During the 3D process, also known as the parison insert method, a robot places the parison into the mould. The extruded parison is picked up by the robot and placed along the product contour in the mould. During or after insertion, the mould closes sequentially and the parison is inflated with compressed air.

The advantage of this technology lies in the elimination of the pinch-off weld (no reduction in strength) of the products so that no refinishing of the article outer contour is necessary. A uniform wall thickness distribution over the product (saving in weight) can be achieved with a reduced mould clamping force and accumulator head volume (smaller extruder units can thus be used). The work of flash trimming and regenerate processing is also reduced, so that less material has to be employed in the circuit. This method is particularly suitable for the production of tubular geometries and also permits production of multi-component parts.