KR20150073727A - Positon error correction device of cloum in super-size machine tool and method therof - Google Patents

Abstract

An object of the present invention is to detect a position error amount of a column caused by thermal strain generated by a temperature in accordance with frictional heat generated when processing in a gate type machining center and change of the surrounding environment in a working field. In case a position error amount exceeds an allowable limit, a position error amount of the detected column is corrected by a column position correction unit to reduce position error correction time and costs of the column. A position error correction device of a column in a machine tool and a correction method thereof may improve processing accuracy of a workpiece.

Description

Technical Field [0001] The present invention relates to a position error correction apparatus and method for correcting a position error of a column in a large machine tool,

The present invention relates to an apparatus and method for correcting a position error of a column in a large machine tool, and more particularly to a system and method for correcting a position error of a column in a large machine tool, And corrects the position error of the detected column when the position error exceeds the allowable limit, thereby reducing the position error correction time and cost of the column, The present invention relates to a position error correction apparatus and method for correcting a position error of a column in a machine tool.

A wide range of machine tools, including turning centers, machining centers, doormat machining centers, swiss turns, electric discharge machines, horizontal NC boring machines and CNC lathes, are widely used in a variety of industrial applications to suit their application.

Most machine tools today have a computerized numerical control (CNC) device that can automatically machine three-dimensional machining by adding a computer function to a numerical control (NC) device.

In general, a double colum type machine center, which is a type of machine tool, is a device that directly processes a three-dimensional shape by exchanging a plurality of head attachments, unlike a lathe which is responsible for simple processing.

1 shows a perspective view of a conventional machine tool. Referring to FIG. 1, a conventional machine tool, particularly a door machining center, will be described. As shown in FIG. 1, a conventional machine tool 1, particularly a door machining center, is provided with a table 2 on the ground and a table 3 mounted on the top of the bed 2 so as to be movable in the X-axis direction. A pair of columns 4 are installed on both sides of the bed 2 perpendicular to the paper surface. A cross rail (5) is provided on the upper part of the pair of columns (4). And the saddle 6 is installed on the cross rail 5 so as to be movable left and right. A spindle unit 7 is installed on the lower portion of the saddle 6 so as to be movable up and down. At one end of the spindle unit 7, a tool for machining the workpiece is detachably mounted. The operation panel 8 controls the machine tool through the CNC. It is possible to process a three-dimensional product in a pre-inputted form through the operation panel 8.

In general, currently used machine tools are designed with a focus on the structural rigidity of the machine tool itself in order to improve the productivity through a strong cutting force. Most of the components of the machine tool are designed and fabricated with steel and casting at 20 ° C to ensure a certain stiffness of the machine tool.

The steel and the cast are deformed by about 12 μm per 1 m whenever the temperature changes by 1 ° C. In today's large-scale machine tools, high-speed machining is frequently performed to improve productivity, and thermal deformation may occur in the column of the machine tool due to frictional heat generated during machining of the workpiece. In addition, thermal deformation may occur in the column due to the temperature difference due to changes in the surrounding environment of the workplace where the machine tool is installed.

The column is also made of steel and casting, and when thermal deformation occurs in the column due to the temperature difference due to frictional heat and changes in the surrounding environment, a positional error occurs in the X-axis direction of the column. Such a positional error of the column has a problem that the precision of the workpiece is deteriorated.

In addition, since the own weight of the column is too heavy, it takes a lot of time and cost to correct the position error of the column, and there is a problem that the accurate position error can not be corrected even if the position error is corrected.

Korean Patent Laid-Open Publication No. 10-2007-0118666

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a method and apparatus for correcting a position error of a column due to heat generated by frictional heat generated in a machining center, And corrects the position error of the column detected when the position error exceeds the allowable limit by the column position correcting unit to reduce the position error correction time and cost of the column and improve the machining accuracy of the workpiece And a correction method of the position error of the column in the machine tool.

In order to accomplish the object of the present invention, there is provided an apparatus for correcting a position error of a column in a large machine tool according to the present invention, comprising: a pair of columns vertically installed on both sides of a bed; A level unit provided on the upper surface of the upper frame to be connected in the X-axis direction; A plurality of sensors disposed at regular intervals on an upper surface of the upper frame so as to be adjacent to the level unit to measure a distance to the level unit; A column position error correction unit for moving the pair of columns in the X-axis direction; And a control unit.

