High Quality Mold Coil Spring Outer Diameter 30mm 50CrVA Material Yellow Type

Compression ratio and lifetime of different types of mold coil springs:

Tips

1. OD
OD =2*ID, so  the OD of spring shoulder be twice of your pins The inner diameter of our mold spring are positive tolerance, e,g.: the diameter of pins is 7.5mm, the OD of spring should be 15mm, we have the standard size 14mm spring only and it is useable.

2. Length
Free length =(stroke + pre-compressed length)/Compression ratioPre-compressed length usually is 10% of the free length.

3. Color and loading
Elastic force=spring constant * compressed length
Generally speaking, the elastic force when the spring is pre-compressed should bigger than 2~2.5 times the weight of the ejector plate,  the elastic force when the spring is compressed should bigger than 1.3 times of all the pressure on it, of course, the force is shared by all springs, so pay attention to the number of them