What is Photochemical Machining?
Photochemical machining, also referred to as photo chemical etching or photochemical etching, is a subtractive manufacturing process that uses photoresist imaging and controlled chemical etchants to selectively remove material from thin metal sheets. Related terms and processes include photo etching, photochemical etching process, chemical etching process, photo chemical machining, and chemical machining. These methods, known by many names, are all used to manufacture intricate, precise, and complex metal parts, offering advantages such as versatility, low cost, quick turnaround, and the ability to process a variety of metals without damaging the material.
Unlike traditional machining methods such as milling, stamping, EDM, or laser cutting, metal photochemical etching does not rely on mechanical force or thermal input. This makes it uniquely suited for producing parts with:
- Fine features and tight tolerances
- Complex internal geometries
- Thin cross-sections
- Stress-free, burr-free edges
The photochemical etching process is a multi-step process that includes metal cleaning, photoresist lamination, and printing.
Photochemical machining is especially effective for applications where dimensional stability, surface integrity, and repeatability are more critical than material thickness. It is widely used to produce precision parts, complex parts, burr-free parts, thin metal parts, and precision metal parts for industries requiring high accuracy and intricate designs.
Compared to other methods, photochemical etching does not affect the internal structure of the metal, preserving its intrinsic properties. The process is limited to relatively thin metals, typically 1.5 mm or less, and is a 2D process that cannot be used to produce 3D parts.
The Photochemical Machining Process
Elcon’s unique and tailored photochemical machining process is tightly controlled to deliver consistent, repeatable results from prototype through production. This is achieved through our comprehensive QMS, as well as our dedicated staff, to support the entire manufacturing process.
- Photoresist Coating
Metal sheets are thoroughly cleaned and uniformly coated with a light-sensitive photoresist, resulting in a photoresist-coated metal sheet. This step ensures the coated metal is ready for precise pattern transfer in subsequent steps. - Imaging and Development
A photo tool, typically a negative image of the desired part printed onto stable mylar film, is used in the imaging process. For double-sided etching, the top and bottom halves of the photo tool are aligned on one or both sides of the metal sheet, often using two sheets of film. The photo tool and metal sheet are brought into intimate contact, ensuring precise registration. UV light is then used to expose the photoresist, transferring the pattern with high accuracy. Depending on the design, a single-sheet or two-sheets setup may be used. Sheet size is considered to maximize material efficiency and optimize the number of parts produced per run. After exposure, unexposed areas are developed away, revealing the etch pattern. - Controlled Chemical Etching
The metal sheet is processed through an etching line, a multi-chambered machine designed for precision and efficiency in chemical milling and photo chemical milling. The chemical etching process removes metal from the exposed areas, targeting the exposed metal and bare metal through an oxidation-reduction reaction at the atomic level. Process variables such as etchant concentration, temperature, and agitation are strictly controlled to ensure consistent results. This process produces burr-free parts with a smooth surface and can achieve a minimum feature size of 0.1 mm, with feature size tolerance typically +/-10% of the material thickness. The process is suitable for very thin gauged metals and foils, with typical thicknesses between 0.005mm and 2.5mm. Parts can be half-etched on one or both sides to reduce metal stress during secondary forming operations. - Stripping, Inspection, and Finishing
The remaining photoresist is stripped, exposing the finished bare metal. Parts are inspected for dimensional accuracy and adherence to specified dimensional tolerances. Subsequent processing and finishing operations can be applied as required for assembly or performance.
Throughout the process, Elcon emphasizes low-cost tooling, the ability to offer unique features, and the elimination of tool wear. Design engineers must consider metal thickness, dimensional tolerances, minimum feature size, and the desired shape when designing precision metal parts. The process allows for the production of multiple parts from a single sheet of sheet metal, with the sheet size optimized for efficiency. This approach is ideal for rapid prototyping and manufacturing of intricate, high-quality components.
Benefits of Photochemical Machining
Photochemical machining offers a unique combination of precision, flexibility, and scalability:
- Burr-free, stress-free parts with no mechanical distortion
- Fine feature resolution for intricate designs
- No hard tooling or die costs, reducing upfront investment
- Rapid design iteration and prototyping
- Scalable from prototype to production without process changes
- Tighter tolerances for high-precision applications
- Smooth surface finish requiring minimal post-processing
- Burr-free parts for high-quality, ready-to-use components
- Unique features and custom profiles at no extra cost
- Quick turnaround for fast delivery of custom parts
The process is cost-effective, eliminates tool wear, and enables low-cost tooling, making it an efficient choice for manufacturing.
