KR101842995B1 - Real-time control method of numerical control machine tool - Google Patents

Abstract

A control method of a real time process in accordance with a measurement cutting load of the present invention comprises: a proper cutting load setting step of setting a proper cutting load; a pre-control section setting step of setting a pre-control section in which a cutting load applied to a tool within a process passage increases or decreases; and a processing step of implementing real time control by increasing and decreasing the transfer speed of the tool such that a cutting load value measured in real time can be equal to that of the proper cutting load relative to the cutting load and the proper cutting load measured in real time when the processing is performed, wherein prediction control applied with the transfer speed of the tool as a predetermined value is performed before real time control in the pre-control section.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method of a real-

The present invention relates to a method of controlling a machining process of a machine tool, and more particularly, to a method of controlling a tool feed rate on the basis of a cutting load measured in real time, And a point is a control method of a machining process in which machining is performed through information obtained arithmetically before machining.

Generally, in machining a workpiece through a numerical control machine tool, a rotating tool is transported in a specific direction and carries out a portion where it intersects with the workpiece.

The machining quality of the workpiece is determined according to the turning amount or the feed speed of the tool, and the time required for machining depends on the amount of rotation and the feed speed. However, the machining quality and machining time are different from each other Therefore, setting the turning amount and the feed rate of the tool so that the machining can be performed by only applying the optimal time for the optimal machining quality is an important factor in the machining operation through the machine tool.

In addition, depending on the geometrical shape of the object to be processed, the cutting load applied to the tool may be drastically lowered or a region where the cutting load increases sharply may be generated. If the control of the proper feed rate is not performed in such a region, Which may lead to the destruction of.

Accordingly, there is a need for an optimized control method for the rotation and the feed speed of the tool, and various techniques for controlling the rotation and the feed speed of the tool have been proposed and carried out.

For example, by simulating the machining operation in advance through factors that may be variables in the machining performance such as the type of tool, the material to be machined, and the machining path, A method of setting the rotational speed or the feed speed of the tool in accordance with the above-described method is also used.

However, when the machining is performed by setting the appropriate tool rotation or feed speed according to the machining path through the simulated information, it is common to secure a stable tool and the behavior of the object by setting a wide tolerance range. And it takes a long time to process.

Alternatively, a method of measuring the physical force applied to the tool or the object in real time and controlling the rotation or the feed speed of the tool immediately according to the measured physical force is widely performed. However, according to the geometrical shape of various objects, There is a possibility that there is a point where the tool or the workpiece is abruptly increased or decreased. In such a section, there is a problem that the tool or the workpiece is often damaged and continuous monitoring is required.

Therefore, a method for solving such problems is required.

The present invention has been devised in order to solve the problems of the prior art described above, and it is an object of the present invention to provide a cutting tool capable of performing optimized processing in real time by controlling a feed rate of a tool on the basis of a cutting load measured during machining, A sudden increase or a sharp reduction period of the cutting load can be predicted through the information calculated through the simulation to provide a machining method capable of performing rapid machining and improving stability.

The problems of the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, the present invention provides a control method of a real-time machining process according to a measured cutting load, comprising: a proper machining load setting step of setting a proper machining load; a step in which a cutting load applied to the tool increases or decreases rapidly In which the cutting load is measured in real time and the optimum cutting load is compared with the cutting load measured in real time by the tool during the machining operation, so that the value of the cutting load measured in real time becomes equal to the proper cutting load. And a real time control is performed by increasing or decreasing the speed. In the control period, the predictive control in which the feed rate of the tool is applied as a predetermined value is performed prior to the real time control.

The predictive control first decreases the feed rate of the tool in a period in which the cutting load of the control section rapidly increases, and increases the feed rate of the tool in the section in which the cutting load of the control section is first reduced rapidly.

Alternatively, in the predictive control, the feed rate of the tool is reduced ahead of the predicted behavior interval in the first region where the cutting load of the control region is rapidly increased, and the feed rate of the tool is decreased .

Then, the length of the section is determined in proportion to the amount of sudden increase or decrease in the cutting load of the control section.

Alternatively, the priority control setting step may include an arithmetic cutting load calculating step of calculating an arithmetic cutting load according to the machining path obtained by substituting the tool type, the object to be machined, the machining path and the feed speed, and the step of calculating the arithmetic cutting load And a priority control period derivation step of setting the rapid decrease period as a priority control period.

In order to solve the above-described problems, the present invention provides a control method of a real-time machining process according to a measured cutting load, in which a cutting load generated during machining is measured to control a feed velocity in real time, Therefore, there is an advantageous effect that the machining time can be shortened and the stability can be ensured even in the sudden increase of the cutting load due to the drastic change of the machining volume which can not be predicted in the control of the feed rate in real time.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims.

