Cutting Tools Additive manufacturing: competitiveness and economy

Editor: Barbara Schulz

Germany - Dr. Dirk Sellmer, head of research and development at Mapal, discusses innovation and how additive strategies are shifting design principles towards new product solutions.

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The cooling concept with spiral ducts improves cooling performance.
The cooling concept with spiral ducts improves cooling performance.
(Source: Mapal)

ETMM: You call the new QTD insert drill a world's first. What makes it so innovative?

Dr. Sellmer: The innovation is based on two aspects: On one hand, the use of additive manufacturing technology for high-precision drills, and on the other an innovative cooling concept.

ETMM: What does that mean specifically?

Dr. Sellmer: We can use a spiral cooling system with laser-melted insert drill. That improves the cooling performance thanks to the higher coolant flow. And we succeeded in offering smaller drills, i.e. expanding the product range downwards.

ETMM: Please describe this cooling concept.

Dr. Sellmer: The changed cooling concept improves the cooling performance. Compared with the previous central coolant supply with a Y diversion, a spiral coolant supply increases coolant flow by 100%. This also increases the core stability via coolant channels which run parallel to the chip flutes. As part of the development, we designed new coolant channel profiles. They deviate from the usual circular form with a slightly triangular shape. In tests, we found that choosing a cross section of this size increases the flow quantity by about 30%. The volume flow in the drill is 1.6 to 2 times greater than conventionally manufactured tools. The ability to offer drills with smaller diameters was almost a side effect.

ETMM: What are the main requirements for a precision drill?

Dr. Sellmer: The ideal drill is very hard outside and somewhat flexible inside. Laser melting makes it possible to generate selective thicknesses and then harden the surface with heat treatment and to create a cellular or honeycomb structure inside if necessary. That makes ductile lightweight solutions and e-modules possible, which we cannot produce conventionally. In detail, manufacturing based on the hull/core principle is immensely important for us. First, the core of an insert drill is built with the cooling system, which is added to the conventional shaft. In a second additive run, the outer hull is built up with higher densities. This is almost the perfect drill – hard on the outside and soft on the inside. We combine ductility with high tensile strength and hardness. Of course, the finished component is then hardened, i.e. heat-treated. We use a vacuum hardening process for this.