Vacuum Casting
Vacuum casting of wire coils removes air from the material surrounding the windings, which results in better thermal control of the component. This process also creates specific physical geometries that enhance the structural integrity of coils and allow for better compliance with space requirements. Vacuum casting is an effective process to protect coils from humidity and contaminants and is helpful in the reduction of winding noises.

Learn more about vacuum casting, how it works, and the benefits and applications of this process.

What Is Vacuum Casting?

Also known as vacuum impregnation, vacuum casting of wire coils involves the elimination of as much air from a structure as possible while replacing it with epoxy that has higher dielectric strength. Epoxies are special adhesives that will bond the wires and other components of the construction to create a more durable assembly.

How Does Vacuum Casting Work?

The vacuum casting process utilizes a chamber capable of handling temperature, vacuum, and pressure. This manufacturing process eliminates the voids or cracks in insulation that will eventually lead to the failure of a part. In coil manufacturing, vacuum casting and impregnation play a key role in protecting coils from corrosion and enhancing their mechanical and electrical characteristics.

The vacuum casting process requires a heated chamber and involves the following steps:

  1.   The coil is placed in a mold within the chamber and heated to remove moisture.
  2.   Air is removed from the chamber through a vacuum process.
  3.   Epoxy/resin is separately degassed.
  4.   Resin is injected into the chamber, filling the mold and fully covering the windings.
  5.   Vacuum is slowly released and the component undergoes a curing process before it is removed from the mold.

Both traditional injection molding and vacuum casting require a mold tool that contains a cavity in the shape of the desired part.

Benefits of Vacuum Casting

A single master pattern can produce many copies of a component, reducing the money and time spent on the prototyping and product design stage. Some principal benefits of vacuum casting include:

  • Thermal Properties: This process improves heat dissipation and is ideal for components subject to high temperatures.
  • Physical Geometries: Vacuum casting allows for greater flexibility in terms of features and shapes as well as adhering to specific space constraints.
  • Improved Coil Impregnation: Compared to other methods that can contain cracks or air pockets, vacuum casting is a more precise method of creating void-free insulation.
  • Improved Electrical Performance and Durability: Eliminates partial discharge and reduces winding noises.
  • Suitable for Various Applications: Vacuum casting allows manufacturers to customize parts for a wide range of properties and features designed into the mold that shapes the assembly.

Applications of Vacuum Casting

Typical uses of vacuum cast coils can include but are not limited to the following applications:

  • Magnetic Resonance Imaging (MRI) Coils
  • Current Transformers
  • High-Voltage Ignition Coils
  • Voltage Transformers

Vacuum Cast Components from Custom Coils

Since 1978, Custom Coils, Inc. has provided our valued customers with design-specific, high-quality manufactured coils, electromagnets, coil assemblies, inductors, solenoids, and more.

From our 23,000-square-foot facility in Benicia, California, we fulfill our customers’ manufacturing requirements, from small or single prototype coils to large-volume coil assemblies. Everything we manufacture is designed to match our customers’ specifications, and we integrate those requirements into a unique manufacturing solution to minimize cost while maximizing quality.

Contact us for more information on our vacuum casting and other custom coil manufacturing capabilities. You can also request a quote, providing us with specific details about your project.

Custom Coils is your Specialty Coil Resource

Whether you are in initial product conception or have detailed specifications, Custom Coils has the knowledge and resources to design and manufacture quality products that meet your system needs.

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