Methods for recycling plastic Nylon 6,6 from vacuum bags to obtain filaments or powder for 3D printing processes. The method to obtain filaments includes a step of providing used Nylon 6,6 vacuum bags, a quality control step to check the status of the used vacuum bags, a step to form smaller parts, such as smaller pieces or pellets, from the used vacuum bags, quality control step to check the status of the smaller pieces or the pellets, an extrusion step wherein the smaller pieces or the pellets are introduced into an extruder, where they are melted, and the molten mixture is cooled and expelled through the die of the extruder to produce the recycled filaments, and a winding step wherein the recycled filaments that go out of the extruder are rolled up in coils.

The invention relates to a heatable mixer (1) for composite products based on thermoplastic material(s), having an elongate structure defining a longitudinal processing path between at least one inlet and at least one outlet (2) and comprising a heated trough (3) in which two mutually interpenetrating parallel twin screws (4 and 4) are mounted, forming member(s) for dimensionally reducing, heating and moving the products to be processed which are inserted at the inlet, each screw (4, 4) comprising a heated and driven support shaft (5) arranged in the path direction (DT). The mixer (1) is characterised in that it comprises, at the or at each outlet (2), a member (20) for controlling the liquid or semi-liquid output stream of processed products, flowing through the associated outlet (2), advantageously under the effect of gravity.

A resin recovery method comprises a crushing step, a sieving step, and a collecting step. In the crushing step, a resin-product-equipped harness is loaded into the crusher having a striking portion that rotates about a predetermined axis to crush the resin product with the striking portion into resin pieces. In the sieving step, the harness and the resin pieces are loaded into a sieving device having an upper sieve and a lower sieve provided below the upper sieve, from above the upper sieve. In the collecting step, the resin pieces that have passed through the upper and lower sieves are collected.