Control of motion in stamping die design
introduction
Cold stamping is the use of molds and stamping equipment (presses, also known as presses) to apply various types of sheets or billets to different parts of the sheet or blank to deform or separate them to obtain parts of a certain shape, size and performance. In general production, vertical presses are used, which determines that the main movement of the stamping process is up and down movement. In addition, there are various mutual movements between the mold and the sheet metal and the various structural components in the mold.
Mechanical movement can be divided into three basic forms of movement, such as sliding, rotation and rolling, and they all exist during the stamping process. However, the characteristics of various types of movement are different, and the impact on stamping is also different.
Since there are so many kinds of movements in the stamping process, various movements should be strictly controlled in the design of stamping dies to meet the requirements of mold design; at the same time, various mechanical movements should be flexibly applied in the design according to specific conditions. Meet product requirements.
The main movement of the stamping process is up and down movement, but the design of the inclined wedge structure, the rotary pin structure, the roller structure and the rotary cutting structure in the mold can convert the main movement into horizontal movement, rotation in the mold and rolling in the mold accordingly. . In the mold design these special structures are more complex and difficult, and the cost is higher, but in order to achieve the shape and size requirements of the product, it is an effective solution.
Blanking die
The basic movement of the blanking process is that the stripper plate first contacts the plate material and is firmly clamped. The punch mold is lowered to contact with the plate material and continues to descend into the die. The relative motion between the convex, concave die and the sheet material causes the sheet material to separate. The male and female molds are separated, and the stripper plate pushes the workpiece or scrap from the punch to complete the punching movement. The movement of the stripper plate is very critical. In order to guarantee the quality of the blanking, the movement of the stripper plate must be controlled. It must be allowed to come into contact with the plate material before the punch and the press force must be sufficient, otherwise the blank will be cut off. Poor face quality, low dimensional accuracy, poor flatness, and even reduced die life.
The blank punching die is designed according to the usual method, and it is often difficult to separate the workpiece from the scrap side after punching. On the premise of not affecting the quality of the workpiece, some protruding limiting blocks can be added on the ejector plate of the convex die, so that after the blanking punching movement is completed, the die ejector plate pushes the workpiece from the die first Then, the punch and die ejector plate pushes the waste from the punch and die, so that the workpiece and the waste are naturally separated.
For some large stampings with local protrusions, the stamping punch can be added to the die ejector plate of the blanking punch die while applying sufficient spring force to ensure that the punching die on the ejector plate is pressed. When the material is contacted with the sheet, the material is deformed to achieve the purpose of pressing, and then the blanking punching motion is continued, which can often reduce one step of the mold and reduce the cost.
Some punching dies have a large number of punching holes and require a lot of punching pressure. This is not good for punching production. There is even a punching machine with enough tonnage. There is a simple method that uses 2 to 4 punches of different lengths to allow stamping. Punching movement is performed in a time-sharing manner, which can effectively reduce the punching force.
For those stamped parts that require high position accuracy on the curved surface (for example, the concentricity of two holes on the opposite side), it is difficult to achieve the hole position if the hole is punched and then bent. The wedge structure must be designed. After punching and bending, use the horizontal punching movement to achieve the goal. For those who require stricter requirements for flange-opening and deep-drawing heights, similar structural designs can also be used.
Bending mould
The basic movement of the bending process is that the stripper plate is in contact with the sheet material and is crushed to death. The punch mold is lowered to contact with the sheet material, and continues to descend into the die. The convex, concave die and the sheet material generate relative movement, resulting in deformation of the sheet material. After bending, the convex and concave molds are separated, and the top bar (or slider) on the bending die pushes out the bent edge to complete the bending motion. The movement of the stripper plate and the ejector pin is very critical. In order to ensure the bending quality or production efficiency, it is necessary to first control the movement of the ejector plate so that it comes into contact with the plate material before the punch and the pressing force must be sufficient. Otherwise, the dimensional accuracy of the bent pieces is poor, and the flatness is poor. Secondly, it is necessary to ensure that the ejector force is sufficient so that it smoothly pushes out the bent pieces, otherwise the bent pieces are deformed and the production efficiency is low. For bending parts with higher precision requirements, special attention should be paid. It is better to have a moving dead point in the bending movement, that is, all related structural parts can be touched to death.
Some workpieces have unusual curved shapes or cannot be detached from the die in the normal way after bending. In this case, wedge structures or pin structures are often used. For example, a wedge structure can be used to complete less than 90 degrees or hook back Bending, using a rotary pin structure can achieve a cylindrical molding.
It is worth mentioning that for some casing parts, such as computer floppy drive casing, because of its long curved edge, the sliding between the elbow and the sheet material, it is easy to wipe out the dander when the bending, the material galvanized layer off, frequent Polishing and bending punches are also not ideal. The usual practice is to plate titanium in the bending punches to increase their smoothness and wear resistance; or to embed the rollers at the corners of the curved punch R, convert the bends of the elbows and the sheet to rolling, due to the friction of rolling over sliding The force is much less, so it is not easy to scratch the workpiece.
