F46 polyimide film wrapped copper wire-pi sintered copper winding wire

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The Sintering Mechanism

The defining characteristic of F46 polyimide film wrapped wire is the sintering process. After the polyimide-F46 composite film is wrapped around the conductor with precise overlap control, the wire is passed through a high-temperature sintering oven. The F46 layer on the film surface melts and flows, filling gaps between overlapping film layers and between the film and the conductor surface . Upon cooling, the molten F46 solidifies, creating a homogeneous, void-free insulation structure.

This sintering process addresses a fundamental challenge of film-wrapped constructions: the geometric discontinuity created by the overlap. As noted in technical literature on polyimide film wrapped wires, delamination cannot be entirely prevented in the overlap region during initial wrapping. However, with sufficient thermal bonding during sintering, the melted FEP layer can fill the open gaps, achieving a continuous insulation structure .

Multi-Layer Configurations

F46 polyimide film wrapped copper wire is available in both single-layer and double-layer wrapping configurations . The 200-grade polyimide-F46 composite film wrapped copper flat wire is specified under the Chinese standard JB/T 6757-1993, which establishes the technical requirements for both single and double-layer constructions .

For double-layer constructions, the two layers are typically wound in the same direction, with the inner and outer overlap seams uniformly staggered to ensure complete coverage . This multi-layer approach provides enhanced dielectric strength and mechanical protection compared to single-layer constructions.

Dimensional Specifications

Round Conductors

F46 polyimide film wrapped round copper wire is available in diameters ranging from 1.50mm to 5.00mm, corresponding to SWG 6# through 17# and AWG 5# through 15# . For applications requiring larger conductors, diameters up to 8.0mm may be available upon request .

Rectangular Conductors

For rectangular profiles, the thickness typically ranges from 0.80mm to 5.60mm for copper conductors, with width ranging from 2.00mm to 16.00mm . Extended dimensions may be available depending on manufacturer capabilities.

Insulation Thickness

Standard insulation thickness options for F46 polyimide film wrapped wire include 0.36mm and 0.54mm, with custom thicknesses available to meet specific customer requirements . Thinner insulation thicknesses, such as 0.20mm and 0.30mm, are also available for applications where reduced insulation build is acceptable .

Thermal Performance

F46 polyimide film wrapped copper wire is rated for continuous operation at 220°C, with the thermal class designation of 200 for the insulation system . This temperature rating reflects the exceptional thermal stability of the polyimide film material, which maintains its electrical and mechanical properties over a wide temperature range from -80°C to +260°C .

The polyimide-F46 composite film combines the high-temperature capability of polyimide with the heat-sealable properties of FEP. This combination ensures that the insulation system remains intact even under prolonged thermal exposure and thermal cycling conditions.

Electrical and Mechanical Properties

Breakdown Voltage Performance

F46 polyimide film wrapped copper wire exhibits outstanding dielectric strength. The breakdown voltage for single-layer constructions must meet specified minimum values, with the 200-level polyimide-F46 composite film wrapped wire providing reliable voltage withstand capability for high-voltage applications .

Conductor Material Specifications

The copper conductor used in F46 polyimide film wrapped wire is manufactured from oxygen-free copper with a minimum copper content of 99.95% (TU2 grade), ensuring excellent electrical conductivity. The resistivity at 20°C does not exceed 0.01724 Ω·mm²/m .

Mechanical and Processing Characteristics

The wire exhibits good flexibility and can be bent on both the narrow and wide sides without cracking the insulation layer . For single-layer constructions, the insulation must withstand 15% elongation without losing adhesion, while double-layer constructions require 10% elongation capability . The maximum spring-back angle is limited to 5° .

Key Applications

F46 polyimide film wrapped copper wire is specified for the most demanding electrical equipment applications, including:

• Submersible Motors and Oilfield Equipment: The insulation system is both waterproof and oil-proof, making it suitable for submersible motors and downhole oilfield pumping equipment .

• Traction Motors: Railway traction motors benefit from the wire’s ability to withstand vibration, thermal cycling, and high-voltage stress .

• High-Voltage Motors and Generators: Large and medium-sized high-voltage motors and generators utilize this wire for its dielectric strength and thermal stability .

• Special Transformers: Dry-type transformers, reactors, and specialized transformers operating in challenging environments .

• Radiation-Resistant Equipment: The insulation system resists radiation damage, making it suitable for nuclear and aerospace applications .

Standards Compliance

F46 polyimide film wrapped copper wire is manufactured in compliance with multiple standards:

• JB/T 6757-1993: The Chinese mechanical industry standard for 200-grade polyimide-F46 composite film wrapped copper flat wire .

• JB/T 5331-2011: The standard covering particular types of aromatic polyimide tape wrapped wire for submersible motors .

• MW 63-C: The NEMA standard for polyimide film insulated magnet wire, class 220°C .

• GB/T 7673-2008: The Chinese national standard for film-covered winding wires