Stamping is a kind of pressure processing method which uses the die installed on stamping equipment (mainly press) to exert pressure on the material to make it separate or deform plastically, so as to obtain the required parts (commonly known as stamping or stamping parts). Stamping is usually the deformation processing of materials at room temperature, mainly using sheet metal to process the required parts, so it is also called cold stamping or sheet metal stamping. Stamping is one of the main methods of material pressure processing or plastic processing, which belongs to material forming engineering.
The die used for stamping is called stamping die, or stamping die for short. Stamping die is a special tool for batch processing materials (metal or nonmetal) into required stamping parts. Stamping die is very important in stamping. Without the required stamping die, it is difficult to carry out mass stamping production. Without advanced stamping die, advanced stamping technology cannot be realized. Stamping technology, die, stamping equipment and stamping materials constitute the three major elements of stamping processing, and only by combining them can stamping parts be obtained. Compared with other mechanical processing and plastic processing methods, stamping has many unique advantages both technically and economically. The main performance is as follows.
(1) The stamping production efficiency is high, the operation is convenient, and it is easy to realize mechanization and automation.
(2) During stamping, because the die ensures the accuracy of the size and shape of the stamping parts, it generally does not damage the surface quality of the stamping parts, and the die life is generally long, the stamping quality is stable, the interchangeability is good, and it has the characteristics of "identical".
(3) Parts with large size range and complex shapes can be processed by stamping, such as stopwatches as small as clocks and watches, as large as automobile longitudinal beams and panels. In addition, the cold deformation hardening effect of materials in the stamping process makes the stamping strength and stiffness higher.
(4) Stamping generally does not produce chips and waste materials, requires less materials, and does not need other heating equipment. It is a material-saving and energy-saving processing method, and the cost of stamping parts is low.
Because there are many kinds of stamping parts, and the shape, size and precision requirements of various parts are different, the stamping process methods used in production are also diverse. To sum up, it can be divided into two categories: separation process and molding process; Separation process refers to the stamping process of separating the blank along a certain contour line to obtain a certain shape, size and cross-sectional quality (commonly known as stamping parts); Forming process refers to the process of plastic deformation of blank without fracture to obtain stamping parts with a certain shape and size.
According to the different basic deformation modes, the above two processes can be divided into four basic processes: blanking, bending, drawing and forming, and each basic process includes a variety of single processes.
In actual production, when the production batch of stamping parts is large, the size is small, and the tolerance requirements are small, it is uneconomical and even difficult to meet the requirements if a single discrete process is used for stamping. At this time, the centralized scheme is often adopted in the process, that is, two or more single processes are concentrated in a pair of molds, which is called combination method, and can be divided into three combination methods: compound-step method and compound-step method.
Compound stamping-a combined method of completing two or more different single processes on the same station of the die in a working stroke of the printing machine.
Progressive stamping-a combination of two or more different single processes in a certain order at different stations of the same mold in a working stroke of the printing press.
Compound-Progressive-A combined process including compound and progressive methods on a pair of molds.
There are also many kinds of mold structures. Generally, it can be divided into blanking die, bending die, drawing die and forming die according to the technological properties. According to the process combination, it can be divided into single-process die, compound die and progressive die. But no matter what kind of mold, it can be regarded as an upper mold and a lower mold.
The upper die is fixed on the workbench or pad of the press, which is the fixed part of the stamping die. When working, the blank is positioned on the lower die surface through the positioning part, and the upper die is driven by the slider of the press to press down, and the blank is separated or plastically deformed under the action of the working parts of the die (i.e. the punch and the die), so as to obtain the stamping parts with the required shape and size. When the upper die rises, the discharging and discharging device of the die unloads or pushes out the punch or waste from the punch and die for the next stamping cycle.
This design designs a set of cold stamping die for a given part, in which the design content is to analyze the stamping process of the part (material, workpiece structure shape, dimensional accuracy), draw up the stamping process scheme and die structure, layout, plate blanking, calculate the stamping process pressure, select the press and determine the pressure center, calculate the cutting edge size of the punch die, design the structure and processing technology of the main parts, and check the press.
