Coating Machine Working Process
This process involves coating rolled substrates-such as paper, fabric, leather, aluminum foil, or plastic film-with a layer of specialized adhesive, coating material, or ink, followed by drying and subsequent rewinding.
Working Principle of Automatic Coating Machines: The fundamental working principle of automatic coating machines used for screen printing plate preparation remains consistent across different units; however, their specific performance characteristics vary depending on the machine model and the manufacturer. Screen coating machines are typically equipped with mechanisms mounted on a vertical frame designed to securely clamp the screen frame. Positioned both in front of and behind the screen area is a horizontal coating assembly; this assembly consists of a coating trough (or coater bar) and mechanical or pneumatic components that regulate the trough's angle and pressure.
The coating assembly is mounted at both ends onto the machine's vertical support arms. Driven by a transmission system utilizing belts, chains, or cables, the assembly moves vertically-up and down-to apply the coating material across the surface of the screen mesh. The transmission mechanism is coupled to a servo or variable-frequency motor, ensuring smooth operation and enabling precise control over the positioning of the coating assembly.
Prior to coating, a clean, properly tensioned screen frame is loaded into the machine-typically from the front, although some models allow for loading from the side. For machines designed to accommodate large-format screen frames, side-loading is a more common practice; given the size and bulkiness of such frames, side-loading minimizes the required lifting height and physical handling effort. Furthermore, side-loading proves particularly convenient when the automatic screen coating machine is integrated and operated in-line with other automated screen processing equipment (such as cleaning units, reclaiming systems, drying ovens, and developing machines).
Regardless of the loading method employed, once the screen frame is correctly positioned, either a pneumatic or mechanical clamping mechanism engages to securely lock the frame in place. To facilitate ease of operation, many machine models feature foot-pedal controls for actuating the frame clamps, thereby allowing the operator to keep both hands free to manipulate and position the screen frame. Once the screen frame has been successfully mounted and the appropriate photosensitive emulsion has been loaded into the automatic coating machine, the coating process can commence. Depending on the specific control system and functional capabilities of the equipment, the machine may be configured to simultaneously apply coating to both sides of the screen mesh. There are two primary methods of coating: the first involves applying a photosensitive emulsion to a screen mesh through a series of "wet-on-wet" passes; the second incorporates a drying step after each individual coating pass. This equipment is designed to apply a precisely metered quantity of liquid (or molten) polymeric materials-such as adhesives or coatings-onto a substrate surface.
It is suitable for the production of flexible substrates, such as PVC and PE films.
Simply put, the process involves applying an adhesive layer onto a film substrate. Specifically, the operation encompasses adhesive application, drying, winding, and tension control.
The substrate material may consist of various films-such as PVC, PE, or PET-or paper-based materials; for instance, applying hot-melt adhesive onto release paper.
