Key Factors in Solenoid Coil Production: Choosing Wire, Insulation, and Overmolding for Optimal Performance

Jun 23, 2025
 

Solenoid coil design plays a crucial role in many electrical and mechanical applications. Whether you’re working on a simple actuator or a complex automation system, understanding how to select the right wire, insulation, and overmolding materials can significantly impact the coil's efficiency, durability, and overall performance. In this article, we will discuss how to choose suitable magnet wire and insulation, select the proper overmolding material, and validate your solenoid coil production to ensure it meets the required standards.

Key Factors in Solenoid Coil Production: Choosing Wire, Insulation, and Overmolding for Optimal Performance

How to Choose Suitable Magnet Wire and Insulation Material for Solenoid Coil Design

Choosing the right wire and insulation material is one of the most important steps in solenoid coil design. The insulated wire you use needs to conduct electricity efficiently, handle the required current without overheating, and fit within the mechanical constraints of the design.

Selecting the Right Insulated Wire

The insulated wire is typically copper or aluminum wire coated with a thin layer of insulation. Copper wire is preferred due to its excellent electrical conductivity and durability. When selecting wire gauge, consider the current your solenoid coil will carry; a thicker wire has less resistance and can handle more current but takes up more space. A thinner wire allows for more turns of wire in the coil but increases resistance and heat generation. For most solenoid coil design projects, copper wire with enamel insulation is common because it offers a good balance of conductivity and insulation thickness. 

Choosing the Right Insulation Material

Insulation material is critical for preventing electrical shorts between coil windings. It must withstand voltage, mechanical stress, and temperature. The most commonly used insulation types in solenoid coil design are:

  • Polyurethane (PU): Commonly rated for Class B (130°C) or Class F (155°C), polyurethane insulation is thin, enabling tight coil winding and high fill factors. It’s also solderable without stripping, making it ideal for cost-sensitive applications like relays, small solenoids, and electromagnetic devices.
  • Polyester (PEW): With thermal ratings of Class B (130°C) or Class F (155°C), polyester insulation offers strong electrical and thermal resistance. It’s more durable than PU and well-suited for automotive solenoids, valves, and moderate-temperature coils.
  • Polyester-Polyimide (PEI): Designed for high-heat applications, PEI insulation is rated Class H (180°C) or Class C (220°C). It provides excellent thermal stability and moisture resistance, ideal for aerospace actuators and industrial solenoids.
  • Polyamide-Imide (PAI): With exceptional thermal and chemical resistance, PAI supports Class H (180°C) and Class C (220°C). Its thin yet strong insulation suits high-temperature uses like welding equipment and harsh industrial environments.
  • Formvar (Polyvinyl Formal): Rated for Class B (130°C), Formvar is abrasion-resistant and flexible—ideal for small solenoids, low-power coils, and manual or automated winding.
  • PTFE (Teflon®): Known for excellent chemical resistance and thermal range from -200°C to +200°C, PTFE is Class C (220°C+). It’s best used in solenoids exposed to extreme environments, such as cryogenics or corrosive applications.
  • Silicone Rubber: With Class H (180°C) thermal rating, silicone offers excellent flexibility and moisture resistance, suitable for automotive applications and motion-intensive devices.
  • Fiberglass/Glass Fiber: Rated above Class C (220°C+), this insulation withstands extreme heat, making it ideal for the most demanding thermal conditions.

When deciding on insulation, always check the operating temperature and electrical requirements of your solenoid coil design. Using the wrong insulation can lead to premature coil failure.

How to Choose the Overmolding Material for Solenoid Coil Design

Overmolding is the process of covering the solenoid coil with a protective layer that provides mechanical protection, electrical insulation, and environmental resistance. The choice of overmolding material depends largely on where and how the solenoid coil will be used.

How to Choose the Overmolding Material for Solenoid Coil Design

Common Overmolding Materials

Overmolding plays a vital role in protecting solenoid coils from mechanical stress, moisture, chemicals, and high temperatures. Below are the most commonly used materials, including those preferred for high-performance industrial (PI) applications:

PET ( Polyethylene Terephthalate)

Widely used in PI solenoid coils, PET offers exceptional thermal and chemical resistance, making it ideal for harsh environments like automotive transmissions and fuel systems. With a heat deflection temperature of up to 155°C and low moisture absorption, PET ensures long-term durability and electrical stability, especially in high-load and high-temperature applications.

LCP (Liquid Crystal Polymer)

Another top choice for  higher temperature overmolding, LCP excels in high-precision solenoid designs due to its ultra-high flow properties and dimensional stability. Withstanding temperatures up to 260°C, it’s ideal for miniature solenoids and medical or aerospace-grade components where thin-wall molding and accuracy are essential.

Epoxy Resins (Thermoset)

Epoxy provides rigid encapsulation with excellent mechanical strength, electrical insulation, and chemical resistance. It’s a preferred choice for potting industrial-grade coils, especially those exposed to demanding mechanical loads and high operating temperatures in aerospace and heavy manufacturing environments.

PBT + Glass Fiber

Reinforced PBT enhances structural stiffness, thermal performance, and vibration resistance. It’s commonly used in industrial solenoids operating in dynamic environments, where moderate cost, flame retardancy, and strong dielectric properties are required.

TPE (Thermoplastic Elastomer)

TPE offers rubber-like flexibility and is frequently used for solenoids in consumer appliances and handheld tools. It provides a moisture-tight seal and shock absorption but is generally not suited for extreme temperatures or aggressive chemicals.

When selecting an overmolding material, consider factors like mechanical stress, moisture exposure, temperature range, and chemical resistance. For example, a solenoid coil used in automotive or outdoor applications will require a different overmolding material than one used in a controlled factory environment.

Understanding How Solenoid Coil Works in Your Design

If you are new to solenoid coil design, it’s helpful to understand how solenoid coils work. A solenoid coil creates a magnetic field when electric current passes through its windings. This magnetic field moves a metal core or plunger, converting electrical energy into mechanical motion. The strength and speed of this movement depend on factors like coil design, wire gauge, and current. In many projects, knowing how solenoid coil works helps optimize your design for the intended application, whether it’s in valves, relays, or locking mechanisms.

Exploring Types of Solenoid Coil for Various Applications

Different types of solenoid coil designs exist, each suited for specific applications. Some common types include:

  • Push-type solenoids: The plunger moves forward when energized.
  • Pull-type solenoids: The plunger is pulled back into the coil.
  • Rotary solenoids: Produce rotational motion instead of linear.
  • Continuous duty solenoids: Designed for long periods of activation.
  • Intermittent duty solenoids: Used for short activation cycles to avoid overheating.

Knowing the types of solenoid coil available will help you make informed choices in your design process.

Why choose PI for your Solenoid Coil Project?

When it comes to solenoid coil manufacturing, partnering with experts can save time and avoid costly mistakes.  As Pantene Industrial owns deep manufacturing experience of hydraulic solenoid coil market, with decades experience, Pantene Industrial team provides comprehensive support to make the customer’s design perfectly implement, ensuring solenoid coil meets exact performance and quality standards.