1
General first cut edge, punch positive, pre-break, pressure line, hit bumps, tear, (incision, stretching), punching after blanking, pressing burrs, forming, two-step bending, first formed half After forming the other half.
2
When punching and blanking, it is usually punched first and then punched in large holes;
Firstly, the surrounding waste is washed and then dropped on other parts: if the punched hole is placed behind, when it is punched, there may be gaps on the corresponding material belt around the punch (the ones that have been washed before Hole). In this way, during the stamping process, the punch will cause uneven force (there will be lateral force). The strength of the hole punch is very weak, and the force is uneven. It is extremely easy to break. Of course, this is only In most cases, sometimes according to the actual situation, the small hole can only be ranked behind, but there are still some solutions. If the thickness of the punch is too small, it can be reinforced: A: The use of precision guide off the board; B: punch Using PG (optical grinding) processing.
3
Determine whether to use the edge:
Cutting edge is generally used on continuous die and blanking die. Its role is rough positioning. It is convenient to feed material during die test. Some trimming edges also have the effect of punching the shape. If the die punches the pinhole first, then immediately use it. Guide needle is positive, generally do not have trimming; no guide needle, we must first cut edge, used to distance, generally used in falling blank embryo blanking mold.
The edge punches have the following shapes:
a: This kind of punch is often used in blanking die and thick material cutting edge, positioning accuracy is low, its length = step width, width as long as the punch strength can be controlled, often take 3.0 ~ 6.0
b: The punch head has a 3/4 arc (R often takes 0.3~0.6), its length is <= step, and the purpose of trimming waste is stuck inside to prevent chipping, and is often used for thinning the material. High speed mold
c; This kind of punch is the same as B, it is a change of its shape, in which the role of the V-shape is used to clip the edge scrap to prevent the turning of the shavings. Its angle is 50°~70°.
d: This kind of punch not only cuts sides but also falls into shape.
This type of step head serves as a guide to reduce lateral forces.
4
Prejudgment, will be broken, but it does not mean (usually in front of the station)
As the hardware electronic products often have plating requirements, for the convenience of electroplating, the small products that are washed out are not directly blanked. Instead, they are pre-cut and left on the material belt. After electroplating, they can be removed by hand or mechanical folding twice. Prediagnosis: Both sides must be cut. The depth of cut into each side is generally 4/1 of the material thickness, so that the product can be taken off only by folding twice (up-down); The width is 0.02~0.05, the angle is 50°~70°, and its length is 0.2~0.5 larger than the length of the pre-broken line.
Explanation: In order to facilitate processing and stock preparation and calibration, the thickness of each template in each factory is generally standardized, and the thickness is specified (except in special cases). In the continuous die, it is a form of material for convenience. To control the preload of the tape and the balance of the template, we often grind a tape groove in the middle of the stripper: the depth of the groove = material thickness -0.03 to 0.05 (that is, the preload is 3 to 5) The width of the groove is larger than the width of the material strip by 2~4mm. Therefore, the thickness of the stripper plate often changes with the thickness of the material. The size = stripper plate thickness + material thickness -0.03~0.05 but in the engineering mold , Generally do not need to grind product trough: Because the engineering model products are generally larger and not as narrow and slender as the continuous die tape, that is, the thickness of the engineering die stripper is generally unchanged.
5
Determine the size and position of the hole:
Generally, the continuous die must be punched in order to accurately position the post process. In the engineering die, the inner hole or the shape of the common product part is used to achieve the positioning of the next process. If there is no inner hole, the outer shape cannot be used for positioning. Then only use craft holes: if the first project hits the convex cell and the second project falls out of shape, then in the first project, two process holes are punched at the same time in the opposite corner of the shape (the hole size is related to the material thickness. : Commonly used? 3.0~6.0) for positioning in the next process High-speed stamping die design knowledge
The first step : Tolerance zoom scaling principle of the product diagram:
Since the product rushes out, it always has tiny flashes: its inner hole is generally small and its shape is generally large. As for the size of the burrs, it is related to the punching clearance and the sharpness of the punch and the knife edge: the bigger the blanking gap, After the burr Yu, punch, after the knife passivation, the burrs will increase, so the punch, knife edge rushed for a certain period of time, often need to wear the edge grinding to 0.3 ~ 1.0, the burrs in the end how much and the thickness of the material Relevant: general thin material (T<=0.5) bilateral large 0.01~0.02, thick material (T>0.5) large 0.01~0.05
Step 2 : Expand the dimensions of the product map:
Spread principle: the principle of using the same volume: the total length of a certain section can be obtained by removing the thickness of the material to obtain the unfolding length in that direction. In fact, the unfolding is because the same dimension also depends on each person’s experience. There is no absolute value, as long as the Tolerance range can be.
