To detect work cutting resistance accurately by a method in which the surface temperature of a blade or the temperature of a work close to a cutting position during cutting, and a value corresponding to the work cutting resistance is obtained based on the degree of the increase in detected temperature from the start of cutting.
In an operation controller 40, when a work having reached a position immediately before the start of cutting, a cutting resistance operation means 41 stores the surface temperature T of a blade, which is read by a temperature sensor 20, as a temperature before the start of cutting. The operation means 41 continuously operates the difference between the surface temperature of the blade and the temperature before the start of cutting and obtains the cutting resistance Fz by multiplying the difference by a coefficient (k). A cutting feed velocity adjusting means 42 compares the calculated cutting resistance Fz with a preset allowable resistance and controls the cutting feed velocity by a cutting feed motor 13 to keep the former not exceeding the latter.
TADERA YOSHIHIRO
HAMAZAKI TATSUMI
