Overview

Etched brass shim production uses photochemical machining to cut thin brass shims with precise outlines, holes and slots out of flat sheet. A photoresist is laminated, exposed with the shim artwork and developed, then the unprotected brass is dissolved in a matched etchant to leave a flat, burr-free part. Shims are typically made from cartridge brass (C26000) or C26800, supplied between 0.05 mm and 1.0 mm thick. Because the metal is chemically removed rather than blanked, the edges carry no roll-over or burr, and the shim keeps the exact thickness of the starting sheet.

Brass is chosen for shims that must seat against mating surfaces without galling, and where the shim may need to be electrically conductive or solderable. Etching holds profile and hole positions tightly while preserving the sheet's original gauge, which is what makes the shim accurate as a spacer. The stress-free edge also means thin brass shims do not warp or curl. This is why etched brass shim parts are specified for valve seats, bearing preload, tool alignment and precision machine assembly where accuracy and flatness matter.

Parameter Window

• Available Materials: brass C26000 (cartridge brass), brass C26800
• Material Thickness Range: 0.05–1.0 mm
• Tolerance: ±0.05 mm on profile, ±0.02 mm on hole position, sheet thickness per mill standard
• Minimum Feature: 0.1 mm hole, 0.15 mm slot width
• Surface Options: mill finish, polished, nickel or tin plated, anti-tarnish
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Shim Design — Convert the outline, holes and slots to vector artwork and confirm the thickness callout against the drawing.
2. Material Selection — Choose C26000 for strength and spring temper or C26800 for deeper drawing, and verify sheet flatness.
3. Cleaning & Lamination — Degrease the sheet and laminate dry film with no bubbles so the edges etch clean.
4. UV Exposure — Expose the shim artwork registered to the sheet edge for accurate hole positions.
5. Development — Wash out the unexposed resist to open the profile, holes and slots, then inspect for blocked features.
6. Etching — Spray etch at controlled temperature; feature size is set by time, pressure and conveyor speed.
7. Stripping & Finishing — Remove resist, neutralize, then polish or plate nickel or tin as required.
8. Inspection & Packaging — Measure thickness, outline and hole positions, then pack flat to prevent bending.

Core Advantages

1. Accurate thickness: The sheet's original gauge is preserved, keeping spacer height true to the mill specification.
2. Burr-free edges: Chemical removal leaves no roll-over or burr, so brass shims seat flat and evenly.
3. No galling: Brass seats smoothly against steel and aluminum without seizing, ideal for assembly shims.
4. Conductive and solderable: Brass carries current and solders readily when the shim doubles as a contact.
5. No tooling cost: Each shim design is a new film, so prototypes and short runs stay economical.
6. Stable and flat: Stress-free etched edges keep thin brass shims flat and free of curl or warp.

Typical Applications

• Valve seats: Thin brass shims for fuel, pneumatic and hydraulic valve assemblies.
• Bearing preload: Spacer shims for setting bearing clearance and preload.
• Tool alignment: Precision shims for aligning dies, molds and machine tools.
• Motor and gearbox: Spacer shims for shaft and gear positioning.
• Electrical spacers: Conductive brass shims that also act as contacts or shims.
• Instrument shims: Fine adjustment shims for gauges and precision instruments.

Design Notes & Process Considerations

1. Thickness callout: Shim accuracy comes from the starting sheet gauge; specify the mill tolerance you require.
2. Feature versus thickness: Keep holes and slots at 1.2 × material thickness or more for clean, straight walls.
3. Flatness: State flatness per 100 mm if the shim must seat against a machined surface without gapping.
4. Temper: Specify full hard or spring temper where the shim must hold its shape under load.
5. Surface finish: Call out plating or anti-tarnish if the shim sits in a humid or corrosive environment.
6. Handling: Provide tab or carrier features if thin, large shims must be handled without bending.