JPH02279256A - Detecting device for wear and breakdown of tool - Google Patents

Abstract

PURPOSE:To decide the state of the wear and breakdown of a tool after completion of each work and to perform the stoppage and earing of a machine, the display of the work data up to the present, etc., by storing and operating a cutting power at the work stage simultaneously with performing the detection of the wear and breakdown of a tool during working. CONSTITUTION:A small power detecting device 17 detecting the power of a main shaft motor 4 or feed motor 11 is installed, the output thereof is digitized via a digital meter relay 18 and the numerical value conformed to the wear or breakdown of each tool is stored to the set value of the digitalmeter relay 18 in advance. The output from the small power detection device 17 and set value are compared, a machine is stopped in case of exceeding the set value and in case of not exceeding the maximum value is transmitted to a wear and damage detection controller 20 via a comparator 21 after completion of each work. The wear and damage detection controller 20 decides the wear and breakdown by comparing and studying the maximum value of a storing work power, outputting the command of the machine stoppage, etc., to a numerical control device 15 and control panel 16.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention uses a minute power detection device to detect only the cutting power with high accuracy, and stores the maximum value of the cutting power. By comparing and examining the maximum value of cutting power on the wear and damage detection controller, a tool wear and damage detection device is installed to detect wear and damage of the cutting tool.

[Conventional technology]

Various methods have been used and put into practical use for conventional tool wear and damage detection [l], such as the 'M method, the cutting force method, the AE method, and the vibration method, but these methods often cause malfunctions and do not detect tool wear. Although this was close to possible, it was not a practical detection method.

The AE method is a method that utilizes acoustic emissions generated in a tool during machining, and the imaging method utilizes acoustic emissions generated in a tool, workpiece, or machine body during machining. The cutting force method is a method that detects the cutting force applied to the tool, and the current method is a method that detects the current generated in the spindle motor or feed motor during machining. The principle is different from that of the present invention.

Although the present invention is a type of electric power method, the conventional detection method based on the electric power method was a method of detecting the total electric power applied to the spindle motor or the feed motor.

Therefore, the sum of the power required to rotate the workpiece or tool and the power required for machining is detected.

This made it difficult to determine tool wear and damage. In particular, it was almost impossible to judge tool wear. Roughly speaking, this method is affected by fluctuations in the supply voltage of the motor, so reliability has been a problem.Since the present invention uses a minute power detection device, only the power required for machining is used. can be detected with high accuracy.

Tool wear and damage can be detected with high accuracy.

(Problem that the invention seeks to solve) Conventional tool wear and tear detection devices often malfunction.

In particular, detection of tool wear is almost impossible.

Furthermore, in order to detect tool wear and damage during machining without using detection data for each machining, the machine is stopped during machining. For this reason, in the case of a numerically controlled machine tool, you have to change the tool, return the machining program to the beginning, and return the machine to the predetermined position. Not only does it take time to recover, but you also have to re-cut the uncut part. I had to.

The present invention has been made in consideration of the above circumstances.

Detection of tool wear and damage is carried out with high accuracy during each machining process, and after each machining is completed, the detection data for each machining process is stored, and the values are examined in various ways on the wear and damage detection controller. Failure 1 (Determine 1 and issue 1 command such as 2 machine stop. By doing this, if the tool wears or breaks faster than expected, the machine will be stopped during machining, and if not, each machining It is an object of the present invention to provide a tool wear/damage detection device that solves the various problems described above by stopping the machine after the completion of the tool wear and tear detection system.

[Means for solving problems]

11 minute power detection units are installed to detect the power of the spindle motor or feed motor of the machine tool.The output is digitized via a digital meter relay, and numerical values are determined in advance according to the level of wear or damage of each tool. , stores multiple setting values in the digital meter relay, automatically calls out the required setting values for each tool, compares the output from the low power detection device with the set value, and detects when the set value is exceeded. If so, the machine is stopped, and if the set value is not exceeded, after each machining is completed, the maximum value during that time is transferred to the wear/damage detection controller via a comparator.

