Chemical etching process step-by-step

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.
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What is chemical etching?

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.

1. Material Selection

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:

• Steel and stainless steels
• Copper and its alloys
• Nickel and its alloys
• Aluminium
• Titanium

2. Pre-clean

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.

3. Lamination

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.

4. Printing

The component design is transferred to the photoresist by exposing the sheet to ultraviolet (UV) light through a photo-tool mask.

5. Developing

The unexposed photoresist is removed to reveal the raw material. The hardened resist will protect the part during etching.

6. 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.

Have a question? Read our 10 chemical etching FAQs

7. Stripping

The remaining photoresist is removed from the sheet, revealing the final etched components.

8. Visual and dimensional inspection

The components are visually and dimensionally inspected using state-of-the-art optical inspection equipment.

9. Finishing

Etching can be combined with other processes including:

• Plating
• Forming
• Electropolishing
• Passivation
• Heat treatment
• Brazing and diffusion bonding
• Wire EDM