In this post, we look at chemical etching step by step. For an in-depth guide to the process, download our free chemical etching whitepaper.
Chemical etching is a method of metal engraving that utilises corrosive metals to etch a desired shape or component. Also known as chemical milling or photo etching, chemical etching is a subtractive sheet metal machining process which can create complex and highly accurate precision components from almost any metal.
Virtually any metal can be chemically etched, in thicknesses from 0.010 mm – 1.5 mm and sheet sizes to 600 mm x 1500 mm.
Typical metals include:
Once a metal has been selected, it is chemically cleaned and degreased to remove debris, waxes and rolling oils, all of which could negatively affect the next step.
A light-sensitive photoresist is applied to the sheet. Good adhesion is essential for highly repeatable, blemish-free components. Any issue with the bonding of the laminate could allow the etchant to come into contact with the protected areas of the metal during etching, compromising the finished parts.
The component design is transferred to the photoresist by exposing the sheet to ultraviolet (UV) light through a photo-tool mask.
The unexposed photoresist is removed to reveal the raw material. The hardened resist will protect the part during etching.
Etchant chemistry, typically ferric chloride, is sprayed onto the developed sheet. The etch-time is determined by skilled technicians taking account of variables such as metal type, grade, thickness and size, all of which affect the end result.
The remaining photoresist is removed from the sheet, revealing the final etched components.
The components are visually and dimensionally inspected using state-of-the-art optical inspection equipment.
Etching can be combined with other processes including: