Chemical etching — also called photo etching — is a metal fabrication technique that transfers parts onto sheets using a photosensitive material. The process necessitates a chemical etchant to remove undesirable portions, leaving only the required dimensions. Furthermore, it does not require heat or hard tooling that can risk deformation, burrs, or metal flatness.
Metal chemical etching is an excellent fabrication method for applications requiring smaller metal components with no flaws. Some of the common applications include automation, electric vehicles, drones, defense systems, and medical devices.
Here is a closer look at the step-by-step process of chemical etching:
Step 1: Creating the Design
Software and applications are used to create and develop designs in chemical etching. Customers are usually expected to submit the concept draft to the professionals before it is converted into a workable file. Then, the technicians will make design changes and modifications to achieve the best possible results.
Step 2: Selecting and Preparing the Metal
It is critical to select the appropriate metal for your application. Although most metals can be etched, not all materials suit every project. Copper, stainless steel, aluminum, and nickel alloys are commonly used for chemical etching. Following the selection, it is cut into sheets and cleaned to remove grease, oil, or oxidation.
Step 3: Preparing the Metal for Photo Etching (Photoresist Coating)
The photoresist material is applied to the sheet using a specialized coating machine. The coating will enable photo etching on metal that needs to be removed while also protecting the part used on the final component.
Step 4: Exposing the Metal to UV Light
After the coating process, the sheet is placed in an exposure unit between two film pieces. Then, the sheet is exposed to UV light on both sides. The photoresist becomes hard or polymerized when the light touches it, while the shaded areas remain soft and loose.
Step 5: Developing
The soft or unexposed photoresist is washed away during development, leaving only the hard photoresist. Subsequently, the areas with the hardened resist will be protected from the etchant and transformed into the desired parts.
Step 6: Metal Chemical Etching
Depending on the chosen material, the chemical etching process uses various etchants sprayed onto the developed sheet. Furthermore, using the right chemicals results in a more efficient fabrication process that allows for quick and effective metal etching. Some of the most common etchants are ferric chloride, ferric nitrate, and sodium hydroxide.
The etch time is determined after considering variables — such as metal type, grade, thickness, and size — all of which affect the final result.
Step 7: Stripping the Photoresist
The remaining photoresist on the sheet is completely removed after the etching process. This results in the final metal components ordered and specified by the customer in the files they submitted.
Step 8: Inspecting the Final Part
Final parts and components are inspected to ensure they meet proper dimensional requirements. This step includes checking every detail for burrs and other imperfections or defects. This is also the stage at which it is determined whether or not value-added services are required. Examples of secondary processes include plating, forming, electropolishing, heat treatment, and diffusion bonding.
Choose PCM Products for Premium Metal Chemical Etching Services
Since 1977, PCM Products has been the industry leader in photo chemical machining, chemical milling, and photo etching. We are based in Central Florida and serve diverse industries, including the aerospace, automotive, electronics, medical, and military sectors.
We have complete in-house capabilities that allow us to provide better lead times, competitive part pricing, and quality control. Moreover, we offer secondary requirements, such as plating, heat-treating, forming, and finishing.