coolEX® - hydraulic honing in a cnc machining centre (VMC/HMC/CNC)

The coolEX® honing tool technology integrates conventional hydraulically controlled honing into a cnc controlled machining centre with no technical modifications, using regular honing kinematics (expansion during machining), thus generating the classical cross hatch at the specified honing angle.

Enormous advantages result during honing on the machining centre from the arrangement possibility of both system parts (tool and workpiece) in fixed clamping:

  • only a small honing allowance is required, thus very short machining times
  • the axis placement of the bore in pre-machining for honing (e.g., fine spindling) permits the elimination of so-called "position honing"
  • separate honing machines can be eliminated
  • highly scalable to fluctuations in production due to use in machining centres
  • no limitations compared to hydraulic 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

coolEX®2 - cnc controlled hydraulic double expansion

The coolEX®2 tool system facilitates 2-stage honing with double expansion (prehoning and finish honing) in a tool without changing to another honing tool. This system is especially suited for plateau honing of grey cast iron cylinder bores

coolEX®LM - hydraulic expansion and bore size controlled by in-process air gauges

The coolex®LM honing tools system integrates an air gauge system into the coolEX® base system for continuous bore sizing during the honing operation. For lossless air supply to the nozzles a DIAHON air distributer on the tools or a machine side available air supply can be used (e.g. interfaces in the HSK-connector).
The evaluation of the measured air flow provides information on the bore size and thus can be used as critera to control the cnc honing process. This system is available both as pre-and post-measurement or as in-process measurement during the honing operation.

coolEX®TB - honing on BTA deep bore drilling machines

The coolEX®TB tool system is a refinement of the coolEX® basic system and was developed for honing on BTA deep bore drilling machines. This system is used to integrate rework (removing rifling or slight dimension corrections) on BTA deep bore drilling machines after drilling. For this the drilling head must only be replaced by the honing tool, thus avoiding taking the part to a separate honing machine.

Technical details - coolEX®

coolEX® honing tools use cooling/lubrication agents both for expansion of the cutting bar and for process cooling directly at the point of contact between the honing stone and bore, thus ensuring optimum cooling and chip removal. The required parameters (such as roughness, cycle time or cylindricity) can be adapted to specifications by adjusting the coolant pressure (throttles in the tool or controlled via the machine) and the specifications of the honing stone.

Depending on the requirements and hole geometry, coolEX® honing tools can be used in different variants:

  • blind hole or passage tools
  • Tool with double expansion (coolEX®2)
  • mounting tools with connecting rod

The use of in-process air measuring devices, for example, with an interface to evaluation systems and feedback into the controls of the processing machine, enables process control identical to that of conventional honing machines.

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.

Verdichtergehäuse - 2-stufige Plateau-Honbearbeitung

Honen von Verdichter-Gehäusen mit einer zweistufigen Plateau-Honoperation mit coolEX®-Honwerkzeugen.

Bauteil: Zylinder-Kurbel-Gehäuse
Durchmesser: 125mm
Material: GG25
Maschinenhersteller: Heller
Maschine: H5000
Aufnahme: DAH115/HSK-A100

Further application examples with coolEX® honing technology

Over 660mm honing length on a diameter 49mm in a Heller MCH-450 machining centre

With the coolEX® tool technology, honing on machining centres proves itself as a highly efficient method for the production of larger grey cast iron parts. The customer geometrically requirements (cylindricity < 10μm) and surface roughness(Ra<0.1μm) were achieved by a 2-stage coolEX® honing process.


Connecting rod, large eye

One-step coolEX® honing operation - connecting rod, large eye, process control according to time or vi

  • Part: Connecting rod
  • Diameter: 51mm
  • Material: 34CrNiMo6
  • Machine manufacturer: MAKINO
  • Machine: a61NX
  • Holding fixture: HSK-C63

The task was successfully completed using the since 2008 proven coolEX® Honing tool technology.

Plateau honing of the cylinder bore

2-stage coolEX® honing process, plateau honing of the cylinder bore in cylinder

  • Part: Cylinder crankcases
  • Diameter: 73.40mm
  • Material: GG25
  • Machine manufacturer: Hüller-Hille
  • Machine: NBH650
  • Holding fixture: HSK-A100

The task was successfully completed using the since 2008 proven coolEX® Honing tool technology.

Cylinder crankcase - Grey cast iron GG25, plateau honed

Honing of cylinder crankcases with a two-stage plateau honing operation with coolEX® honing tools:

  • Part: Cylinder crankcases
  • Diameter: 95mm
  • Material: GG25
  • Machine manufacturer: Heller
  • Machine: MCH 250
  • Holding fixture: DAH115/HSK-A100

The task was successfully completed using the since 2008 proven coolEX® Honing tool technology.