Copper Shims and Copper Shim Washers

Copper Shims and Copper Shim Washers

Copper shims are thin, flat copper pieces used as spacers, gap-fillers, alignment aids, and thermal interface materials in electrical, mechanical, and electronic assemblies. Also known as copper shim washers, copper spacer plates, copper feeler shims, copper packing pieces, copper thermal shims, copper EMI shims, and copper gasket shims, these components are precision blanked from Cu-ETP (C11000) and Cu-OF (C10200) copper foil and strip. Electrical Accessories India manufactures copper shims in thicknesses from 0.05 mm to 5.0 mm, in standard and custom profiles, for electrical OEMs, precision mechanical equipment manufacturers, power electronics, and industrial engineering applications.

Product Overview

Copper Electrical Shims and Contact Spacers

Copper electrical shims, copper contact spacers, copper busbar shims, copper contact adjustment shims, copper terminal spacers, and copper interface pads are used to set contact gaps, adjust contact pressure, and fill dimensional tolerances in switchgear and contactor assemblies. They are manufactured to close thickness tolerances (±0.01 mm for thin foil shims; ±0.05 mm for thicker shims) from annealed Cu-ETP strip. Electrical shims maintain electrical continuity at the interface while compensating for manufacturing tolerances in mating parts. Standard sizes in 0.1 mm, 0.2 mm, 0.3 mm, 0.5 mm, 1.0 mm, and 2.0 mm thickness steps.

Copper Thermal Interface Shims

Copper thermal shims, copper heat spreader shims, copper TIM (thermal interface material) shims, and copper thermal pads are used between power semiconductor devices (IGBTs, MOSFETs, diodes), heat sinks, and cold plates in power electronics, motor drives, UPS systems, and EV inverters. Copper’s thermal conductivity (385–401 W/m·K) far exceeds aluminium (160–200 W/m·K) or graphite pads (<10 W/m·K). A 0.5–2.0 mm copper thermal shim reduces thermal interface resistance and improves heat transfer from device junction to heat sink. Custom sizes from 10×10 mm to 200×200 mm blanked from Cu-OF or Cu-ETP foil.

Copper EMI Shielding Shims

Copper EMI shims, copper RF gasket shims, copper electromagnetic shielding spacers, and copper shield shims are used to fill gaps in EMI enclosures, reduce leakage at seams, and maintain shielding effectiveness. Used in radar equipment, telecommunications cabinets, medical imaging equipment, and military electronics where consistent electromagnetic shielding is critical. Thin copper foil shims (0.05–0.5 mm) compress at joints to provide low-resistance electrical contact across the enclosure seam. Tin plating is standard to maintain surface conductivity over the product life.

Copper Mechanical Shims and Alignment Spacers

Copper mechanical shims, copper precision spacers, copper packing washers, copper feeler gauge shims, and copper levelling shims are used to align machinery, adjust clearances, correct shaft offsets, and set bearing preloads. Common applications include motor shaft alignment, gearbox bearing clearance adjustment, pump coupling alignment, turbine blade clearance setting, and press tool die clearance adjustment. Available in pre-cut sets with incremental thickness steps for rapid selection of the correct shim pack thickness.

Copper Gasket Shims and Sealing Spacers

Copper gasket shims, copper cylinder head spacers, copper compression limiters, and copper crush spacers are used in fluid-handling and heat exchanger applications where metal-to-metal sealing is required. Copper’s malleability allows it to deform and fill micro-irregularities in mating surfaces, creating a reliable seal. Used in hydraulic fittings, oil gallery plug sealing, refrigeration line connections, and heat exchanger tube sheet assemblies. Available in annealed (soft) condition for maximum conformability.

