How to Make an Etching: StepbyStep Process

Making precision metal etching parts, also known as photochemical machining, is a multistage subtractive manufacturing method. Instead of cutting metal with tools or laser heat, it uses photoresist masking and controlled chemical dissolution to remove unwanted material. This process creates burrfree, lowstress metal components including fine meshes, microhole sheets, gaskets, spring contacts, encoder discs and decorative nameplates. While simple hobby etching can be done in small labs, commercial industrial etching follows strict standardized steps to hold tight tolerances and ensure batchtobatch consistency. Below explains exactly how to make an etching with complete stepbystep industrial workflow.

Step 1: Design and DFM Preparation

Every etching project begins long before touching raw metal. Start with a clear CAD drawing that defines part outlines, holes, slots, feature sizes and tolerances. Since wet etching works isotropically, chemical attacks metal vertically and sideways at the same time, creating undercut. Engineers calculate undercut compensation and adjust the production artwork accordingly. If features are too small relative to material thickness, they will suggest design revisions to avoid production failure. Once the design is validated, a phototool film is generated for UV exposure. Without proper DFM review, even perfectlooking CAD files can produce outofspec etched parts.

Step 2: Select Raw Material and Surface PreTreatment

Choose suitable thingauge metal sheets or coils. Common industrial metals for etching include stainless steel, copper, brass, nickel, titanium and kovar alloy. Most production runs use material thickness between 0.02 mm and 1.5 mm.

Surface preparation is critical for good photoresist adhesion:

Degreasing: Immerse or spray the metal with alkaline solution to wash away rolling oil, grease and surface organic dirt. Any oil residue will make photoresist lift off during later processing.

Pickling and activation: Acid solution removes oxidation, tarnish and passive surface films.

Rinsing and drying: Multiple water washes eliminate chemical residues, followed by hotair drying. The final surface must be clean and uniformly microrough. Poor pretreatment is one of the top causes of broken patterns, missing holes and low yield in etching production.

Step 3: Laminating Photoresist DryFilm

Dryfilm photoresist is hotroll laminated onto the clean metal surface. For throughetched parts with throughholes, both sides of the sheet receive dryfilm lamination. Operators carefully control laminating temperature, pressure and speed. Trapped air bubbles, wrinkles or incomplete bonding must be avoided. Bubbles under the film allow etchant to seep beneath the mask and cause random spots or pattern damage. After lamination, the panel rests briefly to stabilise film condition before exposure.

Step 4: UV Exposure to Transfer the Pattern

Place the phototool film precisely aligned over the dryfilmcovered metal sheet inside a UV exposure machine. Ultraviolet light shines through the clear areas of the phototool. Regions that need to remain as finishedpart geometry receive UV light, which cures and hardens the photoresist. Areas corresponding to holes, slots and materialremoval zones stay unexposed, so their photoresist remains soluble. For highprecision microhole parts, doublesided exposure is used. It greatly improves hole roundness and sidewall quality of throughetched openings. Accurate alignment guarantees consistent featureposition accuracy across the whole metal panel.

Step 5: Developing to Open Etching Windows

Feed the exposed metal panel through an alkaline developer solution. The unexposed photoresist dissolves away completely, opening precise windows that reveal exactly the metal areas to be etched away. The UVhardened photoresist stays firmly bonded as a protective mask.

Intermediate inspection takes place right after developing. Operators use visual check or AOI automatic optical inspection to verify pattern integrity. They screen out semifinished panels with broken lines, residual film or blocked microholes before these defective sheets go into the etching tank.

Step 6: Chemical Etching — Core Material Removal

This step physically “makes the etching”. The masked metal panels pass through an automatic circulating spray etching line. Pressured recirculating etchant sprays onto both surfaces of the workpiece. Through redox and complexing chemical reactions, etchant dissolves the unprotected exposed metal. Key parameters including liquid temperature, spray pressure, conveyor speed and chemical concentration are digitally controlled. Operators balance vertical etching depth and lateral undercut to hit target dimensions. For fullpenetration parts, doublesided spray delivers cleaner edges and better dimensional consistency. Etching duration determines whether features are shallow blindetched or fully throughetched.

Step 7: Strip off the Photoresist Mask

Once the target etching depth or full penetration is achieved, move parts to the stripping station. Hot alkaline stripping liquid removes all the hardened photoresist from metal surfaces. Complete stripping is essential. Any leftover resist residue will cause staining and defects on subsequent plating, passivation or electropolishing processes. After stripping, parts go through thorough water rinsing.

Step 8: PostTreatment Processes

Basic etching is finished at this point, yet most industrial parts require additional posttreatment:

Neutralisation rinsing removes all residual corrosive chemicals.

Optional processes include passivation, electropolishing, nickel or gold plating, bending and forming, laser marking and panel separation. These secondary steps enhance corrosion resistance, surface smoothness, electrical performance or prepare parts for final assembly.

Step 9: Final Quality Inspection

The final step of how to make an etching is comprehensive quality control before shipment:

Measure critical dimensions with microscope or video measuring equipment.

Use AOI scanning to check for nicks, missing holes, pattern distortion and surface flaws.

Verify flatness and visual appearance. Manufacturers can provide batch inspection reports to satisfy customer incomingqualitycontrol requirements.

Differences Between Hobby Etching and Industrial Etching

Smallscale hobby etching uses simple manual tanks. It works for artwork samples but struggles with tight tolerance, uniform microholes and largebatch stability. Industrial photochemical etching uses automated spray lines, closedloop chemical control and fullprocess inspection to produce reliable precision components for electronics, medical devices, automotive and newenergy industries.

Conclusion

To make an etching, follow this complete stepbystep workflow: design & DFM review → rawmaterial selection & surface pretreatment → dryfilm lamination → UV pattern exposure → developing → chemical etching → photoresist stripping → posttreatment → final inspection. Every step is interdependent. Highquality etched parts rely not only on correct chemical formulas, but also on strict execution of each manufacturing stage. Understanding how to make an etching helps designers optimise drawings, evaluate manufacturability and select suitable production solutions for thinmetal precision components.