A milling cutter, a drill, an ultimate machining strategy

Mikron Tool offers with the Hexalobe-program a turn key solution for machining medical screws, which is not only based on the cutting tools, but also delivers a package with the best machining strategy and the right parameters. 

The most efficient approach to machining „TORX®“-screws turned out to be the one which could do it with a minimum of different tools: pre-hole drilling with 120° chamfer – milling the hex lobe – subsequent deburring. The time-consuming milling process can be done with helical interpolation (with max. pitch 0.8 x d) or with side milling (with stepover max 0.5 x d).
When machining a screw made of CoCr alloy, a material that is difficult to machine, it is necessary to pre-drill the lobe with our CrazyDrill SST-Inox IK / IN standard drill specially developed for this material.

The four operations (pre-hole drilling – chamfering – milling – deburring) are completed in three operations with two tools.

• First the combined drill CrazyDrill Hexalobe does the center bore and a chamfer and this right away with an excellent surface quality (Ra 0.2µm, Rz 0.8 µm). The CrazyDrill Hexalobe Flat (flat drill bit) is used when a drill point angle does not match the design requirements of the component.
  After the milling of the final shape, this tool will be used once again for deburring → a nearly burr-free surface and superior surface quality are achieved.
• The milling cutter CrazyMill Hexalobe with 3 or 4 flutes (depending on diameter) is available in two standard lengths. Its high stiffness allows machining with high feeds and massive stepover, while still guaranteeing the necessary hex lobular profile accuracy. The surface quality is given by the special geometry which also affords working with high stepover so that the operation can be completed with few steps.

Two respectively three specific geometries have been developed for CrazyMill Hexalobe and CrazyDrill Hexalobe to guarantee a perfect machining of the most used screw materials:

• Titanium
• Stainless Steel
• Cobalt Chrome

Therefore, when milling, a vibration free helical interpolation and, when drilling, good chip breaking and quick chip evacuation are guaranteed.

A specially developed micro-grain carbide with high stiffness and edge chipping resistance meets all requirements in terms of mechanical properties (as high toughness or low thermal conductivity) of Titanium, Stainless Steel and Chrome Cobalt.  

The high-performance coating eXedur SNP is heat- and wear-resistant, prevents buildup edges and promotes uniform chip flushing. The result is long tool life. As the coating is chrome free, a cross contamination on medical part is avoided.

Mikron Tool offers CrazyMill and CrazyDrill Hexalobe also in customized versions:

• Milling cutter with different diameters, lengths and flutes to the standard program
• Combined drill with different diameters, drilling depths or chamfers   

Do you need more information about our possibilities? Contact us here.