An expandable mandrel for the resin dispensing in motors application

For 40 years, Demak has been continuously developing new applications for the resin dispensing technology. The company produces equipment for the degassing, meter-mixing and dispensing of epoxy, polyurethane, silicone and many other kind of resin. The Italian company recently developed a new patented pending tool, useful for the resin dispensing in motors application: an expandable mandrel.

Motor, the expandable mandrel and vacuum chamber.

The Demak Group is an Italian company born in the early eighties, thanks to the futuristic vision of its Managing Director. From 40 years, the company has been continuously developing new applications for the resin dispensing technology, providing always the most advanced solutions for its demanding customers. The company produces equipment for the degassing, meter-mixing and dispensing of epoxy, polyurethane, silicone and many other kind of resin. Moreover, Demak is able to provide the customer with the resins suitable for his processes and production, thanks to its sister company S.E. Special Engines Srl. All the equipment and chemicals provided by Demak are useful for potting and encapsulating, vacuum casting, gluing and bonding, gasketing and coating of industrial components.

The vacuum importance

Many applications require potting or vacuum casting, the electric motors are one of them.

The motors and other components insulation is absolutely necessary in order to guarantee a very high durability of the product, thanks also to the heat dissipation properties of the resin used in the process. A good reason to insulate these final products is clearly the necessity to be completely dry, without any contact with water, humidity, dust, chemicals and other agents that can internally damage the component.

Air bubbles or voids in the resin can create a partial discharge between primary and secondary winding, compromising the performance and the lifetime of the product.

Another reason to avoid any bubbles is the decreasing of heat dissipation provided by the resin, that is essential for a motor durability and high performances.

So, in order to obtain a bubble and moisture free component, the resin has to be forced into all the internal spaces of the motor (especially into undercuts and windings), and the only way to do it is the vacuum dispensing.

The Demak’s way

Demak can guarantee, thanks to 30 years of experience in the electrical components insulation field, a total absence of air into the resin (by means of efficient degassing systems) and also into the final parts due to its Vacuum casting system. Therefore, all the dispensing systems that are used in these kinds of processes are equipped with vacuum chambers, but not only: Demak technology for vacuum degassing starts from the resin loading to finish at the very last dispensing moment.

So, the resin and hardener tanks are equipped with a thin film degassing system for a continuous dehumidification of resin and hardener, to enhance the casting results.

An efficient vacuum casting process, together with High Thermal Class epoxy resin, allows to qualify the motors for all the life tests required by OEM.

Full automatic line for motor casting.

Demak developed a new patented pending tool, useful for the resin dispensing in motors application: an expandable mandrel. In the resin dispensing process it is very important to protect the internal part of the motor, casting the resin only between the windings, not covering or making the stators’ slots dirty. Even existing some Teflon mandrels in the market, the Demak’s one is the only adaptable to the motor’s dimensions being pressure inflatable. Thanks to this peculiar characteristic it’s also possible to deflate it immediately at the end of the curing process and, in this way, avoiding waste of time in waiting the cooling of the part, as it happens using traditional methods. The expandable mandrel can boost the production and guarantee a perfect final condition of the motor.

Resin Vacuum Casting is a great solution to protect various electric/electronic components and the Demak Group experience is always at customer disposal to provide the best technology. The company can assure to its customers the most effective weapons to be competitive and reliable on the market.

 

 

 

 

 

 

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