Most of the impurities come from the particles in the dusting environment and the impurities caused by other factors, and are summarized as follows.
Impurities in 1.1 curing furnace. The solution is to completely clean the inner walls of the furnace with a damp cloth and a vacuum cleaner. The key is to hang the chain and the gap between the pipes. If a large black particles of impurities, you need to see whether the supply duct filter screen damage, and then replace it in time.
1.2 powder injection room impurities. The first is the dust, clothing fibers, abrasive and dusting system fouling equipment. The solution is to use the compressed air blowing system before the start of each day, and completely clean the dusting equipment and powder room with a damp cloth and a vacuum cleaner.
1.3 dangling chain impurities. The key is to hang the chain block and the water supply plate of the spreader (the raw material is hot-dip galvanized sheet), which is corroded by the acid and alkali vapor. The solution is to tidy up the equipment regularly
1.4 powder impurities. First, too much powder additives, uneven pigment, powder powder formed by kneading and so on. The method is to improve powder quality and improve powder storage and transportation.
1.5 pre-treatment impurities. It is mainly the large particle impurities caused by the phosphating residue and the small amount of impurities caused by the yellow rust of the phosphating film. The treatment method is to finish the phosphating tank and the inner slag of the spray pipe in time, and control the concentration and the share of phosphating bath.
1.6 water quality impurities. First of all, the pre-treatment of the use of water containing sand, salt content caused by excessive impurities. Treatment is to add water filters, using pure water as the final two clean water.
Coating shrinkage cavity
2.1, pretreatment of oil is not clean, perhaps after the oil is not clean, the formation of surfactant residues caused by shrinkage. The method is to control the concentration and the proportion of the pre degreasing tank, degreasing bath fluid, reduce the oil content of the workpiece and strengthen the washing action.
2.2 shrinkage of water caused by excessive oil content. The treatment method is to add water inlet filter to prevent the water pump from leaking.
2.3 shrinkage of compressed air caused by excessive water content. The solution is to release compressed air and condensed water in time.
2.4 shrinkage caused by powder wetting. The treatment method is to improve the powder storage and transportation conditions, add dehumidifier to ensure the recovery of powder in a timely manner
2.5 suspension chain oil is air blown onto the workpiece caused by shrinkage. The solution is to change the direction and direction of the air supply outlet.
2.6 shrinkage caused by mixing powder. The treatment method is to complete the dusting system when the powder is changed
Coating chromatic aberration
3.1 chromatic aberration caused by uneven distribution of powder pigments. The solution is to improve the powder quality to ensure that the powder's L, a, and B differ little and are consistent.
3.2, curing temperature is not the same as the color difference. The method is to control the setting temperature and the conveying chain speed so as to adhere to the consistency and stability of the temperature and time of the workpiece.
3.3 color difference caused by uneven coating thickness. The treatment method is to adjust the technical parameters of spraying and make sure the spraying equipment is running well to ensure the uniform thickness of the coating
Poor coating adhesion
4.1, pretreatment, washing, incomplete formation of residual degreasing agent, chrome slag, or washing tank contaminated by lye, resulting in poor adhesion. The treatment method is to strengthen the water washing, adjust the degreasing technical parameters, and prevent the degreasing liquid from entering the bath trough after phosphating.
4.2 yellow, perhaps part of the phosphating film flooding without phosphating film caused by poor adhesion. The treatment method is to adjust the phosphating bath concentration and share, and improve the phosphating temperature.
4.3, the workpiece edge water drying is not net, resulting in poor adhesion. The solution is to increase the drying temperature
4.4, curing temperature does not lead to large areas of coating adhesion. The cure is to cure the temperature
4.5 deep well water, oil content, salt content is too large, resulting in poor adhesion. Treatment is to add water filters, using pure water as the final 2 clean water. After all, powder electrostatic spraying technology and its application methods are still many, in practice, the demand for flexible use.
Powder coated orange peel
5.1, powder coating orange peel appearance of the discriminant method:
(1) visual measurement
In this test, the sample is placed under the double tube fluorescent lamp. A light source of the sample can be obtained by placing the sample plate appropriately. Qualitative analysis of the clarity of reflected light allows visual evaluation of activity and levelling properties. In the case of poor activity (orange peel), the two fluorescent tubes appear ambiguous and obscure, while high activity products yield clear reflexes.
(2) shape measurement method"
In this method, the shape of the surface is recorded by the offset of the high mobility probe. This makes it possible to quickly distinguish between rough, orange peel and poor activity caused by shrinkage holes, pinholes or dirt
5.2 prevent the attack of orange peel
The appearance of the coating becomes more and more important in the manufacture of new equipment. As a result, one of the primary objectives of the coating industry is to achieve the best coating functionality according to the user's final requirements, which include appearance satisfaction. The appearance condition affects the visual function through color, gloss, fog, shadow and appearance structure. Gloss and image clarity are often used to control the appearance of the coating. But using a high gloss coating on its surface, shake degree also affects the appearance of the film all together, think visual effects measure can not shake the luster of manipulation, this effect is also called "orange peel".
Orange peel or jiggle shake is a corrugated structure with a size ranging from 0.1mm to 10mm. In the high gloss coating, people can see wavy, dark and light areas. To distinguish two different levels: long shake shake, also known as orange peel, which is up to 2 ~ 3 interval interval can be observed on the shake; the other is called a short or micro shake shake, this is a distance of about 50cm is observed at shake.
It is important to point out that sometimes, in order to cover the appearance of the base material, defects may be obtained with special coating appearance, while purposeful planning of a certain degree of waviness or waviness is constructed. Therefore, orange peel can be defined as "wavy structure with high gloss appearance", which makes the appearance of paint surface speckle and flat visual appearance. The visual appearance of powder coatings (gloss, haze, leveling control of orange peel) is very important, especially in different parts of the assembly spraying field at.