Kovar Machining: The Ultimate Guide

Alloys are widely used in different components due to their exceptional properties. Kovar is also a widely used alloy, primarily featured in sensitive technological applications.

Let's dive into the guide below to learn about Kovar machining process and its pros and cons.

What is Kovar Alloy?

Kovar is an iron, nickel, and cobalt alloy invented in the 20th century. It is a silver-gray metal with low thermal expansion, similar to ceramics and glass.

Kovar is a very important material used in different components that need tighter tolerance. It is used in versatile industries like medical, aerospace, and electronics.

Pros of Machining Kovar

Kovar comes with various properties that offer significant advantages; some of these advantages are as follows:

• Kovar has exceptional thermal stability and low thermal coefficient. Hence, it can be used in applications that have consistent temperature changes and can withstand them without cracks and breaking.
• It has a high yield and tensile strength, which makes it suitable for high-stress applications. It can easily withstand the pressure without deforming.
• Kovar offers durability and can easily be subjected to harsh environments, and it can resist oxidation, chemicals, and corrosion.
• Kovar is a versatile material and is highly machinable, which helps manufacture components in complex shapes.

Cons of Machining Kovar

Along with advantages, Kovar machining also has some downsides, and these are as follows:

• The material is expensive and, therefore, is mostly not considered when high-volume manufacturing is required.
• It's very rarely available, and securing it is a challenging task.
• Kovar is brittle and can fracture due to sudden shocks.
• It is difficult to work with and needs specialized equipment and expertise to manufacture components of high quality using it.

Typical Processes for Machining Kovar Parts

Kovar machining can be done through various processes based on the application and component requirement. Some of these processes are as follows:

Fraisage CNC

Fraisage CNC uses Kovar to manufacture complex components. The hardness of Kovar requires selecting the right cutting tools and speed to avoid tool wear. Coolants are also needed during milling to ensure precision and prevent tool wear.

Tournage CNC

Tournage CNC is a machining process in which round and cylindrical Kovar components are manufactured. Carbide tools are used for this process, and a moderate cutting speed is maintained to prevent work hardening.

Perçage CNC

Perçage CNC is a process in which holes can be created with high precision in Kovar components. The process uses carbide tools with a slow feed rate to prevent tool wear and achieve accurate holes.

EDM

EDM is one of the most effective machining methods for Kovar, helping in creating intricate shapes. It can machine the thin sections of Kovar. Being a non-contact process, it prevents work hardening and deformation of materials.

Découpe au laser

Laser cutting, as the name suggests, uses a beam of laser to create clean cuts on the Kovar component. It is suitable for applications that need components with high tolerance and precision and reduced thermal distribution.

Key Applications of Kovar Alloy Machining

Koval alloy machining is used in multiple industries. Some of the applications of Kovar machining are discussed in the section below.

Glass Sealing

Kovar is machined for vacuum systems to create glass-to-metal seals. Due to its coefficient of thermal expansion matching that of borosilicate glass, it is the most suitable choice for this application.

Électronique

Kovar is used in the electrical industry for transistors, diodes, and other components that need semiconductive features. It has high mechanical strength and hence can offer reliable connectivity.

Aérospatiale

Kovar alloy can be machined for aerospace components as they have significant temperature changes and tough requirements for sealing, which Kovar meets.

Médical

Machining Kovar helps create components compatible with medical applications. Kovar components offer biocompatibility and are not impacted by temperature changes; hence, they are suitable for implantable devices as well.

Design Considerations When Machining Kovar

When machining Kovar, some design considerations should be followed to achieve the finest quality components, and these are as follows:

• Ensure that the coefficient of thermal expansion of Kovar and the adjacent materials match so that thermal stress can be avoided during machining.
• Machining Kovar needs a slow speed and a high feed rate, so work hardening can be reduced.
• It is suggested that carbide tools be used when machining Kovar to avoid wear and tear.
• In order to ensure dimensional stability in the components made of Kovar, try to conduct pre- and post-annealing on the components.
• You can also opt for a surface treatment after machining Kovar to prevent contamination and oxidation, as well as enhance the component's life.

Challenges in Kovar Alloy CNC Machining

Usinage Kovar comes with certain challenges. This section below features those challenges and the solutions that can be implemented to deal with them.

Work Hardening

Work hardening is a common issue during Kovar machining, making it difficult to conduct the process and even impacting the tool's life.

To prevent this issue, it is suggested that the cutting speed be maintained at a low speed and increased lubrication, which helps reduce the heat.

Tool Wear

Kovar is a tough material and can cause tool wear. A carbide tool is suggested, which can withstand the process of machining Kovar and maintain its sharpness in the long run.

Thermal Expansion Management

Kover has controlled thermal expansion, but sometimes, if the machining process is not managed appropriately, it can become problematic.

Always plan the machining process and consider the thermal expansion based on the operating temperature environment.

Surface Oxidation

Kovar can develop a layer of oxide if it is heated. This impacts the quality of the component, and to control this, you can control the speed of machining and manage heating.

Internal Stress

If Kovar components are not annealed, they tend to develop internal stress. Hence, annealing these parts before machining helps relieve internal stress.

Start Your Kovar Machining Project with DEK

If you are looking for a reliable machining partner for Kovar components, DEK can be your go-to choice. We have experience in Kovar machining and hence can offer you fine, precise, and accurate components.

You can discuss your requirements and industrial application with us, and we can design custom Kovar components machined for you.

En résumé

Kovar is an alloy that is very rarely used. It is very important to understand everything about it before you decide to use it for your project.

As you have gone through the guide above, you must have learned about Kovar machining and how to deal with the associated challenges.