MODERNIZATION OF COOLING UNITS FOR TOOLS AND WORKPIECES IN MACHINE TOOLS

This paper presents some specific issues of the design and manufacturing of cooling units for tools and workpieces in machine tools during the cutting process. Besides the general theoretical aspects, adaptable to most of the existing machine tools, the paper lays particular emphasis on the aspects specific to modern machine tools (CNC ones), on which the machining operations are performed with high speed cutting, in the case of serial or mass production. Also this paper presents some of the simulations made in the design phase of the unit. Using these simulations one can check the behaviour of the unit before it being made, avoiding choosing unapproved parts. The unit designed and manufactured is intended for a milling machining centre with horizontal spindle, type MAXIM 11 and allows the cooling of the tool and workpiece by programmed control on the outside of the tool but, where appropriate, through the inside of the tool. The unit also allows the cooling with air or the blowing of the tool-holder taper during the automatic changing of this one from the tool-magazine. Now the unit manufactured for milling machining centre with horizontal spindle of MAXIM 11 type is functional and did not raise operating or maintenance problems for more than two years. Cooling on the outside of the tool is done with the machine working at a maximum pressure of 10 bar. Cooling onside the inside of the tool is done with the machine working at a pressure of 70-75 bar, but during commissioning it has also been tested at 90 bar.