The chemical etching process for brass creates precision components by selectively removing metal through a photoresist mask. This modern technique offers numerous inherent advantages over conventional sheet metalworking, including the ability to produce parts without degrading material properties since no force or heat is used during processing. It also allows for almost limitless part complexity, with component features machined simultaneously using etchant chemistries.

What is Chemical Etching Brass and How Does It Work?

Chemical etching brass is a metalworking process that uses corrosive chemicals to etch complex and precise components from brass. This process is highly favored in modern metal machining due to its high precision and low failure rate.

The chemical etching process for brass begins by laminating the metal with a light-sensitive photoresist, which is then exposed to UV light to transfer the CAD image of the component. The unexposed photoresist areas are developed and removed, and the exposed metal is sprayed with etchant chemicals to accurately remove the unprotected brass. Finally, the remaining photoresist is stripped away to reveal the finished etched component.

Digital Tooling and Economic Efficiency

One of the key advantages of chemical etching brass is its use of digital tooling. Unlike traditional methods that require expensive and difficult-to-adapt steel molds, digital tooling for etching is quick to adapt and change, often within an hour. This ensures that large quantities of products can be reproduced with zero tool wear, guaranteeing that the first and millionth part produced are exactly the same.

The adaptability of digital tooling makes it ideally suited for both prototype and high-volume production runs. This “risk-free” design optimization incurs no financial penalties and boasts a turnaround time that is estimated to be 90% quicker than for stamped parts, which also require substantial upfront investment in mold fabrication.

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Applications of Etched Brass Components

The chemical etching process is suitable for virtually any brass component between 0.01mm and 1.5mm in thickness. Here are some examples where chemical etching brass truly adds value:

Meshes, Filters, and Sieves: Chemical etching offers greater levels of complexity when producing thin, precision brass meshes, filters, and sieves. Metal is removed simultaneously, allowing multiple aperture geometries to be incorporated without high tool or processing costs. Unlike punch-perforated sheets, photo-etched mesh is burr-free and stress-free, maintaining zero material degradation.

For example, a 150-micron thick precision brass mesh used in radiation detection devices is etched by WET Etched to precision tolerances below the standard ±10% material thickness. The critical honeycomb-shaped mesh array could not be economically produced by stamping due to the high investment required in press tooling, and laser cutting couldn’t achieve the necessary tolerances over such a large surface area.

Flexure Springs and Diaphragms: Often used in safety-critical or extreme environment applications, such as ABS braking systems, medical biosensors, or fuel injection systems, etched flexures can “flex” millions of times faultlessly. Chemical etching ensures that the fatigue strength of the brass is not altered, eliminating potential fracture sites and producing flexures free from burrs and recast layers.

Fuel Cell Bipolar Plates, Cooling Plates, and Fluidic Devices: Brass grades with specific properties are well-suited for fluidic devices used in liquid-to-liquid or liquid-to-gas heat exchangers, fuel cells, and cooling plates due to their excellent corrosion resistance. The complex grooves machined into these plates are well-suited to chemical etching, as they can be machined onto both sides in a single process without compromising flatness or introducing stresses and burrs.

Summary

Brass exhibits an array of characteristics that make it ideal for numerous industrial applications. The chemical etching process offers significant advantages for producing complex and safety-critical brass components, including:

• No expensive hard tooling
• Rapid transition from prototype to production
• Almost unlimited part complexity
• Burr- and stress-free component features
• Unaffected metal properties
• Suitability for all grades, with accuracy to ±0.025 mm
• Lead times measured in days, not weeks or months

The versatility of chemical etching brass, combined with WET Etched’s extensive experience, makes it a compelling option for manufacturing brass components across diverse and demanding applications. This process stimulates innovation, removing obstacles inherent in traditional sheet metalworking technologies.