JPS6274552A - Method for detecting abnormality in machine tool - Google Patents

Abstract

PURPOSE:To detect abnormality even if there is dispersion in a machining starting position as an absolute position by comparing machining loads in the relative positions of a machining tool and a workpiece, with the machining starting surface of said workpiece as the reference position. CONSTITUTION:When there is dispersion in the machining starting surface D' of a workpiece B, its cutting load curve M' rises before the cutting load curve M of a standard workpiece, in the absolute relation of positions. When a cutting tool A is brought into contact with the machining starting surface D', a workpiece touch signal generating part G gives a starting signal to a control part E, to detect a machining load each time the cutting tool A is moved by a unit distance l/n with respect to the workpiece B. The machining load thus detected is compared in order with each of the machining loads which are stored in a memory part I as the position information of 1-n positions. And, if the machining load is out of a tolerable range, the control part E gives an abnormal signal to an abnormality indicating part L.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is designed to reduce the load on the machining tool to 1F' below the so-called standard when an abnormality occurs in the machining tool of a machine tool or yellowing of the workpiece occurs. The present invention relates to a method for detecting a constant load of a machine tool, which detects a constant load of 5TI compared to one load.

(Traditionally, the zodiac is not lit) The machining load when the workpiece is regularly applied is compared with the standard machining load when the workpiece is normally rejected. A machine tool failure detection and monitoring method disclosed in No. 49145 is known. In this method, the iE constant cutting load (standard cutting load) is sampled and detected at predetermined time intervals and stored, and This method performs sampling detection and compares this tooth detection value with the standard cutting load, and if it is not within the allowable range, it is determined to be abnormal.

(Problems to be Solved by the Invention) However, in the conventional method described in 1-1, the starting point of sampling of the cutting load is commanded by a predetermined load L program, so the sampling is performed only when one cutting tool is used. This is done even before contact with the workpiece. Therefore, due to dimensional errors between the standard workpiece and the continuously machined workpiece, if the positions of the pressurization start surfaces of the two workpieces differ from the sunblink start point, there will be a difference in the cutting start time of the two, and the cutting load will be reduced. Sampling with respect to time 1-1
A discrepancy occurs between the cutting load diagram when cutting a standard workpiece and the cutting load diagram when continuous pressure is applied. For this reason, J! I! Even if the cutting load value during continuous application is within the allowable range, it may be determined to be abnormal, or conversely, it may be determined to be normal even though it is outside the allowable range.

Therefore, an object of the present invention is to compare the force load of the workpiece with the pressurized load during normal machining of a standard workpiece, thereby improving the standard To provide an abnormality detection method for a machine tool that can accurately determine whether a machining abnormality is present even if variations occur in the positions of a machining start surface of a workpiece and a machining start surface of a continuously machined workpiece. It is in.

(Means and operations for solving the problem) In order to achieve the above-mentioned object, the present invention sets the starting position of the caloric load on the workpiece to the starting surface of the workpiece. At the same time, sampling detection of the pressurization load is to be performed every rn distance from the pressurization start surface. Specifically, when pressurizing a standard workpiece, apply pressure from the pressurization start surface of the standard workpiece [predetermined pressure 1iI in the direction of movement of the tool! r! a step of setting a trace and equally dividing the machining stress into unit distances of n4V4, and recording the pressurized load each time the machining tool moves the unit distance as the standard machining load; and when machining the workpiece. a step of detecting the machining time and the machining load of the tool every time the machining period moves by the unit distance from the pressurization start surface of the workpiece, and comparing the machining load with the corresponding standard machining load; It has a configuration with the following features.

(Example) Hereinafter, an example of the present invention will be described based on the attached drawings.