FIG. 1 is a flowchart illustrating a step of setting a priority control period of a method for controlling a real time processing process according to a measured cutting load according to an embodiment of the present invention.
2 is a flowchart illustrating a method of controlling a real-time machining process according to a measured cutting load according to an embodiment of the present invention.
Fig. 3 is a schematic view showing a tool and an object to be rotated and transported; Fig.
4 is an ideal graph of a cutting load measured in real time control of a real time machining process control method according to a measured cutting load according to an embodiment of the present invention.
FIG. 5 is a graph showing a change in a feed rate according to a machining path arithmetically determined in order to set a priority control period of a real time machining process according to a measured cutting load according to an embodiment of the present invention.
FIG. 6 is a graph showing that a dangerous period may occur in a rapid decrease and a rapid increase of a cutting load during a real-time control of a real time processing process according to a measured cutting load according to an embodiment of the present invention.
FIG. 7 is a graph illustrating an example in which real-time control and predictive control of a control method of a real-time machining process according to a measurement cutting load according to an embodiment of the present invention is applied.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In describing the present embodiment, the same designations and the same reference numerals are used for the same components, and further description thereof will be omitted.

The control method of the real time machining process according to the measured cutting load according to the present invention can be implemented as follows.

FIG. 1 is a flowchart illustrating a step of setting a priority control period of a method for controlling a real time machining process according to a measured cutting load according to an embodiment of the present invention. FIG. 2 is a flowchart illustrating a real time machining process according to an embodiment of the present invention, And a control method of the machining process.

1 and 2, a method of controlling a real-time machining process according to a measured cutting load according to an embodiment of the present invention is a method of machining an object 20 through a machine tool, (S200) for setting a priority control period, which is a period in which the cutting load rapidly increases or decreases in the machining path, and a cutting load and an appropriate cutting load measured in real time during the machining operation (S320) is performed by increasing or decreasing the feed rate of the tool so that the value of the cutting load measured in real time is equal to the proper cutting load. The control period includes a feed rate of the tool The prediction control S312 applied as the preset value is performed in preference to the real time control S320.

Each of the above-described configurations will be described in detail below.

4 is a graph showing an ideal graph of a cutting load measured in real-time control of a real-time machining process control method according to a measured cutting load according to an embodiment of the present invention, and FIG. 3 is a schematic view showing a tool and an object to be rotated, FIG. 5 is a graph showing a change in a feed rate according to a machining path arithmetically determined for setting a priority control period of a control method for a real time machining process according to a measured cutting load according to an embodiment of the present invention. FIG. 7 is a graph showing that a dangerous period may occur in a rapid decrease and a rapid increase of a cutting load during a real-time control of a real time machining process according to a measured cutting load according to an embodiment of the present invention. Time control and predictive control of a control method of a real-time machining process according to a measured cutting load according to the present invention.

3, in an embodiment of the present invention, in a process in which a tool 10, which is rotated and travels along a constant path, is processed to have a volume that intersects with the object 20, So that the machining can be performed more quickly while maintaining the machining quality, but it is possible to prevent the tool 10 and the object 20 from being damaged.

The object to be processed 20 can have various geometrical shapes and the cutting load added to the tool 10 having the same feed speed and the same amount of rotation varies depending on the shape of the object 20 to be processed.

As shown in Fig. 3, interference occurs between the tool 10 and the object 20 at point a, and the cutting load measured through the tool 10 increases.

the cutting load gradually increases from a to b, and the cutting load generated at the tool 10 is remarkably reduced due to a drastic decrease in the volume cut at the point b.

Thus, if there is no control of the appropriate feed rate, the cutting load applied to the tool 10 at the point b is significantly reduced, but the tool 10 can still be fed at a slower speed and the machining efficiency can be lowered.

At the point c, the cutting load generated in the tool 10 is remarkably increased due to a sharp increase in the cutting volume. Such an abrupt increase in the cutting load causes damage to the tool 10, Which may lead to the destruction of.

The geometrical shape of the object shown in Fig. 3 shows one example in which the abrupt cutting load is reduced or increased, and can be applied to the machining of objects of various shapes according to the embodiment to which the present invention is applied, The shape of the point at which the load suddenly increases or decreases rapidly is not limited to the shape shown in FIG.

The proper cutting load setting step S100 is a step for setting a proper cutting load S100 as a reference for adjusting the feeding speed so that the cutting load generated in the tool 10 can be kept constant as shown in Fig. .

The tool 10 and the object 20 can be stably cut according to the material and the processing path of the tool 10 and the object 20 so that the cutting load value The appropriate cutting load is set.

First, in step S200, information such as material, type, material, shape, machining path, and feed rates of the tool 10 to be applied according to the embodiment of the present invention is stored in the NC (U) through the derived data. In this case, the cutting speed of the cutting load is reduced to a predetermined value, And a priority control period in which the stability of the tool 10 or the object 20 is threatened during the machining process is selected and input to the machine tool.

