Product category:
CNC turning centres, mill/turning, multi-tasking centres, horizontal and VTLs.
News Release from: Okuma Europe | Subject: CNC lathes, machining centres, TFC
Edited by the Manufacturingtalk Editorial
Team on 03 September 2007
Lathes and machining centres cut
precisely
A new generation of thermally controlled lathes and machining centres are designed to cut metal day and night and reliably to within few micron tolerance.
Today's target for European machine shops is preferably the unmanned operation of automated lathes and machining centre cells achieving optimal efficiency as well as a constant machining quality better than 0,01mm tolerances throughout three shift operation A fully air-conditioned machine shop is technically possible to reliably maintain such goals, but is for many smaller companies out of reach, cost-wise
This article was originally published on Manufacturingtalk on 26 Jan 2006 at 8.00am (UK)
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Axis and spindle drives produce plenty of heat.
During cutting, a part of the energy gets into the tools and workpieces.
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Furthermore, the temperature of the machine shop or production line is rarely constant.
In today's automated and unmanned three-shift operations the thermal stability of the machines itself fast becomes a deciding factor.
Thermal machine deviation results in process inaccuracies and can be adjusted by the operator, by more measuring cycles only consume manpower and reduce productivity.
TFC was introduced in 2003 onto the Japanese market after it had been awarded with an innovation prize in late 2002.
Since then, construction philosophy, sensor and control techniques - together with software - have been improved step by step.
Okuma has since equipped most of its new machine tools with FTC.
It ensures operators automatic constantly high machining accuracy as well as high productivity - even under large fluctuations in surrounding temperature.
TFC starts already with the machine design.
A thermal optimised construction is leading to a strictly symmetric thermal expansion of the whole machine.
While subject to temperature changes, the natural machine distortion becomes a predictable factor.
This is important.
The thermal changes on the machine body become calculable by a symmetric growth of the machine.
Within the TFC Okuma engineers also pay attention to a uniform temperature distribution and a good 'insulating' of the cast iron structure.
For example, to keep the influence of the surrounding temperature to the machine minimum, the machine covers are assembled with distance to the cast iron body and the heat exchange is supported by ventilators.
Other items such as control cabinets, are placed outside of the machine cover.
In spite of all the constructive measurements to minimise heat influences within the machine itself due to cutting process itself, every machine becomes subject also to inevitable outside thermal influences of the shop floor.
With the TFC up to one dozen sensors placed in the spindles (TAS-S) and in the cast construction (TAS-C) constantly determine the actual temperature.
The Okuma OSP-P200 control will compensate temperature influences in real-time.
Corrections take place in 0,1 micron steps automatically in real-time.
The process runs unnoticed by the operator in the background simultaneous to the machining and has no influence on machining time of the workpieces.
The result of TFC is sensational: According to Okuma a reliable machining accuracy in a normal workshop with changing outside temperature in continuous three shift operation can be reached, which is, depending on machine model, between 4-8 micron - measured at the tool tip.
Currently, Okuma machines of the model range MA-H and MB-V as well as the multitasking machines, Multus and MacTurn, and lathes of the LT-Series are equipped with TFC.
The Thermo Friendly Concept ensures users significant competitive advantages, since the constant high machining accuracy can be reached without additional measuring and process readjustments by the operator.
This will dramatically improve the unmanned automation, which today is a final factor for European companies to survive in the global race for lowest cost per piece.
* Okuma at EMO 2007, Hannover, Germany, September 17-22, Hall 17, Stand C18.
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