A process for the manufacturing of a pressure vessel made from a thermoplastic material or a thermosetting resin. The vessel comprises a first and a second vessel end part, and possibly an intermediate tube part. The vessel end parts include a circumfering shell (4) and each one dome (3). A number of partition and load distributing walls (5) stretch from the domes (3) towards the open part of each vessel end part. The possible intermediate tube part includes similar walls (5). The edges of the walls (5) will meet when the different parts are joined. A number of cells (6) are formed between the walls (5). A number of crossing areas are formed between intersecting walls (5). At least one crossing area is provided with a determination by achieving a hole (14) from the outside of the dome. The hole (14) is bigger than the crossing area and has a depth greater than thickness of the dome part (3).