Hiroshima University 3D-Prints Tungsten Carbide Cutting Tools With Dramatically Less Waste

Tungsten carbide is one of the hardest materials used in industry, which is exactly why it has been so difficult to 3D print. A team at Hiroshima University, working with Mitsubishi Materials Hardmetal Corporation, has now demonstrated a working additive manufacturing process for tungsten carbide-cobalt cutting tools that preserves hardness while slashing material waste.

Why Tungsten Carbide Matters

Tungsten carbide-cobalt cemented carbides show up everywhere. Cutting tool edges, construction equipment wear parts, drill bits, mining machinery — all rely on the material for its combination of extreme hardness and fracture toughness. Making these parts by conventional powder metallurgy is expensive and wasteful. You press tungsten and cobalt powders together under high pressure and heat, and a significant fraction of the starting material never ends up in the finished part.

The Hot-Wire Laser Breakthrough

The Hiroshima team used a technique called hot-wire laser irradiation. A laser and an electrically preheated tungsten carbide filler wire work together. The wire softens before it contacts the substrate, which increases deposition efficiency. The researchers tested two different fabrication directions. In one, the solid carbide rod leads the fabrication. In the other, the laser leads and deposits material between the rod and the base steel. The second approach proved more reliable.

A nickel alloy interlayer between the steel substrate and the carbide deposit solved adhesion and hardness problems. With careful temperature control — above cobalt's melting point but below the temperature that causes tungsten carbide grain growth — the team produced defect-free material with hardness exceeding 1400 HV. That puts it in the same league as conventionally manufactured cemented carbide, just below superhard materials like sapphire and diamond.

What This Means for Manufacturing

The real win is material efficiency. Additive manufacturing deposits carbide only where the tool edge or feature actually needs it. For complex cutting tool geometries, that means a dramatic reduction in expensive raw material consumption. The process is not yet ready for high-volume production, but the research opens a clear path toward cost-effective, near-net-shape carbide tooling.

The study was led by assistant professor Keita Marumoto at Hiroshima University's Graduate School of Advanced Science and Engineering, together with Takashi Abe, Keigo Nagamori, Hiroshi Ichikawa, and Akio Nishiyama from Mitsubishi Materials, plus Motomichi Yamamoto from Hiroshima University. Results were published in the International Journal of Refractory Metals and Hard Materials.

Source: Hiroshima University research news and 3D Printing Industry