Guida semplice per te sugli stampi per tranciatura

Tempo di lettura stimato: 16 minuti

There are many types of blanking dies. punzonatura and dies are one of the most basic process methods of stamping. For the convenience of research, punching dies can be classified according to different characteristics:

1. Classification of blanking dies

According to the nature of the process, it can be divided into blanking dies, punching dies, cutting dies, slitting dies, cutting dies, trimming dies, etc.

According to the combination of processes, it can be divided into single-process simple molds and multi-process continuous molds, composite molds and continuous composite molds. According to the guide mode of the upper and lower molds, it can be an open mold without guide and a guide plate mold with a guide, a guide pillar mold, a ball guide pillar mold, a guide simple mold, etc.

According to the method of controlling the feeding step, it can be divided into fixed stop pin type, movable stop pin type, automatic stop pin type, guide pin type, side edge type and so on.

According to the material of the convex and concave dies, it can be divided into steel die, cemented carbide die, zinc-based alloy die, rubber die, polyurethane rubber die and so on.

According to the structure of convex and concave molds, it can be divided into integral mold and block mold.

According to the arrangement method of convex and concave molds, it can be divided into positive mold and flip mold.

According to the mold discharge method, it can be divided into rigid discharge mold and elastic discharge mold.

In addition, there are manual molds, semi-automatic molds, and automatic molds according to the methods of feeding, discharging and rejecting waste. According to the size of the die, it can be divided into small die, medium die and large die, and can be divided according to the degree of specialization of the mold. It is special die, general die, combined die, simple die and so on.

According to different process combinations, blanking dies can be divided into single-process blanking dies, progressive blanking dies and compound blanking dies. The above-mentioned different classification methods reflect the different characteristics of the mold structure from different angles.

2. The structure of the oscuramento muffa

Figure 1-1(a) shows the typical structure of the blanking dies. The die is composed of an upper and a lower die. The upper mold is composed of upper mold base 1, mold handle 5, end plate 8, punch fixing plate 9, punch 10, discharge plate 11, guide sleeve 22, screws, pins and other parts. The lower mold is composed of a female mold 12, a top piece block 13, a lower mold seat 14, a top rod 15, a support plate 16, a rubber 19, a guide post 20, a stop pin 21, screws, pins and other parts. The upper die is mounted on the press slider through the die handle 5 and reciprocates up and down with the slider, so it is called the movable part. The lower mold is fixed on the press table through the lower mold base, so it is also called the fixed part.

Figure 1-1 (b) shows a three-dimensional view of the mold. With the help of this figure, the structure and composition of the mold can be better understood. When the mold starts to work, the strip is placed on the concave mold 12 and positioned by the stop pin 21. At the beginning of blanking, the punch 10 and the top piece 13 first contact the strip. When the slide of the press moves downwards, the male mold 10 and the female mold 12 work together to punch out the workpiece. After the blanking deformation is completed, when the slider rises, the unloading plate 11 scrapes the strip from the punch 10 under the rebound force of the spring. At the same time, under the rebound force of the rubber 19, the ejector rod 15 pushes the top The piece 13 pushes the piece out of the concave mold 12 to complete the entire blanking process. Then, the strip is lifted and fed forward, and positioned by the stop pin 21 for the next punching.

According to the role of each component in the mold, the structure of the blanking dies is generally composed of the following five parts, as shown in Figure 1-1.

Parti di lavoro

Working parts refer to the parts that realize the blanking deformation, separate the materials correctly, and ensure the shape of the blanking parts. Working parts include punches, dies, etc. (10, 12 in Figure 1-1). The working parts directly affect the quality of the blanking parts, but also affect the blanking force, discharge force and die life.

Positioning parts

Positioning parts refer to parts that ensure the correct position of the strip or blank in the mold. Including guide plate (or guide pin), stop pin, etc. (21 in Figure 1-1). The guide plate guides the feeding of the strip, and the stop pin restricts the position of the feeding of the strip

Unloading and pushing parts

Unloading and pushing parts refer to the parts that are removed from the workpiece or waste material that is stuck in the hole of the concave die or hooped on the punch due to elastic recovery after punching. The workpieces stuck in the hole of the concave die are pushed down one by one from the hole of the concave die by the punch during punching or the die is ejected by the ejector device (13, 15, 16, 17 in Figure 1-1) , 18, 19). The scraps or workpieces hooped on the punch are removed by the unloading plate (2, 3, 11 in Figure 1-1).

