Plastic pipe extrusion line comprises two parts: head portion and developing die. The head section of the extruder is the leading parts of extruding plastic molding; it turns the molten plastic from an extruder by a spiral movement into linear motion, and additionally, to create the required molding strain, assures the dense, in order to attain the ongoing section bar together with the identical area form. The forming die generally adopts the cooling, strain or vacuum suction approach, stabilizes the shape on the plastic from the idea, and coining, in order to get plastic molding that has more appropriate segment and glossier surface area.

The head element of the extruder can be classified by extruded plastic moldings, quite often such as plastic pipes, rods, plates, sheets, webs, monofilament, aggregates, various special-shaped stuff, blown film, wire, cable etc.

In line with the extruding route of the merchandise, it could be divided into straight head and lateral head. The direction in the stuff during the directly head aligns along with the extruder’s screw axis, this kind of as really hard tube head; but inside the lateral head, material move direction is at an angle to extruder’s screw axis, these types of as cable head. In line with the head stress measurement classification can be divided into minimal strain head (stream pressure under 4MPa), middle pressure head (stream stress 41OMPa) and large strain head (stuff move stress is larger than 1OMPa).

The concepts of extrusion head design which include:

1. Streamline cavity. In order to make the plastic melt move along the channel effortlessly and with success extruded, the head’s cavity must be easily formed, the surface roughness should really be considerably less than1.6-3.2µm.


Sufficient compression ratio. So as to make the plastic pipe production machine products compacting and eliminated the seam resulting from divider brace, according to the different types of items and plastic, the extrusion head really should be designed with adequate compression ratio.

three. Correct shapes and dimensions from the part. Owing to the die swell effect caused by the plastic physical performance and strain, temperature along with factors, and the shrinkage effect due to traction, which make the head in the molding part form and dimension is not as similar as required, so the structure ought to make proper shape and dimension compensation to the idea, and reasonably determine the stream channel size, control the tip molding length, in order to get the right shape and size.

4. Rational selection of materials. The wearing is great when the move channel engages together with the flowing plastic melt; in substantial temperature molding process, some with the plastics will produce chemical gas which will corrode the channel. So in order to improve the service life from the machine, the head materials should really be selected for wear and corrosion resistance, higher hardness of steel or alloy steel.

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