抄録
The authors propose a new method of detecting the operations of a check ring by employing the torque load T in the reverse direction of rotation applied during injection at the servo motor for rotating the screw equipped to electric injection molding machines. Through experiments, the authors confirmed that the torque load T peak and ring closing timing match, and that there exists a clear negative correlation between the T time integral value Bf and molded product weight. In addition, check rings with different closing strokes S and external diameters D were used to investigate the correlations between the closing stroke/external diameter and Bf, and it was found that the larger S is, the greater is Bf, and that Bf increases suddenly as D decreases (interval with the cylinder increases). The torque load of the injection molding machine was monitored using the developed check ring operations detection method based on these results, and it was demonstrated that reverse flow amount can constantly be monitored with this method. These findings suggest that the developed method is useful for predicting the life of check rings.
