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The problems with powder coating application over galvanized surface

Polyester powder coating over hot dip galvanized steel provides a high grade architectural finish to steel items with excellent atmospheric weathering characteristics.The powder coated product ensures maximum durability for steel components, which will generally provide 50 year+ rust free life spans in most architectural applications. Even so there are still some problems during this application. Hot dip galvanized surfaces have been acknowledged as difficult to powder coating since the technology was first developed in the 1960’s. Industrial Galvanizers commenced research inRead More …

How to prevent powder dust explosion

An explosion can be prevented if both or either of the conditions Explosive Limit and Source of ignition are avoided. Powder coating system should be designed to prevent both conditions occurring ,but due to the difficulty of totally eliminating sources of ignition,more reliance should be placed on the prevention of explosive concentrations of powder. This can be achieved by ensuring that the powder in air concentration is kept below 50% of the Lower Explosive Limit(LEL). Determined LELs on the range ofRead More …

Electrostatic spraying gun

The term electrostatics or electrostatic spray finishing refers to a spray finishing process in which electrical charges and electric fields are used to attract particles of atomized coating material to the target (the object to be coated). In the most common types of electrostatic systems, electrical charges are applied to the coating material and the target is grounded, creating an electric field. The charged particles of coating material are drawn by the electric field to the surface of the groundedRead More …

The causes of dust explosion and fire hazards during manufacturing powder coating

Powder coatings are of the fine organic materials, they can give rise to dust explosions. A dust explosion may break out when the following conditions happen at the same time. A ignition sources is  present, including: (a) hot surfaces or flames;(b) electrical discharges or sparks;(c) electrostatic discharges. The concentration of dust in the air is between the Lower Explosive Limit (LEL) and Upper Explosion Limit (UEL). when a layer of deposited powder coating or a cloud comes into contact with anRead More …

More superioritis to liquid coating

For many reasons including environmental speaking,excellent performance ,high productivity and economics application,powder coatings have been used more and more since the 1970’s. It is clean,almost zero VOC. Additionally powder coatings provide easy clean up without harmful solvents and harmful waste. Over-sprayed powder can be recycled and reclaimed for greater economic savings than liquids paint.It reduce the cost of labor to coat products as much of application is automated.Powder coatings can not be modified at the clients site,thus eliminating inconsistency of products.Read More …

Particle Size Distribution

FINE PARTICLES Lower film builds Can blind cartridges and filters Migrate from part into exhaust Reduced fluidization properties Smoother films Absorb moisture more readily COARSER PARTICLES Higher film builds Increased Faraday penetration Increased fluidizaion properties

Powder Coatings Manufacturing

Weigh-up and Mixing ( raw material,such as resins,hardener,pigments,filler,etc) Extrusion Process Milling and Sieving

Phosphating conversion coatings

The recognized pre-treatment for steel substrates just prior to application of powder coatings is phosphating which can vary in coating weight. The greater the conversion coating weight the greater the degree of corrosion resistance achieved; the lower the coating weight the better the mechanical properties.  It is therefore necessary to select a compromise between mechanical properties and corrosion resistance.  High phosphate coating weights can give trouble with powder coatings in that crystal fracture can occur when the coating is subjected to locallyRead More …

Various Substrates for Powder Coating

Substrates Aluminium,steel,zinc alloys,copper and galvanized steel are common metals on which powder coatings are applied.  In a number of cases where normal service conditions apply, satisfactory properties can be obtained on thoroughly cleaned metal. Aluminium For aluminium and its alloys,performance can be upgraded using a proprietary chromate conversion coating, even though the clean surfaces are easily coated and adhesion is excellent Steel For iron/steel surfaces maximum corrosion and salt spray resistance are given by a zinc phosphate conversion coating. Zinc alloys With allRead More …

Main aims in the pretreatment to metal surface before coating

The main aims in the preparation of a metal surface before powder coating may be defined as follows: The conditioning of the surface so as to render it suitable for the coating that is to be applied The complete removal of all foreign matte,e.g,scale,grease,cutting oil,soil,welding splatter,etc The pretreatment should impart uniformity throughout all treated workpiece surfaces,irrespective of the source of the metal or of the contaminants that might adhere. As with other methods of organic finishing attention to the pretreatment stage isRead More …