In another preferred embodiment of the apparatus for correcting a position error of a column in a large machine tool according to the present invention, an apparatus for correcting a position error of a column includes: A correction mode selection unit; And a correction period selector.

In another preferred embodiment of the apparatus for correcting the position error of a column in a large machine tool according to the present invention, each of the column position error correcting units of the position error correcting apparatus of the column includes a power for moving the column in the X- ; A fixing bracket installed on one side of the column; A ball screw having one end connected to the driving unit and the other end connected to the fixing bracket and rotated by the power of the driving unit; A conveying unit that is installed to move on the ball screw through the ball screw; And a connecting member having one end connected to one side of the fixing bracket and the other end connected to one side of the feeding unit.

In another preferred embodiment of the apparatus for correcting the position error of a column in a large machine tool according to the present invention, the control unit of the apparatus for correcting the position error of the column has a height of the pair of columns, a length of the level unit, A basic data storage unit for storing basic data on a positional error with respect to the sensor; A memory unit for storing data on the minimum position error correction amount and the maximum position error correction amount of the column; A signal receiving unit for receiving a signal of a sensor that senses a level unit among the plurality of sensors; A calculation unit for calculating a position error correction amount of the column based on a signal received by the signal reception unit and data stored in the basic data storage unit; A comparison unit for comparing the position error correction amount calculated by the calculation unit with the minimum position error correction amount of the column stored in the memory unit and the maximum position error correction amount; And a signal transmission unit for transmitting a signal for a position error to the column position error correction unit when the position error correction amount exceeds a minimum position error correction amount and is less than a maximum position error correction amount as a result of the determination by the comparison unit have.

In order to accomplish the object of the present invention, there is provided a method for correcting a position error of a column in a large machine tool according to the present invention, comprising the steps of: determining a height of a pair of columns, a length of a level unit, Storing basic data; Storing a minimum position error correction amount and a maximum position error correction amount of the pair of columns in a memory; Selecting a correction mode in the correction mode selection unit; selecting a position error correction period of the column in the correction period selection unit; Receiving a signal from a sensor that senses the level unit among the plurality of sensors in a signal receiving unit; Calculating a position error correction amount of the pair of columns by the signal received by the signal receiving unit and the data stored in the basic data storage unit in the calculation unit; Comparing a position error correction amount calculated by the calculation unit with a minimum position error correction amount of a column stored in the memory unit and a maximum position error correction amount; And a control unit for transmitting a signal for a misalignment to a column position error correction unit to correct a positional error of the pair of columns when the position error correction amount exceeds a minimum positional error correction amount and is less than a maximum positional error correction amount Step.

In another preferred embodiment of the method for correcting a position error of a column in a large machine tool according to the present invention, a method of correcting a position error of a column may further include displaying a position error correction amount on a display unit.

In another preferred embodiment of the method for correcting a position error of a column in a large machine tool according to the present invention, a method for correcting a position error of a column includes a step of comparing a position error correction amount, And displaying on the display unit when the number of display units exceeds a predetermined value.

The apparatus and method for correcting a position error of a column in a large machine tool according to the present invention have the effect of improving the processing accuracy of a workpiece by correcting a positional error of a column in a large machine tool in real time.

In the apparatus and method for correcting position errors of a column in a large machine tool according to the present invention, a position error of a column is accurately corrected by a column position error correcting unit by a plurality of sensors and a controller, The time and cost required for the correction of the position error can be reduced.

In addition, the apparatus and method for correcting a position error of a column in a large machine tool according to the present invention can improve the productivity of a machine tool by minimizing the time required to correct the column position error and correcting the optimum column position quickly have.

