Method for manufacturing thermoplastic resin pre-impregnated fiber structure

A process of manufacturing a fibrous article comprising the steps of:

• submerging a fiber substrate in a bath of first thermoplastic resin to impregnate the fiber substrate with the first thermoplastic resin;
• heating the fiber substrate at a first temperature until the fiber substrate becomes a thick continuous fiber substrate;
• cutting the thick continuous fiber substrate into a plurality of units of predetermined size;
• submerging a thin sheet in a bath of second thermoplastic resin to impregnate the thin sheet with the second thermoplastic resin;
• heating the thin sheet at a second temperature until the thin sheet becomes a thick continuous thin sheet;
• cutting the thick continuous thin sheet into a plurality of units of predetermined size;
• stacking a predetermined number of the fiber substrate units;
• stacking a predetermined number of the thin sheet units on the stacked fibrous structure units to form a stacked structure;
• pressing and heating the stacked structure at a second temperature until a stacked fibrous structure is formed;
• heating a mold to a third temperature;
• conveying the stacked fibrous structure to the mold to melt into a molten fibrous structure;
• cooling the mold to harden the molten fibrous structure into a half-finished article of a predetermined shape;
• removing the half-finished article out of the mold;
• eliminating burrs and sharp edges of the half-finished article;
• conveying the half-finished article to the mold;
• and
• uniformly applying a molten second thermoplastic resin on an inner surface of the half-finished article by injection molding in the mold to produce the finished fibrous article having a second thermoplastic resin layer on an inner surface.