(1) Roll Coating Equipment: The internal seam coating device consists of a paint box mounted on a coating arm connected to the welding arm. After the can body is welded, it is transported by a conveyor to the coating roller for seam coating. In this method, liquid coating is applied to the welded seam using a rotating roller driven by a motor. The amount of coating on the roller is controlled by a scraper, and the roller surface is shaped with different curves to control the thickness of the liquid layer. The roller system is housed in a paint box, which receives paint from a pressurized supply tank equipped with a liquid level detection system to maintain consistent paint supply.
The roller surface is designed with various profiles—convex, straight, and concave—to control the coating thickness. (As shown in Figure 3-66)。
Figure 3‑66 Illustration of Different Roller Coating Effects
The exterior of the internal roller coating device is shown in Figure 3‑67, the connection between the internal coating arm and the welding machine is shown in Figure 3‑68, and the structure of the internal coating arm is shown in Figure 3‑69.
Figure 3‑67 Internal roller coating device, including the coating arm, can conveyor, paint container, and control system.
Figure 3‑68 Internal coating arm connected to the welding machine.
Figure 3‑69 Internal coating arm.
Roll coating for seam coating uses a paint box mounted on a support frame. The paint level is easily controlled using the pressure balance between the inside and outside of the paint bottle, keeping the paint level in the box constant (see Figure 3‑70). Most external seam coatings use roll coating devices, working together with oxygen-free protection to ensure a smooth, rust-resistant can seam.
The external seam coating device is shown in Figure 3‑71, including the paint box, can conveyor, and control system. Liquid paint accessories are shown in Figure 3‑72.
Figure 3‑70 Upward-facing seam external coating device
Figure 3‑71 Downward-facing seam external coating device
Figure 3‑72 Liquid coating accessories, including paint can, viscosity cup, and cleaning basin
