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Quick Drilling of Stainless Materials

Mikron Tool's CrazyDrill SST-Inox is a small drill for hole diameters from 0.3 mm (.012") up to 2 mm (.079") and for depths of 12 x d. The tool, with its corresponding tip geometry and a digressive spiral flute for good chip breaking and quick chip flushing, is specially designed for the difficult conditions of stainless materials.

Coolant ducts are integrated into the drill's shank. These are arranged regularly around the center and exit at the shank cone. The duct shape is designed to allow a large flow of coolant, even with low pressure, without weakening the stability of the tool. However, with smallest hole diameters (starting at 0.3 mm / .012") and a shank diameter of 3 mm (.118"), a coolant pressure of 15 bar (787 IPM) is still necessary in order to achieve a good cooling effect.

"Geometry and cooling allow this drill to operate with higher speeds and feeds in comparison to other products on the market," said a company spokesperson. "For example, drilling in stainless steel 316L (1.4435) with diameter 0.5 mm (.02 inch) in a depth of 6 mm (.236 inch) can be achieved with the following parameters: cutting speed 35 m/min, feed f 0.015 mm/U, first peck Q1 of 2xd, all subsequent pecks 1xd. Up until now only pecks of 1/4xd, max. of 1/2xd were possible."

Since not all users have spindles with through coolant but may still need to machine materials with poor heat conductivity, the R&D engineers at Mikron Tool have developed a second variation of the tool without coolant channels. The tools have the same geometry with its special tip cut for stainless materials and a digressive spiral flute.

"Contrary to the aforementioned `turbo execution,' these tools have to work with speeds and feeds as well as pecking depths reduced by approximately 30% in order to assure good tool life and process stability," said the spokesperson. "For both variants the following is valid: in order to avoid run-out of the bore, pre-machining with a pilot drill (also available from Mikron Tool) becomes necessary starting at 12xd."

The CrazyDrill Pilot SST-Inox pilot drill is a complement to the deep hole drill, which needs good guidance to achieve accurate positioning. This pilot drill also has coolant ducts that are integrated into the shank. Its digressive spiral flutes offer enhanced chip removal characteristics, producing short chips that are flushed away. "The diameters are ground to such precision that no step is visible from the pilot drill to the longer drill, which is a good reason to use both tools in combination," said the spokesperson. "Additionally, simultaneous with the pilot bore, a chamfer of 90° can be made at the entry of the bore, hence an additional chamfer tool is not needed." This tool can also be used as a short drill for depths of 3xd.

For more information contact:

Mikron Corp. Monroe

200 Main Street

Monroe, CT 06468


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