JP2020059073A - Machine tool and machining method - Google Patents

Abstract

To provide a machine tool and a machining method, which can suppress deterioration of production efficiency by the machine tool while machining a work-piece with high accuracy by correcting a correction formula during an operation of the machine tool.SOLUTION: A machine tool 100 includes: an operation execution section 23 which executes a measurement operation for machining a measurement work-piece Wm of a plurality of work-pieces W by a measurement cutter Tm while sequentially machining the plurality of work-pieces W; and a coefficient adjustment section 24 which adjusts coefficients K1 to K5 used for estimating prescribed thermal displacement amount of a prescribed correction formula so as to reduce displacement amount between a dimension of the measurement work-piece Wm after machining and a design value on the basis of the displacement amount.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a machine tool and a machining method.

  A lathe, which is one of machine tools, includes a spindle that holds and rotates a work, and a tool rest that holds a tool for cutting the work. In such a lathe, the main shaft and the tool rest are relatively moved, and the work is performed while the work and the tool are relatively moved. When cutting a work piece, the spindle, the tool rest, and the bed that supports them are thermally deformed due to the cutting heat generated when cutting the work piece, or the heat generated in each part during operation. The distance in the cutting direction between and varies. Because the position of the blade edge of the blade with respect to the workpiece deviates from the assumed value (set value) due to this distance variation, the distance variation due to thermal deformation is appropriately corrected in the cutting direction between the spindle axis and the blade edge. A method is known (for example, refer to Patent Document 1).

JP, 2008-079526, A

  In order to process a workpiece with high accuracy, when the distance between the spindle axis and the cutting edge fluctuates due to heat, it is necessary to accurately correct the movement amount due to the thermal fluctuation. Therefore, it is considered that a correction formula for correcting the movement amount due to heat fluctuation is prepared in advance and this correction formula is applied. In this case, depending on the surrounding environment of the machine tool, the type of workpiece to be machined, the tool (cutting tool) used, etc., thermal fluctuations that cannot be corrected by the above correction formula may occur, so it is necessary to correct the correction formula used. There is. If the operation of the machine tool is stopped when performing this correction work, the production efficiency (workpiece processing efficiency) will be reduced.

  The present invention provides a machine tool and a machining method capable of suppressing a decrease in production efficiency due to a machine tool while machining a work with high accuracy by correcting a correction formula during operation of the machine tool. To aim.

  A machine tool according to an aspect of the present invention includes a headstock that rotatably supports a spindle having a chuck for gripping a workpiece, a tool rest to which a tool is attached, a headstock and a tool rest in a radial direction of the spindle. A bed that is relatively movable, a temperature measuring instrument that measures the temperature of a tool rest, a headstock, or their vicinity, and a spindle that measures the spindle axial position in the spindle radial direction with respect to the first reference position in the bed. Based on the side position measuring device, the tool side position measuring device that measures the third reference position of the tool rest in the spindle radial direction with respect to the second reference position in the bed, and the spindle axis center position measured by the spindle side position measuring device The headstock thermal displacement amount which is the thermal displacement amount of the headstock is calculated, and the tool rest thermal displacement amount which is the heat displacement amount of the tool rest is calculated based on the third reference position measured by the tool side position measuring device, Measured with a temperature measuring device The specified thermal displacement from the workpiece to the machining tip of the tool is estimated based on the measured temperature, and the headstock thermal displacement, the toolboard thermal displacement, and the predetermined thermal displacement are used as the items in the specified correction formula. A calculation unit that calculates the relative movement amount between the tool and the turret, and while sequentially processing a plurality of workpieces by the cutter, at least one of the unmachined workpieces is taken out as a workpiece for measurement An operation execution unit that executes a measurement operation that causes the workpiece to be machined under the same or nearly the same conditions as the machining of the workpiece by the blade with the same or nearly the same measuring blade as the blade, and the dimensions of the measuring workpiece after machining And a coefficient adjusting unit that adjusts the coefficient used for estimating the predetermined thermal displacement amount of the predetermined correction formula based on the displacement amount from the design value so as to reduce the displacement amount.

  In addition, the operation executing unit may take out the plurality of workpieces at predetermined time intervals during the measurement operation so that the plurality of workpieces for measurement are each machined by the blade for measurement. In addition, it includes a measurement headstock that rotatably supports a measurement spindle that has a chuck for gripping a measurement work, and a measurement tool post to which the measurement tool is attached. The tool rest may be installed on the bed so as to be relatively movable in the radial direction of the main shaft. Further, the operation executing unit may process the measuring work with the measuring blade using the predetermined correction formula that is set in advance or without using the predetermined correction formula. Moreover, you may provide the display part which displays that the driving | operation for measurement is being performed. Further, the coefficient adjusting unit may include an input unit capable of inputting the dimensions of the processed workpiece for measurement, and the coefficient adjusting unit may adjust the coefficient based on the dimensions of the workpiece for measurement input to the input unit.

