Powder coating manufacturers for powder coating on powder rate is the most concerned about a problem, powder coating on powder rate generally refers to powder coating coverage, in order to ensure the appearance of powder coating film, mechanical properties, unit profile consumption powder coating quantity affects the production cost.Powder coating on powder rate in addition to powder particle charge, powder particle size, coating formula, the most easily overlooked point is that it and the spray gun also has a greater relationship.
The primary powder rate of the spray gun refers to the ratio of the amount of powder sprayed on the workpiece to the total amount of powder (including the amount of powder recovered without spraying) when spraying, which is called deposition efficiency.The powder recovery is inversely proportional to the deposition efficiency. The higher the deposition efficiency is, the smaller the powder recovery is.
The size of the primary powder rate of the spray gun is related to the type of the spray gun, the process parameters, the shape of the workpiece and the way of spraying.Powder spraying, must not ignore the importance of a powder rate.A good spray gun can achieve 80% powder rating, so only 20% powder recovery can be considered, which can save production costs.Many powder coating manufacturers and customers only noticed the maximum amount of powder is how much, in fact, the amount of compressed air and air pressure increase, the amount of powder can be increased.However, whether the high voltage electrostatic generator can charge so much powder is a question.In the case of the spray gun, the dense powder blocks each other's way of charging, leaving the powder behind with little or no charge.From the point of view of the spraying process, when the coating surface reaches electrostatic equilibrium, the powder particles coming from behind and particles on the coating surface will repel each other, or even fall off due to the opposite motion of reverse ionization, which will be recovered by the recovery equipment.Therefore, the amount of powder should be measured according to the charge capacity of the spray gun, to consider whether these powder are fully charged, but also according to the shape of the spraying workpiece, according to repeated experiments.
Clean and maintain the spray gun equipment regularly to reduce the damage to the recovery equipmentIf the spray gun is not good, high pressure is not enough, or use for a period of time without timely cleaning and maintenance, it will greatly reduce the one-time powder rate, but also increase the burden of recovery equipment.Rated powder rate refers to the workpiece for the ideal flat shape of the measuredIf the workpiece is mesh or long, bending, punching and other shape of the case, the occurrence of empty spray will increase, one on the powder rate is lower.If the workpiece has groove, groove, sharp Angle, hole and other shapes, will produce Faraday shielding, spraying coating will be very thin, leakage bottom, only the use of artificial powder large amount of make-up, powder recovery will increase.
Once the powder rate of the reduction, the overspray powder and the new powder mixed use, will make the second powder rate, three times on the powder rate in turn decrease.After one high-voltage electrostatic charge, the molecular arrangement of resins, hardeners, or fillers in the powder will change, making them less charged and less so on the second charge.Therefore, the second charge, the third charge of the "first powder rate" will decrease in turn, about 5% each time.Powder coating manufacturers in each new spraying, new shape of the workpiece or production chain speed changes, should be carried out experiments to determine the working voltage, output current, compressed air pressure, air flow and hanging workpiece, etc., in order to determine the best process parameters, get the best powder coating rate.
Contact Person: Mr. Don