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Deep Drilling in Small Dimensions

CrazyDrill Flex SST-Inox complements the CrazyDrill Flex family, a series of deep hole drills available for machining steel and titanium. Now Mikron Tool has offered a solution also for stainless and heat resistant materials, when working on small and deep holes. Small and deep means in this case diameters starting at 0.3 mm (.012") and drilling depths of 30 x d or even 50 x d.

The geometry is partially based on the same principles as the earlier siblings of this line: the spiral flute has a length of 10 x d, the full drilling depth is reached due to a straight elongated neck. This middle piece is designed for stability necessary for machining in such small diameters and into these extreme depths. The cooling concept is also the same technology as the earlier Mikron Tool (CrazyDrill Flex) products; three coolant ducts which go through the shank and exit at the cone. The shape of the ducts is defined in a way that the stability of the tool is not jeopardized, even in small shank diameters. Even in the smallest bore diameters a coolant pressure of 15 bar (217 PSI) is sufficient to achieve an efficient cooling effect. Thus the cutting edges receive sufficient coolant for each peck to avoid overheating and guarantee good flushing of chips.

The difference to other Flex-products lies in the geometry. Like other small drills for stainless materials, the CrazyDrill Flex SST-Inox has a digressive flute which assures a good chip breaking and quick flushing of chips.

Associated with this is a drilling process with continuous chip flushing. As an example, in austenitic steel even with smallest diameters of 0.3 mm (.012") one can work with a speed of Vc=20-30 m/min (787 IPM) and a feed of up to two hundredth millimeters (.0008") per turn. After a first peck to a depth of 2 to 3 x d the following pecks should be kept at approx. 0.5 x d. With this strategy a much shorter machining time is reached, compared to other methods like deephole-drilling, erosion or laser piercing. "Important: for holes with high positioning accuracy a preliminary Pilot bore is essential," said a company spokesperson.

First successes of these innovative tools were achieved in different industry segments such as the machining of medical instruments, suction tubes for ocular surgery, watch cases and bracelets and injection nozzles for fuel injection in the automotive field.

CrazyDrill Pilot SST-Inox is a deephole-drill to achieve accurate positioning. This Pilot drill also has coolant ducts which are integrated into the shank. Equally this tool has chip removal characteristics, producing short chips which are flushed reliably and safely. All dimensions are in tune with the following drill, the diameters are ground to such precision so that no step is visible from the pilot drill to the longer drill. Mikron suggests using both tools in combination. Further pluses: simultaneous with the pilot bore a chamfer of 90° can be made at the entry of the bore. Furthermore this tool and also be used as a short drill for depths of 3 x d.

For more information contact:

Oskar Weder

Mikron Corp. Monroe

200 Main Street

Monroe, CT 06468


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