Material BehaviourFiber-breakage evaluation of plasticated resin based on a newly developed heating cylinder with multiple ports for in-process sampling

In the injection molding of long fiber-reinforced resins, the breakage of fibers during the plastication process and while they are flowing past the check ring (CHR) is a common problem faced on manufacturing sites. However, no systematic research has been carried out. For the first time, the authors develop a heating cylinder with multiple ports on the wall for extracting the melted resin from the cylinder inside to perform in-process sampling of the resin. In this study, the new device was used to sample melted resin before and after CHR and to investigate the effects of the shape of the CHR on glass-fiber breakage. The experimental results clearly demonstrate that the breakage of fiber can be minimized to an extent where there is enough space for melted resin to gently flow and bypass the CHR. In addition, it was confirmed that the length of the CHR does not significantly affect glass-fiber breakage.