The Klein Centre Grinding Machines are the market-leading machines for highest precision in run-out. Our machines can machine centre bores which are often out-of-round, oval, scaled and out-of-alignment after hardening.
As never before, there is an ever-increasing demand for higher workpiece accuracies. An amount of workpieces can only be produced using the current machine parks after undergoing very exacting set-up procedures and thus long change-over times.
Together with the dead centre point of the external grinder the centre hole forms a plain bearing. For optimum results the taper of the centre hole must be round and co-axial with the centre hole at the other end of the workpiece.
After hardening the workpiece, its centre holes are neither round nor oval, are out of alignment, covered with scale and too rough. To obtain good results rapidly in circular grinding - essential for productivity - the centre hole must be ground by a Klein Centre Hole Grinder before they are mounted on the external grinder.
Centre Grinding Machine ZSS
Centre Grinding Machine ZSU
Grinding Pins, Dressing Wheels & more
Why centre grinding?
because a high roundness error in the centre means that the position of the workpiece on the dead centre is not defined during machining. This is reflected in at least four effects:
- The workpiece spins on the centre within its roundness error. The roundness error is thus reflected on the outside diameter / runout.
- The ratio between permissible tolerance and diffusion increases. Hence the process capability and reproducibility decreases.
- For the next quality assurance, measurement is made at a different position in the centre between centres, the position is most likely not the same as in the cylindrical grinding process.
- Thin-walled parts can be deformed if the contact pressure of the centres in the centre is high. In this case, the roundness error of the centre is reproduced on the outside. If cylindrical grinding is then performed, the part is only round initially. If the centres are then moved out of the workpiece, the part relaxes and the non-circular-roundness reappears in the centre.