Design theme of blanking die
As shown in figure 1, parts: pad wrench.
Production batch: large batch
Material: 08F t=2mm
Design the stamping process and die for this part.
2 process analysis of parts
2. 1 structure and size
The part is simple in structure and symmetrical in shape.
Hard steel materials are stamped with a free punch. According to Table 3-8 of Cold Stamping Technology and Die Design, the minimum stamping size of the workpiece is 1.3t, and the aperture of the workpiece is φ 6 >1.3t =1.3× 2 = 2.6.
Because the punching edge of the blanking part is not parallel to the edge of the workpiece shape, the minimum hole allowance should not be less than the material thickness t, and the blanking allowance of the workpiece is (20) >: t=2, (10) > 0; T=2, both are suitable for blanking.
2.2 Accuracy
The internal and external dimensions of the part are not marked with tolerance and belong to free dimensions. The dimensional tolerance of workpiece can be determined according to IT 14. After looking up the table, the tolerance of each dimension is as follows:
Part shapes: 58, 38, 30, 16, 8.
Internal shape of parts: 6
Hole spacing: 18 0.2 15,
The common blanking method can meet the requirements of part drawing.
2.3 materials
08F, belonging to carbon structural steel. According to the schedule of cold stamping process and die design 1, the shear strength τ=260MPa and the elongation at break = 32%. This material has good plasticity, high elasticity and good stamping performance.
According to the above analysis, the part has good manufacturability and can be punched.
3. Determine the blanking process scheme
This part includes two basic processes: blanking and punching, and the following process scheme can be adopted:
(a) blanking first, then punching, and adopting a single-process die for production;
(b) blanking-punching composite stamping is adopted, and a composite die is adopted for production;
(c) Punching and blanking are used for continuous punching, and progressive dies are used for production.
Scheme (1) The die structure is simple, but it needs two processes, and two sets of dies can complete the processing of parts, so the production efficiency is low and it is difficult to meet the requirements of mass production of parts. Because of the simple structure of parts, in order to improve production efficiency, compound blanking or progressive die blanking is mainly used. When using compound blanking, the punched parts have good accuracy and straightness, high production efficiency and convenient operation. By designing reasonable die structure and layout scheme, better parts quality can be obtained.
According to the above analysis, the part adopts the compound blanking process scheme.
4. Determine the overall structural scheme of the die.
4. 1 mold type
According to the blanking process scheme of the parts, a compound blanking die is adopted. The main structural feature of the compound die is that it has a double-function structural component-convex-concave die, which is called flip-chip compound die when it is installed in the lower die. The use of flip-chip compound die omits the ejection device, which is simple in structure and convenient to operate, so the flip-chip compound blanking die is used.
4.2 Operation and Positioning Mode
Although the production batch of parts is large, reasonable arrangement of production and manual feeding can meet the batch requirements and reduce the cost of molds, so manual feeding is adopted. Considering the size and material thickness of the parts, in order to facilitate the operation and ensure the accuracy of the parts, it is advisable to use the guide plate to guide, fix the stop pin to stop the material, and cooperate with the guide pin to ensure the accuracy of the feeding position, thus ensuring the accuracy of the parts. In order to ensure the positive blanking distance of the first piece, the first stop pin is adopted, and the purpose of using the stop pin is to improve the material utilization rate.
4.3 Unloading and discharging methods
The elastic unloading mode is adopted for unloading, and the elastic unloading component relies on the elasticity of rubber for unloading, so the unloading force is not great, but it can also play the role of pressing materials during stamping and ensure the flatness of the surface of stamping parts. In order to facilitate the operation and improve the productivity of parts, stamping parts and waste materials are pushed directly from the holes of the female die by the male die.
4.4 Mold base type and accuracy
Considering the convenience of feeding and operation, the mould base adopts the back guide post mould base, which is guided by the guide post guide sleeve. Because the precision requirement of parts is not very high, but the blanking gap is small, I-level mold base precision is adopted.