1 shows a perspective view of a conventional machine tool.
2 is a conceptual diagram of a position error correction apparatus for a column in a large machine tool according to a preferred embodiment of the present invention.
FIG. 3 is a conceptual diagram of a state in which a level unit and a sensor are mounted in a column position error correction apparatus of a large machine tool according to a preferred embodiment of the present invention.
Figure 4 shows a side view of Figure 3;
5 is a conceptual diagram of a column position error correction unit in a column position error correction apparatus for a large machine tool according to a preferred embodiment of the present invention.
FIG. 6 is a conceptual diagram of an installation state of a level unit and a sensor in a column position error correction apparatus of a large machine tool according to a preferred embodiment of the present invention.
7 is a conceptual diagram for calculating a position error correction amount of a column in a column position error correction apparatus of a large machine tool according to a preferred embodiment of the present invention.
8 is a flowchart illustrating a method of correcting a position error of a column in a large machine tool according to a preferred embodiment of the present invention.

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals are used to refer to like elements throughout.

FIG. 2 is a conceptual diagram of an apparatus for correcting a position error of a column in a large machine tool according to an embodiment of the present invention. FIG. 3 is a schematic diagram of a column position error correction apparatus of a large- Fig. 4 is a side view of Fig. 3. Fig. 2 to 4, an apparatus 100 for correcting a position error of a column in a large machine tool according to a preferred embodiment of the present invention will be described. 2, an apparatus 100 for correcting a position error of a column in a large machine tool according to a preferred embodiment of the present invention includes a level unit 10, a plurality of sensors 20, a column position error correcting unit 30 ), And a control unit 40.

The above-mentioned bed 2 is provided on the ground, and the table 3 is provided on the top of the bed 2 so as to be movable in the X-axis direction. A pair of columns 4 are installed on both sides of the bed 2 perpendicular to the paper surface. The upper ends of the pair of columns 4 are connected by the upper frame 11. A cross rail (5) is provided on the upper part of the pair of columns (4). And the saddle 6 is installed on the cross rail 5 so as to be movable left and right. A spindle unit 7 is installed on the lower portion of the saddle 6 so as to be movable up and down. At one end of the spindle unit 7, a tool for machining the workpiece is detachably mounted. The operation panel 8 controls the machine tool through the CNC.

The level unit 10 is installed in the X-axis direction on the upper surface of the upper frame 11 connecting the pair of columns 4. According to a preferred embodiment of the present invention, the level unit 10 may be formed as a straight edge, although not necessarily limited thereto.

A plurality of sensors 20 are installed at regular intervals on the upper surface of the upper frame 11 so as to be adjacent to the level unit 10 in order to measure the distance to the level unit 10. [ There is no limitation on the number of the plurality of sensors 20 installed on the upper surface of the upper frame 11, but it must be installed so as to maintain a constant interval. As the plurality of sensors 20 are installed on the upper surface of the upper frame 11, the tilted distance of the column can be measured more precisely.

The column position error correction unit 30 moves the pair of columns 4 to the left and right along the X-axis direction, that is, the longitudinal direction of the bed 2. However, according to a preferred embodiment of the present invention, the pair of columns 4 are provided respectively in the pair of columns 4, so that the pair of columns 4 are subjected to the same positional error correction So that the machining precision can be further improved.

The control unit 40 is installed in the operation panel.

2 to 4, an apparatus 100 for correcting a position error of a column in a large machine tool according to another preferred embodiment of the present invention includes a display unit 50, a correction mode selection unit 60, And a selection unit (70).

The display unit 50 is installed at a part of the operation panel. According to another embodiment of the present invention, the display unit may be installed on a display portion of the operation panel. When the column position error correction is performed on the display unit 50, the column position error correction amount is displayed. When the column position error correction amount exceeds the maximum position error correction amount stored in the memory unit, a warning message is displayed to the operator.

The correction mode selection unit 60 and the correction period selection unit 70 are provided on a part of the operation panel or a part of the operation panel.

The correction mode selection unit 60 includes a normal correction mode and a correction mode for each machining mode, and the operator can select one of the two modes according to the work situation and proceed. The correction mode is stored in the basic data storage unit of the control unit 70, which will be described later. In the case of the normal correction mode, the position error correction device of the column operates continuously to check the correction amount of the position error of the column and correct it. In the correction mode according to the machining mode, the position error correcting device of the column operates only when the machining mode has a lot of heat generation according to the machining mode to check and correct the position error correction amount of the column.

