Overview

Medallion etching produces relief on metal medallions, commemorative plates and award discs by photochemical machining instead of die striking or hand engraving. The face is coated with photoresist, exposed through a film carrying the artwork, developed, and etched to a controlled depth; repeating the coat-expose-etch cycle builds two or three distinct levels, so a portrait sits lower than a ring of text and the field stays flat. Brass H62, 304 stainless, aluminum 5052 and copper are the common substrates, in 0.3 mm to 3.0 mm stock.

The economics are the reason this process is used for medallions. A struck medallion needs a pair of hardened dies that cost more than a small commemorative run is worth, and every revision means recutting. Medallion etching needs only a film, so a single piece, a run of fifty for a ceremony and a reorder two years later all use the same artwork. Edges stay crisp, fine serif text holds at 0.15 mm stroke, and depth is uniform across the face, which is what makes a painted or plated relief read cleanly at arm's length.

Parameter Window

• Available Materials: brass H62/H65, stainless steel 304/316L, aluminum 1050/5052, copper C1100, nickel silver
• Material Thickness Range: 0.3–3.0 mm
• Tolerance: ±0.05 mm on outline and rim, ±10% of target depth on relief levels
• Minimum Feature: 0.15 mm stroke, 0.2 mm gap between relief levels at 0.5 mm depth
• Surface Options: antique brass, brushed or mirror polish, Ni/Au/Ag plating, enamel or paint fill, epoxy dome, laser serial
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Artwork Review — Convert the design to vector art, separate the relief levels, and check that stroke width and gap suit the requested depth.
2. Material Selection — Match alloy to finish and weight: brass for antique patina and heft, 304 for outdoor exposure, aluminum for low mass.
3. Cleaning & Lamination — Degrease the blank and laminate dry film; a domed or textured blank needs a conforming resist to avoid trapped air.
4. First Exposure — Expose the deepest level through film registered to the rim, so the artwork stays concentric with the blank.
5. First Etch — Etch the deep level to depth, typically 0.3–0.6 mm, then strip and recoat for the next level without disturbing the relief.
6. Step Etch — Repeat coat, expose and etch for the mid and fine levels, holding each depth within ±10% and keeping walls free of undercut.
7. Stripping & Finishing — Remove resist, polish the field, then antique, plate or fill paint; enamel fill is cured and the excess lapped back.
8. Inspection & Presentation — Verify depth, level registration, text legibility and color, then pack in a capsule, pouch or presentation box.

Core Advantages

1. No die cost: A hundred-piece commemorative run carries no die amortisation, so the unit price stays sensible at volumes that strike cannot serve.
2. Multiple relief levels: Two or three depths are built by re-masking, giving a portrait, a ring of text and a background field distinct heights.
3. Fine text that survives: Serif lettering and small dates hold at 0.15 mm stroke, and the recess protects the fill from abrasion.
4. Uniform depth across the face: Etchant circulation is even over the whole blank, so the rim does not etch deeper than the center.
5. Edges without burr or flash: Chemical removal leaves no die flash to file off, which matters when the rim is a visible design element.
6. Single pieces accepted: One-off prototypes and small award batches run on the same line as production, with no minimum tooling step.

Typical Applications

• Commemorative medallions: Anniversary and event pieces in brass with antique finish, usually 2.0–3.0 mm for weight and feel.
• Award and recognition discs: Employee and competition awards with etched text and a plated or enamel-filled field.
• Brand plaques: Product launch plates with a deep logo and a fine tagline, mounted on wood or acrylic backers.
• Collector and souvenir coins: Limited series where each variant needs its own artwork but not its own die.
• Instrument badges: Model badges on equipment, etched in 0.5 mm stainless and adhesive-backed for assembly.
• Architectural dedication plates: Building and donor plates that must stay legible outdoors for decades.

Design Notes & Process Considerations

1. Depth versus gap: Keep the gap between two relief levels at least 0.5 × depth; a narrow gap undercuts and the wall breaks through.
2. Level count: Two levels cover most designs; a third adds cost and registration risk, so reserve it for a genuine focal element such as a portrait.
3. Stroke width: Hold text strokes at 0.15 mm or 1.5 × depth, whichever is greater, since a deep narrow stroke etches as a ragged groove.
4. Rim and outline: Decide whether the rim is through-cut or left as a half-etched border; a cut rim needs a deburr-free edge for handling.
5. Finish sequence: Plate before paint fill if the field is bright, and antique after etch if the recess must stay dark; state the order on the drawing.
6. Presentation and handling: Specify the back finish and mounting method. On medallion etching work, a mirror field shows every fingerprint, so handling gloves and individual bagging are worth writing into the order.