When conventional metal machining just doesn’t cut it, photochemical machining does with a high level of precision, intricacy, and quality.
What is chemical etching?
Chemical etching—otherwise referred to as photochemical machining (PCM), photochemical etching (PCE), or chemical milling—is a subtractive manufacturing method used to create electronic microcomponents from sheet metal.
It’s efficient, highly precise, and capable of creating intricate and complex electronic components out of nearly any type of metal, making it desirable for original equipment manufacturers (OEMs) to produce:
• EMI/RFI shielding
• Grids & meshes
• Printed circuit board components
• Step stencils
• Contacts, pins, connectors, and terminals
• Bus bars and fuse-links
• Intricate springs
These electronic components can be used across a wide range of industries, such as:
A short guide to the chemical etching process
• The correct metal material is selected (steel, nickel silver, copper, etc) and accurately cut to size. This sheet is commonly known as a substrate.
• Once the sheet is cut and ready, it goes through a cleaning phase to remove any impurities from the metal surface. Improperly cleaned metal surfaces may result in less adhesion.
• Next is the laminating phase. The laminate used is known as photoresist (otherwise simply known as a resist), a photosensitive material combining polymer, a solvent, and a sensitiser. Photoresist’s job is to protect the areas of the metal not being chemically etched.
• From there, a photo-tool mask exposes or prints the component’s design onto the metal sheet using ultraviolet (UV) light. The areas of the sheet not exposed to the UV light are then removed (also known as developed), revealing the substrate underneath.
• A chemical etching solution (ferric chloride) is sprayed onto the sheet after being developed. The solution selectively etches and dissolves the unprotected material, leaving manufacturers with the final piece ready to be stripped of any remaining photo-resist.
• Any residue is then removed via a rising and drying phase.
Five reasons why the chemical etching process is a superior choice
Arguably the most beneficial aspect of chemical etching is its cost-effectiveness and affordability. The equipment is completely digitalised, requiring no tooling or setup costs, thus lowering initial investment. Multiple component geometries and features can also be created at the same time. This saves OEMs thousands right from the get-go, as well as further into the machining process.
- Free from burring
Burring refers to noticeable and stubborn imperfections all along the metal’s edge, usually after modification. These imperfections are often viewed as a headache for manufacturers, simply because the burr removal (deburring) process takes time and money to deliver. It can also cause device or component malfunctions and defects if left untreated. Thankfully, the nature of chemical etching significantly reduces burring, meaning manufacturers can save on time, effort, and money.
- Eliminates the risk of thermal stress
Thermal stress is defined as a temperature change in any material (in this case it’s metal). When temperature changes occur, unwanted distortions in the chosen metal can arise, causing annoyances for manufacturers, as well as a decline in component or device performance and overall quality. Thermal stress typically occurs with more traditional manufacturing processes e.g. laser cutting and wire EDM.
- Suitable for almost all metal grades
Chemical etching’s versatility really shines here. It can work with metal as thin as 0.02mm to as thick as 1,0 mm, making it a well-rounded choice for OEMs working on a number of different component types made from various forms of metal.
- Fast Prototyping
One of the biggest benefits of chemical etching is its ability to produce prototypes quickly and efficiently, generally within a 4-5 day lead time, though this varies depending on the order quantity and complexity. The main reason why fast prototyping is an OEM’s dream is parts and components are sent out to market much quicker than other, more conventional manufacturing processes.
Which metals are chemical etching best suited to?
Arguably the most desirable aspect of photochemical milling is its ability to etch complex, intricate, and elaborate component designs onto almost all metals with quickness and ease.
Metal types include:
• Stainless steel
• Beryllium copper
• Phosphorous bronze
Do you want to have an open and non-binding dialog about your components? Contact us.
Feel free to read more about Mekoprints competencies within photo chemical etching.