Mikron Tool expands the successful CrazyMill Cool P&S milling cutter family, developed for roughing and finishing operations, with a toric version. The new tool combines the strengths of milling and drilling and is designed for machining stainless steel, titanium, CoCr alloys and superalloys. Like its cylindrical predecessors, this drill/milling cutter can plunge perpendicularly into the material up to 1 x d and then continue machining laterally. It mills slots and pockets in the tightest of spaces - with no problem at all. When a corner radius is required, it is in its element. The right tool for each shape.

It is available in the diameter range of 1 to 8 mm /.039" to .315" in the following two versions:

Typ A: 2.5 x d CrazyMill Cool P&S Corner Radius, cutting length 2.5 x d, Z3

Typ C: 5 x d CrazyMill Cool P&S Corner Radius, cutting length 2.0 x d, Z3

A unique tool for numerous applications: Milling of holes, ramps, pockets, grooves and sides. Seemingly without resistance, the milling cutter plunges into the materials that are difficult to machine. It cuts powerfully with high precision, stability and excellent cutting parameters, even into the solid - effortlessly. Behind this perfection is a sophisticated technology composed of a multitude of factors.

A geometry thought out in every detail

A new cutting-edge geometry enables process-safe, low-vibration plunging (drilling). The first task was to stabilize the center of the cutting edge, which must be sharp and robust at the same time. This caused quite a few headaches. An ingenious solution was found that reduces the risk of cutting-edge breakout while at the same time reducing the cutting force. The extra-wide chip space in the head section allows chips to be collected during the drilling process and evacuated laterally into the likewise extended flutes. Adjusted rake and clearance angles as well as stable cutting corners assure smooth wall finish and avoid breaking out of cutting edges due to vibration, which is one of the central difficulties when "drilling" with a milling cutter.

Keeping cool is the key

But that's not all. The cooling channels integrated in the shank direct the coolant straight to the cutting edges and guarantee constant and targeted cooling in every position. The cooled cutting edges allow high speed and feed rates. In addition, thanks to the massive cooling jet, the chips are continuously flushed out of the milling zone. This prevents the chips from remaining in the recess and being repeatedly chipped, which causes damage to the milling cutter and the milled surface. The result is long tool life and excellent surface quality.

Attention to the choice of materials!

For this milling cutter, our production specialists use a specially developed ultra-fine grain carbide, which is characterized by high toughness and meets all requirements in terms of mechanical properties. Thus, the robust carbide shank supports stable and vibration-free milling. Highest precision and surface quality are guaranteed.

The high-performance SNP coating not only increases surface hardness, but also enhances wear resistance and heat resistance. The sliding resistance during chip removal is also reduced to prevent the cutting-edge buildup. The result is optimum chip evacuation and a long tool life.

High performance becomes a matter of course

The combination of these factors enables impressive chip removal rates, which are possible thanks to the high cutting and feed rates and an infeed (ae) of 1 x d each. The drill milling cutter impresses with its long tool life and excellent surface quality, and this starting from a one-millimeter diameter. Here a few facts compared to commercially available tools:

• Up to 5 x higher material removal rate
• Up to 5 x less machining time
• Perfectly controlled chip removal
• Excellent surface quality Ra ≤ 0,5 µm (20 in µ)

It's surprising how much technology and power can be packed into such a small tool.

Convincing in the field as well

In an application of the aerospace industry, the toric high-performance milling cutter from Mikron Tool was convincing in initial comparative tests compared to a commercially available corner radius milling cutter. The task was to significantly reduce the machining time during roughing and finishing of 14 grooves with corner radius of a turbine rotor made from stainless steel (material X12Cr13/1.4006). The dimensions of the grooves are:

T = 10 mm (.394"); L = 20 mm (.787") und B = 3,8 mm (.150")

A CrazyMill P&S Corner Radius [diameter 3.7 mm (.146") 5 x d type C] was used. In the roughing process, the tool cuts directly into the solid with an axial depth of cut ap of 1.85 mm (.073") at a feed rate of 0.026 mm (.0110") per revolution per tooth and the material is removed at a cutting speed of 190m/min (623 SFM). In the final finishing process, the final slot dimension is achieved with excellent surface quality. The squareness of the sides is guaranteed.

Overall, the Mikron Tool cutter achieves an excellent time chip volume during the roughing process of 9.4 cm3/min (.00248 gpm) compared to 0.5 cm3/min (.00032 gpm) of a conventional cutter. And that makes all the difference: The machining time, including finishing for the entire workpiece, is just 2 min 5 s compared to 26 min 6 s using a commercially available milling cutter. Mikron Tool is 24 minutes faster.

Alberto Gotti, R&D manager at Mikron Tool, states: "Of course, the tool is crucial, but the interaction of all other elements must be equally correct. Machine, tool, milling strategy, clamping and coolant. If this is the case, the kind of performance shown in this example is achievable. The advantages for the manufacturer are impressive: a 19-fold increase in metal removal rate and a 92% reduction in machining time compared to a conventional corner radius milling cutter with external cooling." Another Crazy Tool from Mikron Tool, simply amazing.