Copper

Description

Copper is easily identifiable by its pinkish-orange color. This material had been in use for thousands of years due to appearing in a malleable metallic form in nature. Nowadays, copper is commonly combined with other metals such as zinc, nickel, aluminum, and others to form a more tough alloy. Though, copper-based alloys do still contain a high percentage of copper with additional metal components not reaching over 40%. These machinable copper alloy families include:

• Brass – a copper-zinc alloy range is utilized for higher corrosion resistance, good strength, and ductility. It maintains fine conductivity while providing decent hardness. The zinc portion is typically under 15% in the final alloy.
• Bronze - a copper-tin alloy type with phosphorus additives widely used for gears and bearings, coins, and musical instruments. Sometimes aluminum or silicone can be used instead of tin to manufacture bronze.
• Nickel-Silver - a mix of copper, nickel, and zinc with higher resistance to corrosion in comparison to brasses.
• Copper-Nickel - combinations of copper and nickel are mostly used in applications requiring ductility and corrosion resistance such as marine equipment.

CNC machining and Turning with Copper

Pure copper appears very malleable and soft making it extremely tough to machine it to precise tolerances. Therefore, copper alloys are used for machined parts.

Brass, bronze, as well as numerous other copper-based alloys, on the other hand, are relatively easy to mill and cut. They also require lower cutting forces compared to metals like steel or titanium. One of the most popular choices for contract turning and machining is free-cutting brass (CuZn39Pb3), which has one of the highest machining ratings, determining how easy material is to work with.

Alternative ways to manufacture machined copper parts include coining, forging, photoengraving, or acid etching and stamping or forming.

Laser Cutting Copper

Copper (as well as many of its alloys) is a reflective material, which complicates the laser cutting process. Improved fiber laser cutters, though, are able to process copper alloys without leaving defects on the surface.

Metal Casting with Copper

Alloys with a great copper percentage in composition (over 96%) are used more in casting or forming technologies for parts requiring high electrical and thermal conductivity. Casted copper provides good tensile strength as well, making it suitable for bearings and gears and used in the transportation sector.

Common Uses

• Electrical components
• Architecture
• Jewelry
• Heat components
• Engineering

Advantages

• Thermal conductivity
• Electrical conductivity
• Corrosion resistance
• Recyclable
• Relatively low-cost
• Artistically pleasing surface appearance
• Maintains mechanical properties at low temperatures.

Disadvantages

• Alloys with high copper content are softer and harder to machine;
• Some copper alloys may contain lead additives, which present a health risk;
• Oxidation;
• Costs are higher compared to plastics, which can perform better in certain applications.

Which material is harder, mild steel or copper?

Mild steel exhibits better hardness and stiffness than pure copper, which is soft and malleable.

How to prevent copper from oxidizing?

Surface treatments like coating and electroplating can help reduce the oxidation of copper parts.