Demoulding

Demoulding means releasing a part from the mould in which it was made. In injection moulding, ejectors push the part out of the opened tool; in casting, the casting is taken from the die or sand mould; in a precast plant the formwork is stripped and the element lifted off.

Different as the processes are, the handling task is the same: a part that has not yet reached its final strength has to be guided out of a confined space without striking anything and without deforming.

The earlier the part is demoulded, the sooner the mould is free again – and the more sensitive the part is. Warm plastic distorts under point load, young concrete has only part of its strength, a hot casting is softer than the cooled one.

For the gripper this means the permissible surface pressure and grip points apply to the condition at demoulding, not to the finished part. Sizing with the values of the cured part produces marks, distortion or spalling.

The first few centimetres are the critical ones. The part sits on cores, guides or in undercuts and has to move out in exactly one direction. Any sideways movement jams it.

A swinging attachment cannot do that. What is needed is a guided movement – a rigid arm that holds the direction while the operator sets the path. With concrete elements, the adhesion to the formwork has to be overcome first; the force required can be well above the dead weight and belongs in the sizing.

Scrap at demoulding usually has one of a few causes.