Robotics

When you say surface cut, do you mean that you are dividing a spring into 2 parts using a plane or something? If you are using the ordinary extrude cut feature and it keeps disappearing, that means that its constraints might be independent from the spring, as in the spring's dimensions change but the surface cut remains the same.

hello dear , To design an elastic spring, you must first design half a step of the spring, then place an axis line for each section, and then set the axes in the assembly environment. The number of rings you insert depends on the dimensions and length of the spring. After this you will have an elastic spring

If you use Autodesk inventor, you can create a cylindrical body and use cylinder's height parameter as changeable. then create a spring between tow end surface of cylinder as start and end plane of spring.

best regards.