Application knowledge of mold making and elastic components

Application knowledge of mold making and elastic components:

The level of modern mold manufacturing, the right and wrong of the cycle depends on the support of many aspects of technology, mainly including the process design of the mold, the software that directly affects the design and manufacturing level of the mold, the equipment for mold manufacturing, the standardization and generalization of various accessories, until The skills of mold design and manufacturing engineering and technical staff are equivalent to many aspects.

However, in terms of requirements for elastic components in mold manufacturing, there are mainly development trends in several aspects, that is, the pursuit of high efficiency, high precision, and good economy and products Flexible and combinable. Neither coil springs nor polyurethane springs can meet the above requirements. With 46 years of nitrogen spring manufacturing technology, DADCO has created a world-class nitrogen spring, which is 40%-50% higher than ordinary nitrogen springs. % Life span and accuracy. Its cost performance is unmatched.

The nitrogen gas spring is a component with elastic function. It seals high-pressure nitrogen in a certain container, and the external force compresses the nitrogen through the rod. When the external force is removed, the high-pressure nitrogen expands the bubble to obtain a certain elastic pressure. In Japan and the United States It has been widely used in advanced mold manufacturing countries such as Korea, South Korea, and Germany. It can improve mold life and simplify mold design. Therefore, only DAD nitrogen gas springs can ensure that your mold performance remains top performance in the next few years. Automotive springs

The first problem you should pay attention to when choosing the application of nitrogen springs in mold design is the choice of elastic pressure, what form of nitrogen spring to choose, and the choice of multi-strength nitrogen spring to meet the requirements of the stamping process. To solve such problems, usually The elastic pressure of the nitrogen gas spring needs to be considered: the number of the gas spring; the boost ratio of the gas spring.

The stroke of the gas spring should meet the requirements of the stamping process, and the required stroke size is different for different stamping processes. The blanking separation process requires Large elastic pressure and small stroke: The drawing process generally requires a relatively large stroke. As a nitrogen spring with a blank holder force function, its characteristic curve is required to be relatively dry and slow.

During the drawing process, the blank holder force basically does not change much, that is, The elastic force remains basically constant: for ejecting and unloading parts, sufficient strength and stroke are required: in the bending and flanging process, the initial force is usually required to be large in order to press the workpiece and prevent the workpiece from being bent. In the case of side slip or movement, generally speaking, the stroke is also required to be relatively large.

The structural design of the nitrogen cylinder and the sealing technology are the key technologies for the quality assessment of nitrogen gas springs. At present, the manufacturing technology of nitrogen gas springs is the most advanced by Meitong DADCO, which accounts for 60% of global sales, which is 50% longer than general nitrogen springs. Reach 1 million times of spring pressure per year.

The manufacture of nitrogen gas springs is a product that integrates various technical applications. Long-term sealing of high-pressure gas is much more difficult than liquid sealing. Among them, there are sealed structures, static seals and dynamic seals. , Form, manufacturing precision of the cylinder wall, surface roughness, surface treatment technology, selection of sealing materials, sealing reliability and life, etc.

The characteristic of the nitrogen spring is that it can produce a larger initial elastic pressure in a smaller middle. There is no need for pre-tensioning, and the force transmission module has elastic pressure when it comes into contact with the nitrogen spring plunger. One nitrogen spring can replace multiple back-pass springs. For molds with the same working stroke, the height of the mold using nitrogen spring is higher than that of ordinary springs.

The height of the mold is much smaller: the elastic force can be basically kept constant throughout the entire stroke: according to the requirements of different cold stamping processes, the size of the elastic force and the position of the force point can be adjusted correctly and conveniently at any time, in the mold design and debugging.

It can easily achieve elastic pressure and balance, simplify mold pressure, unloading and other structures, simplify mold design, and shorten mold manufacturing cycle: improve the quality of stamping parts, ensure stable quality of stamping parts, shorten the time to replace molds on the press, and improve labor Productivity, cost reduction, high mold accuracy, long service life, safety and reliability, simple, reliable and convenient installation and maintenance.

In either case, the total height of the nitrogen gas spring should not be too high to avoid instability, and to avoid the structure of the gas spring when it is installed on the mold, the structure is too complicated, and the tooling cost is increased. If the gas spring is installed in the upper mold , Whether it is a top piece or a blank holder, there must be a gap to ensure that the nitrogen gas spring works smoothly.

For safety reasons, to avoid accidents, DADCO gas springs recommend that designers should also consider when choosing a gas spring. Increase the safety stroke (generally, the safety stroke should be 10% of the stroke of the piston cylinder) to ensure that the nitrogen gas works normally for a long time. In addition, you should also pay attention to the choice of the structure of the nitrogen gas spring.

Take the American DADCO gas spring as an example. There are several types of independent nitrogen gas spring, nitrogen gas spring seat plate type, pipeline connection type, etc. These basic structural forms have their own characteristics and a certain range of applications, which need to be based on the requirements of the stamping process of the parts, the structure of the mold, and the equipment used , Working environment, working conditions, mold cost and convenient adjustment and maintenance, etc., comprehensively consider the selection.

