Plastic extruder comprises two sections: head aspect and developing die. The head part of the extruder is the primary parts of extruding plastic molding; it turns the molten plastic from an extruder by a spiral motion into linear motion, and even further, to crank out the necessary molding pressure, guarantees the dense, in order to get the steady portion bar along with the exact same part form. The developing die generally adopts the cooling, strain or vacuum suction process, stabilizes the shape of your plastic with the tip, and coining, as a way to get plastic molding that has additional exact portion and glossier area.
The head portion of the extruder might be classified by extruded plastic moldings, in most cases including plastic pipes, rods, plates, sheets, webs, monofilament, aggregates, many special-shaped content, blown film, wire, cable and so on.
As per the extruding route of the product, it may be divided into directly head and lateral head. The path from the substance while in the straight head aligns together with the extruder’s screw axis, these as challenging tube head; but inside the lateral head, stuff flow direction is at an angle to extruder’s screw axis, this sort of as cable head. In accordance with the head pressure measurement classification may be divided into lower strain head (stream pressure less than 4MPa), middle pressure head (stream stress 41OMPa) and significant strain head (materials circulation strain is better than 1OMPa).
The principles of extrusion head design and style including:
one. Streamline cavity. So as to make the plastic pipe production machine along the channel easily and successfully extruded, the head’s cavity must be easily shaped, the surface area roughness should really be less than1.6-3.2µm.
2. Sufficient compression ratio. In an effort to make the goods compacting and eliminated the seam resulting from divider brace, based on the different types of products and plastic, the extrusion head ought to be designed with adequate compression ratio.
three. Correct shapes and dimensions from the part. As a result of the plastic pipe extrusion line caused by the plastic physical performance and strain, temperature along with factors, and the shrinkage effect due to traction, which make the head on the molding part shape and size is not as identical as required, so the style and design must make proper shape and dimension compensation to the hint, and reasonably determine the stream channel size, control the suggestion molding length, as a way to get the right condition and size.
4. Rational selection of materials. The wearing is great when the stream channel engages with the flowing plastic melt; in large temperature molding process, some in the plastics will produce chemical gas which will corrode the channel. So in an effort to improve the service life from the machine, the head materials ought to be selected for wear and corrosion resistance, significant hardness of steel or alloy steel.