JPH02139157A - Control system for machine tool - Google Patents

Abstract

PURPOSE:To quickly obtain the optimum working conditions, to prevent abnormal working and to know the cause thereof by forming the working conditions for an optional work object by the data on each unit time of the actual working and accumulating in a computor together with the data of the working object and machine. CONSTITUTION:The working conditions for an optional work object are formed by the data indicating the speed, acceleration or the difference in the acceleration on each unit time of a control object in the actual working thereof and accumulated in a computor 21 together with the data of a work object and work machine. Plural work machines NC1-NCn are connected via a telephone line, etc., to the computor 21 together with input parts I1-In and the data reading display parts D1-Dn consisting of a reading key board, CRT, etc. As a result, the optimum working conditions are quickly obtd. in short time, also abnormal working can be prevented and the cause on the abnormal work can be known.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention mainly relates to a control system for a machine tool, and particularly for a processing machine in which a controlled object rotates or moves during processing.

[Conventional technology]

Conventionally, automation of machine tools has been advanced by numerical control.

Numerical control drives the position and speed of the controlled object using preset numerical data, but that numerical data must be created in advance for each different machined object, even for the same machine tool. First, in its preparation, it is essential to utilize the experience, intuition, or know-how of skilled engineers in so-called on-site technology.

[Problem to be solved by the invention]

However, when there is no skilled engineer available, or even when a skilled engineer is working on a workpiece made of a new material, it is necessary to create numerical data for numerical control. Numerical data cannot be created unless basic data is obtained through repeated trials. In other words, there is a problem in that numerical data for numerical control cannot be created without a great deal of time and effort.

In particular, in recent years, a large number of processed products made of so-called new materials and new materials have appeared, making it even more difficult to create the above-mentioned data.

Further, when the object to be processed is a new material, even in the case of manual processing, the same problem as in the case of creating the above-mentioned numerical data arises in obtaining the optimum processing conditions.

On the other hand, it is well known that even in machining where the data about the workpiece and the machining machine are well known, abnormal machining can occur due to aging of the machine, chipping of the cutter, wear, etc. If the occurrence of such abnormal machining can be predicted in advance, abnormal machining can be prevented, which is convenient for machining.

In view of these problems, the present invention provides a control system that can quickly obtain optimal machining conditions in a short time, prevent abnormal machining, and learn the cause of abnormal machining. Its task is to provide this information.

[Means to solve the problem]

The configuration of the present invention for solving the above problems includes a table,
The spindle, turret, etc. are controlled, and the drive source is
Set arbitrarily regarding the control target.

A signal indicating the scheduled speed per m time that can be changed.

Similarly, a signal indicating the planned acceleration and a signal indicating the difference between the planned accelerations are used as the planned signal, and the device is driven by this planned signal to process the appropriate processing object, and during this processing, the same planned signal obtained from the controlled object side. A signal indicating the actual speed per unit time, a signal indicating the actual acceleration, and a signal indicating the difference between the actual accelerations are extracted as the actual signals.When processing the appropriate processing object, each Comparing and calculating the corresponding signals of the planned signal and the actual signal with an arbitrarily set tolerance for the planned signal and the planned signal for each unit time, and determining whether or not this calculated value is within the preset tolerance. When the calculated value is within the tolerance, the data of the above-mentioned actual value is stored in the computer in a readable manner along with the data regarding each processing object and processing machine, and the calculated value is obtained by processing the same object with the tolerance reduced. The same machining is repeated until the above calculated values deviate from the tolerance, and the actual value data for each machining is recorded in a computer so that it can be read out along with the data regarding each machining object and processing machine.When the above calculated value deviates from the tolerance, the actual value Data on the causes, objects to be processed, and processing machines are stored in the computer in a readable manner.

Data for setting machining conditions for any machining object, or data for determining the cause of abnormal machining that occurs during machining of any machining object, using the data of the machining object, processing machine, etc. as keywords, as described above. It is characterized in that it can be read from a computer.

