Application principle and technical specification of die spring

　 Spring
In the mould, the spring is mainly used as the auxiliary power of the movable components such as the thimble plate, the line position, etc., and the utility model can not be used alone. The mould spring has been standardized, and the following table is the basic technical specification for die springs.
Commonly used in the mold is a light load of the blue spring. If the mold is larger, the number of thimble, must consider the use of heavy spring. Selection of light weight spring should be the following aspects:
(1) pre compression ratio: the general requirements for the spring free length of 10~15%, the larger diameter of the spring to choose a smaller pre pressure ratio, the smaller the diameter of the spring to choose a larger preload ratio.
In the selection of the mold ejector plate return spring, generally do not use the pre compression ratio, while the pre compression, it can guarantee the spring diameter uniform size, pre pressure applied to the ejector plate is not affected by the free length of spring. The preload is generally 10.0~18.0mm.
(2) compression ratio: generally require compression ratio of less than 40%, the smaller the compression ratio, the longer the service life.
(3) as far as possible the spring distribution.
(4) the diameter of the spring can be determined according to the space and the pre pressure required by the mould. Common specifications refer to chapter 15.3, section fifteenth.
When the mold size is greater than 5050, the spring to be used in your 51.0mm.
The free length of the spring shall be determined according to the compression ratio and the amount of compression required.
Method for calculating the free length (L) of the die return spring (as shown in figure 5.5.15)
H1 - plastic parts to be out of height
B - the length of the spring preload, B=L - preloading. The preload is usually 10 ~ 15mm
L = (K+ preload) / compression ratio