Abstract: A method and apparatus for economically regenerating chemical etch solutions for aluminum and the alloys thereof without the use of large, complex and expensive processing apparatus. The method of the invention can be accomplished substantially at ambient temperature thereby avoiding the necessity for substantial investment in complex temperature control instrumentation. In accordance with the method of the invention, the spent etchant which is to be regenerated is first mixed with water in a separate storage tank and is then cold filtered prior to being transferred to the reactor or regeneration vessel. This step substantially reduces contamination buildup within the reactor vessel and thereby avoids costly periodic shut down of operations for clean-up. Due to the unique nature of the regeneration process of the invention, the alumina produced as a by product of the process is of extremely high quality and is snow white in color.

Abstract: A method and apparatus for use in chemical milling operations to automatically cut a maskant material, such as a thin film of plastic, which has been applied to the workpiece. The cutting device of the invention is designed for use with a computer controlled apparatus embodying a rectilinear robot adapted to move the cutting device in first, second and third directions relative to the workpiece. The pressural engagement between the cutting blade of the device and the workpiece is continuously sensed and controlled. Additionally, the angle between the cutting blade and the maskant is controllably varied as the cutting device is moved by the rectilinear robot.

Abstract: A method and apparatus for chemically milling large sheet metal workpieces and the like to uniform wall thickness in which all wall thickness measurements and all cutting of the protective maskant which is applied to the surfaces of the workpiece is accomplished automatically and with extreme precision through the use of a computer directed robot.