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Photochemical etching is a subtractive, non-traditional machining process that uses chemical and photographic techniques to design and shape metal workpieces. After developing the design of the image on the workpiece, a strong chemical solution is poured over the workpiece. As a result, the workpiece corrodes selectively and removes all unnecessary material from areas that are not protected, leaving a sharp image or flawless part. Read More…
Photo EtchingThe process of photo etching can be used on virtually any commercial metal including aluminum, copper, molybdenum, steel and brass, but is limited to a thickness range from .001" to 0.080" for maximum effectiveness.
Great Lakes Engineering is a trend setting manufacturer of surface mount stencils, precision laser cut parts, and photo chemical etched parts. We work with a wide range of materials, including Stainless Steel, Copper, Titanium, Nitinol, Nickel, Kovar and many others.
VACCO is the industry leader of Photo Chemical Etching of metal & polyimide components and devices. We specialize in Stainless steel, Titanium, and Copper, but work with a variety of different materials. We have over 60 years of experience in Chem Etching, and we offer Micro Laser Cutting & Welding, and Diffusion & Adhesive Bonding services along with an extensive range of value-added services. Whether your application is large or small, VACCO can assist you from prototype to production.
Quality. Integrity. Made in USA. Precision etched parts, nameplates, asset tags, graphic overlays, signage and more - our team has been producing high quality products for over 35 years. We serve all industries - automotive, aerospace, military, medical, electronics and equipment manufacturers.
PEI is a leading producer of photochemical machining and photochemical etching precision and decorative metal parts. We use chemical machining and etching as a process to selectively remove material by chemical action, creating extraordinary cost-effectiveness. In business since 1967.
Founded in 1977, we offer photochemical machining to make products from copper-based alloys plus ferrous and high-nickel alloys. We have used chemical milling to produce items for the architectural, decorative, mechanical and motion picture industries. Secondary operations also available.
Photochemical etching is a subtractive, non-traditional machining process that uses chemical and photographic techniques to design and shape metal workpieces.
After developing the design of the image on the workpiece, a strong chemical solution is poured over the workpiece. As a result, the workpiece corrodes selectively and removes all unnecessary material from areas that are not protected, leaving a sharp image or flawless part.
The areas that need to be removed or saved are picked up using photographic methods and procedures like photoresist imaging.
The main advantage of this machining process is that it manufactures and produces precision parts that are impossible to produce by traditional machining methods.
The photo etching process produces thin and flat parts, with the smallest of them about ten microns.
The Photochemical Etching Process
The photochemical etching process makes it possible to etch intricate and highly complex features into a range of different metals.
Photo Tool Plotting
The photographic negative of the artwork or profile desired is the photo tool. Engineering design software is normally used to come up with patterns. Then, the design and its parameters are converted into a photo tool before they are printed onto a photographic film. Photo tool dimensions are affected by the following:
Temperature and Humidity Variations
Dimensional variations are possible because of continuous changes in humidity and temperature. Measures taken to control these variations include using thicker polyester films or plotting in a controlled environment. If variations in humidity and temperature cannot be controlled, it is wise to use techniques such as laser direct writing.
Most of the etchants act isotropically, producing undercuts. An isotropic reaction is considered more prevalent in long etching processes. Longer periods of etchant exposure are needed for deep etches, resulting in more significant undercuts.
The workpiece undergoes cutting and cleaning prior to the application of photoresist coating. This is done to ensure that any dirt, grease, oil, or rust accumulated on the surface of the metal from its handling and primary processing will not stop the photoresist from adhering. There are two main procedures for cleaning: mechanical and chemical.
The latter method involves a mild pickling process in which the material is suspended in a solution containing degreasing agents and mild acids. The former method subjects the material to scrubbing and mild degreasing agents. However, chemical cleaning processes are much preferred over mechanical ones because there is less damage caused to the material.
Photoresists are very light organic materials that are deposited on the workpiece surface. They can cope with etching solutions and leave a well-defined image. When the coating is exposed to ultraviolet radiation, it becomes soluble or insoluble to the solvent, depending on the type. Photoresists are classified as positive or negative. Positive photoresists have areas that become soluble to the developer solvent when exposed. On the other hand, negative photoresists, when exposed to ultraviolet light, become chemically resistant to the developer solvent.
In soft baking, the photoresist is heated or baked to release or vaporize the residual solvents. The process has to be under control since it is associated with a high evaporation rate that causes bubbles to form, creating voids inside the photoresist.
Alignment and Exposure
For multi-layered patterns, it is crucial to ensure the correct alignment of the photo tools. Exposure is a process where the image on the photo tool is brought to the workpiece with a photoresist.
The development of the photoresist follows the above. Then, hard baking is done using nitrogen blow drying and distilled water. The etching process then removes all the unprotected regions of the substrate or wafer by using chemical agents.
Photoresist Removal and Stripping
When the substrate structure required is made, the photoresist is removed. It has to be done very quickly without causing any damage. Various methods can be used to remove the photoresist material, such as solvents or oxygen combustion.
Photochemical Etching Applications and Advantages
The applications and advantages of photochemical etching include: