JPS58181545A - Tool damage detection controller - Google Patents

Abstract

PURPOSE:To turn on an indicating light and simultaneously surely and automatically exchange tools of identical kind when a tool is damaged, by using a timer to change the displacement of the tool. CONSTITUTION:When a tool is damaged, an indicating light PL is turned on and a stop signal OUT is generated to send an identical-kind tool exchange instruction signal tc from a microcomputer CPU to a numerical controller NC. At that time, an identical-kind tool exchange instruction signal t'c is sent out from the numerical controller NC to a tool exchange arm 15 and a tool magazine to exchange tools of identical kind. After the exchange of the tools, a completion signal (h) is sent to the numerical controller NC and a flip-flop FF to reinstate it to turn off the indicating light PL and remove the stop signal OUT. After that, it is detected whether the new tool is damaged or not.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tool breakage detection technique for quickly detecting the presence or absence of tool breakage in a machine tool equipped with an automatic tool changer.

As shown in Japanese Patent Application Laid-Open No. 54-37976, the tool breakage detection technique involves setting the cutting feed start position of the tool at each machining location at a position that is retreated by a predetermined amount from the workpiece surface at each machining location, and There has been proposed a method in which the amount of movement of the tool from the cutting feed start position to the time it contacts the workpiece surface is detected for each machining location, and breakage of the tool is detected based on this amount of movement. The amount of movement of the tool described above is detected by counting with a preset counter for each machining location, and when the count value of this preset counter goes from zero to negative beyond the set value, that is, the amount of movement greater than the set value is detected. At the same time, an output signal is generated from the preset counter to flip 7.
Set the P knob and turn on the broken tool indicator light. The disadvantage of the technique of detecting the amount of tool movement based on the count number of the preset counter is that it requires a circuit that indexes the operational movement state of the preset counter, which not only complicates the circuit configuration but also causes the tool to change when the tool is replaced. Whenever a change occurs in the dimensions, the movement amount setting device must be set to a new movement amount. Moreover, in the tool breakage detection method, when a tool breaks, an indicator light is only turned on to notify that the tool is broken.

For this reason, when a tool breaks, the machine tool stops, and it is impossible to expect that the same type of tool will be replaced and that the machine tool will continue to operate.

The present invention was made in view of the above-mentioned shortcomings in detecting tool breakage in the prior art.The amount of tool movement is determined by a timer, and changes in the amount of movement associated with tool replacement are automatically performed using a plurality of preset timers. The purpose is to Furthermore, we succeeded in automatically replacing tools of the same type in the event of tool breakage, allowing the machine tool to continue operating.

Next, the tool breakage detection control device of the present invention will be explained with reference to embodiments shown in the drawings. In FIG. 1, DE is a tool breakage detection control device of the present invention, which controls tool breakage detection in the model machining center HM. The horizontal machining center decoy is bed 10. Table 11, rotary table 12, column 13, main shaft 14 that engages with the column and moves up and down, tool exchange arm 1
5, a tool storage magazine (not shown), etc., and each axis has a pulse motor PMX, PMY,
PMZ inputs commands from the numerical controller NC through each axis drive circuit DX, DY, and DZ, and outputs the command from the table (X
axial direction) 11, a rotary table (Z-axis direction) 12, and a main shaft (Y-axis direction) 14 having a tool T, respectively. 2o is a contact detector attached to the spindle head 16, which sends a signal when the tip of the tool T comes into contact with the work WK, and this output becomes a rising pulse in the contact detection circuit 21 to maintain this state and prevent failure. The pulse falls when it comes into contact. Reference numeral 22 denotes an inverter connected to the output side of the contact detection circuit 21. When the tool T makes contact, the pulse disappears, and when there is no contact, the inverter 22 outputs a pulse (referred to as a contact pulse) to the next AND element AND. Reference numeral 23 designates a multiple time setter (multiple sets of timers), which automatically selects the timer to be operated and a preset time based on the Z-axis feed signal fz and the tool type signal te sent from the numerical control device NC.

