According to your product shapes ,for example it is complex workpieces or simple product to choose the machine function, for example colo-500star compare with other higher price equipment ,it not so good when spray the corner or do recoating  Or when spray specially metallic powders ,but for mostly work the colo-500star do Good job too. and according to the coating job details for example need to change colors often or only few colors to choose the box feed unit or hopper feed unit ,and choice the hopper size 

 Powder Coating Guns: There are two basic types of powder coating systems to consider, each with their own strengths and weaknesses: Corona and Tribo. The core difference is the way the powder is transported from the powder coating gun to the part. The primary force for material transport in Corona powder coating system is an electric field established between the charged powder cloud and the part. In the Tribo powder coating system, material transport is from the velocity at which the powder is liberated from the powder coating gun, that is, from the air flow provided by compressed air.Corona powder coating guns use a high-voltage generator to disassociate air and produce a stream of negative or positive ions, which in turn imparts a like charge to the powder cloud. The potentials of the charged cloud and gun electrode combine to generate an electric field with the opposite pole (the part). Charged powder particles at the gun seek the lower potential of the opposite pole (the part).Another fundamental difference between Corona and Tribo powder coating systems is the method in which the powder particles become electrically charged. The Corona gun uses a high voltage generator to charge an electrode to a high potential relative to the part. The charged electrode disassociates air and generates a flood of charged particles, effectively charging the powder cloud, creating a charged field with the opposite pole. In contrast, the Tribo gun imparts a charge to the powder strictly by physical contact and movement between the powder and a surface capable of donating or receiving electrons. Powder transport is strictly by the velocity at which the powder is liberated from the gun.Generally speaking, tribo technology is the best choice when:applications requiring the best possible appearance,parts constructed of materials with low charge conductivity, part geometry's susceptible to the generation of Faraday cage areas,applying powders with a low degree of abrasivety, such as many non-metallics,parts requiring a thin coating, parts requiring the highest degree of coating uniformity,touchup applications,epoxy coatings.While generally speaking, corona technology is the best choice for:parts constructed of materials with a higher charge conductivity,part geometry's not susceptible to the generation of Faraday cage areas,applying powders with a high degree of abrasivety, such as many metallics,parts requiring a relatively thick coating.multiple custom coatsThe term "100 kV" applies to Corona guns and refers to the 100,000 high-voltage generator that produces the arc to disassociate air and generate an electron cloud. The electrode of the gun typically has a negative polarity relative to the piecework. Polarities must be reversed for nylon powders, which require a positive charge. Corona powder coating guns with low kV values (some as low as 16 kV) raise significant questions about the quantity of charged particles that such a low kV can generate. To learn more about the operation of powder coating equipment including powder coating systems, powder coating batch ovens and powder coating booths consider attending a powder coating training class such as that offered by the Powder Coating Institute.

 Powder coating is a dry finishing process, using finely ground particles of pigment and resin that are generally electrostatically charged and sprayed onto electrically  grounded parts. The charged powder particles adhere to the parts and are held there until melted and fused into a smooth coating in a curing oven. Before coating, the parts to be coated are first pretreated similarly to conventional liquid coated parts. The pretreatment process is normally conducted in series with the coating and curing operatios.        There is essentially two common ways of applying powder coating: by electrostatic spray and by fluidized bed powder coating. There are several other processes that have been developed, but they are far less used. These include flame spraying, spraying with a plasma gun, airless hot 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·         curingPretreatment.some cases, the feed hoppers vibrate to help prevent clogging or clumping of powders prior to entry into the transport lines. The powder is supplied by a hose to the spray gun, which has a charged electrode in the nozzle fed by a high voltage dc power.Electrostatic powder spray guns direct the flow of powder; control the deposition rate; control the pattern size, shape, and density of the spray; and charge the powder being sprayed .The spray guns can be manual (hand-held) or automatic, fixed or reciprocating, and mounted on one or both sides of a conveyorized spray booth. Electrostatic spray powder coating operations use collectors to reclaim over-spray. This reclaimed powder is then reused, adding significantly to the powder coating’s high transfer efficiency.There are various gun designs that mainly differ in the method of applying electrostatic charge to the powder. In some cases, the powder is electrostatically charged by friction. The advantage is that the powder is 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.CuringWhen a thermoset powder is exposed to elevated temperature, it begins to melt, flows out, and then chemically reacts to form a higher molecular weight polymer in a network-like structure. This cure process, called cross linking, requires a certain degree of temperature for a certain length of time in order to reach full cure and establish the full film properties for which the material was designed. Normally the powders cure 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.