MagShield™

“Heat-shrink solution for magnet retention and protection”

MagShield™ is the Politubes range of heat-shrink tubes designed for the protection and retention of permanent magnets in surface-mounted brushless motors (SPM).
Thanks to its advanced polymer formulation and controlled shrink behavior, MagShield™ ensures maximum holding strength, electrical insulation, and thermal resistance, contributing to the efficiency and reliability of the motor.

Why Choose MagShield™

• Reliable fixation: the tube is placed over the rotor with magnets already in position and heat-shrunk instantly at temperatures well below the Curie point, preventing any degradation of the magnetic flux.
• Integrated protection: unlike metallic retaining rings (steel or brass), the tube also covers the magnet edges, which are prone to corrosion or chipping — common causes of motor failure or rotor seizure.
• Electrical insulation and high-temperature resistance: provides double electrical insulation (4–7 kV) Class II in accordance with IEC 60335-1 and thermal endurance up to 150–155 °C (Class B–F).
• Optimized rotor balancing: with reduced wall thickness (100–250 µm) and inner diameters from 15 to 131 mm, the tube does not interfere with the air gap or magnetic flux and minimizes adhesive tolerance issues.
• Circular economy: at end of life, the tube can be easily removed without damaging the magnets, enabling re-use and minimizing production waste.

Nd-Fe-B Ring Magnets (Neodymium-Iron-Boron)

In motors using ring-shaped Neodymium-Iron-Boron (Nd-Fe-B) magnets, produced by compression molding and bonded with thermosetting resins, the MagShield™ tube also acts as a protective barrier against corrosion.
This additional protection helps preserve the integrity of the magnetic alloy, which is highly sensitive to external agents, and prevents seizing or damage during operation and assembly.

Linear Brushless Motors

In linear brushless motors, our heat-shrink tubes play a key protective role in safeguarding surface-mounted magnets while providing high dielectric strength, excellent thermal resistance, and precise mechanical conformity, ensuring long-lasting performance even in demanding electromagnetic environments.

This results in an extended motor lifetime, preventing magnet detachment, scratches, or short-circuit risks.

The extremely low wall thickness, ranging from 0.055 to 0.16 mm, minimizes magnetic flux losses from the magnets, ensuring optimal system performance.

IPM Brushless Motors

In IPM brushless motors, heat-shrink tubing plays a critical role in ensuring both electrical safety and mechanical integrity.
It provides double electrical insulation (4–7 kV) in compliance with Class II requirements according to IEC 60335-1, allowing manufacturers to eliminate complex and costly grounding systems.

In addition, heat-shrink tubes ensure the secure retention and precise positioning of magnets within the rotor, preventing magnet displacement even under demanding operating conditions and enhancing overall motor reliability.

Technical Application

Protected by European Patent EP 2763283 B1, MagShield™ was developed by Politubes in cooperation with automatic machinery manufacturers to integrate the tube seamlessly into production processes.
This partnership enables the creation of high-efficiency automated solutions that simplify rotor assembly and enhance industrial productivity.

Implement MagShield™ in Your Production Line

Contact our technical department for samples, testing, or a tailored consultation to explore how MagShield™ can be integrated into your assembly process.