Drilling in stainless steel with 4 times more cooling
- March 5, 2017
Mikron Corp. has launched the CrazyDrill Cool SST-Inox, a small drill for stainless steels in the 1 to 6 mm (.039 to .236 in.) diameter range that in a single step can drill a full depth of 10 times diameter without chip flushing, says the company.
Alberto Gotti, head of research at Mikron Tool, says no other tool can keep up with these cutting parameters. This is possible on one side thanks to an innovative geometry with chip breaking effect and flute profile, which facilitates the flushing out of microchips from the spiral flutes.
The drill features a new coating and the performance and process stability of the tool is based by its cooling characteristic: two helicoidal internal coolant channels which go up to the drill tip. These guarantee constant cooling during the entire drilling operation.
The coolant channels in its cross section resemble the shape of a drop and facilitate up to four times more coolant flow compared to the todays common circular cross section channels. With small drill diameters under 3 mm (.118 in.), a “power chamber” provides a sufficient coolant flow: a hollow section in the shank absorbs higher quantities of coolant to be fed into the two coolant ducts.
The advantage of this efficient cooling which goes up to the tip of the tool, is definitely a higher tool life because the overheating of the cutting edges is avoided right from the beginning. Combined with the best suitable geometry this cooling helps that the chips are broken easier and can be flushed out of the spiral flutes more easily. All these factors afford a machining process with higher cutting parameters (speeds and feed).
The self-centering characteristics of CrazyDrill Cool SST-Inox make a pilot or centering operations superfluous. Only if very high positioning accuracy is needed or when one wants to have a chamfer (e.g. for subsequent tapping operation) the use of a pilot drill CrazyDrill Coolpilot is a valid consideration.
CrazyDrill Coolpilot complements the CrazyDrill Cool SST-Inox. This pilot drill also has the helicoidal internal coolant ducts all the way up to the tip and is equally available in the diameter range of 1 to 6 mm (.039 to .236 in.).
Note that the tolerances are conceived in a way so that they match exactly the ones of the long drill which, of course, prevents visible steps in the bore. Using the Pilot Drill gives a high positioning accuracy for the subsequent drilling operation and if desired a counter bore of 90 degrees can also be done. It finds also a perfect application as an autonomous, precision short drill for depths of maximum three times diameter.