What technique is described as moving a stream of electrolyte through a gap to erode material?

The technique being described is electrochemical machining, which is a process that uses a stream of electrolyte to erode material from a workpiece. This method employs a direct current and involves bringing an anodic workpiece into proximity with a negative cathode tool, resulting in the anodic dissolution of the material where the electrolyte flows between them.

Electrochemical machining is particularly effective for creating complex geometries and is often used for machining hard materials that are difficult to cut using traditional methods. The process is efficient and provides a good surface finish while avoiding physical contact between the tool and the workpiece, minimizing tool wear. This makes it a valuable technique in various applications, especially in industries requiring precise machining of intricate components.

The other techniques mentioned serve different purposes. Laser cutting uses focused light to cut materials, electrical discharge machining (EDM) uses electrical discharges to erode material, and plasma cutting employs a high-velocity jet of ionized gas to cut through electrically conductive materials. Each of these methods has applications suited to their unique mechanisms and outcomes.