Extrusion molding process of extruded plastic lighting fixtures

First, select suitable plastic raw materials for lamp production, such as polyethylene (PE) or polyvinyl chloride (PVC) with good toughness and processing performance. The raw materials need to be dried to remove moisture and avoid defects such as bubbles during extrusion. For example, for PVC raw materials, it is usually dried in an oven at 60-70℃ for 2-3 hours. At the same time, an appropriate amount of lubricants, stabilizers and other additives can also be added to improve the processing performance and stability of the plastic. These additives need to be fully mixed with the raw materials, and a high-speed mixer can be used to mix at a certain speed (such as 1000-1500 rpm) and temperature (such as 80-100℃) for 10-15 minutes.

 

Preheat the barrel, screw and head of the extruder. Different plastic raw materials require different preheating temperatures. For example, when processing PE raw materials, the barrel temperature is generally set between 150-200℃, the screw temperature is slightly lower than the barrel temperature, and the die temperature is around 180-220℃.

 

After preheating, debug the extruder to check whether the screw rotates normally, whether the temperature control of each heating zone is accurate, and whether the pressure display of the extruder is correct. At the same time, install and debug the extrusion mold that matches the shape of the lamp, such as a round mold for producing tubular lamp parts or a flat mold for producing frames, to ensure that the mold is tightly connected to the extruder and the shape and size of the outlet meet the design requirements.

The pretreated plastic raw material is added to the barrel of the extruder through the hopper. As the screw rotates, the raw material is gradually conveyed forward, and under the heating of the barrel, the plastic gradually plasticizes and becomes molten. The screw extrude the molten plastic through the die and the mold to form a continuous tubular or strip lamp part. During the extrusion process, the screw speed (usually 20-60 rpm) and the pulling speed should be reasonably adjusted according to the fluidity of the plastic and the shape and size requirements of the lamp parts. The pulling speed should match the extrusion speed to ensure that the size of the extruded parts is uniform and stable. For example, when the extrusion speed is fast, the pulling speed needs to be appropriately increased to prevent the parts from piling up or the size deviation is too large.

The temperature of the newly extruded lamp parts is high and needs to be cooled and shaped immediately. Usually, air cooling or water cooling is used. For some parts with high shape accuracy requirements, water cooling can better ensure their dimensional accuracy. For example, a cooling water jacket is used to cool the tubular lamp parts, and the temperature of the cooling water is generally around 10-20℃. The parts are stable in shape after cooling, and can be subsequently cut, bent, and processed according to the lamp design requirements. For example, the continuously extruded lamp pole is cut to a certain length, or the extruded lampshade frame is bent into the required shape.