[For production]

The machining conditions for any workpiece are formed by data indicating the speed, acceleration, or difference in acceleration of the controlled object per unit time during actual machining, and are stored in a computer together with the data of the workpiece and the processing machine? ? For example, when processing objects made of the same material or similar materials later automatically or manually, the accumulated data can be read out to create processing conditions. Further, immediately before abnormal machining occurs or when abnormal machining occurs, the cause can be read out from the accumulated data of abnormal machining.

〔Example〕

Next, an example of use of the system of the present invention will be explained.

First, the present invention system l) can be applied to a machine that is configured to perform positioning control and speed control using a conventionally known numerical control method, but in this embodiment, the following method is used. Use a device that is controlled by

In order to control the amount of movement and/or the speed of movement of the table, spindle, etc. of an appropriate machine tool (hereinafter referred to as the controlled object), the drive source that controls the movement of the controlled object is The controlled object is moved by supplying a scheduled signal indicating the planned speed, planned acceleration, etc. per unit time as appropriate, which is set in advance. A current signal indicating the current velocity or current acceleration per unit time, as appropriate, obtained directly or indirectly from the side.

There is a device that performs a comparison calculation with the scheduled signal at the supply time of the scheduled signal, and controls the drive source based on the calculation result.

Figure 1 shows an example of the above control system.
2 is a tool post whose positioning and speed are controlled as a control object.
3 is a saddle that guides the tool rest 1, and 3 is a feed screw installed on the saddle 2. This screw 3 is screwed into the nut member 1a of the tool rest 1 to form a clutch.

The tool rest 1 is moved in the left-right direction of the saddle 2 by forward and reverse rotation of a transmission system such as a brake and a deceleration mechanism by an attached feed motor 4.

An example of the control system for the above-mentioned controlled object is configured as follows.

In FIG. 1, reference numeral 6 denotes a speed detection section of the tool rest 1, which receives 100 movement pulse signals per IIW supplied from the position detection section 5 via the movement amount detector 5a attached to the tool rest 2, for example. corresponds to a time pulse signal supplied from a clock pulse generator 7 that generates, for example, 100 pulse signals per second, and the current speed of the tool post 1 is expressed as a distance pulse/time pulse or a time pulse/distance pulse. This is a signal in the form of, for example, detected in units of 1 to 2 μsec, and the current speed in this unit time is detected.

In addition to detecting this current speed, the travel time based on the current speed is sequentially measured, and these speeds and times are sequentially integrated and accumulated to calculate the distance traveled by the tool post based on the current speed and the cumulative distance traveled. put out

In addition, instead of the moving distance signal of the tool post supplied to the speed detection unit 6, a detection signal from an encoder 4a provided on the motor 4 or other appropriate corresponding moving distance detecting means is supplied to form the current speed of the tool post 1. You can do it like this.

Reference numeral 8 denotes an acceleration detecting section of the tool post 1, which sequentially processes the speed and its travel time formed in the speed detecting section 6.

The current acceleration of the tool post 1 in the same unit time as the time of speed detection is sequentially formed, and the running time due to this acceleration is timed and accumulated.

Note that the acceleration may be formed by processing a signal detected by an acceleration sensor such as a piezoelectric element attached to the tool post 1.

9 is a successive comparison of the detected acceleration for each unit time.

A jerk detection unit that detects data indicating the difference between accelerations in each unit time (hereinafter referred to as jerk),
The actual data forming section is formed by steps 5 to 9 above.

Reference numeral 10 denotes a scheduled position setting section, and 11 indicates the speed per unit time of the tool rest 1, which is a numerical value of the same order of m as the current speed detected by the speed detection section 6, and the traveling time of the tool rest 1, which is the total travel or The speed setting section sets the time, and here the set value is outputted every unit time.

