Copper Electroplating

Copper electroplating deposits a controllable copper layer on conductive parts for conductivity, solderability, and as an undercoat, with thickness-driven fit impacts.

Overview

Copper electroplating uses an electrolytic bath to deposit copper onto a conductive surface (or a catalyzed base layer) at controlled thickness. Shops use it to increase electrical conductivity, improve solderability, build thickness for minor dimensional recovery, and create a reliable underlayer before nickel, chromium, or precious-metal finishes.

Choose copper plating when you need a uniform, adherent metallic coating on complex geometry with predictable thickness control (typically a few to tens of microns). Key tradeoffs are thickness variation at edges/high-current-density features, the need for racking/contact points that leave witness marks, and surface prep sensitivity—oils, oxides, and porosity drive adhesion issues. Hydrogen embrittlement risk exists for high-strength steels unless baked. Copper also tarnishes/oxidizes, so cosmetic or corrosion-critical parts often need a topcoat or subsequent plating.

Common Materials

  • Copper
  • Brass
  • Steel 1018
  • Stainless steel 304
  • Aluminum 6061
  • ABS (conductive pre-plate)

Tolerances

±0.0002"–±0.001" (thickness-dependent; mask/allowance critical on fits)

Applications

  • PCB through-hole and via copper build-up
  • RF shields and EMI cans
  • Solderable terminals and bus bars
  • Copper strike layer before nickel/chrome plating
  • Thickness build for worn shafts or bearing seats
  • Battery contacts and connectors

When to Choose Copper Electroplating

Pick copper electroplating when performance is driven by conductivity or solderability, or when you need a controlled metallic undercoat for subsequent finishes. It fits low to high volumes depending on racking vs barrel processing and tolerates complex shapes if contact locations are acceptable. Plan it early for any tight fits because thickness adds to all plated surfaces.

vs Anodizing

Choose copper electroplating when you need a metallic, solderable, highly conductive surface. Anodizing is best for aluminum oxide layers and dye/color, but it’s electrically insulating and not a copper build process.

vs Powder Coating

Choose copper electroplating when you need a thin, conductive coating with precise thickness control and compatibility with soldering or subsequent metal plating. Powder coating is thicker, polymer-based, and typically insulating, making it better for durable cosmetics than electrical performance.

vs E-Coating

Choose copper electroplating when you need metal-to-metal conductivity and a true copper deposit as a functional layer or underplate. E-coating is a paint-like film optimized for corrosion coverage, usually insulating and not suited to solderable electrical interfaces.

vs Nickel Electroplating

Choose copper electroplating when you need maximum electrical/thermal conductivity, easy solderability, or a ductile leveling underlayer. Nickel is harder and more wear/corrosion resistant, but higher resistivity and can be less forgiving for soldering without proper activation.

vs Chromium Electroplating

Choose copper electroplating when conductivity, solderability, or an undercoat/build layer is the goal. Chromium targets wear resistance, hardness, and appearance; it’s typically used as a topcoat and won’t provide the same electrical performance as copper.

Design Considerations

  • Call out required thickness range and measurement locations; thickness varies at edges, corners, and high-current-density features.
  • Add plating allowance on critical fits and threads, or specify masking for no-plate areas to avoid assembly issues.
  • Define acceptable rack/contact witness marks and provide preferred contact locations on non-cosmetic, non-functional surfaces.
  • Avoid sharp outside corners and thin knife edges; they plate heavy and can burn, creating roughness or nodules.
  • Specify post-plate finish needs (anti-tarnish, clear coat, or subsequent plating) if color stability or corrosion performance matters.
  • Identify base material and heat treatment (especially high-strength steels) and include hydrogen embrittlement relief bake requirements when applicable.