Highlights: Steps are as follows
01
Understand the product map, imagine its three-dimensional shape and detailed shape (basic requirements before deployment)
02
Find out the thickness and material of the product
03
Specifically expand the calculation:
1 volume method (usually suitable for thinning bending)
2 Open the formula Because the product is stretched or compressed in some places during the bending process, but the length of the bending line can always be found in a certain layer. This constant layer is called the center layer (not the middle layer). It is to use the center floor to carry out the expansion; therefore, if we want to enter the line, we must find the center floor, as shown in Figure 2 set the center layer coefficient is K, the inner radius of bending is r, the material thickness is t, the bending angle is a, L1, L2 are the length of the straight part, and the expanded length is L, then there is L=L1+L2+2Ï€(r+kt)a/360 The coefficient of the central layer coefficient K can be selected according to practical experience according to the following formula
1 When r/t<=0.50, k=0.25
2 when 0.5 3.0 4.0 5 When r/t>4.0 k=0.40~0.50 This formula is suitable for bending expansion calculation of all material thickness. In practical applications, when R/t takes the upper limit, K should also take the upper limit, such as when R/t=1.0, K=0.30 04 When rounding, the calculation formula at this time is not the same as the above, because when the circle is wrapped, the inner circle is squeezed and the outer circle is stretched, but the extrusion is larger than the stretching, so the material becomes thin or almost unchanged. The neutral layer is close to the middle layer and its development length The coefficient of the center layer K is related to the material thickness and the inner radius of the package circle. 1 When r/t<=3.0, the center layer coefficient K=0.45~0.55 2.0 3.0 4 when 15.0 At 5/t>30.0, the central layer coefficient K=0.50. 05 By looking up the table to find out the size of the central layer coefficient, and then performing the expansion calculation, it is not necessary to elaborate here. 06 Rounding of the product: The fillet on the product generally remains the same, but if it is a sharp corner, when t<=0.5, it is generally simulated with the minimum fillet R0.15; when t>0.5, the minimum is used. Rounding R0.2 ~ 0.3 to degenerate it, for the product on the R0.1 round, try to use R0.15 instead; for R <0.1 round or clear corner, if it is an important size (change will affect the function ) It does not change it, use the cut to meet the requirements. The third step : material belt layout design: Principle of nesting: a strip of material is punched, blanked, pressed, burred, stretched, cored, bent, and formed to form the product. Now you have organized how these steps are organized: which is the first, which is the last How many steps, the mutual adjustment between the various processes, so that they inherited the previous, reasonable design layout: the following steps 01 After determining the product development size, according to the direction of the product's burrs, determine the punching and forming direction. Generally, there is no restriction when there is no burr requirement. If the product has rough edges, it must pay attention to its punching and forming direction: Downward or downward forming) Punching burrs remain on the knife edge surface and blanking burrs remain on the punching surface: In general, the shell parts are left in the inside of the product for the sake of beauty and safety performance requirements. Inside) If there are flashing requirements on the drawings, they must be done according to the requirements. If no flash is written, the edges should be kept as far as possible. If the molding is more convenient, it can be left outside. 02 According to the product development size, the rough estimation step (PITCH=maximum length in the direction of the product +1.0~2.0-except for the connecting belt in the middle) is used to make horizontal, vertical, symmetrical, staggered, and oblique rows using the ARRAY command. Use) several programs, analysis, comparison, synthesis, under the premise of ensuring the smooth production of products, select the best program. Specific attention to the following points: 1 The first step is to consider whether the formation is easy and stable. Whether the later step has a destructive effect on the shape of the previous step, or the latter step cannot be formed, and whether the punch and the permeator are strong enough. 2. Should consider whether the material can be fed smoothly in the die, and whether the material can be smoothly sent to the next step after the former step is formed, including considering the height of the float and the position and strength of the connecting belt, the lower the rise, the better. Generally not 1/2 of the thickness of the lower template: because it is too high, it is easy to cause swing, the positioning of the material belt is not Huai and deformation; the connecting belt (also called carrier-CARRY) has the following forms: 1>: No connection band, no waste lined up, the part shape often has symmetry and complementarity, usually a single PIN cut off or double PIN a blanking off, 2>:The edge material connection belt is a form that uses the strip material as waste material as a carrier. This kind of carrier conveys the material belt with good strength and is simple and is mainly used for blanking type packing. 3>:Single connection tape is to leave a certain width of material on one side of the product's strip, and is connected with the product in the appropriate position to realize the transportation of the product's strips. It is generally suitable for trimming type layout. 