Impregnation Methods

Trickle impregnation machines are designed to apply varnish or epoxy onto parts as they are held and rotated. Materials are dispensed over the part in specific locations at controlled volumes and flow rates. As a result, the resin can be applied very accurately with little or no excess loss. The systems are designed to accurately locate multiple dispense points and to automatically adjust positions for varying part sizes. Rotating the part throughout the process is required to retain the resin in the correct location and reduce the resin traveling to non-desirable areas.

HeatTek will work in our lab and with your coating supplier when designing your trickle impregnation systems and machines to develop the correct coating volumes, rotational speeds, preheat and cure temperatures, and times for the parts being processed. HeatTek trickle impregnation machines are used by automotive, industrial, power tool, and other industry manufacturers.

Roll impregnation systems have one distinctive difference from a trickle system. The part is partially submerged in resin and is completely coated as far as it's submerged. Rotating the part throughout the process is required to retain the resin in the correct location and reduce travel to non-desirable areas.

If parts are preheated before coating, the roll coat system most often includes a resin cooling system due to the heat that is deposited into the resin. Roll coat systems are designed to flow the correct volumes of resin so the material can be cooled, settling of particulate is minimized, and coatings can be kept thoroughly mixed. Fresh resin is added automatically to maintain and extend the life of the resin.

Dip impregnation is a process in which the entire part is submerged in a resin, filling voids and sealing the windings against moisture, dirt, and vibration. After dipping, the components are baked in an oven to cure the resin.

The dip impregnation and cure process can be accomplished with a batch or conveyorized approach.

While powder coating is not an impregnation method, it is a critical secondary insulation process for motor manufacturing. Stator powder coat systems are typically the final step in the motor secondary insulation process. Parts are dipped into a fluidized powder bed past the welded wire connections. HeatTek works closely with epoxy powder suppliers using their published recommendations in developing the exact coating process for each system.  

Typical HeatTek systems may include the part handling, preheat and cure systems, powder delivery and reclaim equipment, as well as fluidized powder beds. 

For industrial motor applications, HeatTek's powder coat systems apply an epoxy powder that is designed to protect and insulate unwound cores from hi-pot failures, giving you the electrical protection required for your parts. Coatings are applied to armatures most often by electrostatically charging the parts before exposure to the powder. Parts requiring a thicker insulation may be processed by preheating and dipping the part into a fluidized bed multiple times.