Photo Chemical Etching Process Defined

Why Should You Use
Photo Chemical Etching

Designers, manufacturing engineers, and purchasing groups are recognizing the advantages photo chemical etching has to offer.

Some of the benefits of this unique manufacturing process are the ability to make a complex part that is beyond hard tool capability and to fabricate the part in dead soft or full hard material without burrs or metal distortion.

Another significant benefit is response time. An order may be filled in days, which allows the design to be proven without incurring the cost of a hard tool.

Photo etching is a growing industry, gaining experience and recognition as a viable method of working metal.

The PCE Process

A photo plotter is used to create a photo tool which is a negative image of the part. The part is nested to maximize the number of parts per sheet. Two laminates are printed, one each for the top and bottom of the metal sheets.

Because each photo-tool is a made of film, tooling can be finished in just hours and at a far lower cost than required by other machining methods. Additionally, these qualities ensure that part designs can be changed and applied to production exceptionally fast.

Proper metal preparation, degreasing, and the removal of surface contaminants is essential for proper adhesion between the raw material and the photo resist during the coating process.

Modern PCM companies have invested in “clean lines” for improved material cleanliness. These conveyorized machines are typically multi-chambered and material is put through a series of clean and rinses to ensure proper surface condition.

The quality and quantity of the finished parts depends greatly on the care taken during this step.

The material is coated with photo resist directly after cleaning which reduces the chance of surface contamination and oxidation. The coating is photosensitive and resistant to the etchant used to cut the chosen metal. Dry film or liquid resist is applied to both sides of the work piece to allow etching for both sides simultaneously.

Advances in resist technology combined with new and improved Computer Assisted Design (CAD) artwork have enabled photo-resist coatings to accommodate extremely complex features.

During this step in the photo etching process, material with the photosensitive coating is exposed to UV light. This is a straightforward process that transfers the photo tool image onto the coated material.

The metal is put into the double-sided phototool and is exposed to UV light on both sides, an image is formed in the photoresist. This is then developed in a liquid formulation to form an adherent, durable image on both sides of the metal.

Virtually all metals can be etched, although some are etched more readily than others. The vast majority of metals can be etched using a relatively innocuous etchant, an aqueous solution of ferric chloride.

First, the metal is rinsed of the remaining photoresist that hasn’t bonded to the metal. Then, etchants are applied to the metal in a conveyor machine. Durring this process, the non-bonded areas of metal are exposed to the etchants and begin to etch upon contact.

Because etchants are applied to the entire sheet of metal at once, PCE maintains the unique ability to make every cut simultaneously, which can save countless hours for parts with complex geometries or features, and especially for fine meshes and screens.

The next step in the manufacture of chemically etched parts is stripping off the protective coating of photo resist. Many companies use machines that have a strip chamber on the etch machines to increase efficiency.

Now your part is finished! or is it?

Parts often require secondary processes or treatments post-blanking before they are completely finished and ready to be shipped. Luckily, Newcut can take care of that.

We offer a wide range of services including heat treatment, plating, and precision forming through partnerships with local treatment firms and our sister company, Incodema. Visit our secondary processes page to explore our capabilities and certifications, or request a quote for free and find out exactly how we can help you with your project.

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