Knowledge Points of Color-Coated Aluminum for Capacitor Housings

Introduction

Color-coated aluminum (pre-painted aluminum coil/strip) is a specialized substrate for stamping capacitor housings, widely used in motor run capacitors, air-conditioning compressor capacitors and power electronic capacitors. It is different from the internal etched aluminum foil inside capacitor cores. The coating is applied on aluminum base via continuous coil coating lines before deep drawing, so capacitor manufacturers can skip the PVC/PET shrink sleeve process after shell forming. CHANGZHOU DINGANG METAL MATERIAL CO.,LTD supplies this grade for global capacitor factories.

Base Material Specifications

Common Aluminum Alloy & Temper

The most popular alloys are 1050, 1060, 3003. These grades feature excellent ductility and deep drawability, which avoids cracking during shell stamping.

• O temper (soft): Preferred for deep drawing cylindrical capacitor shells

• H14 / H24: For shallow forming shells

• Typical thickness range: 0.25 mm ~ 0.50 mm

Coating Systems

Two mainstream coating types are selected based on working conditions and budget:

• PE Polyester coating: ≥18 μm film thickness, good formability, cost-effective for standard CBB60 / CBB65 capacitors

• PVDF coating: ≥25 μm film thickness, superior heat resistance, chemical resistance and salt spray performance for high-end and export orders Coating structure: Primer + topcoat, single-coat or double-coat available. Colors can be customized by RAL or Pantone codes. Double-sided coating is optional for high-humidity corrosive environments.

Key Benefits vs Bare Aluminum Shell + Heat Shrink Sleeve

1. Higher automation efficiency No shrink sleeve assembly after stamping, saving labor and boosting production line speed for capacitor makers.

2. Built-in insulation and anti-corrosion performance The coating prevents bare aluminum oxidation and blackening, provides basic surface insulation and oil resistance.

3. Stable appearance & printing adhesion Uniform color batch to batch; silk-screen marking on coating surface has reliable adhesion.

4. Good heat dissipation retention The thin paint layer barely blocks heat transfer, and the thermal performance is close to bare aluminum housing.

Main Application Capacitor Types

CBB65 Air Conditioner Compressor Capacitors

This is the largest consumption field of color-coated aluminum capacitor shells.

CBB60 Motor & Water Pump Run Capacitors

Widely used in washing machines, water pumps and small motors.

Power Electronic Capacitors

Including inverter, UPS and photovoltaic DC-link capacitors, some bolt-type aluminum electrolytic housings also adopt this material.

Critical Testing Items for Quality Control

• Cross-hatch adhesion test: No paint peeling after deep drawing

• Impact resistance, solvent resistance

• Salt spray test, anti-aging test

• Surface inspection: No scratch, missing coating or pinhole

• Environmental compliance: RoHS, REACH, halogen-free for EU export

Important Notes for Design & Production

• The coating must not crack or flake at deep drawing zones, sealing areas and explosion-proof groove positions.

• The coating only protects the housing surface; it will not change the capacitor’s core electrical performance, explosion-proof function or electrolyte reliability.

• The coating is an insulating layer on the outer surface. The housing itself is only a packaging shell and does not participate in internal electrode conduction.

Why Choose CHANGZHOU DINGANG METAL MATERIAL CO.,LTD

We focus on color-coated aluminum for capacitor housings. We can control alloy, temper, coating thickness, color and slitting width according to customer stamping requirements. Samples are available for forming test, coating adhesion verification and third-party environmental testing before bulk orders. Our material is well accepted by capacitor manufacturers for North America, Europe and Southeast Asia markets.

Conclusion

Pre-painted color-coated aluminum has gradually become a mainstream housing material for metallized film capacitors, replacing traditional bare aluminum plus heat shrink tube. It balances formability, corrosion resistance, appearance and manufacturing cost. Proper selection of PE or PVDF coating, matched alloy and temper is the key to stable capacitor mass production.