Guiding parts are parts that ensure the correct position and movement of the upper mold against the lower mold. It is generally composed of a guide sleeve and a column (20, 22 in Figure 1-1). The guide device can ensure the uniform gap between the male mold and the female mold during punching, which is beneficial to improve the quality of the punched parts and the life of the mold.

Connect fixed parts

Connecting fixed parts refers to fixing the male and female molds to the upper and lower mold bases, and the parts that fix the upper and lower molds on the press. Including a fixed plate 9, a backing plate 8, and upper and lower mold seats 1, 14 and so on.

The typical structure of the punching die is generally composed of the above five parts, but not all punching dies include these five parts. For example, the open die with a relatively simple structure has no guide parts for the upper and lower dies. The structure of the die depends on various factors such as workpiece requirements, production batches, production conditions, and mold manufacturing technology level. Therefore, the die structure is diverse, and the parts with the same function have different forms.

According to the different functions of the parts in the mold, they can be divided into two categories: process parts and structural parts.

Process parts

Parts that directly complete the stamping process and directly interact with the blank, including working parts, positioning parts, and pressing, unloading and top parts.

Structural parts

The parts that do not directly participate in the completion of the process, nor directly interact with the blank, but only guarantee the completion of the process of the mold or improve the function of the mold, including guide parts, supporting parts and coupling parts.

Typical structure of oscuramento dieS

Single process stampo di punzonatura

Single-process punching die means that only one process is completed in one stroke of the press, such as blanking die, punching die, trimming die, cutting die, etc. According to the different mold guiding devices, the commonly used single-process punching dies can be divided into two types: guide plate mold and guide column mold.

• Guide-type single-process punching die

Figure 1-1 shows the guide plate blanking die. The upper mold part of the mold is composed of a mold handle 1, an upper mold seat 3, a backing plate 6, a punch fixing plate 7, a punch 5 and a stop pin 2. The lower part of the mold is composed of a guide plate 9, a material guide plate 10, a fixed stop pin 16, a concave mold 13, a lower mold seat 15, a receiving plate 11 and a starting stop device 18, 19, 20. Among them, the guide plate 9 and the convex mold 5 are in a sliding fit, which guides the upper mold during punching to ensure a uniform gap between the convex and concave molds. At the same time, the guide plate 9 also plays a role of unloading.

The clearance between the guide plate and the male mold must be smaller than the clearance between the male and female molds. Generally speaking, for thin materials (t<0.8mm), the fit between the guide plate and the punch is H6/h5; for thick materials (t>3 mm), the fit is H8/h7.

The structure of the guide-type punching die is simple, but due to the high accuracy requirements of the guide plate and the punch, especially when the mold gap is small, the processing of the guide plate is very difficult, and the guiding accuracy is not easy to guarantee. Therefore, this type of mold is mainly used for thicker materials. , Where the accuracy of the workpiece is not too high. When punching, the punch and the guide plate must not be separated.

• Guide pillar single-process blanking mold

Figure 1-2 shows the structure of the guide pillar single-process bullet top punching die. The mold has two guide pillars. When the mold is working, the guide pillar 20 first enters the guide sleeve 22 to guide the male mold 10 into the female mold 12 to ensure the uniformity of the gap between the male mold and the female mold. After the punching is finished, the upper die is restored, and the punch is restored accordingly. The unloading plate 4 installed on the upper die part unloads the strips clamped on the punch 10, and the workpiece is replaced by the top piece installed on the lower die part. Block 13 is ejected.

The guide pillar mold has high guiding precision, the gap between the punch and the female mold is easily guaranteed, the mold is less worn and easy to install. Most blanking dies use this form.

• Guide plate morire di tranciatura with movable stopper pin

Figure 1-3 shows a guide plate blanking die with movable stop pins. The working principle of the movable baffle pin is as follows: the movable baffle pin 1 with a slope is installed in the guide plate 2, and the upper end of the movable baffle pin is clamped by the plate spring 4. One end of the plate spring 4 is fixed on the guide plate with screws 3, and the other end is embedded in the two straight grooves on both sides of the stopper pin, so that the movable stopper pin is close to the top surface of the die 5 and will not rotate. When feeding, the overlapping edge of the strip is lifted up by the inclined surface of the stopper pin. When the overlapping edge passes, the stopper pin is pressed against the die surface by the plate spring. At this time, the stopper pin is pulled back and used The cylindrical part on the other side of the lap controls the feeding step. The movable stop pin does not have to be lifted when feeding, which is more convenient to use than the fixed stop pin, but it is not convenient to push the strip forward and then pull it back when feeding.

