MASS PRODUCTION OF HFCVD DIAMOND-COATED WIRE-DRAWING DIES WITHOUT FILAMENT THROUGH THE HOLE

Hot filament chemical vapor deposition (HFCVD) diamond-coated small aperture wire-drawing dies from [Formula: see text] to [Formula: see text][Formula: see text]mm are in high demand. A new deposition technique without filaments through the inner hole of wire-drawing dies is proposed, accompanied with the specially designed fixtures. Temperature distribution on the deposition surfaces is studied by computational fluid dynamics (CFD) simulation based on the finite volume method (FVM); both case study and mass production simulations are accomplished. Excellent performance and uniform multilayer MCD/NCD/MCD/NCD films are successfully deposited on the inner-hole surfaces of total 16 cemented carbide (WC-6wt.%Co) wire-drawing dies with an aperture of [Formula: see text][Formula: see text]mm in one batch. Drawing results of gas shield welding wires show that the lifespan of the multilayer diamond coated wire-drawing dies is about 20 times of the uncoated cemented carbide dies and 2 times of the monolayer MCD coated dies.