4.5 punch design
Structure form and fixing method of punch;
The cutting edge of blanking punch is non-circular. In order to facilitate the processing of punch and fixed plate, it can be designed as fixed step type. The middle step of the punch and the fixing plate are in transition fit with H7/m6. The biggest step at the top of the punch is to block the punch with the shoulder, so that it will not be pulled out of the fixed plate of the punch when discharging. The mounting part is designed into a rectangle which is convenient for machining and is fixed with the punch fixing plate through connection.
5 process design calculation
5. 1 Layout Design and Calculation
The shape of the part is approximately rectangular, and the external dimension is 58×30. Considering the convenience of operation, and in order to ensure the accuracy of parts, the waste material is directly laid out. As shown in figure 1:
Check the cold stamping process and die design table 3- 13, the workpiece lap value a=2, and the lap value along the edge a 1=2.2. The feeding step of progressive die is s = 30+2 = 32 mm
The strip width is calculated according to the formula in Table 3- 14:
B -0△=(Dmax+2a 1)-△0 Look up table 3- 15: △=0.6.
B=(58+2×2.2) =62.4 (㎜)
The part drawing approximately calculates the area of a part as 1354.8㎜2, which is the bad material area within a feed distance.
B×S=62.4×32= 1996.8㎜2. Therefore, the material utilization rate within a certain distance is:
=(A/BS)× 100 \u= 67.8
Check the cold stamping process and die design table 3, and the sheet specification is 7 10×2000×2.
When transverse cutting is adopted, the size of the cut strip is 62.4. A board can cut 32 pieces, and each piece can punch 22 parts. The material utilization rate of the plate is:
=(n×A0/A)× 100
=(22×32× 1354.8/7 10×2000)× 100﹪=67.2﹪
When longitudinal cutting is used, the size of the cutting belt is 62.4. The number of strips that can be cut for a board is 1 1, and the number of parts that can be punched is 62, so the material utilization rate of a board is:
=(n×A0/A)× 100
=( 1 1×62× 1354.8/7 10×2000)× 100﹪=59.2﹪
According to the above analysis, the material utilization rate of the plate is higher when it is cut horizontally than when it is cut vertically, so it is cut horizontally.
5.2 Calculate the punching force and pressure center, and select the press.
Punching force: according to the part drawing, the outer circumference of the part can be calculated:
L 1= 16π+8+28+38×2
Sum of inner perimeter:
L=2π×3= 18.84㎜
See attached table1:MPa for cold stamping process and die design;
According to the cold stamping process and die design in Table 3, Kx=0.05 and KT=0.055.
Punching force:
F fall =KL 1 t T
= 1.3× 162.27×2×260
= 109.69 kn
Impact force:
F hole =KL2 t T
= 1.3×6 ×2×260
= 12.74
(=knot) in the sea
Discharge power:
Fx=KxF descent
=0.05× 109.69
= 5.48 kn
Thrust:
Accord to that thickness of the material, the height h of the straight wall of the punching edge is taken as 6,
Therefore: n=h/t=3.
FT=nKtF hole
=3×0.055×25.47
=4.20KN
Total impact force:
Fк= F+F hole +Fx+ FT
Then f ё =109.69+12.74+5.48+4.20.
= 132. 1 1KN
Nominal pressure of the press to be selected: 25t.
Therefore, the press model can choose J23-25.
When the structure and size of the die are determined, the closing height of the press and the installation size of the die can be checked, so as to finally determine the specifications of the press.
Determine the pressure center; Draw the cutting edge of the mold; Establish a coordinate system as shown in the figure;
As can be seen from the figure, the shape is symmetrical up and down about the X axis and left and right about the Y axis, so the pressure center is the geometric center of the figure. That is, the coordinate origin o, and the coordinate of this point is (0,0).
