Moulding apparatus for forming a fastening device

1. A molding apparatus for forming a retaining device, the molding apparatus comprising a molding strip and a molding support, the molding strip having an inside face, an outside face, and a plurality of through cavities extending from the outside face to the inside face, the molding strip extending in a longitudinal direction and presenting both a transverse direction perpendicular to the longitudinal direction, and also a height direction perpendicular to the longitudinal direction and to the transverse direction, the inside face being configured to press against a molding face of the molding support, wherein the inside face of the molding strip and/or the molding face of the molding support includes an array of passages, the array of passages forming vents and connecting together the cavities when the molding strip is pressed against the molding support, wherein each cavity of the molding strip is configured to form a preform of a retaining element, wherein the molding strip is made as a single piece and is perforated.

2. A molding apparatus according to claim 1 , wherein the inside face of the molding strip and/or the molding face of the molding support presents a maximum roughness height Rz that is greater than or equal to 1.0 μm and less than or equal to 50.0 μm.

3. A molding apparatus according to claim 1 , wherein the inside face presents a rim surrounding an open portion of each cavity and projecting from the inside face, the rims defining between them the array of passages, each rim presenting various heights, such that when the molding strip is pressed against the molding support, at least a portion of each rim is not pressed against the molding support, such that each cavity is in connection with the atmosphere via the array of passages.

4. A molding apparatus according to claim 3 , wherein a maximum difference between two heights of a given rim of a cavity is greater than or equal to 1.0 μm and less than or equal to 100.0 μm.

5. A molding apparatus according to claim 1 , wherein the array of passages extends in the longitudinal direction.

6. A molding apparatus according to claim 1 , wherein the array of passages extends in the transverse direction.

7. A molding apparatus according to claim 1 , wherein each cavity defines a stem extending from the outside face towards the inside face and having a head-forming end extending away from the stem towards the inside face of the molding strip.

8. A molding apparatus according to claim 1 , wherein the molding support is a molding roller.

9. A molding apparatus according to claim 1 , wherein the molding strip has 10 cavities/cm 2 to 500 cavities/cm 2 .

10. A molding apparatus according to claim 1 , wherein each cavity has a height in the height direction greater than or equal to 5.0 μm and less than or equal to 5000.0 μm.

11. A molding apparatus according to claim 1 , wherein the molding strip is a continuous, single piece of nickel material.

12. A molding apparatus according to claim 1 , wherein the molding strip presents a length in the longitudinal direction lying in the range 0.5 m to 5 m.

13. A molding apparatus according to claim 1 , wherein the molding strip presents width in the transverse direction lying in the range 5 mm to 3000 mm.

14. A molding apparatus according to claim 1 , wherein each cavity presents symmetry of rotation about an axis parallel to the height direction.

15. A molding apparatus according to claim 3 , wherein a portion of the array of passages surrounding at least one of the cavities presents a shape that is substantially hexagonal.

16. A molding apparatus according to claim 3 , wherein a maximum difference between the height of at least one of the rims and a height of a passage adjacent to said rim is less than or equal to 100.0 μm.

17. A molding apparatus for forming a retaining device, the molding apparatus comprising a molding strip and a molding support, the molding strip having an inside face, an outside face, and a plurality of through cavities extending from the outside face to the inside face, the molding strip extending in a longitudinal direction and presenting both a transverse direction perpendicular to the longitudinal direction, and also a height direction perpendicular to the longitudinal direction and to the transverse direction, the inside face being configured to press against a molding face of the molding support, wherein the inside face of the molding strip and/or the molding face of the molding support includes an array of passages, the array of passages forming vents and connecting together the cavities when the molding strip is pressed against the molding support, wherein each cavity of the molding strip is configured to form a preform of a retaining element, wherein the molding strip is made as a single piece and is perforated,

wherein the cavities are aligned in the longitudinal direction so as to form a plurality of rows in the longitudinal direction, adjacent cavities of one row being spaced apart from each other by a first pitch measured in the longitudinal direction, two immediately-adjacent rows being spaced apart from each other by a second pitch measured in the transverse direction, the cavities of two immediately adjacent rows being offset from each other in the longitudinal direction by one-half of the first pitch.