Reference numeral 12 indicates the acceleration of the tool post 1 per meter time at the same level as the numerical value detected by the acceleration detection section 11, and the amount of travel due to this acceleration is the total travel or total travel time of the tool post 1. In this case, the set value is outputted every unit time.

13 successively compares the set accelerations for each unit time,
Data indicating the difference between each acceleration, ie.

It is a jerk setting section that sets jerk, and it is a jerk setting section that sets jerk, and the above
13 forms a schedule data setting section.

The setting section 11.12 sets, for example, an acceleration section from the start of movement of the tool post 1 to the start of constant speed running, a constant speed section during constant speed running, during the entire running time of the tool post 1. Divided into deceleration sections from constant speed running to positioning,
The speed and acceleration may be set for each travel section.

Further, each of the setting units 10 to 13 is capable of arbitrarily setting and changing an appropriate tolerance for each set value.

14 is a position calculation unit that subtracts and compares the position signals from the position detection unit 5 and the position setting unit 10; 15 is a set speed supplied from the speed setting unit 11 and the speed detection unit 6 after the tool rest 1 starts traveling; A speed calculation section 16 performs a successive comparison operation on the supplied actual speed for each unit time, and 16 compares the set acceleration supplied from the acceleration setting section 12 and the actual acceleration A1 supplied from the acceleration detection section 8 for each unit time. An acceleration calculation section '17 performs a successive approximation calculation on the acceleration difference, that is, a jerk calculation section.

The calculation results of each calculation unit 14 to 17 are sequentially supplied to a control signal forming unit 18.

Since the signal forming section 18 is supplied with each setting signal from the setting sections 10 to 13, the forming section 18 adds or subtracts the calculated value of each signal added from the successive ratio calculation section to the setting signal. At the same time, the calculation results are compared with a preset tolerance, and when each numerical value is within the tolerance, the set signal is corrected, and each actual value is supplied to a computer 21, which will be described later. When the calculation result is outside the tolerance, the iQ constant signal is not corrected and its actual value is supplied to the computer 21.

19 is a drive control unit that forms the setting signal corrected above into a drive control signal for the motor 4 and provides the signal to the motor 4 to control it. An example of a control system for a machine to which this is applied is constructed.

20 is a machining data input section 1. For example, when machining is turning, data known in advance such as the material, hardness, and cutting depth of the workpiece are encoded by operating a numeral board or the like. The processed data can be input to the computer 21 as processed data.

The computer 21 receives the processing data supplied from the processing data input section 20 and the control signal forming section 1.
The data of the actual values of the machining conditions supplied via the input section 8 are stored as a set of data, and together with the machining data from the input section 20, the data is sent to the control signal forming section 18 during actual turning.
The actual value within the tolerance supplied to the actual value is stored.

In the computer 21, machining data such as material, hardness, cutting depth, etc. are sequentially stored for each machining of a plurality of work materials, together with actual values of machining conditions obtained during actual turning.

On the other hand, the computer 21 is also supplied with actual values of the machining conditions when the actual values exceed or under the tolerance of the set value, as data on abnormal machining.

If the actual value exceeds the tolerance of the set value, the turning operation is stopped at that point, and the cause of exceeding the tolerance is determined.
The reason etc. are supplied to the computer 21 by operating a tenet board or the like.

Therefore, in the computer 21, if abnormal machining occurs for each machining of a plurality of work materials, the machining data, the actual value of the abnormal machining, and its causes and reasons are sequentially stored. Become.

A plurality of pieces of data stored in the computer 21 in this way can be accessed by operating the keyboard 22, which includes a CRT for reading data, for example, and indexing any of the stored data or using appropriate keywords. The data is organized in such a way that it can be read out and displayed on the CRT as a batch of data.