The correction period selector 70 can select the position error correction period of the column by the operator. The correction period is stored in the basic data storage unit of the control unit 70, which will be described later by the operator.

5 is a conceptual diagram of a column position error correction unit in a column position error correction apparatus for a large machine tool according to a preferred embodiment of the present invention. 5, a description will be given of a column position error correction unit 30 of an apparatus 100 for correcting column position errors of a large machine tool according to another preferred embodiment of the present invention. 5, the column position error correction unit 30 of the column position error correction apparatus 100 according to an embodiment of the present invention includes a driving unit 31, a fixing bracket 32, a ball screw 33, A conveying unit 34, and a connecting member 35.

The driving unit 31 generates power for moving the column 4 in the X-axis direction. That is, the driving unit 31 is operated by the signal transmitted from the signal transmission unit 460 of the control unit 40. Although not limited thereto, according to one embodiment of the present invention, the driving unit 31 includes a servo motor the housing of the driving unit 31 may be provided with a driving unit 31 that is disposed inside the housing of the driving unit 31 and may include a deceleration unit, And fixed firmly on the ground surface.

A fixing bracket (32) is fixed to one side of the column (4). The fixing bracket 32 may be fixedly attached to the column by known means such as bolts, rivets, or welding, though not necessarily limited thereto.

One end of a ball screw 33 is connected to the driving unit 31 and the other end of the ball screw 33 is connected to the fixing bracket 32. The ball screw 33 is rotated clockwise or counterclockwise by the power of the driving unit 31 when the driving unit 31 is operated.

The transfer unit 34 is installed to be movable on the ball screw 33 through the ball screw 33.

One end of the connecting member 35 is connected to one side of the fixing bracket 32 and the other end of the connecting member 35 is connected to one side of the conveying unit 34. The connecting member 35 moves the fixing bracket 32 in the direction of the X axis in the direction of rotation of the ball screw 33 when the conveying unit 34 firmly fastened by the connecting member 35 moves on the ball screw 33, As shown in FIG. The column 4 connected to the fixing bracket 32 moves along the X-axis direction by a predetermined angle.

Referring to FIG. 2, a control unit 40 of an apparatus 100 for correcting a column position error of a large machine tool according to another preferred embodiment of the present invention will be described. 2, the control unit 40 of the apparatus 100 for correcting a column position error of a large machine tool according to another preferred embodiment of the present invention includes a basic data storage unit 41, a memory unit 42, A receiving unit 43, a calculating unit 44, a comparing unit 45, and a signal transmitting unit 46.

The height of the pair of columns 4 (H in Fig. 7), the length of the level unit 10 (L in Fig. 6), and the position of the plurality of sensors 20 And stores the basic data for the error (see Table 1 to be described later). Basic data for the correction mode and the correction period are also stored.

The memory unit 42 stores data on the minimum position error correction amount and the maximum position error correction amount of the column 4.

The signal receiving unit 43 receives the signal of the sensor 20 that senses the level unit 10 among the plurality of sensors 20.

The calculation unit 44 calculates the position error correction amount of the column 4 based on the signal received by the signal reception unit 43 and the data stored in the basic data storage unit 41. [ A method of calculating the position error correction amount of the column 4 in the calculation unit 44 will be described later.

The comparison unit 45 compares the position error correction amount calculated by the calculation unit 44 with the minimum position error correction amount of the column stored in the memory unit 42 and the maximum position error correction amount.

If the position error correction amount exceeds the minimum position error correction amount and is less than the maximum position error correction amount as a result of the determination by the comparison unit 45, the signal transmission unit 46 outputs a signal for the position error correction unit 30 to the column position error correction unit 30 Thereby correcting the position error of the column. When the position error correction amount is less than the minimum position error correction amount, the signal transmission unit 46 does not transmit a signal to the column position error correction unit 30 and waits until the correction period is selected by the correction period selection unit 70 . When the position error correction amount exceeds the maximum position error correction amount, the display unit 50 displays a warning message in accordance with the signal generated in the signal transmission unit 46. [

FIG. 6 is a conceptual diagram of an installation state of a level unit and a sensor in an apparatus for correcting a column position error of a large machine tool according to a preferred embodiment of the present invention, and FIG. 7 is a schematic view of a large machine tool according to a preferred embodiment of the present invention. A conceptual diagram for calculating a position error correction amount of a column in a column position error correction apparatus is shown. 6 and 7, a method for calculating a position error correction amount in a column position error correction apparatus of a large machine tool according to the present invention will be described.