Deep drawing mould
The basic movement of the deep drawing process is that the stripper plate is first contacted with the sheet material and pressed firmly, the punch mold is lowered to contact with the sheet material, and continues to drop, enters the die, and the convex, concave die and the sheet material produce relative movement, resulting in the board The material is bulk-formed, then the male and female molds are separated, and the female mold slider pushes out the workpiece to complete the deep drawing movement.
The movement of the stripper plate and the slider is very critical. In order to ensure the quality of the drawing piece, the movement of the stripper plate must be controlled so that it contacts the plate material before the punch and the pressing force is sufficient. Otherwise, the drawing piece is easy. Wrinkles, even cracking; secondly, ensure that the pressure of the die block is sufficient to ensure the flatness of the underside of the drawn part.
Deep drawing compound die design is reasonable, it can well control the movement process of the structure, and achieve the purpose of multi-process combination. For example, the design of a typical blanking deep-drawing edge punching composite die.
In addition, some drawing and daily-use drawing parts need to have a curling (or piping) process, roller structure is also used in the mold design, so the rolling friction in the curling process is very small, not easy to scratch the surface of the workpiece .
For deep-drawing structural parts that need to rotate in the motor, the height of the trimming, the degree of jump, etc. are quite high. A special rotary cut structure needs to be designed in the die, and trimming is performed by rotating (cutting) motion, not only ensuring the trimming. The dimensional accuracy is high, and even the trimming burrs and punching lines are quite beautiful. It is worth mentioning that after the actual design improvement, this rotary cutting structure has been very easy to mold and has been applied to continuous deep drawing molds.
Continuous mold
The continuous die often includes punching, bending and deep drawing and other punching processes. Therefore, the mechanical movement in the punching process also includes the basic movement modes of the three processes. The control of the movement in the continuous die should be divided into basics. The process is controlled separately.
Usually, the continuous dies require continuously increasing the ramming speed and increasing the production efficiency. In some stampings with complex shapes and special stampings, the ramming movement is time-consuming and can be decomposed into more efficient ramming movements in the continuous die design.
It needs to be pointed out that the continuous die is also involved in the actual production of feeders, blowers, etc. These factors should be fully taken into account in the design, so that the movement of the punches, molds, feeders and blowers can be matched in time. , Continuous mold can be truly smooth production.
Cold stamping is the use of molds and stamping equipment (presses, also known as presses) to apply various types of sheets or billets to different parts of the sheet or blank to deform or separate them to obtain parts of a certain shape, size and performance. In general production, vertical presses are used, which determines that the main movement of the stamping process is up and down movement. In addition, there are various mutual movements between the mold and the sheet metal and the various structural components in the mold.
Mechanical movement can be divided into three basic forms of movement, such as sliding, rotation and rolling, and they all exist during the stamping process. However, the characteristics of various types of movement are different, and the impact on stamping is also different.
Since there are so many kinds of movements in the stamping process, various movements should be strictly controlled in the design of stamping dies to meet the requirements of mold design; at the same time, various mechanical movements should be flexibly applied in the design according to specific conditions. Meet product requirements.
The main movement of the stamping process is up and down movement, but the design of the inclined wedge structure, the rotary pin structure, the roller structure and the rotary cutting structure in the mold can convert the main movement into horizontal movement, rotation in the mold and rolling in the mold accordingly. . In the mold design these special structures are more complex and difficult, and the cost is higher, but in order to achieve the shape and size requirements of the product, it is an effective solution.
Blanking die
The basic movement of the blanking process is that the stripper plate first contacts the plate material and is firmly clamped. The punch mold is lowered to contact with the plate material and continues to descend into the die. The relative motion between the convex, concave die and the sheet material causes the sheet material to separate. The male and female molds are separated, and the stripper plate pushes the workpiece or scrap from the punch to complete the punching movement. The movement of the stripper plate is very critical. In order to guarantee the quality of the blanking, the movement of the stripper plate must be controlled. It must be allowed to come into contact with the plate material before the punch and the press force must be sufficient, otherwise the blank will be cut off. Poor face quality, low dimensional accuracy, poor flatness, and even reduced die life.
The blank punching die is designed according to the usual method, and it is often difficult to separate the workpiece from the scrap side after punching. On the premise of not affecting the quality of the workpiece, some protruding limiting blocks can be added on the ejector plate of the convex die, so that after the blanking punching movement is completed, the die ejector plate pushes the workpiece from the die first Then, the punch and die ejector plate pushes the waste from the punch and die, so that the workpiece and the waste are naturally separated.
For some large stampings with local protrusions, the stamping punch can be added to the die ejector plate of the blanking punch die while applying sufficient spring force to ensure that the punching die on the ejector plate is pressed. When the material is contacted with the sheet, the material is deformed to achieve the purpose of pressing, and then the blanking punching motion is continued, which can often reduce one step of the mold and reduce the cost.