5.3 Calculate the cutting edge size and tolerance of punch and die.
Because the gap between dies is very small, it is suitable to cooperate with convex and concave dies for processing. Due to the gap between the male and female dies, the falling material or punch hole is tapered. The size of the blanking piece is close to that of the female die cutting edge, while the size of the blanking piece is close to that of the male die cutting edge. When calculating the cutting edge size of punch and die, blanking and punching should be carried out separately. Therefore, the following principles should be followed when determining the size of die-cutting edge and its manufacturing tolerance:
(1) when blanking, taking the size of the female die as a benchmark, that is, determining the cutting edge size of the female die first; Considering that the cutting edge size of the female die increases due to wear during use, the basic size of the fixed blanking part should be smaller within the tolerance range of the workpiece size, while the basic size of the punching punch should reduce the minimum initial gap according to the basic size of the female die;
(2) Punching is based on the size of the punch, that is, the cutting edge size of the punch is determined first. Considering that the size of punch is reduced due to wear in use, the basic size of fixed punch should be larger within the tolerance range of workpiece size, and the basic size of punch should be subject to the basic size of punch plus the minimum initial gap;
(3) The manufacturing tolerance of punch and die depends on the requirements of the workpiece, and the general accuracy is 2-3 levels higher than that of the workpiece. Considering that the female die is slightly more difficult to process than the male die, the female die is one level lower than the male die.
A): the cutting edge size of the blanking die. According to the classification of wear:
I) The increased size of the die after wear is based on the formula of cold stamping process and die design: da = (dmax-x△); Calculation, take Δ A = △/4, and the part accuracy is IT 14, so X=0.5.
58:da 1 =(58-0.5×0.74)= 57.63(㎜)
38 : DA2=(38-0.5×0.62) =37.69 (㎜)
30 : DA3=(30-0.5×0.52) =29.74 (㎜)
16:DA4 =( 16-0.5×0.43)= 15.785(㎜)
8:DA5 =(8-0.5×0.36)= 7. 18(㎜)
Ii) The constant dimension of the worn die is calculated according to the cold stamping process and die design formula: Ca = (cmin+x △) 0.5 δ A:, and δA=△/4, and the precision of the part is IT 14, so X=0.5.
18 0.2 15:CD 1 =( 17.785+0.5×0.43)0.43/8 = 18 0.05375(㎜)
Blanking clearance affects the quality of blanking parts. Under normal blanking conditions, clearance has little influence on blanking force, but has great influence on discharging force and pushing force. Clearance is the main factor affecting the life of die. The gap directly affects the friction. On the premise of satisfying the quality of blanking parts, the gap is generally large, which can reduce the blanking force and improve the die life.
According to table 3-3 of cold stamping process and die design, zmax = 0.360mm and zmin = 0.246mm..
Match the corresponding punch according to the actual size of the female die, and the minimum reasonable gap is 0.246 mm
Dimensions of cutting edge of punching punch. Punching punch is circular, which can be calculated according to the formulas dT=(dmin+x△) and δT=△/4 in cold stamping process and die design. The precision of the part is IT 14, so X=0.5.
12:dt 1 =(6+0.5×0.30)= 6. 15
6 design and select parts, and draw the sketch of die assembly.
6. 1 mold design
Structural form and fixing method of female die: The female die adopts rectangular plate structure and is fixed in the female die fixing plate with screws and pins. The distance between the screw and pin and the hole wall of the female die should not be too small, otherwise it will affect the strength and life of the die. See Table 3-23 of Cold Stamping Process and Die Design for its numerical values.
Structural form of die-cutting blade: Due to the large batch of stamping parts, considering the wear of the die and ensuring the quality of stamping parts, the die-cutting blade adopts a straight side wall structure, the height of the side wall is 6mm, and the leakage part is unilaterally expanded by 0.5 mm along the edge contour.
Determination of outline size of female die;
Check table 3-24 of cold stamping process and die design, and get: K = 0.28.
Check table 3-25 of cold stamping process and die design, and s2 = 36.
Thickness of female die H=ks=0.28×58= 16.24(㎜).
B=s+(2.5~4.0)H
=58+(2.5~4.0)× 16.24
=98.6~ 122.96 (㎜)
L=s 1+2s2
=30+2×36
= 102 (㎜)
According to the calculated outline size of the die, the standard outline size of the die close to the calculated value is selected as L× b× h =125×125× 28.5 (㎜).
Material and technical requirements of female die: T 10A is selected as the female die material. The workpiece is locally hardened to HRC58~62. The edges and corners of the outer contour should be blunt.
