Spray paint machine - water-based paint spraying construction operation 7 techniques Spraying method is one of the most important methods of water-based paint construction. The surface of the object is painted by automatic spray paint to obtain a thin and uniform coating film. For different geometric shapes, there are Small holes, gaps, unevenness, paint can be evenly distributed; for spraying large objects, it is faster and more effective than painting. However, there are some operational skills to be mastered by spraying:
1. Adjust the paint to a suitable spray viscosity with clean water and measure with a coating-4 viscometer. The appropriate viscosity is generally 20 to 30 seconds. If there is no viscometer at one time, visual method can be used: stir the paint with a rod (iron rod or wooden stick) and pick it up to a height of 20 cm to stop and observe. If the paint liquid is continuous in a short time (a few seconds), It is too thick; if it is off the edge of the barrel, it is too thin; when it is just 20 cm high, the paint liquid is in a straight line, and the instantaneous flow is turned into a downward drop. This viscosity is more suitable.
2. The air pressure is preferably controlled at 0.3-0.4 MPa (3-4 kgf/cm2). If the pressure is too small, the spray liquid will be atomized, and the surface will form pitting. If the pressure is too large, it will sag and the paint mist will be too large, which will waste materials and affect the health of the operator.
3. The distance between the nozzle of the automatic painting machine and the object surface is generally 300-400 mm. It is easy to sag too close; the paint mist is not uniform too far, and it is prone to pitting, and the nozzle is far away from the object surface and the fog is scattered on the way. The specific size of the distance should be appropriately adjusted according to the type of paint, viscosity and pressure. Slow drying paint spraying distance can be a little farther, quick-drying paint spraying, the distance can be closer; when the viscosity is thick, it can be closer, when the viscosity is thin, the distance can be farther; when the air pressure is large, the distance can be farther, the pressure can be closer; the so-called A little closer is a small adjustment between 10 mm and 50 mm. If it exceeds this range, it is difficult to obtain a desired paint film.
4. The spray gun can be moved up and down, left and right, preferably at a speed of 10-12 m/min. The nozzle should be sprayed straight on the surface to minimize the oblique spray. When spraying to both ends of the object surface, the hand of the trigger of the spray gun should be loosened quickly to reduce the paint mist, because the two ends of the object surface often need to be sprayed twice or more, which is the most likely place for sag.
5. When spraying, press the next one to hold 1/3 or 1/4 of the previous one, so that there will be no leakage. When spraying the quick-drying paint, it is necessary to spray it in sequence. The effect of refilling is not ideal.
6. When spraying in an open space, pay attention to the wind direction (not suitable for operation in high winds). The operator should stand in the downwind direction to prevent the paint mist from being blown onto the sprayed paint film to create an unsightly grainy surface.
7, the automatic spray paint spraying sequence is: first difficult and easy, first inside and outside. After the height is high, the small area is small. This will not cause the spray mist of the post-spray to splash onto the sprayed paint film and destroy the sprayed paint film.