Key Features

• Thickness range: 0.05 mm to 5.0 mm — thin foil to heavy plate
• Cu-ETP (≥100% IACS) and Cu-OF (≥101% IACS) copper grades
• Thickness tolerance: ±0.01 mm (foil), ±0.05 mm (strip), ±0.1 mm (plate)
• Precision blanked — any 2D profile; round, rectangular, custom shapes
• Soft (annealed) or half-hard temper options
• Tin-plated, silver-plated, bare copper, or nickel-plated finishes
• Custom sizes from 5×5 mm to 300×300 mm
• Material test reports and REACH/RoHS compliance standard

Thickness Tolerance and Precision

Copper foil shims (0.05–0.5 mm) are manufactured from precision-rolled Cu-OF foil to ±0.005 mm thickness tolerance. Strip shims (0.5–3.0 mm) are blanked from rolled Cu-ETP strip to ±0.01–0.05 mm. Plate shims (3.0–5.0 mm) are blanked from plate to ±0.05–0.1 mm. Profile dimensional tolerance is ±0.1 mm for standard blanked parts. Critical interface surfaces are coined or ground to achieve Ra <0.4 μm flatness. For electronic thermal interface applications, lapping to Ra <0.1 μm is available on request.

Thermal and Electrical Properties

Cu-ETP copper thermal conductivity: 385–395 W/m·K. Cu-OF copper thermal conductivity: 395–401 W/m·K. Electrical conductivity: ≥100% IACS. These properties make copper shims the optimal choice for both thermal interface and electrical contact applications where aluminium (160 W/m·K, 35% IACS) or steel (50 W/m·K, 3% IACS) shims are inadequate. For thermal interface applications, surface flatness and surface roughness of the shim are as important as material conductivity — both are controlled in our manufacturing process.

Temper and Forming

Annealed (soft, O-temper) copper shims offer maximum conformability for sealing and mechanical shimming applications where the shim must compress under bolt load to fill surface irregularities. Half-hard (H02) shims offer higher spring-back resistance for applications where thickness must be maintained under load. Quarter-hard and hard tempers are available for spring-loaded contact applications. Temper is specified at order; standard is annealed. Stress relief annealing is performed after blanking on critical thermal shims to eliminate residual stamping stresses.

Custom Profile and Shape Options

Copper shims are manufactured in any 2D profile from customer DXF, PDF, or STEP drawings. Common profiles: round disc, square plate, rectangular plate, washer (ring), semicircle, sector, and complex custom outlines. Holes, slots, notches, and cutouts are punched simultaneously with blanking. Progressive die tooling is used for batch production; waterjet or laser cutting is used for prototype quantities or very large/complex profiles. Minimum feature size for punched holes: 1.5× material thickness. Custom profiles are delivered to ±0.1 mm profile tolerance.

Surface Finish Options

Bare copper shims are supplied for immediate assembly in sealed, controlled environments. Electrolytic tin plating (3–10 μm) prevents oxidation and is standard for electrical interface shims used in switchgear. Silver plating (5–25 μm) is specified for RF/EMI shims and high-current contact shims. Nickel plating (3–10 μm) is used for elevated-temperature applications. For thermal interface shims, bare copper or silver-plated surfaces are preferred as tin plating can increase thermal resistance. All plating is XRF verified per batch.

Technical Specifications

Material Grades and International Equivalents

Product Types and Variants

Round disc shims; square and rectangular shims; washer/ring shims (with central hole); custom profiled shims; thin foil shims (0.05–0.5 mm); medium-gauge shims (0.5–2.0 mm); thick plate shims (2.0–5.0 mm); thermal interface shims (polished, Ra <0.4 μm); EMI shielding shims (tin-plated); mechanical alignment shims (annealed); shim packs (sets of incremental thickness).

Applications in Industry

Switchgear contact gap setting; contactor contact adjustment; power semiconductor thermal interface (IGBT, MOSFET, diode); motor drive heat sink assembly; EMI enclosure seam sealing; bearing clearance adjustment; shaft alignment shimming; pump and compressor alignment; hydraulic fitting sealing; heat exchanger tube sheet shimming; EV battery pack thermal management; LED lighting heat spreader.

Manufacturing Process

1. Material procurement — Cu-ETP/Cu-OF foil or strip to ASTM B152/B187 with MTC
2. Incoming inspection — thickness (micrometer), conductivity, hardness, composition (XRF)
3. Blanking — progressive die blanking or single-hit blanking; fine-blanking for critical profiles
4. Punching — holes, slots, and cutouts punched simultaneously
5. Deburring — precision edge deburring; burr <0.02 mm for foil shims
6. Annealing — stress-relief annealing for thermal shims
7. Surface preparation — degreasing, acid rinse
8. Plating — barrel or rack plating (tin, silver, nickel)
9. Inspection — 100% thickness measurement; sampling dimensional CMM check
10. Packing — interleaved paper packing for foil shims; poly bags for standard shims

Quality Standards and Certifications

Material: ASTM B152, ASTM B187, BS EN 13601. Dimensional: ±tolerance per drawing. Thermal: ASTM E1225 or E1667 conductivity verification available. ISO 9001:2015 QMS. REACH and RoHS compliance. EN 10204 Type 3.1 material test certificates standard.