4>:Dual-connected tapes, which leave a certain width of material on both sides of the product's strips, and are connected to the two sides of the product at appropriate locations to achieve the delivery of the product's strips. It is smoother than single-striped materials. With a higher positioning accuracy, it is suitable for both ends of the product can be connected, especially when the material (t <= 0.4) is thinner, the strength of the material carrier is weak 5>:The center connecting belt is similar to a single carrier. It is a material with a certain width in the middle of the product strip. It is connected with both the front and the back of the product. It saves more material than the former, and it is used more in the bending work piece layout. In the middle of the hole often leading to pull the material, it is often required in the middle of the guide pin staggered plus some elastic top material positioning needle, the selection of the connection band is summarized as follows: After the product is unfolded, carefully analyze the various parts of the product, where it needs to be formed, and where it is only blanked, and then select the appropriate location in the blanking area to draw the connecting tape so that it can ensure the smooth delivery of the material, and it does not Impact on the formation of the product; as for the type of connection to choose, according to the characteristics of the product to be determined. Determine the product size, according to the direction of the product's flash, determine the punching and forming direction, no flash requirements ? third: When the L-shaped bending or single row of the product is encountered, the material utilization rate is too low, symmetrical rows can be considered staggered row, so that the symmetrical forming force is even and the forming is stable; or the material utilization rate can be greatly improved. ? ? Fourth ? To consider punching PIN number and step distance: (Mainly for the connector type of small terminal products, the general hardware shell type or larger workpiece is a single PIN). fifth: It is necessary to consider the material utilization rate, increase the material utilization rate as much as possible, and reduce the production cost. 03 After determining the layout plan, a basic understanding of the entire product stamping and forming process should be obtained at this time. How to arrange the sequence of these processes should be well understood: where to go first and where to go after, which step should be first formed? Which step after the formation, and whether a forming process can be formed at once or in two steps. The size of the guide hole has been described in the previous table. Its position is generally placed on a continuous belt. Sometimes it is placed on the waste and finally washed out together with the waste; generally one guide hole or a few pins Leading hole. 6 ã€Punch blade design Punching knife edge: For the continuous die, it is the part of the material with the waste washed away, leaving the product's unfolded shape and connecting zone; for engineering die, in general, is the punch blanking. The following mainly for continuous die In terms of product development plan, after the tape forming solution is laid out, the next step is how to arrange these steps, generally first hit the bumps, hit the pre-break, punching, tearing, blanking, and then press the edges, forming. The shape is often bizarre, and the shape of the unfolded shape is also necessarily irregular: There may be deep recesses that may be recessed. If the entire shape blanking punch is made in one piece, the collapse may often occur in the punch. Wherever there may be a long, protruding wall, the strength of the knife edge in the area is certainly not sufficient; in some places, the sharp corners are required. In fact, a knife edge punch can not be cut 100%. There is always a sharp corner. The minimum R value (usually R0.15); there is to maintain the stability of the formation of the next step (to increase the pressure area), and first cut a part, after forming, and then cut another part so in order to solve the above problem , we must carry out knife-edge decomposition and put those weak Separate the place to make a different knife edge, use two or more than two steps to cut the overall shape, and note the following points when decomposing: 1 For products that require sharp corners, cutting must be done 2 When there is a strict tolerance requirement (<=%%P0.05) on a certain contour line edge on the product, it is generally not allowed to have a blade joint on this straight line. 3 The punches that are disassembled are simple in shape. Try to use ordinary grinding or wire cutting. 4 The punches to be decomposed must have a certain strength, minimize PG processing, if there is free space, try to make it bigger 5 For the mutual cutting edge, the mutual cutting method (straight line and circular arc) intersecting with the tangent line (usually a straight line and a straight line or a straight line and an arc) or an arc of 60~75%% D is used, and sometimes the arc tangent is also used. (Circles and arcs) or coincident tangent, the length of their mutual tangent lines (usually 0.3 to 0.5 excluding both arcs) should not be too long, too long will produce dust: its purpose is not to produce excessive hair , affect product size and beauty 6 Pay attention to the fillet treatment on the knife edge punch: Usually the line cut min R0.15, but also cut R0.1 round corner but need to change the copper wire (cost increase), so it is not important to round it as much as possible To R0.15, or more R0.2~0.3, but it can not change its functional size: The fillet on the knife edge punch must be shown or added to explain how much the unfilled R is, as for the corner of the stripping plate The rounded corners can be used to clear corners, as well as the edge of the knife. It only acts as a positioning point. When the wire is cut, it automatically clears the corners. PG machining is used for small R0.1 round corners. 