In other words, when turning a certain workpiece material, the material name, hardness,
Alternatively, when machining data that is known in advance, such as the cutting depth, is read out from the data stored in the computer 21 by operating the keyboard 22, the machining data can be retrieved from the actual cutting data that was previously stored. The actual values during cutting for the rigid material that are the same or most similar are selected as machining conditions, read out, and displayed on a CRT or the like.

Therefore, in the present invention, the data of the read turning conditions and the tolerance are given to the setting units 10 to 13 to actually perform turning, and the detected data in this actual turning is
The control signal forming unit 18 obtains the comparison result with the turning data read and set from the computer 21, that is, the planned data. Here, if the obtained data is within the tolerance, the processing data and actual cutting data for this cutting are stored in the computer 21.

In this way, the computer 21 organizes and stores machining data and actual turning data for the actual turning operations that are repeatedly performed as described above for each machining process, so that the quality of the stored data can be improved.

The amount will be expanded over time.

On the other hand, even if the machining data is the same or similar to the machining data already stored in the computer 21, or is machining by a machining machine, actual values during turning may be subject to tolerances due to changes in the machine side, etc. It is possible that it may exceed. In such a case, the turning data is
Since this data is stored in the computer 21 as data indicating the cause of abnormal machining, etc. together with machining data of the machining object (work material), machining machine, etc., this data is also expanded over time.

〔Effect of the invention〕

In this way, for example, the computer 21 in which a large amount of machining data regarding turning and its actual turning data are organized and stored can arbitrarily read out and display the stored data for use.

For example, multiple processing machines NC1 to NCn (these machines may be either manual or automatic) are connected to each machine NC1.
The computer 21 is connected to a telephone line, a dedicated line, etc., along with an input section I-In provided corresponding to ~NCn, and a data reading/displaying section D□~Dn consisting of a reading keyboard, CRT, etc. By connecting through the CRT, the most appropriate turning conditions can be presented to the CRT when processing a workpiece for the first time or when turning is performed by an unskilled technician.

Setting turning conditions, which conventionally took a lot of time, can now be done in an extremely short time.

In addition, just before or when abnormal machining occurs, by comparing the abnormal machining data with the actual machining data, the cause can be quickly determined, so the actual If the data at the time of machining changes over time, it is also possible to determine the final outcome of the change based on the data of abnormal machining.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of the system of the present invention.

Claims (1)

[Scope of Claims] (a) A table, a spindle, a turret, etc. are controlled objects, and the driving source thereof is a signal indicating a scheduled speed per unit time that can be arbitrarily set or changed with respect to the controlled object, and a signal indicating a planned acceleration. A signal indicating the difference between the planned acceleration and the planned acceleration is used as a scheduled signal, and the device is driven by this scheduled signal to process the appropriate processing object, and during this processing, the same signal per unit time as the scheduled signal obtained from the controlled object side is processed. A signal indicating the actual speed, a signal also indicating the actual acceleration, and a signal indicating the difference between the actual accelerations are extracted as the actual signals. (b) When machining an appropriate workpiece, for each machining,
Comparing and calculating the corresponding signals of the planned signal and the actual signal for each unit time with an arbitrarily set tolerance for the planned signal and the planned signal, and determining whether or not this calculated value is within the preset tolerance. (c) When the above-mentioned calculated value is within the tolerance, the data of the above-mentioned actual value is stored in the computer in a readable manner along with the data regarding each processing object and processing machine, and the same object is processed by reducing the above-mentioned tolerance. (d) Repeat the same machining until the calculated values deviate from the tolerance, and record the actual value data for each machining in a computer so that it can be read out along with data regarding each processing object and processing machine. (d) When the calculated values deviate from the tolerance. When a discrepancy occurs, data on the actual value as well as data on the cause, the object to be processed, and the processing machine are recorded in a readable manner in the computer. (e) Data for setting machining conditions for any machining object, or data for determining the cause of abnormal machining that occurs during machining of any machining object, data for the machining object, processing machine, etc. A control system for a machine tool, characterized in that keywords are read from the computer.