SCORIM injection molding

The SCORIM unit is placed between the nozzle of the injection molding machine and the mold (Figs. 14.11-14.13).The gates (i.e., the sprues and runners) are located so that all potential weld lines are placed between them from the flow point of view. 

Shear controlled orientation injection molding (SCORIM) is a novel technique for establishing the alignment of polymer molecules and fiber reinforcements in molded p arts. S olid-state properties, which are highly dependent on molecnlar and additive alignment, can be improved through the use of controlled orientation. 

The SCORIM process employs a unique hardware component that is retrofitted to a conventional injection molding machine. Located between the injection nozzle and the mold, this unit contains a pair of pistons that exert pressure on the melt after it is injected... 

Modified processing techniques have been useful for thermoplastic starch polymers. Recent work [45, 46] has examined the use of coextruded sheet processing to produce polyester / thermoplastic wheat starch / polyester multilayer films. They found that adhesion strength between the layers and stability of the interface were crucial properties in controlling the final performance properties of the films. Work by Sousa [47] has examined use of the novel shear controlled orientation injection molding (SCORIM) process to control morpholoiges and provide tensile property increases of thermoplastic starch/synthetic blends. 

Scorim process See injection-molding melt-flow oscillation. 

Various processes are reported to provide a means to pulsate the melt to improve performance of the extruded product. An example is the Scorim process reviewed in the Injection Molding section in this chapter. A variation in the IM process has been applied to production of reinforced extruded TP pipe. This has been a center of interest, on the argument that a predictable orientation of fiber would considerably increase the pressure resistance of the pipe, without the need to increase wall-thickness (on the analogy of winding a TS resin pipe with continuous filament). The Scorim process combines the extrusion of a fiber-reinforced compound with pressure pulsing around the periphery of the die, which appears to have the effect of orientating the reinforcement. 

The conventional injection molding of polypropylene is introduced in the related chapter. This chapter extends the subject of injection molding of polypropylene with the addition of shear-controlled orientation in injection molding (SCORIM), which has proved to be an excellent way of managing the morphology and hence the physical properties of polypropylene [1, 2]. 

SCORIM is based on the controlled application of macroscopic shears to a solidifying melt in a mold cavity, and formerly referred to as Multiple Live-Feed Injection Molding (MLFM) [3]. In its simplest form, SCORIM... 

The Debye patterns from the SCORIM moldings which have been subjected to straining showed that the y-phase formed in injection molding is stable, and does not transform into other phases by deformation. Pole figures from the y-phase showed that the y-phase exhibits rotational symmetry about the injection direction as for the a-phase. 

SCORIM results in substantial improvements in mechanical properties of isotactic polypropylene and provides an effective route for managing the physical properties of injection moldings. 

Keywords injection molding, SCORIM, structure-propjerty relationships, shear-controlled orientation, molecular orientation, SCORIM pistons, impact strength. Young s modulus, shish-kebab morphology, y-phase, a-phase, p-phase. X-ray diffraction. 

Keywords injection molding, processing parameters, mold temperature, melt temperature, injection speed, holding pressure, skin-core morphol-ogy, spherulites, molecular orientation, a phase, 3 phase. Young s modulus, structure-property relationships, SCORIM, pol)nnorphism. 

When the PP is subjected to shear-controlled orientation injection molding (SCORIM), the molecular orientation may be enhanced, resulting in a self-reinforced molding. For example, by the SCORIM method, moldings of improved stiffness (by 75%) can be obtained [3] - see the related chapter in this book. 

Figure 12.33. 2-D WAXS patterns of (a) neat iPP under a weak shear flow field provided by the conventional injection molding (CIM) (b) neat iPP part under a strong shear field provided by the oscillation injection molding (SCORIM) (c) PET/iPP MRCs under a weak shear flow field by CIM (d) PET/iPP MRCs under a strong shear flow field by SCORIM...

Single Polymer Composites via Shear Controlled Orientation Injection Molding (SCORIM) or Oscillating Packing Injection Molding (OPIM) Techniques... 

The SCORIM Process. It is possible to attach the SCORIM unit to the injection molder to manipulate the filling process of the mold so that in the area of the weld lines the resin is mixed [16]. This will improve the structural strength substantially and at the same time the unwanted orientation of metallic pigments is prevented. This process typically requires a 10-15°C higher temperature of the resin and the mold. The process is based on a prolonged flow ability of the polymer. 

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