7 , knife-edge inserts ( usually son ) size design and production: 1 The purpose of the sub-injection: Its main purpose is to facilitate maintenance: Because many precision hardware has large flash requirements, it must not exceed its specified value, and the mold after punching for a period of time, the punch and knife edge due to frequent friction between the edges of the blunt It becomes unsharpened and causes burrs to increase. If it is done, it is found that where the burrs are too large, it is only necessary to cut the punch edge at the cutting edge grinding 0.2~0.5, and then pad on the back of the corresponding thickness of the gasket If you do not enter the child, then the entire template should be folded down, and then a certain height in the knife edge surface, so that maintenance is more troublesome and reduce the life of the mold; In addition, in the continuous mold and engineering mold, those who easily cracked the edge When the size requirement on a product is very strict, it can be done in this place, which is convenient for maintenance. However, not all molds are made to permeate, because the cost of the mold will increase by 1.5~3. Times, so the specific situation depends on the required accuracy of the product, as well as the production batch and mold type. The following is a brief description of the situation: 1> High-speed precision press die (running speed> 150 times per minute, such as terminal die) In general, the lower die is removed from the panel to infiltrate the permeate. The splint can be used to make no hair. Jianyi (starting from cost saving): No 2> Ordinary continuous die: If the production volume is large, the lower die is generally imported, and the other two are not inserted into the child; when the production volume is small, the lower die may not be inserted into the child; if the size requirement on the product is often changed Or special or difficult to grasp and easy to crack the edge of the knife, where you can design 3>Engineering mold: generally do not enter the child, only in those parts of the knife edge that is easy to crack is designed 2 knife-edge inserts (in) the size of the production, mainly by the stamping material thickness and hardness and knife edge material strength, into the child to do too much, step loose row, this will increase the template, while affecting the template strength It is too small and the knife edge strength is not enough. Therefore, to get the proper value, neither the template nor the strength of the permeator is used. It has been proved that the general outer diameter of the knife edge is generally 3~6mm when it is used for general production. Integer can get the size of knife infiltrated into exudates: For thin materials (T<=0.5), knife edge is often 3~4mm; Jianyi: take 4mm is better; thick material (T>0.5), often knife edge 4~ 6mm, built meaning: take 5.0 1>The material used for the template is usually used: the splint infiltrates the introgression sub-component SKD11, the disengagement of the sub-entry SKD11 or SKH9 (the SKH9 is better than the SKD11), the sub-injection is commonly used SKD11 or SKH9, when large quantities of precision small parts ( Such as the terminal) can also consider the double structure of tungsten steel WC form (WC often take the knife edge 4 ~ 8mm, pad SKD11, the thickness = lower die thickness - upper edge thickness), Note: punch material commonly used: SKD11, SKH9, WC can also be used when the punch is too small (eg PG). 2> lower mold into the child and splint penetrator in order to prevent the installation of reverse, often inverted C angle processing: C angle size often take C1.0 ~ 3.0, off the board due to the presence of lifting ears, can prevent the installation of anti-, generally not Inverted C angle; forming punch with lug or pressure plate groove exists, but also can prevent the installation of anti-, so often do not fall C angle, forming into the child can be inverted C angle Note: There is no strict requirement for the C angle, which is determined by the designer. However, for those parts that are easily mistaken for symmetry and actually asymmetrical, the C corners must be handled. 3> When the template is inserted into the sub-machine, it is generally necessary to hit a threading hole before it can cut the line. Therefore, when drawing the template frame and entering the sub-port, draw a “0.6~1.5 threading hole identifier†in the closed line of the punching knife blade. There are two functions. Of A>: The position of this threading hole can be used for wire cutting reference: if reasonable, the processing personnel will punch the threading hole at this position. This is unreasonable. The processing staff may not punch the thread hole at this position. B>: Another function is to facilitate the design and to check and inquire the relative position relationship between the inner hole and the outer shape to find the mistake. As for this hole, the position of the hole is determined by the size of the knife edge: if the edge of the punch is the smallest Width dimension> 10mm, then draw a threading hole identifier at 5mm from the inner edge line of the hole to reduce the wire cut area, save cost; if <10mm, use a threading hole identifier at the maximum length and width of the inner hole. Drilling threading hole is usually %%C3. If the