the process is for producing in particular an internal conduit and is applied using a mould for realising a plurality of internal conduits for transport of a liquid which is entirely made of plastic material . the mould includes a top die which is translatable with respect to a bottom die and also includes two cores for realising internal profiles of the internal conduit , and an extraction plate associated to a plurality of extractors for expelling internal conduits from the mould at completion of the production process .