What is a hot melt adhesive machine?

The main function of a hot melt adhesive machine is to melt solid polymers and output polymer melts at a uniform, constant temperature, and stable pressure. There are two types of screws: horizontal and vertical. Screws installed horizontally in space are considered horizontal, while screws installed vertically are considered vertical. The installation, disassembly, and maintenance of the horizontal hot melt adhesive machine are convenient, but the screw is an extended beam, and the measuring section is prone to wear and tear. The screw of the vertical hot melt adhesive machine is not easy to bend and has less wear on the head, but the height of the factory increases, making assembly, disassembly, and maintenance more troublesome. Currently, horizontal hot melt adhesive machines are mainly used.

Hot melt adhesive machines can be divided into single thread, double thread, single screw, and double screw extrusion machines based on the difference between the number of thread heads and the number of screws. According to the rotational speed of the screw, it can be divided into universal types (with a rotational speed less than 100r/min) and high-speed extrusion machines. In recent years, the development speed of hot melt adhesive machines has been rapid. Its direction is large-scale, large aspect ratio, high-speed, and the development of new types of screws. This section focuses on the structural characteristics, technical performance, and working principle of the horizontal universal hot melt adhesive machine.

The material enters the screw groove of the screw from the feeding port, and due to the rotation of the screw, the hot melt adhesive machine is pushed forward. The hot melt adhesive machine continuously absorbs the heat energy supplied by the heating device; On the other hand, due to the friction between the hot melt adhesive machine and the hot melt adhesive machine, the friction between the hot melt adhesive machine and the screw and sleeve, as well as the shear effect between the liquid layer, a portion of mechanical energy is converted into thermal energy. As the hot melt adhesive machine advances, the temperature increases and gradually melts into a melt. During the melting process, the polymer undergoes changes in temperature, pressure, viscosity, and morphology, transitioning from a solid state (glass state) to a high elastic state. With further increase in temperature, plastic flow occurs, becoming a viscous fluid (viscous flow state). The polymer in the viscous flow state is transported to the melt pipeline under a certain pressure through the propulsion of the screw and the resistance effect of the screw outlet.

Polymer melting device: mainly composed of screws and sleeves, its function is to extrude solid materials, heat them externally, and melt them into a uniform melt. It is then extruded from the screw head at a certain temperature, pressure, and discharge rate, and sent to the spinning device through a melt pipeline for spinning.

Heating and cooling system: mainly composed of an aluminum jacket heater and a water cooled jacket, its function is to ensure that the polymer is extruded within the temperature range required by the process by heating and cooling the jacket.

Transmission system: mainly composed of a variable speed electric motor and a gearbox, its function is to ensure that the screw operates stably and evenly with the required torque and speed.