minimum width dimension is <4mm, the common punching machine (the same as the discharge principle) will punch out the threading hole; if <0.3, the knife edge is often formed by inserting 4> The distance between the template and the child is set: the distance between the two inlets cannot be too large or too small. Loose rows of too many stations increase the size of the template and increase the material cost; the strength of the too small template decreases. Die life, usually the distance between the two inlets (including the molded inlet) is at least >1.5, such as less than 1.5: either cut through the two inlets together or discharge the station to the next station. Sometimes it is also necessary to consider the smoothness of the material being lifted. This position is necessary to install the guide lifter or tip or lifter and there is no position at this position: if not, the station will also be discharged. Next station to go 5>Determination of the clearance of the punching edge of the template punch: a: Hard material and broken material: The unilateral gap between the punch and the knife edge generally takes 5~7% of the material thickness, often takes 5%, such as stainless steel SUS304-1/2H, 3/4H b: Soft material: The gap between the punch and the knife edge is generally taken from 3 to 5% of the material thickness, often taking 4% such as brass, phosphor bronze, aluminum, stainless steel 301 c: For stamping material thickness <= 0.2, the unilateral gap of the punching edge is often taken as 0.01 because it is limited by the precision of the die again. d: What is the gap on the punch or on the edge of the blade?: For punching, generally based on the punch, the gap is placed on the edge of the blade. For blanking, the die is generally used as a reference, and the gap is placed on the punch. In the continuous die, it is generally the scrap part outside the punched product, which is quite punched, so the gap is placed on the knife edge. For the unilateral cut type, it is quite blank, and the gap is on the knife edge, but this form is also Can not put the gap; in punching blanking composite mold, general convex and concave mold, inside and outside the shared, so there is gap back to the problem, generally based on the die (also known as the mother model) as the benchmark, punch (also known as the male model) How much is unilaterally negative. As far as the inside and the outside are taken off, the clearance is generally matched with the male and female models. As for this gap, we must not draw it out because of the habits of the factories. Some factories do not draw it out, and the punches are as large as the cutting edges. Next to the edge of the knife, note the following instructions: For example: Lower mold in: Single +0.01 T=25.0SKD11 Cut 2.0 below 2.0% of chip thickness; Some factories request to draw directly, only need to write straight edge bit falling chip :Single +0.0 L=50.5 SKD11 mold in: Single +0.01 T=25.0SKD11 Blade depth 2.0 and below 1.1.0%%d chipping Inside and outside the mold share: the outer mold is the reference inner mold unilateral -0.01 male and female mold linear position each 3.0 B>: Straight-edge position and chip slope: When the linear position is too long and the chip slope is too small, the material is liable to be blocked. The linear position is too short and the chip slope is too large. The double weakens the knife edge strength, so it must have a proper value. Practice has proved that: for t<0.8, the straight edge of the blade is 2.0, and the chipping slope is 1°; when t>0.8, the blade straight line is 3.0, and the chipping slope is 1°; for those weaker Punch, in order to prevent the normally broken, the knife edge often takes a straight cut slope of 0.2 ° without leaving a straight line and the knife edge is often made of double-layer structure, which reduces the punching force C>: The determination of the clearance in the inner part (including the knife entrance, the forming part and the punch) Since these ingots or punches are to be loaded directly into the template or into the sub-assembly, there is a problem of whether or not to have gaps, and this gap is placed on the template or on the permeator profile: In order to facilitate drawing, it is generally used to place gaps on the template. , and this gap is not drawn, but in the processing note column shows: If the hole-shaped hole, the unilateral positive, there are punch hole round next to the plus code, and then explain in the comment column: such as F: 3-? 4.00 (punching hole, cutting single +0.007), the following description of the splint stripping mold penetration into the sub-gap clearance a: The splint only acts as a fixed punch or infiltrates the exudation, so its gap is larger, so that it is easy to assemble. If the splint is used as a child, the unilateral gap between the outer shape of the splint and the splint is usually taken as +0.005~0.01. Into the child, knife edge punch and forming punch and plywood unilateral clearance + 0.005 ~ 0.01. b: The stripping plate acts as a guide punch and stripping material, so its gap is made smaller. If the stripping plate is used to infiltrate the exudation material, the unilateral clearance between the permeator profile and the stripping plate is usually taken as +0.003 to 0.005. The unilateral gap between the blade and the punch and the forming punch and the stripping plate is +0.003~0.005. If the unilateral gap between the punch and the blade is >= 0.02, the blade punch and the forming punch and the stripping plate are separated. Edge clearance can also take +0.005~0.01 but it must ensure its clearance <clear and knife edge clearance. 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