As shown in Figure 2:
Figure 2 Punching die
6.2 punch design
6.2. 1 punch structure and fixing method
The cutting edge size of the punching part punch is circular. In order to facilitate the processing of the punch and the fixed plate, the punching punch is designed as a step.
In order to ensure the strength, rigidity and ease of processing and assembly, a circular punch is often made into a step with smooth transition and a cylindrical part with a small end. It is a working part with sharp cutting edge, and the middle cylindrical part is the installation part, which is matched with the fixing plate according to H7/m6. The tail shoulder ensures that the punch will not be pulled out when discharging, and the circular punch is fixed by shoulder.
6.2.2 Calculation of Punch Length
The length of the punch depends on the structure of the die.
When elastic unloading is adopted, the punch length is calculated according to the formula L=h 1+h2+h3.
Where l-punch length, mm;
H 1-thickness of punch fixing plate, mm;
H2—— thickness of discharge plate, mm;
H3- Thickness of unloading elastic element after preloading.
L = 22mm+10mm+18.5mm.
= 50.5 mm
6.2.3 Strength and rigidity inspection of punch
Generally speaking, the punch has enough strength and rigidity. Because the section size of the punch is moderate and the estimated strength is sufficient, it is only necessary to check the stiffness.
Check the rigidity of the punching punch;
The maximum free length of the punch shall not exceed the following formula:
Guide punch Lmax≤ 1200, in which Imin=∏d4/64 is a circular punch.
Then lmax ≤ lmax ≤1200 = 24.00 mm.
It can be seen that the working length of the punch in the punching part cannot exceed 24.00mm, and the length of the punch is 50.5 according to the punch length series in the punching standard.
6.2.4 Punch material and technical conditions
The punch is made of carbon tool steel T 10A, the working end (i.e. cutting edge) of the punch is hardened to HRC 56 ~ 60, and the hardness of the punch tail is HRC 43 ~ 48.
As shown in Figure 3:
Figure 3 Punching punch
6.3 Design of punch and die
6.3. 1 Structure form and fixing method of male and female dies
The structural schematic diagram of the punch is shown in Figure 4:
Figure 4 Punching
The punch die and the fixing plate of the punch die are matched by H7/m6.
6.3.2 Check the strength of punch and die.
When the stamping edge is not parallel to the outer edge of the workpiece, the minimum wall thickness of the punch should not be less than the material thickness t=2mm, while the actual minimum wall thickness is 5mm, thus meeting the strength requirements.
6.3.3 Determination of punch and die size
The size of the outer cutting edge of the punch is matched according to the size of the female die, and the minimum clearance is guaranteed to be Zmin=0.246mm, and the size of the inner cutting edge is matched according to the size of the male die, and the minimum clearance is guaranteed to be zmin = 0.246 mm. ..
6.3.4 Materials and technical conditions of punch and die
The punch and die are made of carbon tool steel T 10A, hardened to 56 ~ 60 HRC.
6.4 Positioning parts
The function of positioning parts is to make the blank or workpiece have the correct position relative to the convex and concave die on the die.
Select a fixed stop pin. The positioning pin is used to block the edge of the strip or the outline of the punch to limit the feed distance of the strip. The fixed stop pin is fixed on the convex-concave die located in the lower die. The specification is GB/T7694. 10-94, the material is 45 steel, and the hardness is 43 ~ 48 HRC.
Select two guide pins. The role of the guide pin is to ensure that the aluminum strip is fed in the right direction. It is located on the back of the test strip (the test strip is transported from right to left), and its size is 6X2, as shown in Figure 5:
Fig. 5 guide pin
6.5 Unloading and discharging device
The discharging mode is the lower discharging mode directly ejected by the punch.
Because the unloading adopts elastic unloading mode, the elastic unloading device consists of unloading plate, unloading screw and elastic element.
Discharging plate:
The plane size of the elastic stripper is equal to or slightly larger than that of the female die, and its thickness is 0.6 ~ 0.8 times that of the female die. The unilateral clearance between stripper and punch is selected according to Table 3-32 of Cold Stamping Process and Die Design. When t > 1 mm, the unilateral clearance is 0.15 mm.