That is, as shown in Fig. 3, the cutting feed rate ν of the tool is determined by the type of tool (T1. T2 + 'r3 @ e ・T?L)
The moving time of the tool from the fixed cutting feed start position Pi to the contact position (cutting position) P2 of the workpiece W also differs depending on K. In the illustration,
The moving time between 21 and 22 is tl' for tool T1, t2' for tool T2, t3' for tool T3, and tn' for tool Tn.
stipulated in The travel times t1' to tn' for the tool types T1 to Tn are set by a detailed circuit of the multiple time setting device 23 shown in FIG. That is, multiple sets of timers t1.
t2. For t3...tn, individual time-up times can be freely set using knobs provided in the time setting device 24. Which timers t1 to tn are activated is determined by the two-axis cutting feed signal ft from the numerical controller NC.
and the tool type signal ts, and the operation of the timer is started by the Z-axis cutting feed signal fz that is transmitted when the tool T reaches the cutting feed start position P1. The multiple sets of timers t1 to tn are connected to a time-up 7711 circuit (one-shot multipipe rake) 25 via an OR element OR, and this circuit 2
5 outputs a pulse voltage to the AND element AND for a short time using the time-up signal from the timer as a trigger. Therefore, the AND element AND which inputs two signals (tool contact pulse, time-up pulse) should set the next stage flip-flop FF when the two pulses are not input at the same time (no tool breakage). Since this is not possible, turn on the broken indicator lamp PL connected to this exit side,
Machine stop signal OUT is not output. On the other hand, AND element A
When the ND detects contact with the tool later than the oscillation of the time-up pulse (tool breakage), the two pulses are superimposed and input, the flip-flop FF is set, and the indicator lamp PL is lit. Along with the stop signal OU
It has a circuit configuration that outputs T. 27 is a reset switch, which connects the flip-flop F via input or 28.
Reset F.

Next, a description will be given of the configuration of a portion that performs the function of replacing a tool of the same type when a tool breaks. In Fig. 1, the flip-flop FF is turned off due to tool breakage, and the stop signal O
When UT is output, this output is input as a similar tool exchange command tc to the numerical control device NCR1 by the microcomputer CPU. Then, tool exchange 7- is performed from the numerical control device NC.
The same type of tool exchange command tc' is transmitted to the system 15 and the tool storage magazine (not shown),
After exchanging the same type of tool, the length of the completion signal issued from the tool exchange arm 15 etc. is used to send the Z-axis feed signal fz and tool type signal tg from the numerical controller NC to the drive circuit DZ.
is transmitted to the multiple time setting device 23. On the other hand, the completion signal ★ is also input to the reset terminal of the flip-flop FF, so that it is possible to detect tool breakage again.

The present invention is an embodiment as described above, and its operation will be explained below with reference to the time chart of FIG. 4 in addition to FIGS. 1 to 3.

First, the technique for detecting tool breakage will be explained. In order to detect breakage of the tool T1 before machining the workpiece W, the tool T1 is advanced from Po to the cutting feed start position plK in rapid traverse as shown in FIG. When the tip of tool T1 reaches the preset cutting feed start position P1, a preset cutting feed command (tool T1
), and the multiple time setter 23
A two-axis feed signal fg and a tool type signal te are output. Now, the multiple time setter 23 is set to the tool type signal to
The selection circuit 26 that receives this starts the operation of the corresponding timer t1, and the table 11 on which the workpiece W is placed starts cutting feed in the direction of the tool T1. Then, as shown in FIG. 4, the contact detector 20 detects the tool T on the work W a moment earlier than the time amplifier pulse α of the timer t1 generated after tl'.
1 is sensed (no tool breakage), the pulse b of the inno-contact 22 disappears, and the two pulses α and b do not overlap and input to the AND element AND. Therefore, the clip prop FF is not set, and the tool breakage indicator lamp PL and machine stop signal OUT are not output. Subsequently, after machining the workpiece W with the tool T1, the tool exchange arm.

15, the tool is replaced with a new tool T2, and then the tool T
2 is fed from the origin Po to the cutting feed start position P1 by rapid traverse tIQ, taking a time of to. When the tip of the tool T2 reaches the preset cutting feed start position P1, the two-axis drive circuit D is sent from the numerical controller NC as before.
Cutting feed command predetermined for Z (value corresponding to tool T2)
At the same time, a two-axis feed signal fz and a tool type signal tg are output to the multiple time setter 23. As a result, the corresponding timer t2 of the multiple time setter 23 starts operating, and the table 11 on which the workpiece W is placed starts cutting and feeding in the direction of the tool T2. When the tool T2 comes into contact with the workpiece W earlier than the time-up pulse α' of the timer t2, which occurs after t2', the pulse b of the inverter 22 disappears, and the two pulses α' and b are superimposed into the AND element AND K. do not. This will make it clear that the tool has not broken. Subsequently, when the tip is replaced with tool T3 and reaches the cutting feed start position P1, a predetermined cutting feed command (value corresponding to tool T3) is output to the Z-axis drive circuit DZ, and multiple time settings are performed. Two signals fz and te are output at the value 23. As a result, the multiple time setter 23 starts to operate the corresponding timer t3, and the chiffle 11 carrying the workpiece W starts cutting and feeding in the direction of the tool T3. If the tip of the tool T3 does not come into contact with the work W even if the time-up pulse α'' of the timer t3 is generated after t3' (tool breakage occurs), the pulse b of the inverter 22 and the time-up pulse α' counter element AND A superimposed output is made to set the flip-flop FF.As a result, the broken tool indicator lamp PL is lit, and the operation of the machine tool is stopped by generation of the machine tool stop signal OUT.

