Drum coating is to place the coated object and paint in a sealed drum-shaped container, and apply the paint evenly on the surface of the coated object by means of the rotation of the drum. This method is suitable for the coating of small-scale hardware workers with large batches.
1. Drum coating equipment
The tumbling effect of the drum is better, generally octagonal phase and octagonal conical phase, welded with steel plates, lined with solvent-resistant rubber, with a diameter of 0.5~1.2m and a length of 0.6~2m, as shown in Figure 2_7_11.
2. Drum coating process
(1) Process requirements
(1) Carry out the necessary pretreatment before coating on the object to be coated, and put it into the drum for coating after passing the test.
(2) The amount of the object to be coated in the drum is about 5% of the volume of the drum.
(3) The rotational speed of the drum should be controlled at about 30r/min.
(4) The viscosity of the paint is generally 18~23s (coated with _4 cups, 20°C).
(5) A small amount of paint should be put in first, and then added according to the coating situation of the object to be coated during operation.
(6) The transfer time is generally only a few minutes.
(7) After the transfer coating is completed, the object to be coated is spread on the metal mesh row and transferred to the drying process.
(2) Operation points
(1) The paint should be low viscosity and high solid content.
(2) If the shape of the object to be coated is flat or sunken, the effect of transfer coating is poor, and it is necessary to obtain a satisfactory effect. It can be mixed with other shapes of objects to improve the effect of transfer coating.
(3) When the drum is used up or not used for a long time, it should be cleaned to prevent the residual paint from drying out and affecting the quality of the coating film.