In order to facilitate reliable unloading, when opening the die, the working plane of the unloading plate should be 0.3 ~ 0.5 higher than the end face of the punch edge. The size and specification of the discharging plate are:125mmx125mmx10mm, and the material is 45# steel. As shown in Figure 6:
Fig. 6 Discharging plate
Discharge screw:
The discharging screw is a standard stepped screw, and four discharging screws are selected according to the size of the discharging plate. The specification is JB/T7650.5-94. As shown in Figure 7:
Fig. 7 Discharge screw
Unloading equipment:
Rubber is chosen as an elastic element because it allows to bear a large load and is easy to install and adjust.
Selection principle of glue discharge:
In order to ensure the normal work of unloading, the elastic force of rubber should be greater than or equal to the unloading force FX.
FXY=AP≥FX=5.48KN
Where FXY— refers to the elastic force of rubber when working, a refers to the cross-sectional area of rubber, and p refers to the unit pressure related to rubber compression. Generally, the compression during preloading is 10% ~ 15%. According to the cold stamping process and die design drawing 3-64, take P=0.6MPa and get a = 91.3cm2. According to the formula in table 3-33 of cold stamping process and die design, the rubber size specification is 35×26×24.
According to the material thickness of the workpiece is 2mm, the depth of the punch entering the female die during blanking is 1mm, the grinding allowance is 2mm during die repair, and the stripper is higher than the punch 1mm during die opening, the total working stroke is obtained: h workpiece =6mm,
When using rubber, the maximum compression should not exceed 35% ~ 45% of the free height of rubber, otherwise the free height of rubber should be:
H=h/(0.25~0.30)
=6/(0.25~0.30)
= 20 ~ 24mm
The preloading in the process of mold assembly is:
H pre = ( 10% ~ 15%) h
= 2.4 ~ 3.6 mm
Take hpre = 3 mm.
It can be seen that the height dimension of the mounting rubber is 2 1 mm,
H in the formula refers to the required working schedule.
The height obtained from the above formula is still checked by the following formula:
0.5≤H/B≤ 1.5
If the H/D exceeds 1.5, the rubber shall be divided into several sections and steel rings shall be placed between the rubber.
According to the formula in Table 3-33 of Cold Stamping Process and Die Design, the rubber size is 35×26×24.
6.6 Selection of templates and other components
6.6. 1 die handle
The function of the die handle is to fix the upper die on the slider of the press, and at the same time make the center of the die pass through the pressure center of the slider. The diameter and length of the die handle are consistent with the slider of the press. The die handle is a flange die handle, which is fixed on the upper die base with 3 ~ 4 screws.
As shown in Figure 8:
Fig. 8 Mold handle
Die base
The standard die frame is selected according to the type of die frame and the coextensive size of the die.
Upper die holder: 65438+125mm×125mm× 35mm; ;
Lower die holder:125mm×125mm× 45mm;
The die base is made of gray cast iron, which has good shock absorption and adopts brand HT200.
pad
The function of the backing plate is to bear and disperse the pressure transmitted by the punch or die to prevent the die base from being damaged by extrusion.
Whether to use this board can be checked by the following formula:
P=F 12/A
Where p is the unit area pressure of the punch end face to the die holder;
F12-the total pressure of the punch;
A refers to the end face and bearing area of the punch.
Because the calculated P value is greater than the allowable pressure of die base material in Table 3-34 of Cold Stamping Technology and Die Design, a backing plate is added between the working part and the die base.
The backing plate is made of 45 # steel and its quenching hardness is HRC 43 ~ 48. Its dimensions and specifications are as follows:
125mm×125mm×10mm.
The upper and lower surfaces should be smooth to ensure parallelism.
As shown in Figure 9:
Fig. 9 gasket
The standard die set with rear guide pillar is selected as the die set:
Upper die holder: l× b× h =125mm×125mm× 35mm.
Lower die holder: l× b× h =125mm×125mm× 45mm.
Guide column: d× l = ~ 22mm× 150mm.
