| Chemical Milling in industry is also known as etching. It | | | | sheet metal, and then chemically dissolving material |
| is a process that uses bases, acids or other chemicals | | | | from the unmasked areas. |
| to dissolve unwanted materials such as | | | | Photo chemical milling processes are as follows :o A |
| semiconductor materials, glass or metal. | | | | photo resistant coating applied to make the metal |
| This process is used on a wide variety of different | | | | sensitive to lighto A photo mask is placed over the |
| metals, and the removal of depths as large as 0.5 | | | | sensitized sheet metalo The sheet of metal is |
| inch or 12 mm are achieved. It has applications in the | | | | exposed to ultraviolet lighto The photo resist is |
| semiconductor fabrication and printed circuit board | | | | developed into the masked patterno The sheet is |
| industries, and is also employed in the aerospace | | | | etched to remove the exposed metal areas leaving |
| industry, to remove thin layers of metal/materials | | | | the final parto The part is then cleaned |
| from large aircraft components, such as extruded | | | | This type can offer high precision and detailed shapes |
| parts and missile skin panels. | | | | in thin metal sheets, and the process is particularly |
| There are different types of chemical milling. One is | | | | competitive for complex shapes and parts. |
| wet etching and another is photochemical etching. | | | | It can make almost any 2D shape in thin gauge sheet |
| Different materials require different types of | | | | metal. Applications can include :o Electrical shieldso |
| etchants, for instance, sodium hydroxide is used for | | | | Optical interrupterso Eraser shieldso Gasketso Shims |
| aluminum, and ferric chloride or ammonia or | | | | Electro chemical milling is a method of removing metal |
| ammonium persulphate is used for copper. It is widely | | | | by electrochemical processes, and is usually used in |
| used to manufacture integrated circuits, and the | | | | mass production of extremely hard materials. Electro |
| semiconductor industry uses plasma etching. | | | | chemical milling can cut odd or small shapes in very |
| Another type is photo chemical milling. This is a | | | | hard steels such as carbide, kovar, inconel and |
| process that produces 2D shapes and parts by | | | | titanium, and is also widely used as an effective |
| creating a chemical resist mask on the surface of the | | | | deburring process. |