Two of the most commonly used processes for metal etching are chemical milling and laser cutting. Both methods are efficient, economical, and highly precise, but each of them offers distinct benefits and has unique applications.
Factors such as time, budget, and the quality and complexity of the project or design should be taken into consideration when deciding between chemical milling or laser cutting.
Also referred to as chemical etching, photochemical machining, or photochemical etching (PCE), chemical milling involves applying an etchant — typically acid — to metal. Certain characteristics of the metal are manipulated or altered by masking sections of it and exposing other parts to the etchant, then corrosively machining the surface and allowing the acid to etch the exposed areas. The chemical etching process is particularly well-suited for producing smooth surfaces without sharp edges on a wide range of metals including copper, silver, brass, and aluminum.
- Advantage: The chemical etching tooling is inexpensive, making it more cost-effective than laser cutting.
- Advantage: Complex parts can be produced quickly because the PCE tooling is digital and the process etches all components simultaneously.
- Advantage: Photochemical machining is versatile and has a high degree of precision, making it ideal for intricate and niche projects.
While laser etching is another type of subtractive manufacturing process, it works differently than chemical etching. Laser etching uses a computer-operated, high-powered optical laser to cut through metals and other materials. It quite literally etches the surface of the material, rather than creating depth and texture in the way that PCE does.
- Disadvantage: Because of the intense thermal heat involved with the laser etching process, metal properties can be altered and degraded.
- Disadvantage: Laser cutting involves a complex, extensive machine setup and in many cases, humans or robots, making it a considerably more expensive option than photochemical machining.
- Disadvantage: Lasers cut each individual design component individually, so more intricate designs take more time.
Because of its efficiency in both cost and time, photochemical milling is equally appropriate for creating prototypes and mass-producing. Its ability to quickly make design changes and etch intricate details makes it a superior choice over laser for creating detailed components such as sensors or battery grids. While laser cutting is often appropriate for smaller-scale projects with minimal complexity, chemical etching has more universal applications.