Guide sleeve: d× l× d = φ 35mm× 85mm× φ 38mm.
Formwork closing height:160 ~190 mm.
Thickness of backing plate:10mm; ;
Thickness of punch fixing plate: 22 mm
Thickness of upper die bottom plate: 35 mm,
Thickness of female die: 28.5mm.
Rubber thickness: 24 mm
The thickness of the discharge plate is10mm.
Thickness of die fixing plate: 45 mm,
Thickness of bottom plate of lower die: 45 mm
Mold closing thickness:
HD = 35+ 10+22+28.5+2+ 1+45+45
=188.5mm
Selection of stamping equipment
Select open double-column tilting press J23-25.
The nominal pressure is 25t,
The stroke of that slide block is 65 mm,
The maximum closing height is 270 mm,
The distance from the center line of the slider to the lathe bed is 200mm,
Worktable size: 370 mm× 560 mm,
Pad thickness: 50 mm,
Hole size of die handle: φ 40mm× 60mm.
Selection of fasteners
Upper die screw: the screw plays the role of connection and fastening. The upper die has six screws, made of 45 steel with the size of M8X70, and the lower die has six screws, made of 45 steel with the size of M6X55. The pin plays the role of positioning, and also bears a certain bias force. There are three upper dies, made of 45 steel and 6X60 in size.
7 Check the pressure
7. 1 nominal pressure
According to the nominal pressure, the press model is J23-25, and its pressure is 25t >: 15.79t, so the pressure can be checked.
7.2 Sliding stroke
The stroke of the slider should ensure that the blank can be put into the mold smoothly and the stamping parts can be taken out from the mold smoothly. Here, only the thickness of material t=2mm, the thickness of stripper H= 10mm, and the maximum depth of punch into female die 2mm, that is, S1= 2+10+2 =14mm.
7.3 Number of trips
The train number is 105 times/minute. Because the production batch is a medium batch, and it is manually fed, it can't be too fast, so it can be checked.
7.4 Dimensions of Worktable
According to the lower die holder L×B= 125mm× 125mm, 60~ 100mm is left on each side, that is, L1× b1= 325mm× 325mm, and the press table L2× B2 =
7.5 Slider die handle hole size
The die handle hole on the slider is 40mm in diameter and 60mm in depth, and the selected die handle clamping part is 30mm in diameter and 48mm in length, which meets the requirements and can be checked.
7.6 Closing height
According to the press model, hmax = 270mm = 80h 1 = 70.
hmin = Hmax–M = 270-80 = 190
(m is closing height adjustment/mm, and H 1 is gasket thickness/mm)
According to the formula, (hmax–h1)-5 ≥ h ≥ (hmin–h1)+10, and.
(270–70)-5≥ 188.5≥( 190–70)+ 10
That is,195 ≥188.5 ≥120, so the selected press is suitable, that is, the press can be checked.
8. Preparation of machining program for main parts of mould.
8. 1 Technical Requirements for Manufacturing Stamping Die
Die precision is one of the important factors affecting the precision of stamping parts. In order to ensure the mold accuracy, the following technical requirements should be met during manufacturing:
A. The material processing accuracy and heat treatment quality of each part of the stamping die should meet the requirements of the corresponding drawings.
B, template components should comply with the specified processing requirements, the assembled template should be able to move freely, and meet the specified requirements of parallelism and verticality.
C, the function of the mold must meet the design requirements.
D, in order to identify the quality of stamping parts, the assembled die must be tested under production conditions, and trimmed according to the problems existing in the test die until the qualified stamping parts are tested.
8.2 Assembly process
The general assembly drawing is shown in figure 15:
Figure 15 assembly drawing
1-lower die holder 2-guide post 3-socket head cap screw ￠ 8× 70 4-socket head cap screw ￠8×60.
5— guide sleeve 6— punch fixing plate 7— punch 8— backing plate 9— upper die holder 10— pin
11-die handle12-punch13-connecting push rod14-punching die15-discharging plate
16— pusher 17— mold 18— movable pin 19— push plate 20— elastic rubber.
21-die fixing plate 22-discharging screw 23-guide pin