Copper Material: A Useful Guide for Rapid Prototyping and Production

Copper is a common name in rapid prototyping due to its suitability for making products used in different capabilities. Using copper material in any project comes with understanding its different properties. Generally, copper has great electrical conductivity, thermal conductivity, strength, and machinability. However, this depends on the type of copper material you are using.

Choosing the right copper material might seem challenging. Therefore, to help you select the right copper type for your project, this article will act as a copper material guide. It will introduce copper and its properties. It will then dwell and expatiate more on the types of copper material you can use for your project. Let us dive in.

Copper in Manufacturing

Copper is a highly machinable metal employed in different capabilities based on its mechanical properties. It has good strength, hardness, superior thermal and heat conductivity, and corrosion resistance. Consequently, it is a popular material valued for its functional and aesthetic functions. Copper can also be made into alloys to improve its mechanical properties. There is three rough division for copper alloy based on their machinability.

• Machinability Rating of 70 – 150%

Copper alloys in this group have very high machinability. Consequently, they are the best choice for copper CNC machining processes that require high tolerances. Examples of copper alloys in this group are free-machining bronzes, brasses, and coppers.

• Machinability Rating of 30 – 60%

These alloys have good machinability. However, machinists use the copper alloys in this group based on other properties apart from their machinability. An example of copper alloys under this category is unleaded brasses.

• Machinability Rating less than 30%

These alloys are difficult to machine. Some of them may be too hard or heat up excessively during machining. They also take longer times to machine. Therefore, using them in rapid prototyping will drive up the cost of machining. These include copper alloys formed with aluminum.

Properties of Copper

Copper has unique properties making it suitable for a variety of uses. Common properties include immense strength, conductivity, and anti-corrosion factor. Below are the properties of copper and how they apply to rapid prototyping.

· Electrical Conductivity

One of the greatest distinguishing copper properties is its electrical conductivity. Copper conducts electricity so well that it is a standard when measuring the conductivity of other metals. However, the process and the elements combined to form copper alloys may alter their electrical conductivity. For example, when you use cold working, it results in lower electrical conductivity.

· Thermal Conductivity

The superior heat conductivity of copper also makes it a material of choice for use in electrical components. This is because a lot of heat can be generated during the current flow, which can damage components. Therefore, copper’s heat conductivity is suitable for making heat sinks or other products that can dissipate the heat generated by such appliances.

· Ductility

One of the most distinguishing copper properties is its ductility. However, different alloys of copper have varying ductility. A popular application of high copper alloys is their use for making wires and cables. This is due to their high ductility, which allows them to be drawn into wires.

· Resistance to Corrosion

Copper belongs to the group of non-reacting metals. This stability makes it resistant to oxidation and, therefore, corrosion. Copper and its alloys, due to their anti-corrosion properties, are suitable for making products used in fresh and seawater applications. For example, copper is a suitable metal for making potable water pipes due to its corrosion resistance. It is also ideal for making pipes used in marine environments and those exposed to chemicals.

Pros of Using Copper in Rapid Prototyping

Copper material has many advantages. Consequently, it is suitable for making products employed in different scenarios. Below are the pros of making use of copper in prototyping. 

· Corrosion

Copper and its alloys are extremely non-corrosive. Consequently, many rapid prototyping processes uses copper in making products used in different environmental conditions. For example, it is suitable for making CNC fixtures, roofs, pipes, underwater installations, circuit boards, and heat sinks.

· Ductility and Malleability

These two properties are responsible for the ability of copper to take on any shape. Consequently, copper is an important material employed in rapid prototyping processes such as CNC machining. Here, machinists can draw copper into thin wires, flat shapes depending on the end consumer’s wants.

· Recyclability

The recyclability of copper doesn’t only make it a friend to the ecosystem but also to rapid prototyping processes as well. Copper parts can undergo recycling and still retain about 90% of their original cost. Due to its high recycling value, recycling old copper material can help save costs on CNC copper machining. Also, recycling helps to elongate the availability of copper in the earth’s crust.

· High Level of Conductivity

Copper is one of the cheapest materials with an almost non-existent resistance to electricity. Due to this property, CNC copper parts commonly find applications in the electrical industry. For example, it is common to see machinists use copper materials in making superconductors, microchips, electromagnets, etc.