The wear and tear detection controller compares and examines the maximum values of machining power for each machining process stored, determines wear and damage, and issues commands such as one machine stop to the numerical control device and control panel.

[Effect]

Since the present invention is configured as described above, wear and damage of a tool can be detected with high accuracy. The present invention constantly compares the set values for tool wear and breakage with the cutting power during machining, detects unexpected sudden wear and breakage, and can stop the machine, while each process continues normally. After finishing.

By storing the maximum value of cutting power during each machining process and processing it to determine wear and damage, a machine stop signal can be issued after each machining process is completed. This is the case for numerically controlled machine tools.

Kanib: ``The machine is ordered to stop after the machining process with one tool in the 7 grams is completed normally.

Just by exchanging the tool, you can immediately start machining with the next tool. The advantage of this becomes clear when considering the case where a machine that has stopped midway through machining is returned to its original position, the tool is replaced, and machining is started again.

〔Example〕

The present invention will be explained below based on the drawings.

An embodiment of the tool wear and damage detection device according to the present invention is shown in FIG. 1, and in this example, a case will be described in which the power of the spindle motor of a numerically controlled lathe is measured to detect tool wear and damage. It is easy to apply the present invention to other machine tools.

For example, in machine tools that rotate tools such as milling and drill cutting, it is sufficient to detect the power of the motor that drives the tool, and in machine tools where the cutting force is often reflected in the feed force, the power of the feed motor can be detected. do it.

Before explaining this device, the configuration of the machine tool will be explained.

1 is a headstock supported on the bed 2.

A main shaft 3 is rotatably supported on the headstock 1 via a bearing, and its rotation is transmitted and driven by a main shaft motor 4 via a drive device 5. Reference numeral 6 denotes a chuck attached to the tip of the main spindle 3, which grips and releases the workpiece.

Reference numeral 7 denotes a tool stand that consists of a vertical tool feeder 8 that can move forward and backward in the direction of the rotational axis of the main spindle 3, and a horizontal tool feeder 9 that can move forward and backward in the direction perpendicular to the rotational axis of the main spindle 3. The feed is controlled by driving the servo motor 10 and the servo motor 11. A turret 12 holds a plurality of tools 14 such as bites extending in the radial direction and center direction of the workpiece 13, and is rotatably supported on the tool stand 7 via an indexing means. There is.

Next, the structural relationship between the machine tool and the device of the present invention will be explained.

The main shaft motor 4 is controlled by a numerical control device 150 command.

The electric power driven via the control panel 16 and used to drive the spindle motor 4 is detected by the minute electric power detection device 17.
The detected power value is output as a voltage by the minute power detection device 17, and the voltage is converted into a numerical value by the digital meter relay 18. The digital meter relay 18 has a structure that allows easy input of upper and lower limit set values when the tool is worn or damaged, and is capable of storing upper and lower limit set values to be engraved on various tools.

The upper and lower limit set values for each tool are set by the numerical controller 15.
The control code (M
When the code) is read, it calls up the required upper and lower limit settings stored in the digital meter relay 18.

The power during machining with each tool is constantly detected by a micro power detection device 17 and sent to a digital meter relay 18.
The value is constantly compared with a predetermined set value, and if it exceeds the upper limit set value, a detection signal is sent to the wear/damage detection controller 20 via the timer 19. The timer 19 keeps the output at the upper limit set value for a certain period of time. When the value exceeds the set value, a detection signal is sent to the wear/damage detection controller 20, making it possible to ignore momentary exceedance of the set value. If the output does not exceed the upper limit setting, it is assumed that the tool has not experienced wear and tear. The output from the digital meter relay 18 is constantly sent to the comparator 21, which stores the maximum power of 1+1 during processing.

After finishing machining with each tool, * wear and damage detection controller 2
The maximum value of power during processing is transferred to 0.

