Summary: Currently, many mechanical and electrical products use enameled winding wires made of aluminum wire treated with concentrated sulfuric acid method.

The concentrated sulfuric acid method can effectively promote the oxidation of aluminum wires, ultimately resulting in the insulation layer of enameled winding wires. However, when using the concentrated sulfuric acid method, a large amount of irritating gases are generated, which can cause certain harm to the human body and serious pollution to the atmospheric environment.

Therefore, the use of concentrated sulfuric acid to treat aluminum wire can certainly meet the development needs of mechanical and electrical products, but it also produces very serious pollution and harm. This article mainly analyzes from two perspectives: the formulation design of electrostatic powder coating for enameled winding wire and the analysis of electrostatic powder spraying process for enameled winding wire.

preface

With the continuous development of the economy, China's modern industry is showing a high-speed growth trend, and the development speed of the electromechanical, electronic, and automation industries is also relatively fast. These industries have a relatively large demand for enameled winding wire, and the quality requirements for enameled winding wire are also relatively high.

In recent years, many domestic enterprises have paid attention to the research and production of powder coatings for enameled winding wires. This article mainly starts with the formula of electrostatic powder coatings and briefly introduces how to use the formula of electrostatic powder coatings for insulation treatment of enameled winding wires, and analyzes the spraying process of electrostatic powder coatings.

The development of powder coatings has both advantages and disadvantages. The advantage of powder coatings is that they can achieve a relatively good thickness through multiple overlapping coatings to improve the quality of the entire electrostatic powder coating; The disadvantage is that the flowability and viscosity of powder coatings are relatively high;

Therefore, it is very easy to have pinholes during the powder coating process, and pinholes cannot be treated by simple stacking, which can lead to a significant problem.

To overcome this problem, we can choose to add solvents to powder coatings, which can reduce the viscosity of the coating, thus reducing the occurrence of pinholes during the coating process. Moreover, experiments have shown that powder coatings with added solvents can greatly reduce the occurrence of pinholes after multiple overlapping applications.

The electrostatic spraying insulation polyester epoxy powder coating for enameled winding wire is composed of polyester resin and epoxy resin as the main film-forming substances, with the addition of electrical insulation pigments, fillers, and special additives.

The choice of film-forming material for electrostatic powder coating of enameled winding wire is also different. Polyester resin is synthesized by different manufacturers and specifications of polyester epoxy powder, and the formula of polyester resin is completely different from that of epoxy resin.

Therefore, after the application of polyester resin, the film formation of the entire enameled winding wire is relatively complete. From the appearance of the enameled winding wire, the glossy film tends to be perfect.

From the practicality of enameled winding wire, the bending and insulation properties of enameled winding wire can be tested with standard coatings, which can effectively provide insulation and isolation.

The selection of pigments and fillers in the formulation of electrostatic powder coatings is mostly based on single and composite varieties that have been selected. The coating film formed by the combination of these raw materials is more viscous, but the most important thing is that the final performance of the integrated formula of the raw materials needs to be determined through electrical insulation tests on the enameled winding wire.

The electrical insulation properties of enameled winding wire raw materials directly determine the raw material properties of electrostatic powder coatings. Therefore, the percentage content of pigments and fillers is also selected through experimental testing of the insulation properties of the final film, and the insulation properties of different materials are different.

Some materials themselves do not have conductivity and magnetism, so they can achieve a relatively good insulation effect, while others have good conductivity.

So when selecting formula raw materials, attention should be paid to balancing the characteristics of different materials to make the selection. After multiple combinations and adjustments, the most suitable variety and dosage of raw materials can be selected.

The formula of epoxy resin is also different from that of polyester resin, and the resin structure, softening point, epoxy value, and overall powder coating presented by epoxy resin are completely different from those of polyester resin.

There are significant differences in the appearance and color of the coating, as well as the wrapping, bending, and insulation properties of the enameled winding wire. Moreover, the electrostatic powder coating formula of epoxy resin is a standardized coating form that can be tested and meet the satisfaction of customers and factories.

The issue of pinholes is also a common problem in the film formation of enameled winding wires. Therefore, this problem must be considered in the formulation process of powder coating, which requires the quality of powder coating for enameled winding wires to reach a better level.

Especially in terms of the leveling of the entire coating, it is necessary to ensure the coverage of the edges and corners of the entire coating, to ensure the thickness of the coating at the circular curvature of the enameled winding wire, and to strive to ensure the electrical insulation of the powder coating of the entire enameled winding wire.

