Injection molding machine ring

Figure 125. Injection molding machine parts composed of Mo2FeB2-based alloys (a) cylinder (b) auger (c) check valve (d) seal ring (e) auger head.

Even though the CRD-NRV is designed for injection molding machines the same principle can be used in conventional extruders. In this case there is no axial motion of the slide ring however, there will still be a difference in rotational speed between the slide ring and the rest of the screw. The velocity difference will enhance the mixing action. 

Use is made of screw tip valves, popularly called non-return valve, ball check valve, or sliding ring valve. They are used in reciprocating injection and injection blow molding machines (IMM and IBMM) to control the melt flow in one direction (Chapter 4). There is also the smearhead for IMM, IBMM, and extruder. Back flow will not occur... 

More recent is the University of Twente mixing ring (or TMR). This device is made olf three parts smooth wall barrel extension, a torpedo with semi-spherical indentations (similar to these in CTM) and a perforated sleeve that goes between them. The sleeve provides shallow indentations. It slowly rotates between the torpedo and the barrel by the virtue of a drag flow. The flow in TMR is both dispersive and distributive. The advantage of TMR is its suitability to improve mixing in injection or blow molding machines [Housz, 1989]. 

The seating ring centers the sprue bushing on the injection platen of the machine directly in line with the nozzle of the injection cylinder. The sprue bushing should be as short as possible from the nozzle to the parting line of the mold and have a taper of at least 3 deg in order to maintain the heat of the melt. Cold slug wells should be used wherever possible to permit the leading cold resin to be trapped and to permit the hot resin to... 

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