Roll coating is an important coating method, mainly used for UV paint construction. Compared with drip coating and spray coating, it has the advantages of high production efficiency, low coating loss and cost, and can flexibly combine related equipment according to the actual situation of furniture companies, forming a production line with higher degree of automation. It is widely used in flat workpiece coating.
Roll coating machine is a device that uses a set of rotating rollers to apply a certain amount of paint to a flat surface material. The coating thickness can be adjusted by changing the pressure between the two rolls. Typical roller coater machines include roller coaters, pressure roller coaters (gravure roller coaters), positive and negative roller coater machines, etc. In addition, coating machines that use small-diameter coating rolls instead of coating scrapers are also called roller coater machines.
The main function of roll coating machine is to use the rotation of the steel roller and the rubber roller to evenly coat the paint on the workpiece. During construction, it is often the case that the rubber roller and the steel roller are not pressed together tightly before oil is applied, resulting in the UV paint flowing to the conveyor belt, which wastes the coating and increases the difficulty of cleaning in the later stage. The correct way is to wait for the steel roller and the rubber roller to be parallel and close together, and then evenly flow the coating into the V-shaped space between the two rollers. Generally speaking, the gap between the two rollers should be just enough for a A4 paper with regular thickness to pass through, and the gap should not be too large.
If the height of the rubber roller is not adjusted properly before the plate is released, it is easy to damage the rubber roller. It is recommended to first adjust the height of the rubber roller to be slightly higher than the thickness of the workpiece, place the workpiece flat under the rubber roller, and avoid the edges and corners of the workpiece from contacting the rubber roller before adjusting.
Mass production without accurately checking and correcting the first workpiece, resulting in inadequate coating amount or effect, and then reworking. The correct way is to follow up the first workpiece throughout the whole process, check the viscosity, coating amount, curing energy, and coating effect of the paint in time, and confirm that it is correct before mass production.
As mentioned earlier, roller coater machine is mainly used for flat workpiece coating, so the flatness of the workpiece directly affects the coating effect. It is recommended to use high-quality plates to ensure that the flatness is within a suitable range. (Generally, the difference in bending degree within 1m length must be controlled within ±2mm). Before online coating, sanding machine with constant thickness must be used for sanding treatment, and the thickness error of the plate must be controlled within ±0.05mm. At the same time, it is necessary to ensure that the width of the workpiece is within 1300mm and the thickness is between 2 and 80mm. In addition, it should be noted that when roll coating at low temperature, the workpiece must be preheated to avoid excessive temperature difference between the workpiece and the paint, resulting in poor paint film.