· It is Less Expensive

Compared to other metals such as titanium, copper is less expensive. Consequently, it is a better choice in many rapid prototyping processes as it is available and easy to fabricate.

Cons of Copper in Rapid Prototyping

The disadvantages of copper and its alloys stem from its comparison with other materials. Generally, its advantages make it an ideal rapid prototyping material. However, when compared to materials such as steel and plastic, you can encounter some. For example, when you compare copper to steel, copper costs less. However, it is costlier than plastic. Also, in terms of flexibility, copper is flexible, but plastic is more flexible and it has better machinability. Therefore if you are to use copper in rapid prototyping, know its properties, how to work it, and whether another material will do a better job.

Different Grades of Copper Used in Rapid Prototyping

In choosing a copper material for rapid prototyping, you must know that properties change slightly with the grade/alloy. Therefore, a machinist needs to know the different grades of copper and their properties. There are six grades/types of copper used in rapid prototyping. Below is detailed information on the six grade.

· Pure Coppers

Pure coppers are one of the purest forms of the mentioned copper grades as they have no more than 0.7% impurities. They are very soft and extremely malleable, and they are very popular among many rapid prototyping companies.

To boost the mechanical properties of pure copper, some alloying elements can be added in extremely small quantities. Based on the type and amount of alloy elements added, the UNS assign numbers from C10100 to C13000 to pure copper grade.

· Oxygen-Free Coppers

This copper grade is the purest grade of copper obtainable. They contain a minimum of 99.99% of copper. They are manufactured through induction using a bar of copper as the cathode.

Oxygen-free coppers possess extremely high electrical and heat conductivity. Therefore, they are the right material in machining products that requires huge electrical conductivity or other copper properties. These coppers are assigned the numbers C10100 and C10200.

· Electrolytic Copper

This grade is formed from electrolysis and boasts an electrical conductivity of 100%. It is also very workable. This is evident in its ability to be subjected to hot and cold processes. Electrolytic coppers contain less than 50 ppm metallic impurities. They are important materials in rapid prototyping suitable for making products such as windings, wires, and cables—the UNS assigned to this grade of copper the number C11000.

· Copper-Nickel Alloys

This grade of copper uses nickel as an alloying agent. It is composed of 1.5 to 45% of nickel. The addition of the nickel alloy improves mechanical properties such as strength and hardness. However, it reduces the ability to machine them due to the reduction in ductility and machinability. Also, copper-nickel alloy grades have better corrosion resistance properties for both elements.

Copper-nickel alloys are suitable for making many products. For example, they are used in making coins, heat sinks, and cooling systems. The UNS assigned to this grade of copper numbers C70000 to C73499.

· Nickel Silver

Despite the naming of this copper alloy, it is not made with any silver. The concentration of nickel in this grade of copper ranges from 9% to 30%. The concentration of copper usually stands at about 65%, while the zinc concentration varies as the nickel changes. Greater quantities of nickel lead to greater corrosion resistance at the expense of malleability.

Nickel silver is suitable for making architectural fittings, cutlery, and the keys of some musical instruments. The UNS assigned the grade numbers C73500 to C79999.

· Free-Machining Coppers

These coppers have a huge machinability potential. Consequently, they are very common in CNC machining and other rapid prototyping processes. They usually contain telluride or sulfur as alloying agents. They are suitable for making parts used in electrical systems and tips of welding torches—the UNS assigned numbers based on the alloying agents. For sulfur, the number is C14700 and C14500 for telluride.

From the above explanation, it is evident that each copper grade has its uses and affiliation with rapid prototyping. Understanding the different properties might be a little challenging, especially if you only want a quality product and you are not really into rapid prototyping. Therefore, attaining such quality comes with getting in touch with a rapid prototyping service that can assure you of quality. This is where we at RapidDirect come in. We have a team of machinists, engineers, and designers with a perfect understanding of copper. Not only copper material. We can advise you based on other materials that can do the job better than copper. Do you want quality? Just click on “Get a Quote.”

