Available in the UK from Floyd Automatic Tooling, the latest addition to the CrazyDrill range from Mikron Tool will be introduced at the EMO exhibition in Hanover from the 16th to 21st September. In Hall 3 on booth H11, the characteristics of the small drill CrazyDrill Cool SST-Inox will be demonstrated for show visitors to absorb.
Small, deep and fast, certainly characterizes the new CrazyDrill Cool SST-Inox that incorporates internal coolant ducts and an innovative geometry and coating technology for the machining of stainless steels, nickel based super alloys and CrCo-alloys. With process stability guaranteed, the new drill that will be available from Baldock based Floyd Automatic has been significantly simplified and stabilised for the processing of small diameters as well as deep bores.
The range includes through coolant drills in six different working lengths that include 6XD, 10XD, 15XD, 20XD, 30XD and even 40XD. For machining holes between Ø1mm – Ø2mm, the max depth available is 20XD. From Ø2mm the entire range is available up to Ø6mm. In addition, there is a short pilot drill for a max bore depth of 3XD.
Why a newly designed drill?
Whilst drills with spiral coolant ducts are available already in the small diameter ranges, many of these drills get into trouble with tough-elastic materials or with the poor heat conductivity of super alloys. Here the cooling through ‘classic’ round ducts is insufficient, even with high pressure. Premature edge chipping, packing of chips, build-up of the flutes are all symptoms that prevent process stable drilling.
This is important for industries that produce products from valuable materials and even more valuable finished parts. Markus Schnyder, head of Mikron Tool International and one of the initiators of the new tool, knows all about the problem: “For many years, our customers have been reaching the limits when drilling stainless steel. The process was not stable and it was too slow; thus, machining became extremely expensive. We wanted to find a solution. The development took us several years and we have depended on a close cooperation with our partners and this has included the use of the right blank material and a truly efficient coating.“
A new geometry provides a chip-breaking effect at the front and short and curved chips are the result. In the back, an open flute profile facilitates the perfect evacuation of micro-chips. There is a variant for long drills as they incorporate an open profile and polished flutes to help the easy evacuation of chips from the bore.
Performance and process stability is mainly given by the cooling of the tool with two spiral internal coolant ducts up to the drill tip. This guarantees a constant and massive coolant flow during the entire drilling process and this is an important factor to prevent overheating of the tool, even with high cutting speeds.
The coolant ducts have the largest possible diameter and are tear drop shaped. These ducts are located in an area with little stress and therefore the stability of the tools is not jeopardised. Comparing to the conventional round diameter, these ducts afford a 4-time higher coolant flow. At diameters under 3mm, a power chamber in the shaft reduces the length of the ducts and provides higher coolant pressure.
The advantage of the efficient supply of coolant to the drill tip increases tool life as overheating of the cutting edge is avoided right from the beginning. Combined with the innovative tip geometry, the cooling helps to break and flush out the chips from the flutes. All these characteristics make it possible to work with higher cutting parameters and to drill in one single stroke.
Starting with a drill for a depth of 10XD, new and longer versions were introduced until the 30XD and 40XD were presented at the Prodex 2019 show in Basle. When drilling starting at 15XD, it helps to have a short pilot operation to reach a high positioning accuracy. It also helps to guide the subsequent long drill and guarantees good straightness. So that this centring fits perfectly, Mikron Tool developed the complimentary pilot drill whose tolerances are precisely tuned to the long drills. If requested, the tool can also simultaneously do a chamfer of 90 degrees. It also has the internal coolant to the tip and is available in diameters from 1 to 6mm. For further information, please visit the Mikron booth at EMO or alternately call small tooling specialists Floyd Automatic Tooling for further details.
