What is Photochemical Machining?

Photochemical machining (PCM), which is also commonly known as photochemical etching, is a type of precise milling for thin metal parts, sheets, and components that utilizes an etching process to remove selected areas. The precision metal parts are typically coated in a polymer and then etched chemically.

Common Photochemical Etching Questions:

Tecomet Etch answers frequently asked questions about chemical etched parts and the photochemical etching process. For more specific questions, please Contact Us today!

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Photochemical Etching Answers:

Q. What is the difference between Etching and Photo-Chemical Machining?

A. Photo-Chemical Machining or PCM is the correct name of the process by which metal is removed using chemicals. However other names such as etching, photo-etching, chem-etching, and chem-milling are popular among users.

Q. How does the etching process work?

A. Thin metal sheets are cleaned and laminated with a photo-resist film. Using a photo-tool, images are exposed on both sides of the sheet. The sheets are then etched in acidic chemicals and subsequently, the residual photo-resist film is stripped in alkaline solutions. Thorough rinsing ensures parts are free of chemical residue.

Q. What are the advantages of the etching process?

A. The etching process is precise, quick, economical, and flexible. It cuts metal clean without any burrs and is a low-temp process that eliminates heat affected zones, dross, and striations commonly seen on laser-cut or stamped parts. Etched parts can be formed, shape-set, plated, or finished in a variety of ways. It is cost-effective at high volume productions as well.

Q. Does the etching process leave chemical residue on the metal surface?

A. Surface contamination is always a concern for medical devices. Etched parts go through a neutralization process during stripping of the photo-resist and then triple spray rinsing with regular or DI water to ensure parts are free of residual chemical.

Q. Any concerns about the surface condition of etched parts?

A. No, etching does not alter metal surface conditions at all unless the customer specifically requests to roughen surface texture. We can do minor etching on the metal surface.

Q. What metals can you etch?

A. Tecomet Inc. can etch a wide range of metals such as aluminum, beryllium copper, brass & bronze, carbon steel, Co-Cr alloys, constantan, copper alloys, copper-nickel-zinc, elgiloy, HY-MU 80, Inconel, iron-nickel, Kovar & invar, molybdenum, nickel, nitinol (Ni-Ti), stainless steel, and titanium.

Q. What is the thinnest metal you can etch?

A. We can etch metals as thin as 0.0001" (2.5 microns) and routinely etch 0.0003" (7.7 microns) and 0.0005" (12.5 microns) thick foils with excellent dimensional controls.

Q. What is the thickest metal you can etch?

A. We can etch metals up to 0.125" (3.18 mm) thick copper alloys and up to 0.070" (1.78 mm) thick stainless steel. Such thick metals produce noticeable bevel on the edge and require a higher tolerance range.

Q. Can you etch from one side only?

A. Yes, we can etch either partial or complete parts from one side. However, there are certain limits on thickness and type of metal. Please consult our engineers for your specific application.

Q. Can you etch STEPS on parts?

A. Yes, we can etch one step (half etch) on parts. Multi-step etching is possible but has some restrictions. Discuss with our engineering team if you have this type of application.

Q. What are the design guidelines for etching?

A. Please refer to our "Design Guideline for Chemical Etching" insert. Our engineering team is always available to guide you for your specific requirements.

Q. What is a photo-tool and etch-allowance?

A. Also, know as artwork, a "photo-tool" is a precise layout of components, typically on high-quality mylar sheets. In cases where ultra-high resolution is needed a glass tool is used in place of a mylar. "Etch-allowance" is any adjustment made to the external and internal dimensions based on type & thickness of metal to be etched.

Q. What secondary operations can you perform on etched parts?

A. Tecomet Inc. can perform a variety of conventional and non-conventional secondary operations. Examples are heat-set nitinol, passivation, plating (gold, tin, etc.), forming, anodizing, heat treatment and electro-polishing.

Q. What is your typical lead time?

A. Typical lead time is two weeks or less. However additional secondary operations may extend the lead time depending upon complexity and number of processes. We also offer an expedited option to process your orders with one week or three-day turnaround.

Q. What information do I need to submit for a price quote?

A. Your print including specifications and desired quantity are all we need to initiate a price quote. For a conceptual design, we can guide you for an optimum selection of material, thickness, and tolerance.

Q. Would you sign an NDA (Non-Disclosure Agreement) before we send you print?

A. Yes. We routinely work with R&D engineers and customers who have proprietary designs and confidential information. Our employees are bound by a Tecomet Inc. Confidentiality Agreement and we limit disclosure of your information to only those employees who have a need to know in order to produce the parts.