Plastic flame spraying technology introduction
Plastic flame spraying
is a kind of spraying technology that forms a coating by spraying powder onto the surface of a workpiece after the powder is heated to a molten state by a flame of a spray gun.
Plastic flame spraying is mainly used to improve the physical, chemical and mechanical properties of the material surface, as well as the role of decorative surface. At present, the technology has been gradually applied to product manufacturing, equipment maintenance and preparation of anti-corrosion coating and so on. With the modernization of all walks of life needs and the development of plastic flame spraying technology, the application of plastic flame will be more and more widely.
A plastic flame spraying principle
Plastics used for flame spraying are thermoplastics and thermosets. When heated, the thermoplastic will soften and melt as the temperature increases, and will harden upon cooling. At the same time, this process is reversible.
This feature of thermoplastics is what flame spraying needs. Therefore, the plastic currently used for flame spraying is mainly thermoplastic, the most used of which is polyamide 1010, namely nylon 1010, and polyethylene, such as PE polyethylene.
The common feature of thermoplastics is the low melting point. For example, the melting point of nylon 1010 is 200-210 degrees and the melting point of polyethylene is 123-130 degrees. The difference between the ignition temperature or the decomposition temperature of the powder and the melting point temperature is small. Therefore, the flame plastic spraying must be effective in controlling the flame temperature and the degree of heating of the plastic powder. To ensure that the heated plastic particles are both in the molten state, but also lower than the ignition or decomposition temperature, or plastic powder will burn or deterioration. This is the key technology of plastic flame spraying. The solution to this problem is to add a layer of air (aerosol or air curtain) outside the oxy-acetylene flame of the gas torch based on the original gas torch. The flame directly heats the air, and then let the air heat the plastic powder. You can reach the desired spray heating temperature, complete the spraying operation.
Two plastic spraying process
To be sprayed surface degreasing and cleaning --- to be sprayed surface blasting --- flame preheating to be sprayed surface --- spray plastic coating ---- to reduce or eliminate stress treatment --- cooling cleaning (to be sprayed The surface of the degreasing and cleaning, depending on the specific circumstances of the parts may be divided into the thickness and precision cleaning. When cleaning, commonly used acetone cleaning).
Blasting surface to be sprayed Application Shot blasting gun, compressed air pressure 0.4 - 0.7MPa, the sand is sharp white corundum, particle size of 20 mesh. Sandblast to be sprayed surface should be carefully, until the surface to be sprayed was uniform silver white. The purpose of preheating is to increase the cohesion of the coating.