Brass and Bronze: Comparing Them to Copper

If you have heard about copper, there is no doubt you would have heard about brass and bronze. The three materials are one of the common things students, machinists, and any other metal worker comes across due to their unique properties. Brass and bronze are simply alloys of copper. Therefore, they have different characteristics that make them useful for different applications. Below is an introduction to brass and bronze and a comparison of the three materials.

Bronze and its Applications

Bronze is one of the most commonly known alloys of copper. It is made up of copper and tin. In some instances, it also contains aluminum, arsenic, and silicon.

Bronze has a characteristic dull-gold color. The bronze material used in rapid prototyping usually has copper with about 35% tin and 10% lead.

Applications of bronze include its suitability for applications in large bodies of water thanks to its high resistance to saltwater corrosion. Also, it has excellent thermal conductivity making it a great choice for use in high-temperature applications.  It also has the highest melting point (950°C) of the three alloys, hence, justifying its latter application above.

Brass and its Applications

Brass is another popular alloy of copper used in rapid prototyping for making machined parts. For example, it is suitable for making gears, pipes, and bearings.

Machining with brass has various advantages, which make it a material of choice over many other metals. For example, brass machining is said to be 20% faster than the machining of other metals. Consequently, it is a suitable material for rapid prototyping processes. While brass is suitable for rapid prototyping, it is susceptible to stress cracks due to its high stiffness.

Comparing Bronze, Brass and Copper: Similarities

• The three alloys all have good thermal and electrical conductivity, hence, making them quite suitable for use in electrical and high-temperature applications.
• Also, they are all corrosion-resistant making them a good choice for use underwater.

Comparing Bronze, Brass and Copper: Differences

• Among all three, copper is the best for use in the food industry, thanks to its antimicrobial properties.
• While the three alloys are all recyclable, brass has the best recyclability because it has high non-ferromagnetic properties.
• Also, copper and bronze have better stress durability than brass as their high stiffness makes them easily susceptible to cracking.

Applications of Copper

The wide range of copper properties makes it a suitable material for use in various industries. Below are a few of the industries where machinists use copper for CNC machining:

· Electrical Industry

Thanks to its low resistance to electricity, copper is one of the best materials to use in this industry. CNC copper parts find applications in high-transmission power lines, high-conductivity wires, superconductors, etc.

· Food Industry

One of the copper properties is its ability to kill microbes exposed to its surface. This property makes it a good fit to use for making protective packages in the food industry. Also, its recyclability makes the disposal of food-protective packages made from copper more eco-friendly.

· Automotive Industry

Aside from its use in the electrical wiring of automotive, CNC copper parts also have applications in the making of radiators and oil coolers. This is another industry where the recyclability of copper is quite useful. This is because car parts have high recyclable value, hence, making copper a good candidate for making automotive parts. 

How to Choose the Right Grade of Copper

With the abundance of copper alloys, it could be challenging to choose the right copper material among the different grades of copper available. However, one easy way is to pick a copper material with properties that best suit the application. Below are some factors/copper properties that play a huge role in selection includes:

· Ductility Or Machinability

These two properties are some of the most sought-after properties of copper when considering it for copper CNC machining. However, the various grades of copper have varying levels of both, as we’ve seen earlier. Hence, the goal of the copper CNC machining process will determine the copper material that will be suitable.

· Non-Corrosive Property

For CNC copper parts made for underwater applications, the corrosion resistance of the copper alloy used matters a lot. Hence, when choosing an alloy for the machining of prototypes for use in such applications, their anti-corrosive property is a major attribute to look out for. An alloy of copper known for its high resistance to saltwater is bronze alloy.

· General Applications

For general-purpose applications, copper is a great material choice. However, since there’s no particular property needed for these applications, it is advisable to choose a copper grade with a good mix of the various copper properties. A such copper grade should be inexpensive and easily machinable, and malleable.

FAQ

Conclusion

With the various properties of copper and its uses mentioned above, it is easy to see why copper is one of the best materials to choose for CNC machining. Its high ductility and conductivity make it a great choice to use for various machining applications. However, with the various grades available, you might find it hard to pick the best copper grade for your project. Therefore, this article introduces copper, its properties, grades, and how to choose the right grade. Is copper your choice of material in a machining project? At RapidDirect, we offer professional advice on material selection and various machining services that suit different applications. We can help solve your machining dilemmas today.