Chemical machining is also known as photochemical machining or photochemical milling, a process involved with the fabrication of sheet metal components using photoresist and etchants. However, there is another type of chemical machining called electrochemical machining, where metal is instead removed using an electrochemical process.
Photochemical machining is used to machine away selected areas of sheet metal, and can produce highly complex parts that are used in a variety of different industries. Photochemical machining was born during the 1960s as part of the printed circuit board industry, which needed access to highly refined and complex parts that could be produced in an economic fashion.

The process of chemical machining has a number of advantages when compared to similar alternatives like stamping, punching, laser cutting, and water jet cutting, and also has some advantages over electrical discharge machining. The process of prototyping is necessary in many industries, and chemical machining makes it easy to come up with detailed and quickly produced prototypes that allow for quick and simple changes in mass production. Chemical machining or photochemical machining is also known as PCM, and is a process that can be used on practically any metal or alloy substance of any hardness or size.

The process of chemical machining has a number of different stages, with the process starting by printing the desired shape or pattern onto two clear and stable pieces of photographic film. Once this printing has taken place, the sheets used can then be placed on to the top and bottom halves of the machining tool, where they are used during the machining process. UV sensitive photoresist is used to cut, clean, and laminate the metal sheets being produced, and a vacuum is used to ensure maximum contact between the photo tool and the metal plate being machined. The etching stage of the process uses an aqueous solution of acid that is heated and directed under pressure, with ferric chloride often used for this process. There are a number of applications for this process, including fine screens, battery grids, sensors, springs, microwave circuits, metal gaskets and seals, electrical contacts, and semiconductor leadframes.