The wear and tear detection controller 20 has a memory that stores the maximum value of power required for the first machining with each tool to the maximum value of power required for the current machining. These numerical values are processed to detect the state of wear and damage, and a detection signal is sent to the numerical control device 15 or control panel 16 to stop the machine 9.

The structure is designed to reduce forced machine stops during machining due to exceeding the set value of the digital meter relay 18, and to display the current degree of wear or damage of the tool to call attention to it.

Digital meter relay 18. The comparator 21 and timer 19 are generally commercially available.

FIG. 2 is an example showing the state of electric power generated in the main shaft motor. The spindle motor is started, and after reaching a certain number of rotations, a load is applied by cutting, cutting is finished and there is no load, then the number of rotations is further increased, cutting is performed, and cutting is finished and there is no load. It shows the change in the power of the spindle motor when the state is reached. a is the state when stopped, b is the overshoot state after starting, c-d is the state when there is no load * e
-f is the state of steady cutting; 9g to h are the no-load state after machining; 1=j- is the overshoot state when the rotation speed of the spindle motor is increased, and the no-load state after the rotation speed has stabilized. The state under load, 1 to m represent the state of the next steady cutting, and no represents the state under no load after machining.

In this way, the power required at no load changes each time the rotation speed of the spindle motor changes, and the no-load power is a large value compared to the cutting force, so the cutting power can be calculated by detecting the total power of the spindle motor. It is difficult to estimate.

An example of the principle of a commercially available micro power detection device is a power meter equipped with a hold circuit and an amplifier with a variable amplification factor.When a hold signal is input, the current power value is held, and subsequent power values are This method detects the difference between the value and the held value, displays the difference through an amplifier, and outputs it. An example of this operation is shown in FIG. a to h are power values of the main shaft motor. When a hold signal is input at the time of 210, the power values Wc and d between 06 and 06 are memorized, and the value of Zl-d open after that is output as the amplified value of (W z I, cl - We, d). do. The power value during 06 is constant.

Since W c and d, the output in this case is 0.

(Power value between ef W e * f - W c + d)
The value obtained by multiplying the value by the amplification factor becomes the output value between 0M+. This shows how the micro power detection device was developed during this period.

Zl' + d', e', f', g', h'.

This allows only the cutting power to be amplified and detected with high accuracy. FIG. 4 shows the change in power of the spindle motor when only the cutting power is amplified and detected using this property. The rotation speed of the spindle during machining is constant.

When the spindle is started and a predetermined rotational speed is reached at point 21 between 06 and 06, tool monitoring (power monitoring) is started and at the same time a bold signal is sent to the minute power detection device. Micro power detection lI
The device holds the power value at the time Zl when the hold signal is received, amplifies the difference between the power value after that and the held value, and calculates Zl', d', e', f", g', h'11
Detect the value of ZJ '+J''. Here, e I 11
The values in between are values that amplify only the cutting power. Tool monitoring (power monitoring) changes the rotational speed of the main spindle in the 0th order, which ends at g', and changes the rotational speed between jk and 2nd when the predetermined rotational speed is reached.
At point 2, tool monitoring (power monitoring) is started, and at the same time a hold signal is sent to the minute power detection device to obtain a value between l'm' in which only the cutting power is amplified. in this way.

Since this method amplifies and detects only the cutting power based on the electric power immediately before measuring the cutting power, it is possible to minimize the influence of fluctuations in the voltage supplied to the spindle motor.

Next, a description will be given of the wear and tear detection controller 20 that detects tool wear and damage using accurately detected cutting power. FIG. 5 shows an example of the configuration of the wear and tear detection controller. The wear and tear detection controller 20 is
It has almost the same configuration as a general commercially available personal computer, and the = from the digital meter relay 18.
A receiving unit that receives a signal of q exceeding the fixed value via the timer 19! , a receiving section 2 receiving the maximum value from the comparator 21;
Input unit 1 Display unit, storage unit, calculation unit, control unit.

and numerical control device 15. It has an output section that sends a signal to the control panel 16.