Fig. 1 shows an embodiment in which the method of the present invention is applied to a machine tool for drilling a hole C in a workpiece B with a cutting tool A, and Fig. 2 shows a block diagram of the apparatus used to implement this method. represents a diagram. In Figure 2, E is the control section, F is the command section, G is the workpiece signal generation section, H is the calculation section, ■ is the storage section, and J
indicates a position detector, L indicates a cutting load detector, and L indicates an abnormality display section, respectively.

The following describes the process of normally machining a standard workpiece, detecting the standard machining load, and recording it. In this process,
When the command section F issues a command to the control section E to detect and store the cutting load during normal machining, J Set , and specify the value of n when dividing the father into n equal parts.When the cutting tool A rotates and comes into contact with the pressurization start surface of the workpiece B, the workpiece tangent strength generation part When G issues a start signal to the control section E, the control section E calculates the fraction of n calculated by the niT calculation section H according to the command from the command section F.

Based on the relative position signal of the cutting tool A with respect to the workpiece B, which is emitted by the position detector J, and the cutting load signal, which is emitted by the load-bearing detector K, the distance cutting is divided by n1''V. The cutting load of 9J at each point ~n is detected as the standard machining load, and the soil is fertilized at each of the points 1~n as the positional information of 1.M in Figure 1 is like this. 1.
The cutting load curve obtained is shown below. Then, the cutting load after point a is detected at every predetermined position interval and recorded tα.

Next, the process of continuously machining the workpiece B will be explained.

In this case, if there is variation in the machining start surface D' of the workpiece B and the profile D' is located in front of the pressurization start surface of the standard workpiece, then in terms of the absolute positional relationship, the first
As shown in the figure, the four negative cutting curves M' are in front of the cutting load curve M of the standard workpiece; However, in the method of the present invention, when the cutting tool A comes into contact with the pressing start surface D', the workpiece contact signal generation section G issues a start signal to the control section E, and (
The machining load is detected every time the machine moves by 1/n.

In this way, the detected machining load is recorded.
, , (Sequentially compared with TANIKACHO-4η stored in IBI as the position information of l-n position, and if it is outside the permissible range, a permanence signal is issued to the control unit E or the abnormality display unit.

The same applies when the machining start surface of workpiece B is located behind the machining start surface of the standard workpiece.

Note that by increasing the value of n used to divide the Kacho distance sentence, the one-detection performance can be easily improved.

Fig. 3 shows a workpiece touch sensor for detecting when cutting tool A comes into contact with the machining start surface of workpiece B. In the figure, the movable part S1 of switch S corresponds to cutting tool A; 4j, 32 corresponds to the machining start surface D (D') of the workpiece B. T is an exciting core for passing a circulating current through the machine tool, and when the cutting tool contacts the workpiece and the swift S is closed, a closed loop is formed, and the circulating current is detected by the detection core U.

In addition, although a cutting tool was used as a processing tool in the above-mentioned example, it is not limited to this.

(Effects of the Invention) As explained above, according to the abnormality detection method of the present invention,
Based on the machining start surface of the workpiece, add 1 r, 4t
Since the applied load at the relative position between the machine and the workpiece is compared, it is possible to accurately detect the presence or absence of an abnormality even if there is a 7-7 deviation in the machining start position as an absolute position.

1) 9I'Ii explanation of 4 drawings FIG. 1 is a diagram for explaining the present invention in detail.

FIG. 2 is a block diagram of an apparatus for carrying out the method of the invention.

FIG. 3 is a schematic configuration diagram of the Tanchi sensor.

A: Cutting - [tool B: Work D, D': Machining start surface M, M’: Cutting load diagram Hair: processed 1/n: Unit distance

Claims (1)

[Claims] (1) When machining a standard workpiece, set a predetermined machining distance from the machining start surface of the standard workpiece in the direction of movement of the machining tool, and equally divide the machining distance into n unit distances,
storing a machining load as a standard machining load each time the machining tool moves the unit distance; A method for detecting an abnormality in a machine tool, comprising the steps of: detecting a machining load and comparing the machining load with the corresponding standard machining load.