Vacuum Investment Casting of Oxygen-Free Copper (OFHC): Why Controlling Oxygen Below 10 ppm Is Critical

In the realm of high-performance electrical applications—where reliability, conductivity, and durability are paramount—Oxygen-Free High Conductivity Copper (OFHC) has established itself as the material of choice. But to unlock its full potential, especially for high-voltage and high-current environments, controlling oxygen levels below 10 parts per million (ppm) during casting is absolutely essential.

At Pahwa MetalTech, we specialize in Vacuum Investment Casting of OFHC copper, achieving oxygen levels of less than 10 ppm. This precision enables us to deliver parts that meet the stringent requirements of the electrical and switchgear industries.

Why OFHC Copper Matters

Oxygen-Free High Conductivity Copper (OFHC) is a high-purity copper alloy with:

• > 99.99% copper content

• Oxygen content < 10 ppm

• Electrical conductivity > 101% IACS

• Superior thermal conductivity

• Excellent formability and corrosion resistance

Because of its superior properties, OFHC copper is widely used in:

• High-voltage switchgear and circuit breakers

• Electrical contacts and terminals

• Busbars and current collectors

• Power semiconductor packaging

• RF and microwave systems

  
  

The Problem with Oxygen in Copper Castings

Copper is highly reactive with oxygen. During conventional casting methods, even in inert atmospheres, oxygen gets absorbed, forming oxides and impurities such as:

• Cuprous oxide (Cu₂O): A non-conductive phase that reduces electrical performance.

• Gas porosity: Trapped gases can create voids and weaken structural integrity

• Hydrogen embrittlement: Oxygen combines with hydrogen to create water vapor, causing internal cracking during heat treatment or brazing

  
  

Just 15–20 ppm of oxygen can degrade the electrical and mechanical properties, making it unsuitable for critical electrical applications.

Vacuum Investment Casting: The Game-Changer

To overcome these challenges, vacuum investment casting is an innovative process capable of delivering the precision, purity, and consistency required for high-performance OFHC copper parts.

Key Benefits of Vacuum Casting for OFHC Copper:

• ✅ Maintains Oxygen < 10 ppm: Completely eliminates air exposure during melting and pouring

• ✅ Superior Surface Finish: Ideal for electrical contact surfaces

• ✅ High Dimensional Accuracy: Near-net-shape castings reduce the need for post-processing

• ✅ Consistent Metallurgy: No inclusions or impurities, ensuring uniform performance

• ✅ Complex Geometries: Supports intricate shapes that are difficult to machine

Pahwa MetalTech: Your Partner in High-Purity Copper Castings

At Pahwa MetalTech, we have invested in a state of the art vacuum investment casting facility to manufacture ultra-pure OFHC copper castings with oxygen levels < 10 ppm.

Our Capabilities Include:

• Dedicated Vacuum Casting Machines: Sealed chambers prevent oxygen ingress

• Custom Tooling & Prototyping: Rapid development and optimization for customer-specific parts

• Small to Medium Batch Production: Ideal for precision electrical components

• Experienced Engineering Support: From design optimization to final product qualification

Why Sub-10 ppm Oxygen Matters in Electrical Systems

The purity of copper directly impacts the performance of components in high-voltage and high-frequency environments.

Oxygen Level (ppm)	Impact on Conductivity	Suitability for Electrical Use
> 50 ppm	Significant reduction	Not suitable for high-performance systems
20–50 ppm	Minor degradation	Risky for critical applications
< 10 ppm	Optimal conductivity	Required for OFHC applications

🔧 Looking for Precision OFHC Copper Components?

Let’s talk.

At Pahwa MetalTech, we bring cutting-edge casting technology, deep metallurgical expertise, and a commitment to quality that matches the critical nature of your application.

📩 Contact us at info@pahwametaltech.co.in to explore how our vacuum investment casting solutions .