stress state of the plastic condition , plastic deformation occurs at the same time , accompanied by the bending and stretching . As the deformation increases , the mold population, stress concentration generated in the vicinity until the stress reaches a maximum and the emergence of micro- cracks.
( 3 ) fracture splitting . Continuously pressed into the punch has formed the upper and lower micro-cracks within the material gradually expanded to extend the crack when the two coincide , or intersect, the separated material will be cut .

2 , blanking die gap
Based on the analysis of the process to know punching , blanking convex , concave die for blanking the gap between the quality of life and die punching force such a great impact .
( 1 ) determine the value of blanking die gap
① theory to define the method of theoretical determination method is to ensure that the main basis for punching material , while the next two overlap shear cracks intersect at a connection.
② empirically determined law . According to practical experience , often using the following empirical formula to calculate a reasonable gap .


C = mt

( 2 ) blanking blanking die gap on the impact of
3 , convex, concave Edge Sizes calculation
Dimensional accuracy of the mold edge blanking dimensions that affect the accuracy of the primary factors that have to die a reasonable clearance by the mold dimensions and tolerances to ensure cutting edge .
4 , blanking force and reduction method
( 1 ) punching force calculation : Calculate blanking force aims to design a reasonable selection of presses and molds. Obviously the press must be greater than the calculated Ton punching force to meet the requirements of blanking .
( 2) reduce the punching force approach: the punching or thick high-strength material , the surrounding length of the workpiece , the required punching force may exceed the available press tonnage, the case must be considered to reduce the punching forcemeasure.
5 , fine blanking
( 1 ) Fine blanking France : fine blanking method , also known as the ring gear plate blanking method . This method and the conventional blanking blanking on the difference in the process , in addition to convex and concave mold small gap and die with rounded outer edge , in the mold structure is also more loaded than ordinary punching die plate with a ring gear a top of the circle .


( 2 ) Semi- fine blanking
6 , renovation
( A ) the outer edge of renovation : the pre- renovation left margin blanking piece is placed on the refurbishment of the die , the punch will be pressed into the die blank , with the remainder being concave die out. Refurbishment and renovation of the outer edge of the mass number , renovation and refurbishment margin mode structure and other factors.
( 2 ) bore renovation : Bore renovation process and the outer edge of the refurbishment similar to the difference is that it is the use of the inner hole punch excision repair margin .The purpose is to correct hole renovation coordinate position , improve the finish and dimensional accuracy of the hole .

3.2 bending
1 , the bending deformation process
( 1 ) Elastic bending phase. Sheet under the applied bending moment bending deformation occurs , the first stage through the elastic bending .
( 2 ) plastic bending phase. With the increase of the applied bending moment , the bending deformation increases, the inner and outer surface of the metal yield limit is reached first , started by the elastic deformation of the sheet metal phase to plastic deformation .

2, the bending deformation characteristics
( 1 ) in the bending deformation of main parts of the fillet portion , and away from the area of the two fillets are not deformed.
( 2 ) In the bending deformation region , the outer region of the tangential length of the metal under tension , the inner region of the tangential pressure reduced to the metal . In both deformation area, the same length with a metal layer , i.e. the strain neutral layer .
3, the minimum bend radius
( A ) the location of the strain neutral layer . In the press sheet , in order to determine the minimum corner radius punch and bending parts of the rough size , you must first determine the location of the strain neutral layer .


( 2 ) to determine the minimum bend radius . In the bending process , the material at the outer fiber tensile stress , when the material thickness is constant, the smaller the bending radius , the larger the tensile stress .
4, the bending springback phenomenon
( 1 ) Rebound values ​​are calculated . After the bending deformation when the external force is not always accompanied by elastic deformation of the bending angle between the center of curvature of the bending radius becomes inconsistent with the size of the mold , a phenomenon known as rebound .

( 2 ) Factors affecting springback

① Mechanical properties of materials ; ② bending deformation ; ③ curved central angle ; ④ bending mode ; ⑤ shape of the workpiece ; ⑥ mold structure


( 3 ) Measures to reduce rebound
5 , a process of bending member
The process of bending a workpiece is bent shape, size , accuracy , material selection and technical requirements such as whether it is bending process requirements.
( 1) The bending radius of the bending member
( 2 ) the shape of the bending member
( 3 ) bending piece hole edge distance

( 4 ) bending pieces straight edge height

( 5 ) the design process , the groove


3.3 Principle drawing
The plates were made ​​of rough openings through the drawing die cylindrical or other cross-sectional shape of parts , or other tubular or cylindrical cross-sectional shape of the blank and then made or other cross-sectional shape of the parts, such as deep drawing process ( or drawing ) .

1 , drawing deformation process
( 1 ) die orifice flange portion . This part of the material tensile stress in the radial and tangential stress joint action , the material plastic deformation gradually into the die .


( 2 ) rounded part of the die in addition to the region that part of the material that the radial tensile stress and tangential compressive stress , is also exposed to the pressure at the die radius , friction and bending stress generated , which is a transition zone .

( 3) The tube wall section. This material has a tubular part , the material will not have a large deformation .
( 4 ) punch fillet portion . This part of the punch fillet material to withstand the effects of radial and tangential tensile stress. Also withstand the pressure and punch bending radius in the thickness direction of the stress.
( 5 ) cylindrical bottom portion . Further material drawing process remain flat , does not produce large deformations , but because the tensile force of the punch , the material to withstand tensile stress and bidirectional slightly thinner.

2 , the mechanical analysis of deep drawing process
( 1 ) The stress distribution flange deformation zone

( 2 ) analysis of wrinkling phenomenon

( 3 ) crack problem analysis

( 4 ) to overcome the crack and wrinkling of the main measures
① the main measures to prevent crack
② prevent wrinkling of the main measures

3 , drawing coefficient with drawing number
Deep drawing process in the development process and design drawing dies , it must be able to use a pre-determined parts drawing deep drawing process or procedure .
( A ) drawing coefficient

( 2 ) Factors affecting drawing coefficient

( 3 ) Drawing Views

( 4 ) for the first time after drawing each time drawing method

4 , drawing parts and stretching step calculation process
( A ) requirements for deep drawing process

( 2 ) calculation of deep drawing process