Next, a technique for replacing tools of the same type based on tool breakage detection will be described. The tool T3 that broke in the previous section generates an indicator lamp PL and a stop signal OUT, which sends a similar tool replacement command tc from the microcomputer CPU to the numerical controller NC.
Output as . The same type tool exchange command tc is also sent from the numerical control device NC as a similar type tool exchange command tc' to the tool exchange arm 15 and a tool magazine (not shown) to cause the same type tool exchange to be performed. When the tool change is completed, the completion signal length is sent to the numerical controller NC and clipprop FF,
The flip-flop is reset to turn on the display lamp PL and extinguish the stop signal 01JT. Thereafter, the operation for detecting the broken state of the newly replaced tool T3 is performed in the same manner as described above. That is, the detection operation is as shown in the time chart shown on the right side of FIG. In this detection, tool contact occurs and the pulse b disappears earlier than the generation timing of the time amplifier pulse α'' of the timer t3, and therefore no tool breakage has occurred, so the process moves on to cutting and feeding the workpiece W.

According to the present invention, the contact detector of the tool is connected to the AND element, while the multi-time setting device that inputs the Z-axis cutting feed signal and tool type signal output from the numerical control device is equipped with a large number of timers. A timer corresponding to the cutting feed determined for each tool is activated by a selection circuit, and the time amplifier pulse from the multiple time setting device is input to the AND element to overlap with the contact pulse from the contact detector. Since the structure detects tool breakage based on the input state, there is no need for a circuit to index the operational movement state of the preset counter, which was a drawback in the conventional technique of detecting the tool movement amount based on the count number of the preset counter. In addition to simplifying the circuit configuration, even if the tool changes, the timer is automatically selected in response to the change, which has the effect of reliably executing tool breakage for a new tool. Furthermore, when a tool breaks, it is possible to automatically replace a tool of the same type with certainty, allowing the machine tool to continue operating.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the tool breakage detection control device of the present invention, Fig. 2 is a block diagram showing the detailed configuration of the multiple time setting device 23, and Fig. 3 is a block diagram showing the rapid traverse/cutting feed of the tool cutting edge and this time. A partial diagram showing the relationship, FIG. 4 is a time chart diagram. DE...Tool breakage detection control device, HM---Horizontal machining center, T (Tl~T?l)...Machining, D
z...Z-axis drive circuit, NC...numerical control device, 15...tool exchange arm, 20...contact detector,
21... Contact detection circuit, 22.28... Isoharter, 23... Multiple time setter, 24... Time setter,
25... Time amplifier pulse circuit, 26... Selection circuit, OR... Off element, AND... AND element, t
1\tn・1 timer, Pl...Cutting feed start position, P
2...Touch position, FF...Flip-flop circuit,
PL...Breakage indicator lamp, OUT...Machine stop signal, fz...2-axis cutting feed signal, te...Tool type signal, tc-tc'...Similar tool replacement command, k.・・・
Completion signal, 27...Reset switch, CPU...
Microcomputer. Male l Fat DE 2nd side 4 Male 3 N

Claims (1)

[Claims] In tool breakage detection, which detects tool breakage by detecting the amount of tool movement from the cutting feed start position of the tool cutting edge to the workpiece surface, which is determined by a predetermined amount, while connecting the contact detector of the tool to the ant element, The multi-time setting device that inputs the Z-axis cutting feed signal and tool type signal output from the control device is equipped with a large number of timers, and a selection circuit operates the timer corresponding to the cutting feed determined for each tool. 1. A method for detecting tool breakage, characterized in that a time-up pulse from a plurality of time setters is input to the AND element, and the tool breakage is detected based on the manual state of superimposition with the contact pulse from the contact detector. Detection control device.