coolEXstep® - the patented combination of coolEX® and Xstep® tool system for machining centres

The coolEXstep® tool system (patent pending) is based on a combination of the coolEX® and Xstep® tool systems. This combination enables multi-expansion (2 or more honing stages in one tool) and is especially suitable for plateau honing: 

  • step-controlled pre-honing on the tolerance lower limit, for generating the cylindricity of the bore and achieving the Rk and Rvk surface values (corresponding to VOIL: oil capacity)
  • subsequent hydraulic finish or plateau honing for generation of the Rpk surface values

The coolEXstep® tool system facilitates conventional, mechanically controlled honing in a machining centre with a tension/compression rod available on the machine or with a tool-changeable U-axis (e.g., KomTronic® from KOMET). The machining is done with regular honing kinematics (expansion during machining), thus generating the classic cross hatch in the specified honing angle. The activation of the individual honing operations (pre-honing and finish honing) is done without interrupting the honing kinematics, thus permitting very short cycle times
Enormous advantages result during honing operation on the machining centre from the arrangement of both system parts (tool and workpiece) in fixed clamping:

  • only a small honing allowance is required, thus very short machining times
  • separate honing machines can be eliminated
  • highly scalable to fluctuations in production due to use in machining centres
  • no limitations compared to conventional honing with honing machines
  • Process control and availability of advanced measuring facilitate 100% testing of components
  • no additional costs for separate devices or articulation connections for the honing process required

Process control is integrated by the step control in a closed control loop and measurement of the part is done downstream outside of the machine main times.

Information for builders of machining centres

Prerequisites for the successful use of the technology:

  • pre-machining of the hole in the same fixture (no reclamping)
  • fine filtration of coolant depending on surface requirements (about 30-50µm or less)
  • positioning accuracy of the bore axis to the tool axis within 5μm (tool changer)
  • high axial acceleration at the stroke end positions depending on the diameter and required honing angle

Selection of projects on various machining centres from different machine manufacturers

Click here to find a selection of successful completed projects on various machining centres from different manufacturers.