It is not uncommon for several versions of a molded part to be produced by the same injection mold, especially when the batches are so small that it would be uneconomical to have a separate mold for each version. Changeable inserts specially designed for ease of handling are indispensable for achieving the desired flexibility. This requires that the inserts can be changed inside the machine, i.e., without the mold having to be dismounted and dismantled.

Where small-to-medium-size molds are involved, this is a routine job. But when the size and weight of the changeable inserts require a giant for the job, it soon exceeds the skill and personal safety requirements of the operator. The solution to the problem is to compensate human limitations of strength and reach by augmenting them with an appropriately robust manipulator. In the absence of suitable commercial equipment, the designers at Haidlmair Werkzeugbau GmbH of Nussbach, Austria, have developed a manipulator together with the mold. It consists of a carrier construction and the actual manipulator with an electric drive. Prior to each retooling, the carrier construction is brought to the mold by the shop crane and screwed onto each half of the mold.

The linear axis of the manipulator is supported on one end by the carrier construction and on the other in the mold cavity. The manipulator docks onto the changeable insert with its gripper. Prior to this, the insert is unscrewed from the fixed mold and the inserts raised into takeover position by a manually operated spindle drive within the mold. The operator has keys for guiding, raising, pulling and turning one insert at a time into a position outside the mold where he can pick it up with a crane. Cavity inserts are remounted or “blind inserts” mounted by reversing the sequence. Especially advantageous is the precision with which the changeable inserts are removed and mounted, since it provides maximum protection against damage. When retooling has been completed, the manipulator is uncoupled and removed from the injection molding machine.