FIG. 6 is an example of the contents of a storage section that stores items necessary for determining tool wear and damage. For example, tool number 1 corresponding to 1M code M101 performs breakage detection, initial 1tllF1 is the measured value of cutting power in the first or test machining with a new tool, and upper limit set value U1
is the upper limit set value that is forcibly detected by the digital meter relay 18, and the lower limit set value Ll is the lower limit set value where it is assumed that the tool has fallen off and machining has not been performed if it is not exceeded even once during machining. In this case, there are 9 steps such as stopping the machine, and the number of machining operations is 1, 2. ...N is the number of times of machining with the same tool, and the first cutting power adjustment value A1, 2
Measurement of cutting power for the first time [A2°...AN is stored in sequence. Software setting [1, 2°...M is the setting value on the software, and SL in d1 is the upper limit setting value on the software, and when the measured value of cutting power exceeds this value will issue a signal to stop the machine.Since the value of Sl is set to a value smaller than the upper limit setting 1 + IU1, when the measured value of cutting power is between 51 and Ul, the two machines will not stop during machining. The software setting value SM is a value in which it is considered that there is no problem if the measured value of cutting power is less than that, and the values of 92 to SM-1 are determined by adjusting the values of Sl and SM appropriately. The software setting values S1 to SM can be input manually, but the initial values Fl,
It is also possible to automatically determine the upper limit setting value U1 according to a predetermined calculation formula. These values can be set according to the shape and material of the tool, the material of the workpiece, cutting conditions, etc., and the operation for determining wear and damage.

Perform this when the measured value of cutting power exceeds the software setting (itISM).

Exactly the same procedure can be performed for other M codes and tool numbers.

Next, the case of damage detection will be explained as an example. Figure 7 is M
101. For tool number 1, set the number of software settings to 6.
The measured value of the cutting power shows an example when the machine stops after the 25th machining.

The damage judgment operation starts from A18, which exceeds the software setting value S6, and the value of A25 exceeds the upper limit S1 of the software setting value.
Because it does not exceed the upper limit setting value U1.

By digital meter relay 18 during processing.

One machine is stopped after the 25th machining without being forced to stop.

In this case, the values from A18 to A25 are Sl-S
Because it is rising one step at a time between the 6 sections.

It is believed that small damage occurred little by little, and eventually major damage occurred and one machine stopped. [If the measured value B of cutting power is less than the lower limit setting 1lIIL1.

If a tool falls off, a signal is issued to stop the machine.

] FIG. 8 is an example showing the process of damage. In the case of (a), the measured value of the cutting power increases by two steps between the software settings (11 S1 to S6).

It is thought that medium-sized damage continued and then became major damage.
It is said to be large-scale because it rises in two stages.

It is believed that medium-sized damage resulted in major damage.
In case (c), the rise is 1 step, 3 steps, and 1 step, so it is thought that the large damage was caused by small-scale, large-scale, and small-scale damage, and in case (d), the damage increased by 4 steps at once. Since the step is rising, it is thought that very large-scale damage has occurred. Considering the impact on the work, measures such as stopping the machine or issuing a strong warning even if the upper limit set value S1 in the software has not been exceeded are taken. Take. In the case of (e), it is considered that a large damage occurred suddenly, and the upper limit setting value 01 is exceeded, so the digital meter relay 18 is used.

The machine is forced to stop during processing.

As described above, by providing software setting values, it is possible to know the pattern of damage in considerable detail.

The same is true for wear detection, and it is possible to know in considerable detail under what conditions wear has occurred.

By storing and calculating the values actually measured for the cutting power of each tool as described above, it is possible to accurately determine wear and damage.

Furthermore, if these measured and stored numerical values are displayed for each tool in the form of a figure as shown in FIG. 7 via the display section 9, the condition of the tool can be clearly confirmed visually.

