An extension spring must produce a certain force when extended to a particular extent; is that possible?

The force of an extension spring is determined by the spring rate on the one hand and the initial tension on the other hand. The spring rate is determined by the type of material, the wire thickness, the spring’s diameter and the number of coils.

The initial tension is determined by factors that cannot be defined as accurately. The initial tension depends on the production method. All of this can be adjusted according to the client’s needs!