Machines for electric cables and optical fibers
WTM polyimide cable taping lines, for double coating and sintering
Polyimide is a high-performance plastic material that has been used for around 70 years across a wide range of applications, particularly thanks to its resistance to high temperatures, chemicals, and wear. Its excellent behavior under high-temperature conditions has made polyimide especially important in the production of specific magnet cables for transformers and electric generators.
Polyimide tapes are accurately wrapped around the conductor and then thermoset through a controlled heat treatment. This process creates reliable and effective electrical insulation, enabling the cables to withstand demanding operating conditions. Polyimide can also be combined with other components to enhance specific insulation properties.
Considering the importance of the insulation process for this type of cable, a polyimide taping line requires high levels of accuracy and process control at every stage. From conductor preparation and tape application to thermal treatment, each step must be carefully managed to achieve consistent insulation quality.
Thanks to extensive experience with this specialized process, WTM has optimized its taping equipment for polyimide tape applications, providing customers with:
• solutions for proper conductor preparation;
• accurate conductor tension management for precise tape application;
• taping heads equipped with dynamic dancers to improve process accuracy, including when working with rectangular conductors;
• advanced heat-treatment systems, complemented by downstream cooling devices;
• in-line taping quality control using camera systems and spark testers;
• pay-off and take-up systems designed to ensure smooth, accurate cable handling.
Polyimide taping line equipment
The following video shows a taping machine designed for this application and equipped with:
• cable pay-off and take-up units with traversing movement to keep the wire straight and aligned with its axis;
• a wire straightening unit featuring steel rollers and a brush cleaning device for optimal conductor preparation;
• taping units with heads designed for large cross-wound spools or heavy pads. WTM's dynamic dancer keeps tape tension stable and constant, supporting a disturbance-free process. This is particularly beneficial for flat wires with a high width-to-thickness ratio;
• pulling units, including a combined caterpillar/capstan unit and a final caterpillar, for precise control of line speed and wire tension;
• a rapid preheating stage using a high-frequency induction heater, followed by infrared sintering ovens;
• a compacting unit designed to promote complete adhesion of the polyimide layers to the conductor;
• a cooling system using recirculated cold water and air wipers to dry the cable;
• in-line insulation quality control through cameras and a spark tester.
For manufacturers of magnet cables, WTM can evaluate specific technical requirements and develop a polyimide taping line tailored to the application. To discuss your production requirements, contact WTM via the references on this page.