Some punching dies have a large number of punching holes and require a lot of punching pressure. This is not good for punching production. There is even a punching machine with enough tonnage. There is a simple method that uses 2 to 4 punches of different lengths to allow stamping. Punching movement is performed in a time-sharing manner, which can effectively reduce the punching force.
For those stamped parts that require high position accuracy on the curved surface (for example, the concentricity of two holes on the opposite side), it is difficult to achieve the hole position if the hole is punched and then bent. The wedge structure must be designed. After punching and bending, use the horizontal punching movement to achieve the goal. For those who require stricter requirements for flange-opening and deep-drawing heights, similar structural designs can also be used.
Bending mould
The basic movement of the bending process is that the stripper plate is in contact with the sheet material and is crushed to death. The punch mold is lowered to contact with the sheet material, and continues to descend into the die. The convex, concave die and the sheet material generate relative movement, resulting in deformation of the sheet material. After bending, the convex and concave molds are separated, and the top bar (or slider) on the bending die pushes out the bent edge to complete the bending motion. The movement of the stripper plate and the ejector pin is very critical. In order to ensure the bending quality or production efficiency, it is necessary to first control the movement of the ejector plate so that it comes into contact with the plate material before the punch and the pressing force must be sufficient. Otherwise, the dimensional accuracy of the bent pieces is poor, and the flatness is poor. Secondly, it is necessary to ensure that the ejector force is sufficient so that it smoothly pushes out the bent pieces, otherwise the bent pieces are deformed and the production efficiency is low. For bending parts with higher precision requirements, special attention should be paid. It is better to have a moving dead point in the bending movement, that is, all related structural parts can be touched to death.
Some workpieces have unusual curved shapes or cannot be detached from the die in the normal way after bending. In this case, wedge structures or pin structures are often used. For example, a wedge structure can be used to complete less than 90 degrees or hook back Bending, using a rotary pin structure can achieve a cylindrical molding.
It is worth mentioning that for some casing parts, such as computer floppy drive casing, because of its long curved edge, the sliding between the elbow and the sheet material, it is easy to wipe out the dander when the bending, the material galvanized layer off, frequent Polishing and bending punches are also not ideal. The usual practice is to plate titanium in the bending punches to increase their smoothness and wear resistance; or to embed the rollers at the corners of the curved punch R, convert the bends of the elbows and the sheet to rolling, due to the friction of rolling over sliding The force is much less, so it is not easy to scratch the workpiece.
Deep drawing mould
The basic movement of the deep drawing process is that the stripper plate is first contacted with the sheet material and pressed firmly, the punch mold is lowered to contact with the sheet material, and continues to drop, enters the die, and the convex, concave die and the sheet material produce relative movement, resulting in the board The material is bulk-formed, then the male and female molds are separated, and the female mold slider pushes out the workpiece to complete the deep drawing movement.
The movement of the stripper plate and the slider is very critical. In order to ensure the quality of the drawing piece, the movement of the stripper plate must be controlled so that it contacts the plate material before the punch and the pressing force is sufficient. Otherwise, the drawing piece is easy. Wrinkles, even cracking; secondly, ensure that the pressure of the die block is sufficient to ensure the flatness of the underside of the drawn part.
Deep drawing compound die design is reasonable, it can well control the movement process of the structure, and achieve the purpose of multi-process combination. For example, the design of a typical blanking deep-drawing edge punching composite die.
In addition, some drawing and daily-use drawing parts need to have a curling (or piping) process, roller structure is also used in the mold design, so the rolling friction in the curling process is very small, not easy to scratch the surface of the workpiece .
For deep-drawing structural parts that need to rotate in the motor, the height of the trimming, the degree of jump, etc. are quite high. A special rotary cut structure needs to be designed in the die, and trimming is performed by rotating (cutting) motion, not only ensuring the trimming. The dimensional accuracy is high, and even the trimming burrs and punching lines are quite beautiful. It is worth mentioning that after the actual design improvement, this rotary cutting structure has been very easy to mold and has been applied to continuous deep drawing molds.
Continuous mold
The continuous die often includes punching, bending and deep drawing and other punching processes. Therefore, the mechanical movement in the punching process also includes the basic movement modes of the three processes. The control of the movement in the continuous die should be divided into basics. The process is controlled separately.
Usually, the continuous dies require continuously increasing the ramming speed and increasing the production efficiency. In some stampings with complex shapes and special stampings, the ramming movement is time-consuming and can be decomposed into more efficient ramming movements in the continuous die design.
It needs to be pointed out that the continuous die is also involved in the actual production of feeders, blowers, etc. These factors should be fully taken into account in the design, so that the movement of the punches, molds, feeders and blowers can be matched in time. , Continuous mold can be truly smooth production.
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