Why Choose Electrical Accessories India

Electrical Accessories India manufactures precision copper shims from ultra-thin foil (0.05 mm) to heavy plate (5.0 mm) at its Jamnagar facility. Our precision blanking dies achieve ±0.05 mm thickness tolerance and ±0.1 mm profile tolerance. Copper stock in Cu-ETP and Cu-OF from multiple international mills is maintained for fast turnaround. We support R&D prototype quantities as well as high-volume production orders. Full documentation — MTC, dimensional, plating certificates, REACH, RoHS — is standard with every shipment.

Frequently Asked Questions (FAQ)

What is the thinnest copper shim you can manufacture?

We manufacture copper shims from 0.05 mm (50 μm) foil thickness upwards. Ultra-thin foil shims at 0.05–0.1 mm are precision blanked from Cu-OF foil and require careful handling to avoid deformation.

What is the thickness tolerance for copper shims?

Foil shims (0.05–0.5 mm): ±0.005 mm. Strip shims (0.5–3.0 mm): ±0.05 mm. Plate shims (3.0–5.0 mm): ±0.1 mm. Tighter tolerances are achievable for critical applications by material selection and grinding.

Are copper shims suitable for thermal interface applications?

Yes. Cu-OF copper at 395–401 W/m·K is one of the best thermal interface materials available. Copper shims are used in power electronics, motor drives, and EV inverters between power semiconductors and heat sinks. Surface finish Ra <0.4 μm ensures low thermal interface resistance.

Can copper shims be supplied with a central hole?

Yes. Washer-form copper shims with central holes from M4 to M30 are available as standard. Custom hole diameters and non-circular holes are punched to drawing.

What is the minimum order quantity?

Standard profiled shims: 100 pieces minimum. Custom profiled shims with new tooling: 500 pieces minimum. Prototype samples of 10–25 pieces are available for engineering qualification.

Are copper shims REACH and RoHS compliant?

Yes. Pure copper is inherently REACH SVHC-free and RoHS compliant. Tin and silver plating are also compliant. REACH declaration and RoHS certificate are provided with each shipment.

What size copper shims can you manufacture?

Standard blanking: up to 300×300 mm. Larger profiles are available by waterjet or laser cutting from copper plate. Minimum practical size is approximately 5×5 mm for standard blanking.

Can copper shims be supplied in incremental thickness packs?

Yes. Shim packs in sets of 5–10 incremental thicknesses (e.g., 0.1, 0.2, 0.3, 0.5, 1.0, 1.5, 2.0 mm) are supplied for mechanical alignment and gap-setting applications.

Equivalent Terms – Multilingual Reference

Related Products and Linked Terms

• Copper Pressing and Copper Pressed Parts
• Copper Busbar Links – Flexible Busbar Connectors
• Copper Grounding Terminals – Earth Terminals
• Copper Earthing Tags – Earth Tags and Grounding Labels
• Copper Switch Contacts – Electrical Contact Tips
• Copper Fuse Clips – Pressed Copper Fuse Clips
• Copper Shims and Copper Shim Washers
• Copper Washers and Copper Plain Washers
• Copper Sealing Washers – Crush Washers
• Copper Pipe Brackets and Copper Pipe Clamps
• Copper Deep Drawn Sheet Metal Parts
• Copper Machined Parts

Indicative Pricing

Copper Items: US$ 15.80 per kilogram, CIF USA Port

Prices are indicative and subject to change based on quantity, specification, alloy grade, and market conditions. Contact us with your RFQ for a firm quotation.

Request a Quote

Supply your drawing, sample, or specification and receive a detailed technical and commercial proposal within 24 hours. Electrical Accessories India engineers are available to advise on thickness, profile, temper, and surface finish for your copper shim requirements.

Contact us: Send your RFQ with quantity, drawing (PDF/DXF), thickness, and application details. We respond within 24 business hours.