Flat heat pipe and method for manufacturing the same
An exemplary flat heat pipe includes a hollow, flattened casing and a first wick structure and a second wick structure received in the casing. The casing includes a top plate and a bottom plate opposite to the top plate. The first wick structure is formed by weaving wires, and the second wick structure is made of sintered metal powder. The first and second wick structures are disposed at inner sides of the bottom and top plates of the casing, respectively. The first and second wick structures contact each other. The casing defines two vapor channels at opposite lateral sides of the combined first and second wick structures, respectively. A method for manufacturing the heat pipe is also provided.
1. A method for manufacturing a heat pipe, the method comprising:
providing a cylindrical mandrel, a hollow cylindrical tube and a first wick structure, the mandrel defining an elongated notch and an elongated cutout in a circumferential surface thereof, the notch and the cutout located directly opposite each other across a center axis of the mandrel, and an inner diameter of the tube being substantially equal to an outer diameter of the mandrel;
inserting the mandrel and the first wick structure into the tube, wherein the first wick structure is received in the notch of the mandrel;
filling an amount of metal powder into the cutout of the mandrel in the tube, and sintering the metal powder to form a second wick structure;
drawing the mandrel out of the tube, wherein the first and second wick structures remain attached to portions of an inner surface of the tube, and face each other;
injecting a working medium into the tube, and evacuating and sealing the tube; and
flattening the tube until the first wick structure obliquely contacts the second wick structure with the first wick structure being flattened, thus forming a flat heat pipe, wherein the flat heat pipe defines two vapor channels at opposite lateral sides of the combined first and second wick structures, respectively;
wherein an inmost extremity of the cutout is planar, and after the mandrel is drawn out of the tube, a transverse cross section of the second wick structure comprises a straight line and an arcuate line connecting the straight line, with the arcuate line corresponding to a portion of the second wick structure attached to the inner surface of the tube;
wherein after the tube is flattened, the second wick structure generally tapers from one side thereof farthest away from the first wick structure toward another side thereof in contact with the first wick structure.