JPH02292157A - Machine tool controller - Google Patents

Abstract

PURPOSE:To prevent deformation or damage of a cutter during cutting work by radiating a beam to the cutter, by acquiring deformation amount of the cutter through detection of a reflected beam, and by directly controlling the cutting feeding speed. CONSTITUTION:A beam such as laser light is radiated to the inside of a body of a cutter 3 from a beam radiating device 4 during cutting work, and change of a reflected beam is detected by a reflected beam detecting device 5. And deformation amount in the cutting reaction direction of the cutter 3 operated and processed at an operation part 9 of a controlling means 6 is collated and compared with the strength of the cutter 3, a cutter deformation allowable value and so on stored in a memory part 8. The optimum feeding speed is sent to a control part 10 base on the data in the operation part 9 and the cutting feeding speed is controlled. In the meantime, if the time up to detection of the reflected beam after radiation of the beam is detected, movement, removal and so on of the cutter due to loosening of a set screw and so on at a cutter 3 installation can be also predicted.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a control device applied to a numerically controlled tin (NC) type machine tool, etc. The present invention relates to a machine tool control device suitable for.

(Prior art) As is well known in the past, machine tools such as multi-axis NO lathes are capable of processing workpieces ranging from simple to complex shapes, and the shape of the workpiece is There is a wide variety. In particular, when cutting a three-dimensional free-form surface shape such as the blades of a water turbine launch, a cutting tool (hereinafter referred to as a power ivy) that cuts while rotating itself is used.
This cutter is subjected to reaction forces in multiple directions, and is forced to perform cutting while inevitably causing deformation such as bending.

Furthermore, as the hardness of the workpiece to be cut (m1) or the duration of the cutting process increases, the cutter must cut under more severe conditions, and the cutter is also required to have the strength and durability of the material 71.

However, since there is a limit to the material strength and durability of the cutter, if the strength limit of the cutter is exceeded for some reason, the cutter will be damaged.

In that case, the cutting process must be interrupted, the cutter replaced, and the process restarted, resulting in a decrease in work efficiency and operating efficiency. Particularly in recent years, as NC machine tools have been operated continuously day and night, and the shape of workpieces has become more complex, the cutting conditions for cutters have become stricter, leading to an increase in damage to cutters. is the reality.

(Problems to be Solved by the Invention) As described above, in cutting by NC machining, cutting must be continued even when the cutter is under severe conditions.

However, it is difficult to accurately grasp the reaction force acting on the cutter and deformation such as bending, and in the past, operators made judgments based on sounds and vibrations during cutting, and the cutter feed rate was artificially adjusted. Attempts have been made to prevent damage through adjustments and other methods, but this has not always been sufficient.

In addition, during long-term cutting operations such as continuous unattended operation day and night, even if the cutter is damaged, the machine tool continues cutting using the damaged cutter, which may cause damage to the workpiece. It was also unfavorable in terms of quality and safety.

If the set screw of the cutter attachment part loosens, problems such as a decrease in the processing accuracy of the workpiece may occur.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a machine tool-based In device that can prevent cutter deformation and damage during cutting and that can perform highly accurate cutting.

(Structure of the Invention) (Means for Solving the Problems) A machine tool control device according to the present invention includes a light beam emitting device that emits a light beam to a cutting tool of a machine tool, and a reflection device that detects a reflected light beam from the cutting tool. a light beam detection device, a displacement calculation means for calculating the displacement of the cutting tool in the cutting reaction force direction and the tool attachment direction based on the detection signal from the reflected light beam detection device, and a preset tool trajectory, tool strength, and tool displacement tolerance. Information storage means for storing information regarding the value, and calculation processing for determining whether the displacement generated in the cutting tool is within the tool strength by a comparison calculation between the output value of the displacement calculation means and the output value of the information storage means. Do that, and that's part 3! I
! The present invention is characterized by comprising a control means for controlling the feed rate and operation of the cutting tool based on the results.

(Function) According to the present invention, the light beam reflected from the cutting tool is detected, and thereby, changes in the reflected optical axis, etc. are determined. Then, based on this, the tool deformation flatness etc. are calculated, the cutting feed rate etc. are adjusted so as not to exceed a preset deformation tolerance value, and the cutting pressure of the tool is controlled appropriately.

(Embodiment) Hereinafter, an embodiment of the machine tool iiijl apparatus according to the present invention will be described with reference to the drawings.

This embodiment concerns the control of a multi-axis NC machine tool.

FIG. 1 shows the configuration of the device. The machine tool of this embodiment is for cutting, for example, the blade surface of a water turbine runner. A cutter 3 with a holding structure is attached. On the central axis of this cutter 3, a light beam emitting device 4 for emitting a light beam such as a laser is installed. A reflected light detection device 5 is provided for detecting the reflected light rays.All of these devices are installed inside the machine tool 1.

The light emitting device 4 and the reflected light detecting device 5 are each connected to a control stage 6 via a communication circuit. Control unit @6
The apparatus has a storage means consisting of an input section 7 for inputting cutter locus information, cutter strength, cutter deformation tolerance, etc. during cutting, and a storage section 8 for storing the input information.

The control means 6 also includes a calculation section 9 as a displacement calculation means for calculating the cutter deformation m and the optimum feed rate based on the signals output from the light beam emitting device 4 and the reflected beam device 5, and a machine tool. 1, and a control section 10 that controls the operation of the device. The calculation section 9 is connected to a graphic display device 11 through a communication circuit, and visually displays the deformed state of the cutter 3.

Next, the effect will be explained.

