What Is Chemical Etching?

Chemical etching and photo etching are common terms in modern manufacturing. Both are one and the same process often referred to as photo chemical etching. A form of subtractive manufacturing, this is a milling process by which chemical compounds are used to dissolve material to form precision metal parts.

How Chemical Etching Works

The chemical etching process requires the use of computer-aided design software and photography. Customers can send a drawing or .DXF/.DWG file, which is then converted into a photo tool by experienced technicians. This process is cost-effective because adjustments and redesigns can be completed quickly.

Once the metal type is selected, it is cut into thin sheets, cleaned, and prepared for etching. A photosensitive material, or photoresist, is added to the sheet using a coating system. The photoresist is acid-resistant and light-sensitive. A reusable plotter film includes all the part characteristics, so the same part can be produced as many times as needed. High quantities can be produced at low production costs.

The metal sheet is then placed between two pieces of photographic film (tooling) detailed above and exposed on both sides to ultraviolet (UV) light. The exposed resist becomes hardened, while shaded areas of the resist remain soft. The softer resist is washed away during developing, leaving behind exposed material for the heated etchant to dissolve. The hardened resist will protect the desired material from the etchant to create the desired parts.

After chemicals are applied, the photo resist is removed, and the metal parts are inspected to ensure they meet the customer’s specifications.

Benefits of Chemical Etching

With chemical etching, metal as thin as 0.0003 to 0.063 inches can be processed. Chemical etching is a low cost method for producing thin metal parts with no sacrifice in precision or quality. Because unwanted material is dissolved away, there are no sources of mechanical stress introduced to the remaining material, leaving no burrs, mechanical damage, or deformation.

All the mechanical and dimensional properties of the metal are maintained. This is a challenge with other methods, such as stamping, punching, and laser cutting.

In addition, parts of almost unlimited complexity can be produced. You can create complex prototypes or large numbers of complex parts within days. Digital tooling allows an increase in design flexibility and complexity without any difference in lead time.

What Metals Can Be Chemically Etched?

The etching process can be used with a wide range of metals. These include aluminum alloys (1100, 1145, 3003, 5051, and 6061), which are light, inexpensive, and suited for many applications. Copper alloys such as alloys 101, 102, and 110, beryllium copper, phosphor bronze, brass, and nickel silver are used in chemical machining as well.

Photo chemical etching can also be used when machining nickel and nickel alloys, including HyMu/Mu metals, Monel, and Inconel 600 series materials and alloys 42, 48, and 49. Stainless steels suited for metal etching include types 301, 302/304, 304L, 316, 321, 347, PH15-7Mo, and 17-7PH.

Chemical Etching Applications

Parts that can be etched include high-precision RFI and EMI shielding. Components with one or two pieces or with peel-away tops can be manufactured using different materials. These parts are used in electronic devices and military equipment, in accordance with Federal Communications Commission standards, as well as in board-level shielding, medical equipment, and aerospace systems.

Shims, which fill narrow gaps between parts, can be produced in tight flatness tolerances. Complex parts can be as thin as .0003 inches and as flat as .001 inches. Shims include washers, CPU protectors, and damping components in military and aerospace applications.

Chemical etching is also precise enough to make apertures for optical applications, and encoder disks with slots that are wider than the thickness of the material. Very small battery springs and contacts, fine screens and webs, and small covers and step lids can be produced, as can custom thin metal parts per the specifications from the customer.

United Western Enterprises: Chemical Etching Since 1969

An AS 9100D / ISO 9001:2015 certified company, United Western Enterprises, Inc. has been working with chemical etching for more than 50 years. We can quickly produce precision parts in virtually any quantity or complexity. In addition, we also offer finishing services such as anodizing, black oxide finishing, heat treatment, painting, plating, in-house forming, and laser welding. To learn more, fill out/submit our online contact form or request a quote today.

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