Overview

A custom stainless steel shim is a thin, flat spacing or alignment part cut by photochemical machining from precision-rolled 301, 304 or 316L stainless. Because the thickness of a shim is the functional dimension, suppliers hold the incoming coil to tight gauge and the etched part to as little as ±0.005 mm, with half-etched steps that create multiple thickness zones in one blank. Etching removes metal chemically rather than shearing it, so shims leave the line burr-free, stress-free and flat, with no rolled edge to disturb a stack height or a bearing preload. Thicknesses from 0.02 mm to 2.0 mm cover everything from optical spacers to gearbox adjustment packs.

For a buyer, a custom stainless steel shim is purchased against a thickness tolerance, not just an outline. The drawing should state the nominal gauge, the acceptable band, and whether the tolerance applies before or after any plating or passivation, because a few microns of finish can consume the whole budget. Photochemical machining lets a single part carry several etched-in thickness levels, so a stepped shim replaces a stack of loose washers and removes a source of assembly error. Prototypes are etched from the same certified coil as production, so a stack-height check passed on a sample holds at volume, and a new part number needs only a new film.

Parameter Window

• Available Materials: precision-rolled 301, 304, 316L, 17-7PH stainless, 430, cold-rolled to tight gauge
• Material Thickness Range: 0.02-2.00 mm; stock certified to ±0.005 mm gauge for thin shims
• Tolerance: ±0.005 mm on thickness, ±0.02 mm on outline, ±5% on half-etched step depth
• Minimum Feature: 0.15 mm hole and 0.15 mm web at 0.10 mm stock; step transition 0.20 mm or wider
• Surface Options: passivated, electropolished, deburred edges, black oxide, plated, adhesive-backed, laminated shim packs
• Compliance: ISO 9001 process control, RoHS/REACH material traceability

Manufacturing Process / Workflow (8 Steps)

1. Gauge & Tolerance Review — Confirm nominal thickness, the tolerance band and whether it applies before or after finishing.
2. Certified Coil Selection — Select a coil with a mill certificate showing actual gauge and flatness, matched to the target thickness.
3. Cleaning & Lamination — Laminate dry film on both sides so through-cuts and half-etch steps form in one pass.
4. Exposure — Expose the outline, hole and step artwork in register to the sheet for panel-level accuracy.
5. Development & Step Mask — Develop the image, then mask the finished thin zones before the second etch where multi-level steps are needed.
6. Etching — Etch in controlled ferric chloride, timing the dwell so each zone reaches its target residual thickness.
7. Stripping & Finishing — Strip resist, passivate or electropolish, and verify that finishing has not eaten the thickness budget.
8. Inspection & Packaging — Measure thickness at defined points with a micrometer or laser gauge, then pack flat with certificates.

Core Advantages

1. Tight thickness control: Certified coil plus controlled dwell holds shim thickness to ±0.005 mm on thin gauges.
2. Burr-free stacking: Chemical cutting leaves no rolled edge, so shims stack flush and preload stays repeatable.
3. Multi-level in one part: Half-etched steps create several thickness zones in one blank, replacing loose washer stacks.
4. Flat and stress-free: No stamping force means the shim stays flat and does not spring after clamping.
5. Fine features at any gauge: Holes, slots and tabs hold 0.15 mm detail even on 0.10 mm stock.
6. No tooling charge: A new part number is a new film, so adjustment packs and frequent revisions stay economical.

Typical Applications

• Bearing preload: Adjustment shims that set axial play in gearboxes, spindles and electric motor assemblies.
• Optical alignment: Spacers that fix lens, sensor or mirror standoff to a few microns.
• Valve and pump clearance: Thin shims that set impeller, vane or seat clearance in fluid equipment.
• Mould and die shimming: Stacked shims that correct parting-line and cavity height in tooling.
• Aerospace assemblies: Lightweight corrosion-resistant spacers in control-surface and actuator stacks.
• Semiconductor fixtures: Precision standoffs in wafer chucks, bonders and inspection jigs.

Design Notes & Process Considerations

1. Thickness callout: For a custom stainless steel shim, state nominal gauge, tolerance band and whether it applies before or after finishing.
2. Gauge certificate: Request the coil mill certificate; etched tolerance can only be as good as the incoming strip.
3. Finishing allowance: Passivation or plating adds microns, so reserve part of the budget or measure after finish.
4. Step geometry: Keep step transitions at least 2 × the thickness change, or the etch forms a sloped ramp.
5. Flatness and burr: Call out flatness per 100 mm and require burr-free edges for stacked or bonded shims.
6. Measurement plan: Define the number and location of thickness measurement points so inspection is repeatable.