Unidirectional long fiber three dimensional fiber structure produced by short fiber intertwining and production method thereof

A method of producing a unidirectional long fiber three dimensional fiber structure, comprising:

• providing a first die with a channel of a predetermined cross section, wherein the cross section of the channel of the first die gradually narrows down from the inlet to the outlet;
• inserting a plurality of unidirectional long fibers into an inlet of the channel of the die, wherein the plurality of unidirectional long fibers is confined and shaped by the channel to form a first three dimensional structure;
• and
• performing needlepunch to the first three dimensional structure in the channel while drawing the plurality of long fibers from an outlet of the channel of the die, so as to intertwine the plurality of long fibers in a three dimensional manner using nap-like fibers generated by the needlepunch to form a first unidirectional long fiber three dimensional fiber structure.