Trickle and Roll Dip Impregnation

Trickle and Roll Dip Impregnation

In the Trickle Impregnation process, the part to be impregnated is fixed on a rotating mandrel, and a low-viscosity resin is trickled onto it through nozzles. The trickle process is ideal for parts that require only certain areas to be impregnated, such as e-motor rotors and stators. Huntsman offers both single- and dual-component resin systems for Trickle and Dipping Impregnation.

Optimal Resin Systems for Trickle and Roll Dip Impregnation

Ensuring flawless insulation and physical protection of electric motor components can vastly improve the efficiency and durability of the motor. Typically, the stator or rotor wires are first coated with a layer of varnish (primary insulation) to ensure electrical insulation. After winding, impregnating resin is applied to fill all voids within the windings and between the winding and laminations.

In the Trickling Process, the stator is pre-heated to 100° C, and attached to a continuously rotating mandrel. Resin is trickled on the stator winding heads through nozzles at different positions and penetrates the windings by capillary action. This ensures good impregnation of windings in order to deliver reliable electrical insulation, high bond strength and excellent chemical and mechanical protection. After trickling, the stator is cured at 170-180° C for 20-40 minutes.

This process allows mass production with high productivity, as there is no need for material pre-treatment, and no loss of impregnating resin. The process is simple to manage, as there is only one component material —a VOC-free epoxy resin— and the curing cycle, which is needed in order to reach the final properties of the resin, is short.

A related process is Dipping Impregnation, which can be either simple dipping or roll dipping. In the roll dip impregnation process, the impregnating resin is contained in one or more temperature regulated bath, and kept constantly flowing by means of pumps. The bath automatically rises on the rotating stator or rotor, so that it will be dipped up to a specific level. The amount of resin penetration though the windings is controlled by adjusting three parameters: time, rotation speed and dipping level. The process is completed with gelation and curing of the resin.

Huntsman’s automotive products have been developed over many years of leadership in the global electrical insulation sector. We continuously study and update our materials in order to deliver the shortest possible curing cycles and meet the most challenging productivity targets.

Huntsman technical support is available to guide customers through the setup phase of all processing parameters. We offer a training program aimed at understanding both insulating materials and processing technologies, including production of sample parts by simulation of casting processes.

Insulating Resin Systems for Electric Vehicles

Insulating Resin Systems for Electric Vehicles

Discover our ARALDITE® encapsulants for electric motors, battery and power electronics. 


Frequently Asked Questions

What are the main automotive applications of the Trickle and Roll Dip Impregnation processes?

These processes are ideal for parts that are subjected to high temperatures, high voltages, and/or high rotation speeds and vibration, such as electric motor stators and rotors.

What are the main benefits of the Trickle Impregnation process?

Trickle Impregnation ensures void-free impregnation of high-voltage windings, which results in reliable electrical insulation, good heat dissipation, and excellent chemical and mechanical protection of the windings. There is no loss of impregnating resin. Short cycle times make the process suitable for fully automatic continuous production lines, enabling mass production with maximum productivity.

What are the main resin requirements for Trickle Impregnation applications?

Trickle Impregnation requires solvent-free resins of a high thermal class, with high tracking resistance, dielectric strength, mechanical strength, humidity and chemical resistance.

Which specific Huntsman products are recommended for Trickle Impregnation processes?

ARALDITE® CY 38340 resin / ARADUR® 38341 hardener is a dual-component epoxy system that features fast cure times at low temperatures. It exhibits high toughness and good adhesion.

ARALDITE 38600 single-component epoxy system features fast cure times and a high glass transition temperature (Tg). It exhibits improved wetting and superior adhesion to primary insulation.

What specific Huntsman product is recommended for the Roll Dip Impregnation process?

ARALDITE® 38500 single-component epoxy system is for Dipping Impregnation. It features low bath viscosity, high bath stability and improved crack resistance.

Huntsman and bdtronic are leading the way in trickling impregnation of electric motor stators

Huntsman and bdtronic are leading the way in trickling impregnation of electric motor stators

New mobility are emerging at a rapid pace, bringing with it a number of new challenges such as motor reliability and longevity. At the heart of electric motors, flawless insulation is vital for achieving long-term performance.

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