What is the plastic extrusion die and its principle and characteristics
What is the mold of plastic extrusion mold production with continuous shaped plastic material products, also called extrusion die, extrusion die or die. The trudere (extrude) is the word "ex" (left) and the "push" of the plastic extrusion die, which describes the extrusion process of applying pressure to drive the material through the mold. The Czech extrusion die in the processing, it is usually a powdered or granular form of polymer is added to the extruder barrel, the screw or plunger under the action of polymer along the spiral groove or barrel to move forward, and gradually melt and become sticky fluid, then set in the mold barrel at the end of the formation and die die shape similar to the continuum, finally after cooling, can be formed into the desired shape of the product, such as a variety of plastic tubes and bars, sheets, plastic steel doors and windows, decorative film, baseboard and other plastic extrusion mold total points in design of extrusion die is the core part of extrusion, the extrusion die is directly related to technical condition to the quality stability, extrusion extrusion, extrusion mold production efficiency and the service life. Therefore, the design of extrusion die is very important. In the design, should pay attention to the following points:
1 die cavity to streamline to make the material evenly along the die extrusion, avoid the material due to stagnation and thermal decomposition, must not be in the head sharply reduced, but can not have dead and stagnant zones, should try to make the smooth flow, suggest that the surface roughness Ra value at 0。4 m
2 sufficient compression ratio according to the plastic products and plastic varieties, designed to produce enough compression ratio of the head, in order to eliminate due to shunt stent caused by the joint, so that the product density。
3 correct profile due to the factors of plastic properties, pressure, density, shrinkage ratio, die forming sectional shape and shape of products real head is different, the design should consider this factor, the die has a reasonable section shape.
4 compact, easy to assemble and disassemble in order to meet the conditions of mechanical properties, to design the rhythm of walking, tight junction, uniform heat transfer, easy disassembly and assembly, and no leakage of the nose.
5 selection of reasonable head to choose corrosion resistance, friction resistance, good tensile strength, high hardness steel。 Some also according to the situation of chromium plating。