Due to their length, the glass fibers are oriented in the direction of flow during the injection process. By injecting reinforced polymers with high fluidity, the formation of a thin polymer layer on the surface of the pieces is favored, preventing the fiberglass from accumulating in this area, and preventing a good quality surface finish.

Also, the large differences in shrinkage between PA6 and fiberglass can lead to rough surfaces. The fiberglass prevents the contraction of the polyamide, especially in the longitudinal direction of the fiber, thus producing an uneven surface.

Thanks to their high fluidity, our Promyde High Flow grades allow the manufacture of injected parts with a good surface finish, especially when using grades with a high reinforcement content. The high fluidity of the base polymer helps the dispersion of the fiberglass during injection. Thus the polyamide enters the mold cavity first, filling the surface of the final part. Afterwards, the fiberglass fills the internal volume, preventing the outcropping of the fiberglass on the surface.

Using the proper injection parameters when processing Promyde B300 P2 Gx S grades will also help to achieve the best possible surface finish: increasing melt and mold temperature, injection speed, and increasing the pressure of maintenance, will contribute to obtaining a better surface quality.