Workpiece Is Ejected By An Opposite Direction And Two-Step Ejection Systems

Fig 6.47 is the con yguration that the workpiece is ejected by an opposite directic two-step ejection systems. The two ejection systems start at the same time, the"upper system stops on and in the second step only the "lower"system moves further.

The mold is complicated to some extent by the fact that the safe ejection of the workpiece requlred an opposite direction ejection and a two-step ejection system as shown in Fig. 6.47. This was because if the intermediate cylindrical part of the workpiece were lifted by the ejector pin, then it is conceivable that the outer surface would break into the nest.

Operation: during the nozzle of barrel 2I goes back, the sprue out off the sprue bush 22 by the actuation of spring 20 when the mold is still closed (Fig. 6.47a). when mold begins to open, the upper cup 2 under the influence of spring 24 forces the workpiece to remain in the mobile part of the mold as shown in Fig. 6.47b. Upon engagement of ejector sleeve 16 with the stop of the machine, it presses the ejector plate 12. The ejector 18 moves together with the ejector sleeve 16 and presses the ejector plates 8 and 11. So that the two ejection systems start at the same time and lift the workpieces out of the lower cup 5 in first ejection step(Fig.6.47c). At the following ejection process, the ejector plates 8 and 11 cannot move any further because they are stopped by supporting plate 7, only the ejector plate 12 lifts the tapered ejector pin 15 further, and this in turn lifts the workpiece out of the tapered ejector 4 as shown in Fig. 6.47d

Advantage: The mold is operated fully automatically. The ejection is completely safe.The workpieces fall into the box by their own weight.

Disadvantage: preparation of the tapered ejector pins and tapered ejector sleeves requires careful work and mold production is costly