Process control of electrostatic automatic spraying machine
The coating line uses high-pressure electrostatic automatic spraying system, in the actual process of production, we have to constantly figure out the construction characteristics of various colors; for different coatings, you need to choose the right automatic sprayer parameters (paint volume, forming air pressure, voltage value), the impact of the adjustment range on the appearance are to be figured out in the actual production, which is very important for on-site construction adjustment. Of course, to get a uniform coating film, it is not enough to adjust only by these three parameters. It can also be achieved by switching the main needle of the spinning cup in different positions and the speed of the spinning cup. In addition, the appropriate use of profiling design parameters to adjust, such as automatic spraying machine profiling route, according to different positions to adjust the different spraying distance (generally in 27 ± 1cm gun distance), up and down the left and right swing, spinning cup distance, spinning cup spraying angle and other parameters, so as to get the best spraying profiling route. The selection and optimization of the equipment operating parameters are also very important. The set high pressure electrostatic value, rotational speed, pressure of forming air, viscosity of paint, etc. must be adjusted repeatedly at the production site until the best range, in order to reduce the orange peel to a minimum.
1 The rotational speed of the rotating cup is the most influential factor on the atomized particle size. If the speed is too low, the atomization of paint is not good, which will lead to roughness of paint film. For solvent-based paint, the speed of medium and color paint should be controlled from 20000 to 30000r/min, and the speed of varnish from 25000 to 35000r/min.
2 The amount of forming air can control the spraying fan, the lower the amount of forming air, the larger the spraying fan. Adequate reduction in the amount of forming air can reduce the long wave of paint film, but the amount of forming air is too low, it will cause pollution of the spinning cup.
3 Spray cup and the body of the spraying distance should generally be controlled at 250 ~ 300mm, such as the distance is too large, not only will affect the utilization of paint, but also for the smoothness of the coating will cause adverse effects.
4 Spraying flow is an important factor affecting the thickness of the paint film, so that the medium and clear coat film thickness to reach the maximum, can improve the fullness of the coating, effectively reduce the coating orange peel. In fact, when the spraying volume reaches the critical state of hanging, the surface effect of the coating is the best. At present, the vast majority of domestic automobile factories spray paint room only heating without cooling, spray paint room temperature is generally controlled at 18 ℃ ~ 36 ℃, in the production process can be determined according to the temperature of the spray paint room several sets of different spraying parameters to ensure that the amount of spraying always reaches the state of seemingly flowing non-flowing.
5 spraying electrostatic voltage on the coating orange peel also has an impact. Generally controlled at 30,000 volts to 100,000 volts.