Up data (Table 1 below) when a signal is generated in each sensor 20 is stored in the basic data storage unit 41. [

Sensor number Position error (e) ㎛ One 25 2 22.5 3 20 4 17.5 5 15 6 12.5 7 10 8 7.5 9 5 10 2.5 11 0 12 -2.5 13 -5 14 -7.5 15 -10 a -12.5 b -15 c -17.5 d -20 e -22.5 f -25

In Table 1, the minus (-) marks are for indicating the left and right sides around the reference point in the X-axis direction. That is, when the left side is positive (+) at the reference point, the right side becomes negative (-).

As described above, the plurality of sensors 20 do not necessarily have to be provided in an odd number or an even number, and may be provided at a constant distance from a plurality of sensors. In FIG. 6, the length L of the level unit 10 is 200 mm, and the number of the sensors 20 is 10 mm (d). In Fig. 7, the column height is H, the position error is e, and the position error correction amount between them is?.

tan? = e / H - (1)

θ: Position error correction amount, e: Position error, H: Column height

The position error correction amount? Can be calculated by the following equation (2) by the above equation (1).

θ = arc tan (e / H) - (2)

θ: Position error correction amount, e: Position error, H: Column height

8 is a flowchart illustrating a method of correcting a position error of a column in a large machine tool according to a preferred embodiment of the present invention. A method of correcting a position error of a column in a large machine tool according to a preferred embodiment of the present invention will be described with reference to FIG. 8, a position error correction method for a column in a large machine tool according to a preferred embodiment of the present invention includes a basic data storage step S1, a minimum position error correction amount and a maximum position error correction amount storage step S2, The position error correction amount calculation step S6 of the column, the position error correction amount comparison step S7, and the position error correction of the column (step S7) Step S8.

The basic data for the height of the pair of columns 4, the length of the level unit 10 and the positional errors for the plurality of sensors 20, the correction mode, and the correction period are stored in the basic data storage unit 41 .

After the basic data storage step (S1), data on the minimum position error correction amount and the maximum position error correction amount of the pair of columns (4) are stored in the memory unit (42).

 After the minimum position error correction amount and maximum position error correction amount storage step S2, the correction mode selection unit 60 selects the correction mode.

After the correction mode selection step (S3), the correction period selector 70 selects the position error correction period of the column 4.

After the correction period selection step S4, the signal receiving unit 43 receives the signal of the sensor 20 that senses the level unit 10 among the plurality of sensors 20.

After the sensor signal reception step S5, the calculation unit 44 calculates the position error correction amount of the pair of columns 4 by the signal received by the signal reception unit 43 and the data stored in the basic data storage unit 41 .

After the position error correction amount calculation step S6, the comparison unit 45 compares the position error correction amount calculated by the calculation unit 44 with the minimum position error correction amount of the column stored in the memory unit 42 and the maximum position error correction amount .

If the position error correction amount exceeds the minimum position error correction amount and is less than the maximum position error correction amount as a result of the comparison by the comparator 45 after the position error correction amount comparison step S7, (30) to correct the position error of the pair of columns (4).

As shown in FIG. 8, in a method of correcting a position error of a column in a large machine tool according to another preferred embodiment of the present invention, a position error correction amount is displayed on the display unit 50 after the step S8 of correcting the position error of the column (Step S9).

As shown in FIG. 8, in a method of correcting a position error of a column in a large machine tool according to another preferred embodiment of the present invention, after the step S7 of comparing a position error correction amount, (S7-1) of displaying on the display unit 50 when the position error correction amount is exceeded. Accordingly, when the position error of the column 4 is too large, it is notified to the operator so that the safety accident can be prevented in advance through regular inspection or replacement.

Accordingly, the apparatus and method for correcting a position error of a column in a large machine tool according to the present invention can improve accuracy of processing of a workpiece by correcting a positional error of a column in a large-sized machine tool in real time, The time and cost required for error correction can be reduced, and the productivity of the machine tool can be improved.

