Generally, in a pressure drop control valve that uses a piston and a spring (for example, in jet engines to control fuel flow), there is always potential for error in terms of the height of the spring. As we know, a shim is usually used to fix this. However, I was wondering if there are alternatives to such a procedure. Are there other ways to correct the height on a valve spring, or perhaps produce the spring in a way that reduces the need for a correction method like shimming?
I was thinking maybe laser correction could be a viable method for correcting a spring that is off by a few thousands of an inch? It is extremely accurate, but then the main disadvantage is cost. Are there other methods or technologies that exist or are perhaps being worked on at the moment?