Selecting the suitable copper alloy for your CNC machining is a difficult task. The quality of the copper alloy tells the efficiency of the machine. Copper alloys are the most widely used non-ferrous material used in various machinery. With the upgradation in the engineering industry, the use of copper alloys has become extensive worldwide. Different physical and chemical parameters of copper alloys determine the suitability of that alloy for CNC machining. Following are the features of CNC machining copper alloys that will help you learn more about copper alloys.
Copper alloys have good electrical and thermal conductivity, bright color, high tensile strength, and corrosion resistance. Some of the remarkable characteristics of copper alloys are given below:
Electrical conduction is one of the most significant characteristics of copper alloys. Pure copper has a high IACS percentage of about 100%. Advanced processing methods and purity ingots have slightly improved the electrical conductivity of copper from 100% to 103%. The mechanical processing of the copper to generate commercial copper alloys can change the conductivity of copper. Commercial copper alloys with the greatest strength have slightly decreased electrical conductivity. The addition of alloying elements to copper also alters the electrical conductivity. Copper elements made with magnesium, chromium, or iron give high electrical conductivity ranging from 75% to 92%. Industrial Copper alloys made with zinc, cobalt, boron, phosphorus, or tin provide great strength with a conductivity of 60%.
The high corrosion resistance of copper alloys makes them a perfect choice for CNC machining. This property is due to the chemical stability of copper alloys. Copper alloys protect the CNC machining from corrosion against water, air, and other non-oxidizing acids. The galvanic effects of the alloys can enhance the corrosion resistance of the copper. Alloy elements like stainless steel and titanium demand cathodic protection to prevent corrosion.
Stress relaxation resistance:
The stress relaxation resistance of copper is not strong. Soluble elements that enhance the copper’s softening temperature can be used to increase this resistance. The addition of metals that have large-sized atoms also increases the stress relaxation resistance of the copper. Zinc cupronickel, tin brass, and silicone bronze have excellent stress relaxation resistance. Manufacturers avoid ordinary brass as it does not provide significant resistance. Also, brass is only used to make copper parts at room temperature.in contrast, Silicone, aluminum, or zinc are added to the copper at a higher temperature.
Surface treatment of CNC machining copper parts:
The copper parts of CNC machining are processed and oxidized at variable temperatures to enhance their characteristics.
- Passivation of copper parts is necessary to enhance the corrosion resistance of the copper alloys. They are exposed to some elements to remove the iron contaminants like free iron. This removal restores the original resistive power of the copper.
- Copper parts are properly cleaned to give them a neat and shiny look.
- Anodization of the copper is also done to give it an anodic oxide finish. Aluminum is preferred for the process of anodization. It makes copper durable and robust.
- Zinc, Nickel, or chromium is used for electroplating copper parts.
- Finally, copper is polished with specific chemicals to give it a final look.