The control section may be a point at which a sudden impact or vibration may be generated in the tool 10 or the object 20 by deviating from the increasing / decreasing width of the appropriate cutting load, or the cutting load may be rapidly reduced, It can be set as a section in which the feeding can be set quickly.

The machining step S300 basically increases the feed rate of the tool 10 when the cutting load measured as shown in Fig. 4 is lower than the optimum cutting load, and when the measured cutting load is a value higher than the proper cutting load Real time control (S320) is performed to reduce the feed rate of the tool (10) and maintain the feed rate of the tool (10) when the measured cutting load is equal to or within the tolerance range of the appropriate cutting load value.

This real-time control (S320) promptly responds to the cutting load in real time to determine the feed speed of the tool (10), so that it is possible to control the tool (10) promptly according to the actual processing conditions, There is an advantage that machining can be performed at the tool 10 feed rate.

However, as shown in Fig. 6, the cutting load reducing portion U and the cutting load increasing portion D can be generated in accordance with the change of the geometrical shape of the object 20, The start of increasing the feed speed of the tool 20 is relatively slow and the sharp impact may occur in the cutting load span D and the tool 10 such as the danger zone R on the graph, There is a point where a large impact is generated in the tool 20, and the possibility of causing the tool 10 or the object 20 to be damaged at such a point is remarkably increased.

Therefore, in one embodiment of the present invention, the prediction control S312 may be performed prior to the real time control S320, and the prediction control S312 may be performed in the set priority control period.

Therefore, the processing step S300 can be performed according to the flow as shown in Fig.

If the current machining point is the first control period in the machining, the predictive control (S312) is performed. If the machining point belongs to the machining cut-off period (U) in the control period, So that the feed speed of the post-tool 10 is quickly increased.

More specifically, as shown in FIG. 7, the feed speed is increased at a position where the cutting load is reduced at a position spaced by a certain distance from the point b at which the sharpening section U starts, So that the tool 10 can be quickly moved without affecting the quality of the tool 10 because the tool 10 is changed in the speed of the tool 10.

The predictive behavior section G can be determined in proportion to the sharpness or the sharpness of the cutting load depending on the geometrical shape of the object 20, and can be variously determined according to the embodiment to which the present invention is applied.

If the cutting speed is within the cutting load surplus period D in the control period, the feed speed of the tool 10 is decreased by the predicted behavior period G and the tool 10 and the workpiece 20 So as to mitigate the impact between the two.

The predictive behavior section G in the cutting load surplus period D can also be determined in proportion to the surge of the first control period or the cutting load value which is rapidly reduced as described above.

The amount of increase or decrease in the feed rate of the tool 10 during the execution of the predictive control S312 in the control period may be determined according to the amount of cutting load or the amount of rapidly increasing cutting load in each priority control period.

If the current machining point does not belong to the priority control period during the machining, the real time control of the above-described method (S320) is performed, and this series of machining steps (S300) can be repeatedly performed until machining is completed.

It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or scope of the invention as defined in the appended claims. It is obvious to them. Therefore, the above-described embodiments are to be considered as illustrative rather than restrictive, and the present invention is not limited to the above description, but may be modified within the scope of the appended claims and equivalents thereof.

10: Tools
20: object to be processed
R: Hazard section
U: Cutting load
R: Increasing cutting load
G: Predictive behavior section

Claims (5)

A method of processing an object to be processed through a machine tool,
An appropriate cutting load setting step of setting a proper cutting load;
A priority control period setting step of setting a priority control period in which the cutting load rapidly increases or decreases in the machining path; And
A machining step in which real time control is performed by increasing or decreasing a feed rate of a tool so that a value of a cutting load measured in real time in comparison with a cutting load measured in real time in real time and a proper cutting load becomes equal to the proper cutting load; Including,
Wherein the priority control period is performed in such a manner that a predictive control in which the feed rate of the tool is applied as a predetermined value is prioritized over the real-
Wherein the predictive control comprises:
Wherein the feed speed of the tool is reduced in advance in a section in which the cutting load of the priority control section is rapidly increased by the predicted behavior section and in the section in which the cutting load of the priority control section is reduced rapidly, A Method for Controlling Real Time Machining Process in Accordance with Measuring Cutting Load.
delete delete The method according to claim 1,
The predictive behavior section may include:
Wherein the length of the section is determined in proportion to an increase or decrease in the cutting load of the priority control section.
The method according to claim 1,
Wherein the priority control period setting step comprises:
An arithmetic cutting load calculating step of calculating an arithmetic cutting load according to a machining path obtained by substituting a tool type, an object to be machined, a machining path and a feed rate; And
A priority control period derivation step of setting a rapid or abrupt period of the arithmetic cutting load according to the machining path as a priority control period;
A method for controlling a real time machining process in accordance with a measured cutting load.

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