2 Powder coating manufacturing

The manufacturing method of electrostatic powder coating for enameled winding wire is roughly the same as that of general electrostatic spraying powder coating, and its main process flow is also roughly the same.

It is mainly divided into pre mixing raw materials in a high-speed mixer, using an extruder to melt the previous raw materials for mixing treatment, cooling the extruded material of the extruder, then using lacquer flakes for fine crushing and cyclone separation, and finally using a screening machine to screen and process the fine powder for separation and packaging work.

At this point, the entire manufacturing process of powder coating has been roughly completed.

The main use of powder coating is for insulation electrostatic treatment of enameled winding wires, so the insulation requirements of powder coating are relatively high. This requires attention to not introducing raw materials doped with metal impurities into the powder coating during the selection and production process.

In order to achieve better metal isolation, a magnetic material separator can be added at the feeding port of the extruder. This allows for the separation of magnetic materials before processing, ensuring the insulation properties of the raw materials.

Secondly, it is also possible to add some solvents to the melt mixing effect of the extruder. In order to prevent and reduce the occurrence of particle sensation and pinholes in the coating during the coating process, it is recommended to use equipment with lower melt extrusion material temperature in the extruder.

This process is mainly aimed at addressing the particle and needle perforation problems that often occur during the coating application of powder coatings, which may lead to adverse conditions in the overall use of powder coatings. In the end, multiple coating thickness treatments may be required to achieve a good effect in the use of powder coatings.

3 Powder coating spraying process

The spraying process of electrostatic spraying polyester epoxy insulation powder coating for enameled winding wire mainly includes the following steps: aluminum ingot→ Extrusion drawing→ Heat treatment→ Oil removal→ Washing→ Passivation→ Drying→ Powder coating→ Baking curing→ Cooling→ Retract (product).

Simply put, when using electrostatic powder coating formula for insulation treatment of enameled winding wire, the most basic issue is the smoothness of spraying, that is, the overall smoothness of the appearance of the enameled winding wire.

This is the most intuitive feeling and the basic point that is first seen during powder coating spraying. Therefore, when spraying, the first thing to pay attention to is the smoothness of the appearance of the entire enameled winding wire, which is mainly determined by the motor penetrability of the coating film.

In other words, if the surface smoothness of the enameled winding wire is not high enough, or there are particles and burrs, then the coating of the entire enameled winding wire will inevitably have uneven spraying.

And in areas where the coating thickness is relatively weak, it is easy to experience electrical perforation. Therefore, there must be a significant issue with the electrical insulation level at this location, which cannot meet the insulation requirements of the enameled winding wire. There may even be adverse situations such as electrical perforation and leakage short circuit.

In addition, if the surface of the aluminum wire of the enameled winding wire is not treated well, the coating of the entire aluminum wire will inevitably be affected, which cannot truly guarantee the mechanical strength performance of the powder coating coating.

In other words, the spraying results of powder coating indicate that factors such as impurity content and heat treatment of aluminum wire have a significant impact on the insulation and usability of the coating.

Therefore, in order to truly ensure the insulation performance of the enameled winding wire coating and the usability of the insulated wire, it is necessary to choose metal wires that are easy to handle, and the surface of the metal wire should be relatively flat, which can be well coated with powder coating.

Finally, a flat and relatively good edge wrapping coating is formed, and there is no graininess or pinholes on the surface of the coating.

To truly achieve such a goal and effect, the requirements for the spraying process of powder coatings are also relatively high.

Firstly, when conducting powder spraying, it is important to ensure that the powder coating speed and fluidization state are good, and that the movement speed and powder output of the spray gun are uniform and consistent;

And during the baking curing process, it is also necessary to follow the diameter of the metal wire to ensure the complete wrapping of the entire coating and the complete wrapping of the coating in the edge area of the metal wire. This can be adjusted during the baking curing process, and finally strive to achieve a smooth coating curing effect.

3 Conclusion

This article mainly analyzes the development and production of electrostatic powder coating formulas, as well as the spraying process of powder coatings.

The formula of electrostatic powder coating for enameled winding wire needs to be selected based on the insulation performance requirements of the enameled winding wire. When carrying out specific matching and production, special attention should be paid to not doping magnetic substances into the raw materials;

When carrying out the spraying process, special attention should be paid to the wrapping of the enameled winding wire coating. This not only requires attention to the coating of the spray gun coating, but also to the edge baking and curing of the metal wire. These are the key points that need special attention when using electrostatic powder coating for insulation treatment of enameled winding wires.