October 18, 2012
Dealing with thermal deformation can be a time-consuming activity for the machine operator. When Okuma engineers were struggling to find a way to control the natural tendency of machine components to expand during machining operations, they had an epiphany, according to Okuma’s Senda Harumitsu. “We were doing thermal analysis day after day when a new idea emerged: Even if we go all out and cool or insulate the machine room or the heat-generating parts as we do the spindle, it won’t work. It would drive up costs too high and no one would use it. What we need is high-accuracy machining merged with thermal-deformation control.”
The result was a three-pronged approach that has successfully addressed this issue: (1) Simple machine construction that allows heat to transmit evenly, which makes expansion and contraction highly predictable; (2) a thermally symmetrical, double-column, box-build design plus strategic placement of front covers and the rear control cabinet for even heat distribution; (3) Highly Accurate Compensation Technology, managed by the Okuma-developed THINC OSP control system that responds to changes in room temperature, and heat produced by frequent spindle speed changes and dry cutting.
Okuma machines equipped with the Thermal Friendly Concept accurately control deformation due to temperature variations, in part, through a Thermo Active Stabilizer – Spindle (TAS-S). Because thermal deformation affects the spindle when it is turning and at rest, TAS-S monitors spindle rotation, spindle speed changes and spindle stoppage as well as spindle temperature, to control thermal spindle deformation regardless of the number of changes in spindle speed during an operation.
Another significant component is Thermo Active Stabilizer – Construction (TAS-C), using strategically placed sensors to monitor expanding or contracting machine components and axis position. These sensors feed data to the controller which, in turn, predicts and accurately controls thermal deformation.
Gosiger technical specialists can explain more details of how the Thermal Friendly Concept and other Intelligent Technology can help reduce operating costs and improve productivity.