What are the technical requirements of the protective film coating machine?
film coating machineThe viscosity and other rheological properties of the protective film adhesive are important properties that affect the coating behavior of the protective film. According to the dependence of the viscosity on the shear rate, the fluid can be divided into three types: Newtonian fluid, swelling body and pseudoplastic body. With the change of time, the fluid is divided into Newtonian fluid, thixotropic body and rheological body. The greater the deviation of the rheological properties of the adhesive from Newtonian fluid. Various quality problems are more likely to occur in the coating operation, especially when the adhesive exhibits the properties of an expanding body, since its viscosity will increase rapidly with the increase of the coating speed during the coating process, it is necessary to use a larger mechanical Therefore, the faster the coating speed, the more difficult it is to obtain a uniform coating, and the substrate is often broken due to excessive force, or even the scraper is damaged. When the adhesive exhibits thixotropic properties, the adhesive layer The leveling property is very poor, so it is difficult to obtain a smooth and smooth adhesive layer.
The working principle of the automatic coating machine used for screen printing plate making is the same, but its performance varies according to different models and different manufacturers. The screen coating machine is equipped with a device that can clamp the screen frame on the vertical frame. Before and after the screen area is a horizontal coating mechanism, which consists of a coating tank, and mechanical or pneumatic components that control the angle and pressure of the coating tank.
Both ends of the protective film coating mechanism are installed on the vertical support arm of the coating machine, and the coating mechanism is moved up and down through the transmission of belts, chains or cables to coat along the surface of the wire mesh. The transmission mechanism is connected to the servo or frequency conversion motor, which makes it operate smoothly and can precisely control the position of the coating mechanism.
Before coating, load the clean and stretched screen from the front of the coating machine, and some models can also load the screen from the side. Among the models designed for large-format screen frames, side loading is more common, because the screen frame is large and bulky, and side loading can reduce the amount of lifting and moving.
When the automatic screen coater is running in-line with other automatic screen processing equipment, it is more convenient to load the plate from the side.
Regardless of how the screen is loaded, once the screen is in the correct position, the pneumatic or mechanical clamping device closes and locks the screen.
For more convenient operation, many models have foot pedals to control the action of the plate clamp, and the operator can free both hands to control the screen plate. After installing the screen, pour the corresponding photosensitive emulsion into the automatic coating machine, and then start coating. According to the functions of the control system and the equipment, the equipment can coat both sides of the wire mesh at the same time.