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Several issues to be considered when selecting nitrogen gas spring in cold stamping die design

Time:2021-05-23    Edit by TengFei

Nitrogen gas spring technology has its own characteristics and a certain range of application. Only by correctly restricting the application range of this technology can its function be fully exerted and the desired effect can be obtained.

(1) How to choose the characteristic curve of nitrogen gas spring?

For various stamping processes, there are different process requirements. When selecting the nitrogen spring technology, it must be adapted to the process requirements. For example, the elastic pressure is required to be basically constant throughout the working stroke. This should be said only for the drawing and pressing effect. For other processes, the elastic pressure is not necessarily required to be basically constant. Whether the elastic pressure is constant or not will affect not very big.


But from an economic point of view, it will have a greater impact, because the price of nitrogen gas springs produced by various factories is related to their performance. The same elastic force, the use of constant force nitrogen gas springs are more expensive than those of the same specification. The longer the stroke of the gas spring, the more expensive it is. At present, nitrogen gas spring technology has not been put into the market for a long time. The cost of one-time input of nitrogen gas spring is higher than that of other elastic components. If the economy is not fully considered, the blind selection of high-performance nitrogen gas spring will definitely affect the increase of mold cost. And it is not necessary. Therefore, it is necessary to select different nitrogen spring characteristic curves according to different process requirements, so as to obtain the best performance price and the best economic benefits.

(2) Elastic pressure balance

In the mold design, the transmission of the elastic pressure should be balanced. There are often more than one choice of nitrogen springs. Then, the layout of the focus point needs to solve a balance problem. From the perspective of the stamping process, it is also necessary to consider the balance of the punching force. In order to improve the service life of the mold, to ensure the quality of stamping parts. From the use of nitrogen gas springs, it is known that nitrogen gas springs are in direct contact with the parts. They are all designed to transfer the elastic pressure to the working parts of the mold through the designed top plate, top piece block, blank holder, diagonal wedge and other mold parts. Whether the movement of the top plate and other mold working parts is balanced or not is related to the layout of the force system; on the other hand, the top plate also plays a role in transmitting force to the nitrogen spring, so in order to avoid the nitrogen spring being biased, the nitrogen spring is improved To increase the service life of the mold and increase the service life of the mold, a design method in which the center of the pressure system of the nitrogen gas spring coincides with the center of the punching force should be adopted.

(3) Stability

Nitrogen gas springs require considerable stability and reliability when installed or in operation. Because of its large elastic pressure, a nitrogen gas spring needs to release hundreds of kilograms or even several tons in a small volume. Strength, and this process is repeated continuously, therefore, maintaining the stability of its work is very important. When installing and tightening, especially the nitrogen gas spring with greater force, it must be ensured firm, especially when the nitrogen gas spring is inverted or installed on the upper mold. The gas spring needs to move continuously with the movement of the slider, only Only a firm connection can ensure the normal and stable operation of the nitrogen gas spring. Therefore, it is often designed to install a nitrogen gas spring, or a certain depth of installation counterbore is opened in the cylinder or in the plunger to ensure its correct position and avoid deflection.

(4) Avoid shock

It should be said that the working nature of the nitrogen gas spring belongs to the category of flexibility. During the working process of the mold, the opening and closing should be relatively smooth, and there should be no impact phenomenon. In order to achieve this goal, the designer must fully adopt the independent nitrogen gas spring. Take this into consideration. Because as mentioned earlier, the frequency response of nitrogen gas springs is very high. Once the parts touch the piston rod of the nitrogen gas springs, they can generate elastic pressure. There is no need to pre-tighten the process. Then, as the press slider goes up and down, Movement, the opening (expansion) and closing (compression) response of the nitrogen gas spring is very fast. If the design is improper, especially if the gas spring is used on a small tonnage press, the gas spring may push the sliding block back, which will damage it. The movement curve of the slider of the crank press causes vibration and shock. Therefore, this phenomenon should be avoided as much as possible.