Hollow-profile composite technology

A process for producing a composite component, the process comprising:

• a) providing an injection mold having at least one openable cavity and a mold dimension (A) in closure direction and a mold dimension (B) at right angles to the closure direction of the mold and a cavity circumference (UW) corresponding to the circumference of the cavity in the region of mold dimensions (A) and (B), and at least one secondary cavity,
• b) providing at least one hollow profile in the form of a hollow cylinder having
• i) the hollow profile circumference (UH), the wall thickness(S), the external diameter (C) and the longitudinal axis (L),
• ii) at least one bend with angle (W) and
• iii) at least one perforation along its longitudinal axis (L),
• and in unbent regions of the hollow profile,
• iv) having a ratio of external diameter (C) to wall thickness(S) in the range from 5:1 to 300:1, where the external diameter (C) in the region of the mold contact surfaces (K) is greater by a range from 0.1% to 5% than the mold dimension (A) and is less by a range from 0.1% to 5% than the mold dimension (B), and
• v) the figures for external diameter (C) are based on 90° viewed in the direction of the longitudinal axis (L) of the hollow profile, and
• vi) the hollow profile circumference UH=C·π corresponds to the cavity circumference (UW) of the at least one injection mold cavity in the closed state, and
• vii) the mold contact surfaces refer to the sealing surfaces of the mold in the closed state with the hollow profile,
• c) introducing the at least one hollow profile into the at least one cavity of the injection mold,
• d) closing the at least one cavity of the injection mold and compressing the hollow profile at its mold contact surfaces in closure direction of the at least one cavity,
• e) injecting plastic into the interior of the hollow profile while the at least one cavity is closed and the hollow profile is compressed, and simultaneously filling the at least one secondary cavity via the at least one perforation in the hollow profile,
• f) expressing an excess of the plastic injected into the interior under step e) through at least one of the two lateral openings in the hollow profile by injecting gas and/or fluid thereby rendering the hollow profile with a remnant coating of the plastic on an inner surface thereof and a hollow bore,
• g) cooling down the plastic melt introduced into the hollow profile and into the secondary cavity in e), and
• h) removing the finished composite component from the injection mold and optionally removing sprues,
• with the proviso that the figures for mold dimension (A), for mold dimension (B) and for cavity circumference (UW) in process step a) relate to regions of the injection mold in which unbent regions of the hollow profile lie, and the hollow profile is based on metal or on a composite.