Method and apparatus for composite manufacture

A method, comprising:

• (a) moving a tow of long continuous fibers through a processing chamber;
• (b) discharging a pressurized fluid stream entrained with a number of resin particles into the processing space through an orifice, the stream diverging from the orifice to distribute the particles in the processing chamber;
• (c) generating an electric field between the tow and an electrode to direct at least a portion of the particles received into the chamber onto the tow, the electrode being separated a first distance from the tow and the orifice being positioned a second distance from the tow, the second distance being greater than the first distance;
• and
• (d) at least partially melting particles in contact with the tow.

A method, comprising:

• (a) moving a tow of long continuous fibers through a processing chamber;
• (b) providing a number of charged resin particles in the chamber;
• (c) disposing an elongate wire electrode in the chamber, one of the wire electrode and the tow being positioned above another of the wire electrode and tow, and the tow being exposed to a length of at least one centimeter of the wire electrode;
• (d) generating an electric field between the electrode and the tow, the field emanating along the length of at least one centimeter of the wire electrode;
• (e) depositing the resin particles charged on the tow;
• and
• (f) fixing the resin particles deposited to the tow after said depositing.

A method, comprising:

• (a) electrostatically depositing a number of resin particles on a tow having a number of long continuous fibers;
• (b) heating the tow to form a molten resin matrix from the particles;
• (c) pulling the tow between a pair of surfaces, at least one of the surfaces engaging the tow under a spring bias to controllably compress the tow and matrix between the surfaces, the spring bias being adjustable;
• and
• (d) adjusting the spring bias to change pressure exerted on the tow by the pair of surfaces to improve impregnation of the tow with the molten resin matrix.

A method, comprising:

• (a) electrostatically depositing a number of resin particles on a tow having a number of long continuous fibers;
• (b) heating the tow to form a molten resin matrix by melting the particles;
• (c) pulling the tow through a first station along a travel axis, the first station having a first pair of opposing surfaces pressing the tow therebetween, at least one of the first pair of surfaces engaging the tow under a first spring bias;
• and
• (d) moving the tow through a second station positioned downstream of the first station along the travel axis, the second station having a second pair of opposing surfaces pressing the tow therebetween, at least one of the second pair of surfaces engaging the tow under a second spring bias.

An apparatus for manufacturing a composite by depositing a number of resin particles on a tow, the tow having a number of long continuous fibers, comprising:

• a processing chamber;
• a transport configured to move the tow through said processing chamber;
• a particle source in fluid communication with said processing chamber, said particle source being configured to provide the resin particles in said processing chamber;
• an elongate wire electrode coupled to said processing chamber, said wire electrode and the tow being configured with one over the other;
• a voltage source configured to be electrically coupled to the tow and said electrode, said wire electrode being disposed relative to the tow to provide a generally cylindrically shaped charging region about said wire electrode to electrostatically charge the resin particles and generate an electric field between said electrode and the tow to direct deposition of the resin particles on the tow when said voltage source is coupled to the tow and said electrode;
• and
• a fixation unit configured to receive the tow from said processing chamber to fix the resin particles to the tow after deposition.

An apparatus for manufacturing a composite by depositing a number of resin particles on a tow, the tow having a number of long continuous fibers, comprising:

• a tow-conveying device configured to move the tow through a particle deposition chamber;
• a particle source in fluid communication with said chamber, said particle source being configured to discharge the resin particles into said chamber;
• an electrode positioned within said chamber, said electrode being configured to electrostatically charge the particles received within said chamber for deposition on the tow;
• a first processing stage configured to receive the tow from said chamber, said first stage including a first surface opposing a second surface, said device being configured to pull the tow between said first and second surfaces, said first surface being engaged by a controllable actuator to exert a first controlled pressure on the tow when positioned between said first and second surfaces, at least one of said first and second surfaces being heated to form a molten resin matrix from the particles deposited on the tow;
• and
• a controller operatively coupled to the first stage, the controller being configured to generate a first control signal to regulate the first pressure exerted by the first surface.