  A machining method according to an aspect of the present invention includes a headstock that rotatably supports a spindle having a chuck for gripping a workpiece, a tool rest to which a tool is attached, a headstock and a tool rest in a radial direction of the spindle. A bed that is relatively movable, a temperature measuring instrument that measures the temperature of a tool rest, a headstock, or their vicinity, and a spindle that measures the spindle axial position in the spindle radial direction with respect to the first reference position in the bed. A machining method using a machine tool, comprising: a side position measuring device; and a tool side position measuring device that measures a third reference position of a tool rest in a radial direction of the spindle with respect to a second reference position on a bed. Calculating the headstock thermal displacement amount, which is the thermal displacement amount of the headstock, based on the spindle shaft center position measured by the position measuring device, and based on the third reference position measured by the toolside position measuring device. Heat of the table Calculating the tool post thermal displacement amount, which is a unit, and estimating the predetermined thermal displacement amount from the workpiece to the machining tip of the tool based on the temperature measured by the temperature measuring device, and the headstock thermal displacement amount, Calculating the relative movement amount of the headstock and the turret by a predetermined correction formula that has the turret thermal displacement amount and the predetermined thermal displacement amount as each item, and while sequentially processing a plurality of workpieces by the turret, At least one of the unmachined workpieces is taken out as a measurement workpiece, and the measurement workpiece is the same or almost the same as the blade, and under the same or almost the same conditions as the processing of the workpiece by the blade. Based on the displacement of the measured workpiece after machining and the design value, it is possible to reduce the displacement based on the displacement of the measured workpiece after machining, Coefficient used Including and adjusting, the.

  According to the above-described machine tool and machining method, while performing machining of a plurality of workpieces in sequence, a measurement operation of machining a workpiece for measurement out of the plurality of workpieces with a measuring blade is executed, and measurement work after machining is performed. Based on the displacement between the work size and the design value, the coefficient used to estimate the predetermined thermal displacement of the predetermined correction formula is adjusted to reduce this displacement. ) Can be corrected without stopping, the work can be machined with high accuracy, and the production efficiency of the machine tool (working efficiency of the work) can be prevented from decreasing.

  Further, in the configuration in which the operation executing unit takes out a plurality of workpieces for measurement by the measuring blade by taking out the workpieces at a predetermined time interval during the operation for measurement, the workpieces are processed during the predetermined time. Since the process is continuously performed, it is possible to reliably suppress the decrease in production efficiency. In addition, it includes a measurement headstock that rotatably supports a measurement spindle that has a chuck for gripping a measurement work, and a measurement tool post to which the measurement tool is attached. With the configuration in which the turret is installed on the bed so that it can move relatively in the radial direction of the spindle, machining of the work for production and machining of the work for measurement are performed separately, so a decrease in production efficiency is ensured. Can be suppressed. Further, in the configuration in which the operation executing unit processes the measurement work with the measurement blade with or without using the preset predetermined correction formula, the design when the predetermined correction formula is used Since the predetermined correction formula is corrected based on the deviation from the value or the deviation from the design value when the predetermined correction formula is not used, the work can be processed with higher accuracy. Further, in the configuration including the display unit that displays that the measurement operation is being performed, it is possible to easily notify the operator that the machine tool is in the measurement operation. Further, in the configuration in which the input unit capable of inputting the dimension of the measurement work after processing is provided, and the coefficient adjusting unit adjusts the coefficient based on the dimension of the measurement work input to the input unit, the operator inputs the coefficient. The predetermined correction formula can be easily modified only by inputting the size of the work by the section.

