Introduction to Chemical Etching
Chemical etching may also be referred to as “chemical milling” or “industrial etching”, is a type of subtractive process in the world of manufacturing. It involves the process of spraying metals and immersing metals with chemicals that have been temperature-regulated to remove some specific parts of the metals to get the shape, thickness, geometric features, as well as designs that have been planned initially. By utilizing chemical etching, manufacturers can make metal components even the ones that have the most complex and difficult designs, all while being able to achieve consistent product quality and high repeatability.
What are the Steps Involved in Chemical Etching
The typical chemical etching process consists of a series of a few steps. The first step in the chemical etching process is cleaning. This step involves the process of preparing the metal surface to be etched by eradicating oils, grease, residues as well as other kinds of impurities. Cleaning is a very crucial step because a surface of the material that is contaminated would cause the adhesion of the photoresist film to be weak which consequently will cause a lot of problems. Then, the next step in the series of chemical etching would be lamination. In this step, the dry film photoresist is applied to the surface of the material. Photoresist functions to protect the parts of the metal that will not be etched later on.
Then, there is exposure where the material is guided between two masks which have a negative image of the components to be made. These types of masks are made by glass or mylar. Rays of ultraviolet lights will then be allowed to be focused through masks. After the exposure process, the material needs to be developed. In this step, the non-crosslinked film that exposes the bare metal that is located underneath will be dissolved chemically. Soon after the process of development, the metal will be put into the etching chamber where it will be sprayed with enchant completely. The unprotected metal will then be etched to obtain the desired product. It will then undergo the process of stripping, rinsing and drying.
Advantages of Chemical Etching
Chemically etched parts may be manufactured in a large volume environment
Reduced production and tooling costs
Has the ability to hold extremely tight tolerance for the size of a small feature
Has a high degree of consistency and repeatability
Precision metal parts that are burr-free with ultra-fine pitches