In addition, in the design of cold stamping molds, nitrogen springs should also be selected according to different requirements. The same spring pressure uses a nitrogen spring with constant air force. It is more expensive than the non-constant gas force. The longer the stroke of the gas spring of the same specification, the more expensive. Therefore, according to different process requirements, different gas spring characteristic curves should be selected to obtain the best price and best economic benefits.

In the mold design, the transmission of elastic pressure should be balanced. There are often more than one choice of nitrogen springs. Then, the layout of the focus needs to solve a balance problem. From the perspective of the stamping process, it is also necessary to consider the issue of stamping balance. It is helpful to improve the service life of molds and ensure the quality of stamping parts.

From the use of DADCO nitrogen springs in the United States, it is known that nitrogen springs are in direct contact with parts, all through the designed top plate, top piece block, blank holder, Die parts such as the inclined wedge block transfer the elastic pressure to the mold working parts, then the movement of the top piece plate and other mold working parts is balanced or not. It is related to the arrangement of the force system: on the other hand, the top piece plate also serves to transmit force to the nitrogen spring Therefore, in order to avoid the bias load of the nitrogen gas spring, improve the bias load bearing capacity of the nitrogen spring, and ensure the service life of the nitrogen spring, a design method in which the center of the pressure system of the nitrogen spring coincides with the center of the pressing force should be adopted.

In recent years, the demand for molds for industrial products has increased, and the original conventional elastic components have certain shortcomings, which cannot meet the needs of this situation and cannot ideally solve the requirements of the stamping process. This situation is often It will affect the quality of stamping parts, make the design of the mold structure more complicated, and affect the replacement time of the mold on the press: At the same time, the mold space occupied by conventional elastic elements is too large, which increases the cost of mold manufacturing.

For example, coil springs, Polyurethane springs all need to be preloaded to achieve the elastic pressure required for setting the juice, and their elastic pressure increases significantly with the increase in the stroke. This non-constant elastic pressure performance may cause the parts to fail. Forming is not ideal for drawing pressure. Another example is coil springs. The initial force of polyurethane springs is not large. This is not ideal for processes such as bending and flanging that require relatively large initial forces. The result of this is that the quality of the stamped parts is unstable, and the adjustment of the mold is time-consuming and laborious.

For the blanking process of intensive punches, such as the use of coil springs and polyurethane springs, the discharge of the mold is often encountered. There is not enough space to place coil springs and polyurethane springs, so it is necessary to increase the mold space to solve such problems. Many such examples can also be cited. For this reason, people strive to develop a new type of elastic functional parts to replace the conventional The elastic element completes the work that is difficult to complete with conventional elastic elements, and the nitrogen gas spring has emerged as a new type of elastic functional part.

It can be used as an independent part and installed in a mold, or it can be designed as a tube-type ammonia gas spring. Participating in the work as part of the mold can easily achieve constant elastic pressure and delayed action in the system. It is an elastic component with flexible properties. Nitrogen springs can not only be widely used in the mold industry, but also can be used in other industries Fields, such as injection molding, automotive, electronics, instrumentation and other industries. In China, DADCO nitrogen springs appear as a high-tech product. Whether it can insight into the opportunities will become the treasure of the majority of mold manufacturers in the market wave.

Nitrogen gas springs require considerable stability and reliability both during installation and operation. Because of its large elastic pressure, a gas spring needs to release hundreds of kilograms or even several tons of force in a small volume. , And this process is repeated continuously. Therefore, it is very important to maintain the stability of its work.

Especially when using a gas spring with a large force, it must be firm, especially if the gas spring is reversed or installed in For the upper mold, the nitrogen gas spring needs to continuously move relative to the movement of the slider. Only a firm connection can ensure the normal and stable operation of the gas spring. Therefore, when the nitrogen spring is designed and installed, the cylinder body or the plunger is opened.

The counterbore should be installed with a certain depth to ensure its correct position and avoid deflection. It should be said that the working nature of the nitrogen gas spring belongs to the category of flexibility. During the mold work, the opening and closing should be relatively smooth, and there should be no impact. In order to achieve this goal, for the use of independent nitrogen gas springs, designers must fully consider this.

As mentioned earlier, the frequency of the nitrogen gas spring is correspondingly high. Once the parts contact the nitrogen gas spring plunger rod, the elastic pressure can be generated. There is no need for a pre-tightening process at all, so as the press slider moves up and down Movement, the opening (expansion) and closing (compression) response of the nitrogen spring is very fast.

If the design is improper, especially if the nitrogen spring is used on a small tonnage press, it may happen that the helium spring pushes the sliding block to return and damages The curve of the slider movement of the crank press leads to the phenomenon of vibration and shock. Therefore, it is reasonable to avoid this phenomenon as much as possible.

Mold manufacturing all over the world is developing rapidly in the direction of precision, complexity, efficiency, and long life. It is hoped that domestic mold manufacturers can make full use of foreign advanced technology and products to make our own world-flow mold.