Optimum temperature and flash point for enamels

The optimum temperature in the tank is that temperature that results in the best quality wire. I don't know what kind of enamel applicator system that you have but the best type system would only pump enough enamel to a particular st or group of wires as needed to obtain the desired finished size wire. That would minimize the amount of enamel returning to the tank.

The idea is that your bare wire goes through the pre annealer and is cooled enough to prevent discoloration or the wire being too hot when it enters the applicator. If the wire is not cooled enough it will discolor. If too cool then you have to worry about water or moisture being on the bare wire when it enters the applicator. Since I don't know much about your applicator or if you have a cross strung oven or individually strung oven, I can only speculate.

If the wire entering the applicator is that hot then you've got other issues. The wire is obviously hot when leaves the oven but there should be cooling between that exit and the sheaves. If the wire is too hot going onto the sheaves the coating may still be soft or even sticky. Between the top or exit end of the oven and when it gets back to the applicator it should cool even more.

Tell us more about your equipment.

Helping through this media is convenient but for it to be most effective and helpful to the enquirer and others it would be nice if you would provide more details and when given suggestions, provide feed back as to outcome. Thanks

Dear Richard
You are absolutely right. Regarding our equipment It's for MAG and it's applicator system works like bellow:

1- enamel tank is a close system and it has a element after tank befor applicator. set point of element is 45 oc .
2- the wire temperature before it comes to applicator is about 80 - 90 oc . (die enamellig system). In this version of machine, there is not water quench after annealing.
3- The machine is horizontal with max speed about 200 m/s.
4- enamel leave the applicator with temperature about 60 - 65 oc. And it return to enamel tank . thereforetotal temperature of enamel tank raises to 60 oc or more specially in summer. Because flash point of this type of enamel is 41oc, I wanted to know do me must reduce the temperature of enamel tank below the flash point. I have to note that the enamel tank has a water circulation system but we don't use it in this two years (after first installation). Last summer we have a small fire on applicator of this machine (the first summer).

Best Regards

I assume that you are using solid dies and not felts.
The enamel tank temperature controller is used to standardize and control the temperate of the enamel. In theory if the solvent loss is controlled, and the enamel temperature controlled then you are controlling the viscosity of the enamel which is important.

Some of these machines have enamel heaters just in front of the applicator. Some of the machines are designed so that you control the flow of enamel to the applicator so that you are only delivering the amount that you need and very little returns to the enamel tank. If you minimize the amount of enamel returning to the enamel tank you minimize the effect of the temperature. Also if you are at temperatures that are above the flash point it means that you are evaporating the solvents from the enamel. When the solvents evaporate it causes the viscosity of the enamel to increase and you really don’t want your viscosity to fluctuate and you don’t want to have to be continuously be adding solvent to control viscosity.

What is the purpose of the water circulation system? Is it used to heat the enamel or cool it? If it is for cooling then give it a try.

The firsts step to reduce the temperature of the enamel in the tank is to set the thermoregulatory below the flash point. If the water circulation is for cooling then turn it on. I would also regulate the flow of enamel to the individual dies or applicator module – you supply just enough enamel to coat the wire so that when it goes into the die there is enough enamel to fill the die completely. You don’t need to flood the wire, you need just enough to completely cover the wire when in the die.

This will reduce the amount of enamel returning to the tank, the temperature will be easier to control, you will not be evaporating solvents and your system will be in better control.