What exactly is chemical etching?
Chemical etching also referred to as “chemical milling” or “industrial etching”, happens to be a subtractive procedure in manufacturing. The process involves the spraying or immersion of metals using temperature-regulated chemical substances for removing some particular areas in the metal so as to produce the required thickness, shape, and geometric features or complicated designs.
Chemical etching allows the producers to produce metallic components even with the most complicated and difficult designs, all whilst achieving consistent production quality and high repeatability.
How does the process work?
The conventional chemical etching process involves a sequence of essential steps:
In this step, the metal surface to be etched is prepared by getting rid of oils, grease, residues, plus some other pollutants. Cleaning happens to be a vital step given that a polluted surface might lead to improper adhesion of the photoresist film that can cause defects in the long run. When the process is completed, the workers must not handle the material using their hands since the material can become polluted by the oils and sweats from the human skin.
In this step, a dry film photoresist is going to be applied to the surface. The areas of the metal which won’t be etched will be protected by the photoresist. These films will be applied to either side at the same time by laminating or rolling onto the material by making use of temperature, pressure, and at times water.
The material, in this particular step, will be guided between a couple of “masks” having the negative image of the component that has to be produced. Either glass or mylar will be used for making these masks. Subsequently, collimated, high intensity, and ultraviolet light will be shined through the masks from either direction, thus crosslinking the film in sites where the mask images are not blocking the light.
The material has to be developed following the exposure. This particular step dissolves the non-crosslinked film chemically which is responsible for exposing the bare metal underneath. The material which is left safeguarded by the film will become the finished product in the long run.
After the development phase, the chemi etch chambers will be fed by the metal where etchant will be sprayed from the top as well as bottom at the same time. This procedure dissolves or etches the metal which is unprotected for achieving the desired item. Careful monitoring is needed by an etchant bath when it comes to the composition, concentration, and temperature of the etchant.
The film will be removed from the etched material during this process by making use of one more concentration of chemistry.
7. Rinsing and Drying
During this phase, the product has become complete and the films are going to be removed. All residuals must be removed by significant rinsing. This process will be performed by making use of deionized water and reverse osmosis water.
Materials which are Ideal for Chemical Etching
Metals ideal for chemical etching consists of a wide array of nickel alloys, stainless steels, beryllium copper, copper, brass, as well as phosphor bronze.