Furthermore, the present invention is not limited to the modifications shown in the drawings and the embodiments described above, but can be extended to other embodiments falling within the scope of the appended claims.

1: machine tool, 2: bed,
3: table, 4: column,
5: cross rail, 6: birds,
7: Spindle unit, 8: Operation panel,
10: level unit, 11: upper frame,
20: sensor, 30: column position error correction unit,
31: driving part, 32: fixing bracket,
33: ball screw, 34: conveying part,
35: connecting member, 40: control unit,
41: basic data storage unit, 42: memory unit,
43: signal receiving section, 44: calculating section,
45: comparison section, 46: signal transmission section,
50: display section, 60: correction mode selection section,
70: correction period selector,
100: position error correction device for column,
L is the length of the level unit, H is the height of the column,
d: distance between sensors, e: position error,
θ: Position error correction amount.

Claims (7)

A machine tool comprising a pair of columns vertically installed on both sides of a bed,
A level unit installed on the upper surface of the upper frame connecting the pair of columns in the X axis direction;
A plurality of sensors disposed at regular intervals on an upper surface of the upper frame so as to be adjacent to the level unit to measure a distance to the level unit;
A column position error correction unit for moving the pair of columns in the X-axis direction; And
And a controller for controlling the position error of the column in the large machine tool.
The method according to claim 1,
The apparatus for correcting a position error of the column comprises:
A display portion provided on a part of the operation panel;
A correction mode selection unit; And
And a correction period selection unit for selecting a correction period for each of the plurality of columns.
3. The method of claim 2,
The column position error correcting unit comprises:
A driving unit for generating power for moving the column in the X-axis direction;
A fixing bracket installed on one side of the column;
A ball screw having one end connected to the driving unit and the other end connected to the fixing bracket and rotated by the power of the driving unit;
A conveying unit that is installed to move on the ball screw through the ball screw; And
And a connecting member having one end connected to one side of the fixing bracket and the other end connected to one side of the transferring unit.
The method of claim 3,
Wherein,
A basic data storage unit for storing basic data on height of the pair of columns, length of the level unit, and positional errors with respect to the plurality of sensors;
A memory unit for storing data on the minimum position error correction amount and the maximum position error correction amount of the column;
A signal receiving unit for receiving a signal of a sensor that senses a level unit among the plurality of sensors;
A calculation unit for calculating a position error correction amount of the column based on a signal received by the signal reception unit and data stored in the basic data storage unit;
A comparison unit for comparing the position error correction amount calculated by the calculation unit with the minimum position error correction amount of the column stored in the memory unit and the maximum position error correction amount; And
And a signal transmission unit for transmitting a signal for the position error to the column position error correction unit when the position error correction amount exceeds the minimum position error correction amount and is less than the maximum position error correction amount as a result of the determination by the comparison unit A device for correcting the position error of a column in a large machine tool.
Storing basic data on a height of a pair of columns, a length of a level unit, and a positional error with respect to a plurality of sensors in a basic data storage unit;
Storing a minimum position error correction amount and a maximum position error correction amount of the pair of columns in a memory;
Selecting a correction mode in the correction mode selection unit;
Selecting a position error correction period of the column in the correction period selection unit;
Receiving a signal from a sensor that senses the level unit among the plurality of sensors in a signal receiving unit;
Calculating a position error correction amount of the pair of columns by the signal received by the signal receiving unit and the data stored in the basic data storage unit in the calculation unit;
Comparing a position error correction amount calculated by the calculation unit with a minimum position error correction amount of a column stored in the memory unit and a maximum position error correction amount; And
A step of correcting a position error of a pair of columns by transmitting a signal for a position error to a column position error correction unit when the position error correction amount exceeds a minimum position error correction amount and is less than a maximum position error correction amount And correcting the position error of the column in the large machine tool.
6. The method of claim 5,
And displaying the position error correction amount on the display unit.
The method according to claim 6,
After comparing the position error correction amounts,
And displaying the calculated position error correction amount on the display unit when the calculated position error correction amount exceeds the maximum position error correction amount.

Images