Effect of glass bead content and diameter on shrinkage and warpage of injection‐molded PA6

Abstract

A simple technique has been introduced to evaluate the shrinkage and warpage behavior of injection molded products. Using the shrinkage values measured on specific locations of the specimen, three deformation factors have been defined to characterize the warpage behavior of the materials examined. Experiments were carried out to determine these properties of injection molded polyamide 6 (PA6) composites with solid glass bead (GB) contents of 10, 20, 30, 40 wt% and diameters of 11, 85, 156, 203 lm. It was concluded that the flow directional shrinkages can principally be described by the change in the bead content and diameter; it was proven that the increase in bead content and in bead diameter induces a reduction in flow directional shrinkage. The rising bead content and diameter increased the deformation factor, defined by the shrinkage differences caused by the pressure drop. It was pointed out that the ideal bead content can be determined in the function of bead diameter.

Injection moulded all-polypropylene composites composed of polypropylene fibre and polypropylene based thermoplastic elastomer

“…The highest shrinkage was detected in length direction in contrast to the glass fibre reinforced and glass bead filled products where the shrinkage (and warpage) in flow direction is decreased [25][26][27]. In case of 160°C the shrinkage of the specimens increased in length direction (side and middle section, too).…”

Polypropylene Filled With Glass Spheres in Extrusion‐Based Additive Manufacturing: Effect of Filler Size and Printing Chamber Temperature

“…This trend toward an improved warpage reduction for the compounds containing smaller fillers is attributed to the bigger effective interfacial area between the filler and the matrix for the smaller fillers. [17] The observed trend is in agreement with studies on injection-molded talc [17] and glass bead compounds [16] and 3D-printed perlite composites. [10] The observed good matrix-filler adhesion and the homogeneous distribution of the fillers (Figure 2) further promote an improved shrinkage and warpage.…”

Optimization of mechanical properties of glass‐spheres‐filled polypropylene composites for extrusion‐based additive manufacturing

“…Glass microspheres are widely used in the industry to improve stiffness, flow properties and stress distributions and are relatively inexpensive and readily available. Their geometry allows good dispersion and a close packing, resulting in an improved dimensional stability for different thermoplastics . So far, many studies have been devoted to PP filled with the conventionally used inorganic soda lime glass, also known as A‐glass .…”