Sumitomo's Detachable Head SMD Multi-Drill Provides Up To 12:1 Depth-To-Diameter Ratio

A factor of Sumitomo Electric Hardmetal’s continuous development programme is the ability to enable deep holes to be drilled between 12 mm and 42.5 mm diameter with up to 12:1 depth-to-diameter ratio. The new drill range has the advantage of a detachable replacement head that brings new orders of flexibility and tool inventory reduction by enabling up to five sizes of drill head to be accommodated by a single drill body.

SMD Multi-Drill heads can also be selected to suit the machine type and power available plus the material being processed. In addition, the new Sumitomo drill programme is able to achieve a level of hole tolerance normally only met by adding the reaming process with the added bonus of maintaining improved hole consistency and increased in-cut life. The drill head inserts can also be reground which increases overall useful life and furthers economic returns.

The complete Multi-Drill SMD programme covers the SMDH replaceable head type drill holder, MTL Type drill head for high efficiency drilling of general steels and MEL for soft steel, grey cast iron, exotic metals and low rigidity setups plus MB for structural steel and single layer laminates. There is a large range of diameters available between 12 mm and 42.5 mm which can be specified in Sh ort Series (3 x D), Long Series (5 x D), Deep Hole Series (8 x D) and Ultra Deep Hole Series (12.1 x D) giving effective drilling depths up to 300 mm.

Due to the toughened body and balanced design, and the use of a tungsten carbide substrate drill head with ultra-hard and smooth coating, tool vibration and noise generated under cutting conditions are reduced. Optimised heat dissipation is achieved via precisely positioned through- the-tool coolant holes and the high rigidity clamping system ensures edge security and repeatable hole size for the exchangeable drilling heads which are bolted to the body against fixed precision ground radial serrations.

There are two variants of drill head with ultra-hard and smooth PVD coating, having improved peeling and chipping resistance. MTL ACX70 is for general purpose drilling applications and MEL ACX80 where the design of the drill head will provide higher performance on lower powered machine spindles. This is achieved due to the decrease in cutting force (thrust) requirement that is some 25 per cent lower, making this variant of the drill ideal for stainless steel or more difficult cutting conditions.

The SMDT-MEL drill head has a light edge preparation and is coated with Sumitomo’s latest ACX80 ideal for soft steel where cutting speeds between 80 and 130 m/min and feed rates between 0.15 and 0.4 mm/rev can be maintained. Stainless steel and super alloys can be drilled between 50 and 90 m/min with feed rates between 0.1 to 0.25 mm/rev and grey cast iron 50 to 100 m/min with 0.2 to 0.45 mm/rev feed.

Meanwhile, the SMDT-MTL drill head type has a standard edge preparation and is coated with ACX70 for general carbon steel applications with cutting speeds between 80 and 130 m/min and feed rates of 0.15 to 0.35 mm/rev. Hardened steel (HRC45) can be drilled between 50 and 90 m/min with feed rates of 0.1 to 0.25 mm/rev. Nodular cast iron components can be processed at speeds of 70 to 110 m/min and feed rates between 0.15 to 0.4 mm/rev.

The special MB designation of drill head is for use on applications involving structural steel, rolled steels and single layer laminate material This drill head has a robust substrate with a reinforced edge treatment, a 150 deg point angle and highly polished wider J-grooved flute surfaces.