Photochemical etching allows for rapid prototyping and quick turnaround on production parts orders.
The process can achieve a minimum feature size of 0.1 mm, with feature size tolerance typically +/-10% of the material thickness.
These advantages make precision photochemical machining an ideal alternative to stamping, laser cutting, or EDM when part performance and design freedom are paramount. It is especially suited for producing precision parts, complex parts, and precise components required in demanding industries.
Materials for Photo Chemical Etching
Elcon Precision supports a wide range of materials for photo chemical etching, including:
- Stainless steels
- Copper and copper alloys
- Nickel and nickel alloys
- Specialty and exotic metals
Photo chemical etching is compatible with metals such as stainless steel, aluminum, copper, titanium, and nickel alloys.
The process can be applied to virtually any metal that is soft, hard, or brittle, but is generally not suitable for precious metals such as gold. Soft annealed thin metals etch as well as thicker, extremely hard tempered metals.
Material selection is guided not only by etching performance, but by compatibility with brazing, ceramic metallization, and downstream assembly requirements. Photo chemical etching is ideal for producing precision metal parts from various types of sheet metal, enabling the creation of intricate metal parts and high-precision components for demanding applications. This system-level perspective helps ensure etched components perform reliably as part of larger, high-complexity assemblies.
Photochemical Machining at Elcon Precision
At Elcon, photochemical machining is rarely an isolated operation. It is a foundational capability used to create functional internal metal components that enable advanced systems.
Common part types include:
- Control grids
- Shields and masks
- Springs and current shapers
- Electrical contacts
- Microwave circuits
- Precision components
- Precision internal metal features
Photochemical etching is used in the fabrication of printed circuit boards (PCBs), medical devices, aerospace components, and automotive applications. The process is commonly used in the electronics industry for applications such as microwave circuits and electrical contacts. The medical industry utilizes photochemical machining to create precision parts like stents and micro-scalpels. Photochemical etching is employed in aerospace applications to manufacture components such as fine mesh screens for aircraft engines. Photochemical machining is effective for producing small, complex parts for automotive applications, including battery terminals and speaker grills.
These etched components are routinely integrated into:
- Precision brazed assemblies
- Ceramic-to-metal feedthroughs
- High-voltage and high-vacuum systems
The process allows for the customization of the desired part, enabling the creation of intricate and precise patterns to achieve the desired shape, making it ideal for manufacturing complex parts across various industries.
By combining photochemical machining with in-house metallization and brazing expertise, Elcon delivers solutions that reduce supplier handoffs, improve alignment, and accelerate development timelines.
Industries & Applications
At Elcon Precision, we pride ourselves on supporting mission-critical applications across demanding industries, including:
- Defense and RF/vacuum electronics
- Aerospace and space systems
- Photonics and optics
- Nuclear and advanced energy
Photochemical etching offers broad industrial applications, including the production of screens, masks, fuel cell parts, and semiconductor leadframes, making it suitable for sectors that require precision and delicate fabrication.
Engineers in these sectors rely on Elcon’s ability to translate complex designs into manufacturable, high-reliability hardware.
Benefits
- Competitive cost
- Fast turnaround
- Burr-free, stress-free parts
- Low cost tooling
- Metallurgical properties preserved
- Design flexibility
- Wide range of materials
- Dimensional repeatability
- Precise and complex geometries
Capabilities
- Material thickness: 0.0005 in. to 0.100 in., depending on the features. Contact us with any questions!
- Step etching
- Half etching
- 3D photoetching
- Knife and needle edges
- Selective plating
- Typical minimum hole diameter: 1.2x material thickness
- Typical minimum feature spacing: 1.2x material thickness
- See our Design Guidelines for more detail.
Specifications
View applications for photochemical machining, the equipment we use, alternative naming conventions, and more below.
Ready to Explore What’s Possible?
Looking for a photochemical machining partner who understands your full system?
The team at Elcon Precision brings deep process knowledge, material expertise, and assembly integration under one roof, making us the best-value choice for complex, performance-driven applications.
We don’t just supply parts; we produce solutions that last the lifetime of your design.