〔Effect of the invention〕

As described above, according to the present invention, tool wear and damage can be detected during machining and at the same time.

By memorizing and calculating the cutting power at each machining stage,
After each machining is completed, the state of wear and damage of the tool is determined and
It is possible to stop the machine, give warnings, and display the current machining data.

Since checks are performed by the software and by the digital meter relay 18 in this way, the reliability of wear and damage detection is further increased.

Due to the rapid development of electronics technology in recent years, a storage unit is required to configure one device.

Computers with arithmetic units, input/output units, display units, control units, etc. can be obtained at low cost and easily, and recent numerical control devices have these functions, so they are inexpensive. But it is quite manageable.

Although this example is for calculating the power of the spindle motor of a numerically controlled lathe, it can be easily applied to other machine tools as well.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a tool wear/damage detection device according to an embodiment of the present invention, Fig. 2 is a diagram showing an example of the power state generated in the spindle motor, and Fig. 3 is a diagram showing an example of the operation of the micro power detection device. Figure 4 is a diagram showing an example of the operation of amplifying and detecting only the cutting power by a micro power detection device, Figure 6 is a diagram showing an example of a wear and tear detection controller, Figure 6 is a diagram showing an example of a wear and tear detection controller. The figure which shows an example of the content of the memory|storage part of. FIG. 7 is a diagram showing an example of the operation of the tool wear and damage detection device;
81st! I is a diagram showing an example of a damage process. 1- Headstock 2- Bed 3- Spindle 4- Spindle motor 5- Drive device 6- Chuck 8- Vertical tool feeder
9-Horizontal tool feed stand 10--Ball screw 11--Servo motor 12--Tareft 13 15-Numerical controller minute power detection device 18 Ray 19-Time management roller 21 Workpiece 14-Tool 16-Control g4 Iwa 17 Izoi Digital meter 2〇 - Destruction/damage detection comparator

Claims (1)

[Claims] 1) A micro power detection device that magnifies and detects only the cutting power of a motor during machining using a tool whose wear and damage are to be detected, and a plurality of set values for detecting wear and damage. a digital meter relay that receives the output from the minute power detection device, a comparator that receives the output from the digital meter relay and detects its maximum value, a timer that receives the output from the digital meter relay, and a timer and a comparator. A receiving section that receives the output from the device, a storage section that stores data, an input section that inputs the required data, a calculation section that calculates the stored and input data to judge wear and damage, and the stored data and A tool wear and damage detection device that includes a wear and damage detection controller that has a display section that displays the determined results, an output section that outputs the determined results to a control panel or numerical control device, and a control section that controls each part. 2) The digital meter relay has multiple upper and lower limit set values for detecting wear and damage, and constantly compares the measured value of the cutting power of the motor during machining with the upper and lower limit set values. If the upper limit set value is exceeded, it is determined that wear or damage has occurred and the machine is stopped, and if the measured value of the cutting power of the motor during machining never exceeds the lower limit set value, it is determined that the tool has fallen off. A tool wear/damage detection device that stops the machine. 3) If the digital meter relay does not determine wear, damage, or tool dropout, it receives and stores the output from the comparator, calculates it using multiple variable software settings, and determines whether the wear or damage has occurred. A tool wear and damage detection device characterized by having the above-mentioned wear and damage detection controller that makes a determination and stops the machine, and determines patterns of wear and damage. 4) Insert multiple control codes (M codes) into the machining program for the tool that should detect wear and damage, and detect only the cutting power by holding the output of the micro power detection device using one control code. and
Another control code starts the measurement of the cutting power generated by the tool, another control code ends the measurement, and only the cutting power during this measurement period is sent to the digital meter relay and transmitted through the comparator. A tool wear and damage detection device having the above-mentioned wear and damage detection controller, characterized in that it receives the maximum value during the measurement period and determines wear and damage.