A method of heating thermoplastic filament in additive manufacturing systems, such as 3D printing systems. In accordance with the illustrative embodiment of the present invention, the temporal rate $\frac{\mathrm{dE}}{\mathrm{dt}}$
at which heat dE is added to a portion of a segment of filament is a function of the temporal rate $\frac{dm}{\mathrm{dt}}$
at which the mass dm of the portion of the segment of filament is deposited. In particular, the temporal rate $\frac{\mathrm{dE}}{\mathrm{dt}}$
at which heat dE is added to a portion of a segment of filament is a non-linear function of the temporal rate $\frac{dm}{\mathrm{dt}}.$

A horizontal heat treatment device continuously subjects an untreated continuous flat object to heat treatment while horizontally transferring the untreated object within a heat treatment chamber. Seal chambers are interconnected to the untreated-object loading opening and treated-object unloading opening of the heat treatment chamber. A passage is connected to an opening of each of the seal chambers, the opening located on the side opposite the heat treatment chamber. The untreated-object passage loading opening interconnected to the untreated-object seal chamber loading opening and the treated-object passage unloading opening interconnected to the treated-object seal chamber unloading opening are the untreated-object loading opening and treated-object unloading opening of the heat treatment device. A pair of gas ejection nozzles are provided at upper and lower positions of the passages. The nozzles eject gas in specific directions, and the nozzle openings have a specific shape, a direction, and a length.

A method of producing a liquid crystalline polyester fiber includes subjecting a yarn prepared by melt spinning a liquid crystalline polyester to a solid-phase polymerization after applying inorganic particles (A) and a phosphate-based compound (B) to the yarn. The method can optionally include cleaning the liquid crystalline polyester fiber after the solid-phase polymerization.

The invention is directed to carbon fibers having high tensile strength. The invention also provides a method and apparatus for making the carbon fibers. The method comprises advancing a precursor fiber through a plurality of passes through an oxidation oven, where stretching during the initial passes is minimized or eliminated entirely, or made negative, followed by controlled stretching over a series of passes, using rollers of increasing speed.

An apparatus for processing yarns includes a first roller set for extending yarn bean; a node generator installed after the first roller set for forming node section of the yarn beam; a first cleaning chamber installed after the node generator for cleaning the yarn beams; a material chamber for adding additive to the yarn beam; a second roller set installed after the material chamber for extending the yarn beam; a first heating chamber installed after the second roller set for thermally setting additives to the yarn beam so that the additives are firmly secured to the yarn of the yarn beam; a third roller set installed after the heating chamber for controlling the heating time of the yarn beam in the first heating chamber; and a fourth roller set installed after the third roller set for winding the yarn beam to a desired shape.

An apparatus and method for straightening filaments. The apparatus includes a transport device for transporting filaments; a heating device including a heating channel forming a transport path for the filaments; and a cooling device arranged downstream of the heating device in a direction of transport, including a cooling channel that continues the transport path for the filaments. Cross-sectional areas of the heating channel and the cooling channel at least partially overlap.

A stretching apparatus of fibre tows in a pressurized steam environment comprises a plurality of stretching chests (1) and associated supporting structures (3, 4, 6) arranged side by side, at the same level, on a holding frame. The stretching chests (1) are each formed by two opposed metallic half-chests (1b, 1t), delimiting a stretching chamber (2). The stretching chamber (2) has a generally rectangular section of a low height and opens outwards in correspondence of the two transversal edges of the stretching chest (1) through tow entry and exit openings. Inside the stretching chambers (2) the tows are treated with saturated or overheated steam at high temperature and pressure and simultaneously undergo a mechanical stretching operation.

A stretching apparatus of fibre tows in a pressurized steam environment includes an elongated stretching chamber having a generally rectangular section of a low height, within which the tows are treated with saturated or overheated steam at high temperature and pressure and simultaneously undergo a mechanical stretching operation. The stretching chamber has a width sufficient to house multiple tows mutually flanked in a running plane and is formed within a stretching chest made of aluminum. The stretching chest is housed in a supporting structure, having a higher structural rigidity than the stretching chest, which includes a plurality of contact elements apt to determine a predefined position of the stretching chest with respect to a direction perpendicular to the tow running plane and to allow a limited mobility of the stretching chest in the other two mutually perpendicular directions which lie in the plane, length and width respectively.

An example oven for heating fibers includes a chamber having upper and lower portions and a supply structure between first and second ends of the chamber, wherein the supply structure is in communication with a first heating system and is configured to direct first heated gas from the first heating system into the upper portion of the chamber to heat fibers in the upper portion at a first temperature, and wherein the supply structure is in communication with a second heating system and is configured to direct second heated gas from the second heating system into the lower portion of the chamber to heat fibers in the lower portion at a second temperature different than the first temperature such that the upper and lower portions of the chamber maintain the different temperatures without a physical barrier between the upper and lower portion.

A device for shaping at least one thread-like material (1), which is formed in a forming unit and is deposited on a transporting device (6) for the subsequent thermosetting process, wherein a retaining means (4, 14, 15, 22) and a drivable, curved depositing tube (5) are arranged one after the other in the thread transporting direction.