powder coating conveyors are used industry-wide in powder coating, wet spray, dip line, and E-coat painting applications

Electrostatic powder coating line

Powder coating is a dry finishing process, using finely ground particles of pigment andresin that are generally electrostatically charged and sprayed ontoelectrically grounded parts. The charged powder particles adhere to theparts and are held there until melted and fused into a smooth coating ina curing oven. Before coating, the parts to be coated are firstpretreated similarly to conventional liquid coated parts. Thepretreatment process is normally conducted in series with the coatingand curing operatios.      

Thereis essentially two common ways of applying powder coating: byelectrostatic spray and by fluidized bed powder coating. There areseveral other processes that have been developed, but they are far lessused. These include flame spraying, spraying with a plasma gun, airlesshot spray, and coating by electophoretic deposition.
To get an overview of the technology used in the powder coating industry click on the items below:

• pretreatment

• Electrostatic Spray

• curing

Pretreatment.

Phosphating,or conversion coating, is the application of an iron or zinc phosphatecoating to the substrate. Conversion coating can be a very critical partof the pretreatment process, adding significantly to the performance ofthe finished coating. A phosphate coating converts the metal substrateto a uniform, inert surface, which improves bonding, minimizes thespread of oxidation if the coating is scratchedand improves the overallcorrosion resistance of the final part.

Aconversion coating can be iron, zinc, polycrystalline, chromate, ormanganese phosphate film. They are developed on both ferrous (ironbased) and non-ferrous surfaces (zinc, aluminum, terne and manganese).Parts are subjected to an acidic bath and a chemical conversion forms acomplete film on the part surface, changing the chemical and physicalnature of the metal surface.

Henkelhas introduced a big breakthrough in surface treatment: Bonderite NT –a new surface pretreatment which is considerably more efficient, lesscomplicated and more cost-effective than conventional iron phosphating

Electrostatic Spray

Electrostatic spray powder coating uses a powder-air mixture from a small fluidized bed in a powder feed hopper. In somecases, the feed hoppers vibrate to help prevent clogging or clumping ofpowders prior to entry into the transport lines. The powder is suppliedby a hose to the spray gun, which has a charged electrode in the nozzlefed by a high voltage dc power.

Electrostaticpowder spray guns direct the flow of powder; control the depositionrate; control the pattern size, shape, and density of the spray; andcharge the powder being sprayed .The spray guns can be manual(hand-held) or automatic, fixed or reciprocating, and mounted on one orboth sides of a conveyorized spray booth. Electrostatic spray powdercoating operations use collectors to reclaim over-spray. This reclaimedpowder is then reused, adding significantly to the powder coating's high transfer efficiency.

Thereare various gun designs that mainly differ in the method of applyingelectrostatic charge to the powder. In some cases, the powder iselectrostatically charged by friction. The advantage is that the powderis free to deposit in an even layer over the entire surface of the part,and deposition into recesses is improved.

The film thickness is dependent on the powder chemistry, preheat temperature, and dwell time. Film thicknesses of (40 - 60 µm) in case of plain powder ( 80 – 100 µm) in case of texture can generally be applied on products.

Curing

Whena thermoset powder is exposed to elevated temperature, it begins tomelt, flows out, and then chemically reacts to form a higher molecularweight polymer in a network-like structure. This cure process, calledcross linking, requires a certain degree of temperature for a certainlength of time in order to reach full cure and establish the full filmproperties for which the material was designed. Normally the powderscure at 200°C (390°F) in 10 minutes. The curing schedule could vary according to the manufacturer's specifications.

The application of energy to the product to be cured can be accomplished by convection cure ovens or infrared cure ovens.

We supply:

Powder spray gun spare parts

Test powder coatng gun

Electrostatic powder painting

Electrostatic powder coating

Electrostatic powder spraying machine

Manual Powder Painting System

Electrostatic Powder coating machine

Powder painting machine

Powder spray gun

Electrostatic powder spraying machine

Electrostatic powder coating

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