As shown in FIG. 2(a), when cutting the blade surface 12a of the water turbine runner 12 as a workpiece, the finished blade surface data point group 13 (
a) is set. The force cutter 3 then operates along the cutter offset point 13(b) shown in the figure. by the way,
The cross-sectional shape of the finished blade is as shown in Figure 2(b).
It has irregular extra thickness 14. Katsuta 3
Cut off the cutlet 1 while cutting off the excess meat 14 like this.
- Cut "C8" along point 13(b), but as the opening of the extra thickness 14 increases, the reaction force acting on the cutter 3 also increases.Then, when the reaction force exceeds the strength of the cutter 3, the cutter No. 3 causes defects, etc., and the workpiece is also damaged.

FIG. 3(a) shows the relationship between the reaction force acting on the cutter 3 and the feed rate when cutting is performed using a conventional control device.

The cutter operating distance IIIli1 shown on the horizontal axis in FIG. 3(a) corresponds to the operating amount of the cutter 3 along the cutter offset point 13(b) in FIG. 2(b). Here, as shown in Fig. 3(a), when the cutter 3 operates at a constant feed speed ■,
The reaction force U acting on the cutter 3 increases or decreases depending on the amount of excess material, and if the reaction force U exceeds the cutter strength RH, the cutter 3 will be damaged.

In contrast, in this embodiment, a light beam such as a laser beam is emitted from a light beam emitting device 4 into the body of the cutter 3 shown in FIG. 1 during cutting, and changes in the reflected beam are detected by a reflected beam detector 5
Detected by. Then, the amount of deformation of the cutter 3 in the direction of the cutting reaction force calculated by the calculation section 9 is compared with the cutter strength, cutter deformation tolerance, etc. stored in the storage section 8, and the data in the calculation section 9 is used. Based on this, the optimum cutting feed rate is transmitted to the control unit 10, and the cutting feed rate is controlled.

FIG. 3(b) shows the relationship between the reaction force exerted on the cutter 3 and the feed rate when cutting is performed by the control device of this embodiment. As shown in the figure, according to the present embodiment, even if the amount of excess material increases and the reaction force U acting on the cutter 3 increases, the control unit 10 reduces the cutting feed rate to prevent the cutter 3 from working. Since an increase in the reaction force U can be suppressed, control can be performed so that the reaction force U does not increase beyond the cutter deformation allowable value RMo stored in the storage unit 8.

Note that if the deformation of the cutter 3 does not remain within the deformation tolerance even if the cutting feed rate is made extremely small, the calculation unit 9! A command to stop feeding is output to the control section 10, and the machine tool 1 immediately stops. Then, at the same time as cutting is interrupted, the graphic display device 11 displays a warning that the cutter is missing or damaged. This also makes it possible to speed up operator recognition and processing.

On the other hand, by detecting the time from when the light beam is emitted until the reflected light beam is detected, it is possible to predict the movement or falling off of the cutter due to loosening of the set screw of the cutter 3 attachment part.

That is, as shown in the first factor, the distance MIo between the cutter 3 fixed to the cutter mounting part 2 with a set screw or the like, and the light beam rli wire device 4 and the reflected light beam detection device 5 is Since the time from that point until the cutter is removed is essentially constant, the time t from when the light beam is released until the reflected light beam is detected by the reflected light detection device 5 is constant, as shown in FIG. 4(a).

However, for example, if the reflected light detection time t increases or decreases, the distance 1114! shown in FIG. 1 increases! .

It can be determined that the distance I! has changed as shown in X2 and X2 in FIG. 4(b), and the distance I! Changes in o, ie, the cutter 3 coming off, etc., are displayed, allowing the operator to recognize them.

〔Effect of the invention〕

As described above, according to the present invention, the amount of deformation of the cutter is determined by emitting a light beam to the cutter and detecting the reflected light beam, and the cutting pressure can be optimally controlled by directly controlling the cutting feed rate. , damage to the cutter can be prevented and the life of the cutter can be extended. In addition, by detecting the time from when a light beam is emitted to when it is reflected, it is possible to prevent the cutter from attaching abnormally or falling off, improving work safety, and greatly improving the operating efficiency of machine tools. The effect is produced.

[Brief explanation of drawings]

Fig. 1 is a purchasing diagram showing one embodiment of the present invention, Fig. 2 (a>
．． (b) is an explanatory diagram showing the cutting state, and FIG. 3(a). (b) is a graph showing the relationship between reaction force and feed rate by comparing the conventional example and this embodiment.
) is a graph showing the effect of predicting the coming off or falling off of the cutter based on the detection time of the light beam. 1... Machine tool, 3... Cutting tool (cutter), 4...
...Light ray emitting device, 5...Reflected ray detection device, 6...
- Control means, 7, 8... Information storage means (input section, storage section) 9.10... Displacement calculation means (calculation section, control section).

Claims (1)

[Claims] a light beam emitting device that emits a light beam to a cutting tool of a machine tool;
a reflected ray detection device for detecting a reflected ray from the cutting tool; a displacement calculation means for calculating the displacement of the cutting tool in the cutting reaction force direction and the tool mounting direction based on the detection signal from the reflected ray detection device; tool path,
Information storage means for storing information regarding tool strength and tool displacement tolerance; and a comparison calculation between the output value of the displacement calculation means and the output value of the information storage means, and the displacement generated in the cutting tool is within the tool strength. 1. A machine tool control device comprising: a control means for performing arithmetic processing as to whether or not the cutting tool is being fed, and for controlling the feed rate and operation of the cutting tool based on the processing result.