Progressive punching muffa

Progressive blanking die refers to a die that completes two or more blanking processes on different parts of the die in one stroke of the press.

In one stroke of the press, a die that simultaneously completes several stamping processes on different parts of the die is called a progressive die, which is a punching die with multiple stations and high efficiency. The forming of the entire stamping part is gradually completed in a continuous process. Continuous forming is a process intensive process method, which can make trimming, incision, grooving, punching, plastic forming, dropping and other processes to be completed in one mold, according to the actual needs of the stamping parts, arrange multiple in a certain order The stamping process (referred to as the station in the progressive die) performs continuous stamping. It can not only complete the stamping process, but also complete the forming process, and even the assembly process. Many complex stamping parts that require multi-process stamping can be completely formed on a pair of molds, which provides favorable conditions for high-speed automatic stamping.

Figure 1-4 shows a continuous die for punching and blanking with a fixed pitch with guide pins. The upper and lower molds are guided by guide plates. The same distance between the punching punch 3 and the blanking punch 4 is the feeding step s. When sending the test, the fixed stop pin 6 is used for initial positioning, and the two guide pins 5 mounted on the blanking punch are used for precise positioning. The fit of the guide pin and the blanking punch is H7/r6, and its connection should ensure that it is easy to disassemble during the grinding of the punch. Therefore, the hole for the blanking female mold to install the guide pin is a through hole. The shape of the head of the guide pin should facilitate the insertion of the punched hole during the guide, and there should be a slight gap between it and the hole. In order to ensure the positive distance of the first piece, in the progressive die with guide pin, the initial stopper device is often used. It is installed in the middle of the guide plate under the guide plate. When punching the first piece on the strip, push the stopper pin 7 by hand so that it protrudes from the guide plate to resist the front end of the strip, and then the two holes on the first piece can be punched. After each blanking, the feed step is controlled by the fixed stop pin 6 for rough positioning.

Progressive molds have higher productivity than single-process molds, reduce the number of molds and equipment, and have higher workpiece accuracy, which is easy to operate and realize production automation. For particularly complex stamping parts or small hole margins, when it is difficult to punch with simple or compound dies, progressive dies can be used to gradually punch them out. However, the progressive die has a larger outline size, more complicated manufacturing, and relatively low cost. It is generally suitable for mass production of small stamping parts.

Compound punching die

In one stroke of the press, a mold that completes more than two processes at the same position of the mold is called a composite mold, and multiple blanking processes such as blanking and punching can be completed in one position at the same time. The composite punching die has a concave and convex die which is both a blanking punch and a punching die in the structure.

According to the position of the die, there are two types of compound blanking dies: upside-down and formal. The front-mounted composite punching die is shown in Figure 1-5(a). The waste punched during punching falls on the lower die or strip, which is not easy to remove and is generally rarely used. The structure of the flip-chip composite punching die is shown in Figure 1-5 (b). The punzonatura waste is directly dropped from the convex and concave die holes, and the parts are pushed into the concave die holes by the convex and concave die, and will be pushed out by the pusher plate when the punching is finished.

Figure 1-6 shows a typical blanking and punching compound die. When the die starts to work, the strip is placed on the discharge plate 19 and positioned by three positioning pins 22. At the beginning of blanking, the die 7 and the push block 8 first contact the strip. When the press slide moves downward, the shape of the convex and concave mold 18 and the concave mold 7 work together to punch out the shape of the part. At the same time, the punching punch 17 and the inner hole of the punching and concave mold 18 work together to punch out the inner hole of the workpiece. After the blanking deformation is completed, when the sliding block rises, under the action of the striker 15, the pusher block 8 is laid down, and the workpiece is discharged out of the die 7. Under the action of the rubber rebound force, the discharge plate 19 scrapes the strips out of the convex and concave molds, thereby completing the entire blanking process.

The composite blanking die has a compact structure, high production efficiency, and high workpiece accuracy, especially easy to ensure the position accuracy of the inner hole of the workpiece to the shape. This type of mold has low requirements for strip material, and the leftover material can also be stamped. However, the composite mold has a complex structure, high manufacturing accuracy requirements, and high cost. It is mainly used to produce blanking parts with large batches and high accuracy requirements.