Abstract: After a thermal displacement correcting program has started, a temperature is measured with a temperature sensor in S1, then when a rotational speed of a spindle is changed during the measurement (S2), a counter starts (S3). Then in S4, from a preset relationship between the rotational speed of the spindle and a setting-equivalent heat value, a correction factor that is a difference in setting-equivalent heat value between before and after the change in rotational speed of the spindle is calculated. Subsequently, in S5, a temperature-equivalent heat value is calculated, and then in S6, a compensation amount is calculated from the correction factor and a time elapsed after the change in rotational speed of the spindle. In S7, an equivalent heat value for compensating a dead time is obtained based on the sum of them S8, an estimated calculation for thermal displacement conversion is performed, and a correction process by an NC unit is performed in S9.

Abstract: After a thermal displacement correcting program has started, a temperature is measured with a temperature sensor in S1, then when a rotational speed of a spindle is changed during the measurement (S2), a counter starts (S3). Then in S4, from a preset relationship between the rotational speed of the spindle and a setting-equivalent heat value, a correction factor that is a difference in setting-equivalent heat value between before and after the change in rotational speed of the spindle is calculated. Subsequently, in S5, a temperature-equivalent heat value is calculated, and then in S6, a compensation amount is calculated from the correction factor and a time elapsed after the change in rotational speed of the spindle. In S7, an equivalent heat value for compensating a dead time is obtained based on the sum of them S8, an estimated calculation for thermal displacement conversion is performed, and a correction process by an NC unit is performed in S9.

Abstract: A method for estimating the thermal displacement of a rotatable component of a machine tool is provided which includes the steps of: (A) generating a signal representative of the temperature of at least one rotatable component of a machine tool, the component being rotatable having a variable rotational speed and a variable temperature; (B) converting the signal representative of the temperature into a numerical value; and (C) estimating the thermal displacement of the rotatable component based on the numerical value using an operational expression. In this method, the operational expression includes a coefficient which is a function (f(n)) that changes with time or the number(n) of compensation operations performed, with the function (f(n)) determined by a relational expression T(N)) relating the time constant (T .delta.) of the thermal displacement and the rotational speed (N) of the rotatable component.

Abstract: There is provided a method for estimating the thermal displacement of a component of a machine tool comprising the steps of detecting the temperature of at lease one rotatable component of a machine tool having a variable rotational speed and a variable temperature; converting the detected temperature into a numerical value; and estimating the thermal displacement of the component based on the numerical value using an operational expression which includes a time-varying coefficient.

Abstract: A temperature measuring device measures the temperature of a main shaft as a numerical value based on the outputs from temperature sensors. A temperature recorder stores the value as time series data. When the heat-induced displacement of the main shaft is in a stationary state, a heat-induced displacement estimate computing unit estimates the displacement based on the instantaneous temperature measurement. When the displacement is in a transient state due to a change in the rotation speed of the main shaft, the computing unit estimates the heat-induced displacement of the main shaft by multiplying the elapsed time from the beginning of the transient state by the ratio of the heat-induced displacement time constant to the temperature time constant and estimating the heat-induced displacement based on the time series data of the time preceding the current time by the result of the multiplication.