SU476134A1 - Device for monitoring cutting tool wear - Google Patents

Description

by changing the pulse repetition rate. The output of generator 1 via multi-position switch 2 is alternately connected to identical integrators 3 and 4. The outputs of integrators 3 and 4 through switch 2 are connected to the inputs of solving circuit 5, designed to determine the sign of the difference in voltage accumulated by integrators 3 and 4, and generate a control signal. . A reset circuit 6, connected to the output of solving circuit 5, serves to return the device to its original state. The device works as follows. The use of an adaptive control system (ACS) for feeding on metal-cutting machines allows maintaining a constant cutting power by changing the feed with a change in cross section along the machining length and increasing tool wear. As a result of an increase in tool overloading, when machining identical workpieces, machine time t from part to part increases. In the general case, the characteristic dependence of the machine time t on the number of passes of the cutting tool N (where, 2, ... i ...) when using an ACS feed has the form shown in FIG. 2. In the case of processing the same blanks, L is the serial number of the part. The vicinity of the point L (in Fig. 2) characterizes the zone of optimal tool wear, and the rise of the branch of the curve to the right from point B indicates the approach of catastrophic wear of the cutting tool. Removing the tool for regrinding upon reaching the section AB allows to realize its greatest total resistance. As follows from FIG. 2, from the passage to the passage, the angle φF enclosed between the abscissa axis and the segment connecting the current ordinate ti with the origin is reduced. Starting from the (/ g + 1) th passage (i.e., outside the zone of optimal blunting of the cutting tool), this angle increases and, consequently, ig (fi ti / Ni, therefore the time of the onset of the blunt-4 nor the tool corresponding to the neighborhood of point A can be fixed by changing the sign of the difference (tg fg-tg ft l). For the initial sections of the function t (N) the difference (tg fg-tgi fg-i) 0. Reversing the sign of the different-5 STI to the opposite (tg fg-- tg fg-l) 0 indicates that the tool has reached the zone of optimal wear. At the moment the cutting tool 5 is inserted into the workpiece, a calibrated pulse generator 1 is fed through a switch 2, for example, from an adaptive machine control power sensor, generator 1 generates a sequence of pulses calibrated in duration and amplitude and having a repetition frequency f / N, where L is the sequence number of the workpiece or the passage of the cutting tool. In this case, during the first pass ti, a pulse sequence with a frequency f / Ni is generated, as a result of which, at the output of the generator 1, Vits () l / tgfl pulses. For the passage, the corresponding (f / Ni) -ti f-tg f ,. The output of generator 1 cyclically for the duration of the passage of time ti is connected through switch 2 to the input of one of the integrators 3 and 4. The integrators 3 and 4 operate in a linear accumulation of pulses from generator 1 and form voltages proportional to the number of these pulses during time g -th passage and, therefore, proportional tg f, -. Thus, during the current t-ro cutting cycle, one integrator is in a mode of accumulation of pulses - the receiving integrator, and the other - in the mode of storing the result of the previous, (i-1) -th cutting cycle - memory integrator. at the time of the end of the passage of the cutting tool, the Myo-position switch 2 receives a pulse of the command Stop, formed, for example, from the output voltage of the power sensor of the adaptive control system of the machine. This impulse connects the outputs of the integrators 3 and 4 to the inputs I and AND of the decision circuit 5. When the condition (1fg-tg fg-l) is met, the output of the decisive circuit 5 is a control signal that can be used to turn on the light or sound signaling device , giving the command to replace the tool. At the same time, the reset circuit 6 is activated, completing the cycle of the device operation. If, after another pass of the cutting tool (tg fg-tg fg-l) 0, then the pulse "Stop using switch 2 will reset the voltage from the memory integrator, transfer this integrator to the receive mode and transfer the second integrator from the receive mode to the memory mode and also switching the pulse generator 1 to a pulse sequence generating mode with a lower repetition rate. Item of the Invention A device for monitoring wear of a cutting tool, comprising a duty cycle sensor and a counting circuit generating a signal L to tool change, characterized in that, in order to determine the optimal tool blunting moment-ja, it is equipped with a switch, two integrators, a reset unit and a pulse generator, changing the frequency depending on the number of cutting tool cycles, and the generator output is connected via the switch to the integrator inputs, the outputs of which through the switch are connected to the counting circuit, and to the output of the latter, a reset unit is connected to return the device to its initial state.

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