Abstract: A reciprocating drive mechanism having a housing with upper and lower internal chambers with a spool slidably positioned inside the upper internal chamber. There is at least one fluid inlet and fluid exhaust communicating with the upper internal chamber and at least one slide valve positioned within the upper internal chamber and traveling with the spool. A piston positioned in the lower internal chamber divides the lower internal chamber into an upper and lower cylinder space. A valve stem is connected to the piston and includes a bore communicating with the upper internal chamber and an exhaust passage is positioned between the upper and lower internal chambers.

Abstract: Solder bumps are electrodeposited onto a substrate with carefully controlled heights by forming patterned conductors on an substrate, depositing and patterning a layer of material, such as titanium that is easily oxidized, and electrodepositing the solder bumps. The solder does not deposit on the titanium. Solder bumps of uniform height are obtained because the titanium layer acts as part of the electrical circuit during electrodeposition.