Spraying method in Can production process
This coating method so that the powder, causing the electric field from the positively charged powder particles with a negative charge, in this case, the cans or the lid is grounded, so that you can absorb the powder particles.
This corona coating method is the power to remove the powder particles electric charge by friction, this triboelectrification method to reduce the electrostatic shielding effect, the powder particles can be moved to the corner location and crannies of parts of cans or lid, which is particularly applicable for paint cans and lid.
There are two kinds of painting techniques include continuous spray technology, and intermittent spray technology are widely used, the former applies to the outside of the paint cans, spray gun start when the tank parts into the coating District, in the painting area can be a variety of spraying method, powder particles directly coating tank parts to be painting parts; the latter is a coating method to switch gun when the cans or lid into the spray District. Gas or powder in order to control the gun switch, adjust the control in a control tube, re-adjust the air flow through a shunt to control the gun down the workpiece coating amount and quick off the flow.
This process is achieved through a series of solenoid valve control, powder pump solenoid control valve to control the dose to be required for coating the workpiece parts powder. The powder pump to send the powder lose powder hose blowing control tube, powder amplifier accelerate, optimize the uniformity of powder or gas at the same time through an atomizing nozzle. Into the control tube, the tube with the control wall contact with the powder particles are brought electrostatic charge charged powder through the nozzle of the spray gun, paint cans or lid on the workpiece, the pump shut down at the same time airflow shunt open. shut down the gun, cans or lid workpiece repeat this cycle of operation.
Single operating cycle speed depends on each job requires a number of coating powder. For example, after the lid of the epoxy coating repair, each gun handling capacity of 300 to 350 per minute. When placed into the gun before the lid via a positioning mechanism, this friction type electric gun will spray the lid with the electrostatic charge of powder, the powder overspray will be a collection of re-entering the supply hose into the system recycling, and then painting a good lid transferred to the conveyor belt after a curing oven, the powder melted in the oven, scratch parts into the workpiece and welding area.
This process regardless of the lid on the outside and voltage can coating, the coating amount is generally in the 60-80 mg. In order to increase the quality of the appearance of the lid lateral powder amount to be bigger. For three of the inside of the cask body powder coating, a new powder coating process, this coating process, the maximum coating speed of each gun per minute spray rate of about 75 single-piece. By positioning delivery agency will tank open end of the transmission to the friction from the electric gun in front of the charged powder is injected into the tank, and any excessive dusting device recycling and re-enter the system of recycling. The tank was then sent to the flat belt transmission oven roasting, curing and roasting time in the 425F temperature insulation about 2 minutes. International standards, the coating is generally the average accuracy rating for the 10-15 micron modified epoxy powder, and Health-grade canned coating film of about 15-20 microns. This canning factory availability of the excellent quality of the coating to eliminate volatile organic compounds of the workpiece, the material utilization can be as high as 99%, due to the cleaning and coating process, can greatly reduce the workpiece cleaning and maintenance costs.
And canning factory, can benefit from the feed end of the coating process is a food packaging manufacturer, canned improved coating quality is excellent, as well as powder coating to improve the shelf life of food, the leakage, corrosion and iron smelly paircanned food to reduce the impact to a minimum, that is, the powder coating layer excellent protective film between the food and packaging containers, thereby improving the quality of life of the bottling plant products.
After the powder coating of the canned products with longer shelf life. Powder coating metal cans can completely replace the cans of liquid paint handling in the field of variety of food products and canned products of different specifications.
Need of food canned powder coating materials and processes relevant manufacturers are being gradually improved, excellence, in order to achieve more suitable for the requirements of food cans.
Now, powder and raw material production plants need to develop more types of resin products. Powder used to improve a variety of available properties and help to overcome the defects of powder coating resins and additives are not enough.
Powder manufacturers also need to understand the potential metal coating, determine what kind of coating technology has practical value, whether it is three cans, spray cans, pot lids, canning, sheet or coil, each material require a different resin modified powder coating, in order to get the best performance.
The inner wall coating spray cans need to have anti-fog ability, and three food cans must have anti-erosion ability of certain foods, and to have anti-cooking. Performance changes, depending on changes in the composition of the metal raw materials. For example, the good performance of coating on tinplate cans powder aluminum cans can not be accepted.
Clean of powder coating technology, with high gloss polished surface of the tank container is more excellent quality, health, appearance, more compelling, these are the cause customers to pay attention to the selling point at the time of purchase, or to open the cans and rinse re recycling convenient place.
As a result of the new and improved powder-coated containers, environmental compliance and improve the quality of stored food, packaging Chamber of Commerce, which will grade their products greatly improve.