Mollart Engineering’s spray mist system keeps gundrill cool down deep holes
Mollart Engineering has developed a low-cost, spray mist coolant system that can be used on deep hole drilling applications and retrofitted to any machine tool. It is fed from a standard compressed air line at pressures up to 10 bar and is usable on holes between 5 and 25 mm diameter by up to 2 m deep.
Air passing through the spray mist system absorbs precisely timed pulsed jets of vegetable-based cutting oil from an integrated reservoir. The efficiency of the system is easily demonstrated, says Mollart, as if the gundrill is removed from the component it will be found to be immediately cool to the touch.
The oil lubricates both the tip of the drill and its guide/support pads which prevents any seizure occurring in the hole. Meanwhile the air purge effectively cools the cutting edges of the tool and its guide pads. The pressure of the air behind the chipped swarf forces it back along the vee groove (flute) between the outside diameter of the gundrill tube and the drilled hole to clear the cutting zone.