It is a figure which shows an example of the machine tool which concerns on 1st Embodiment of this invention. It is a perspective view showing an example of a main part. It is a figure which shows an example at the time of seeing a main-body part from the + Y side. It is a figure which shows an example at the time of seeing a main-body part from the + Z side. It is a time table which shows typically the processing situation of the workpiece | work in normal operation and operation for measurement. It is a figure which shows an example of the display screen displayed on a display part. It is a flow chart which shows an example of processing which computes the amendment value of the distance of the direction of the X-axis of a spindle axis and a cutting edge. It is a flow chart which shows an example of processing which performs measurement driving. It is a figure which shows an example of the display screen displayed on a display part, and has shown the display screen before performing driving | operation for measurement. It is a figure which shows an example of the display screen displayed on a display part, and shows the display screen when the measurement driving is started. It is a figure which shows an example of the display screen displayed on a display part, and shows the display screen when inputting a workpiece diameter. 7 is a flowchart showing an example of coefficient adjustment processing in a predetermined correction formula. It is a figure which shows an example of the display screen displayed on a display part, and has shown the display screen about the situation after coefficient adjustment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the modes described below. Further, in the drawings, in order to describe the embodiment, a part of the drawing is enlarged or emphasized, and the scale is appropriately changed. In each of the following drawings, the directions in the drawings will be described using the XYZ coordinate system. In the XYZ coordinate system in each of the following embodiments, the rotation axis direction of the main axis is the Z direction, the plane parallel to the horizontal plane is the YZ plane, and the direction orthogonal to the Z direction is the Y direction. The direction perpendicular to the YZ plane is the X direction, and this X direction is the direction that defines the cutting amount for the work. In each of the X direction, the Y direction, and the Z direction, the direction indicated by the arrow in the drawing is the + direction, and the opposite direction is the − direction. Further, in each of the following embodiments, the direction around the Y axis is represented as the θY direction, and the direction around the Z axis is represented as the θZ direction. Regarding the θY direction and the θZ direction, the clockwise direction when viewed from the + Y side and the + Z side is the + direction, and the counterclockwise direction is the − direction.

  A machine tool 100 according to the embodiment will be described with reference to the drawings. FIG. 1 is a diagram illustrating an example of a machine tool 100 according to the embodiment. 2 is a perspective view showing an example of the main body 1. FIG. 3 is a diagram showing an example of the main body 1 viewed from the + Y side. FIG. 4 is a diagram showing an example of the main body 1 viewed from the + Z side. The machine tool 100 shown in FIGS. 1 to 4 is a lathe. The machine tool 100 includes a main body 1 and a control device 2.

  As shown in FIGS. 1 to 4, the main body unit 1 includes a bed 3, a headstock 4, a tool rest 5, a moving device 6, and a measuring device 7. The bed 3 is, for example, a fixed base placed on the floor or the like. A cover C that surrounds the headstock 4 and the tool rest 5 is provided on the bed 3. The headstock 4 is supported by the bed 3 via a moving device 6. The headstock 4 can be moved in the X direction and the Z direction by a moving device 6. The headstock 4 has a main spindle 10. The main shaft 10 is supported by bearings (not shown) so as to be rotatable in the θZ direction around a main shaft axis AX1 parallel to the Z direction. A chuck drive unit 11 is provided at the + Z side end of the main shaft 10.

  The chuck drive unit 11 has a plurality of grip claws (chuck) 11 a for holding the work W. Each of the plurality of grip claws 11 a is movable in the radial direction of the spindle 10. The chuck drive unit 11 moves the plurality of grip claws 11 a in the radial direction of the main shaft 10 to hold the work W. When the work W is held by the gripping claws 11a, the rotation center of the work W coincides with the spindle axis AX1. A plurality of grip claws 11a are arranged at equal intervals around the rotation axis of the main shaft 10. As the number or shape of the grip claws 11a, any configuration capable of holding the work W is used.

  The tool rest 5 is fixed to the bed 3. The turret 5 includes a turret 50. The turret 50 is supported by the tool rest 5 in a state of being rotatable in the θX direction around an axis AX2 parallel to the X direction. The turret 50 holds the blade T and the blade Tm for measurement in a replaceable manner. As the blade T and the blade Tm for measurement, a rotary tool such as a drill or an end mill may be used in addition to a cutting tool for cutting the work W. The measuring blade Tm processes the measuring work Wm in which at least one of the unprocessed works W of the plurality of works W is taken out.

  The measurement work Wm is the same as or substantially the same as the work W in a normal processing target. The blade Tm for measurement is the same as or almost the same as the blade T. Therefore, the processing of the measuring work Wm by the measuring blade Tm can be the same as or substantially the same as the case of processing the workpiece W by the blade T. The blade T is held by the turret 50 via the holder 51. The measuring blade Tm is held by the turret 50 via the holder 52. The blade T and the measuring blade Tm can be selected by rotating the turret 50 in the θX direction.

  A cooling device 30 is arranged below the bed 3. The cooling device 30 discharges a coolant to the processed portion of the work W to cool it. The cooling device 30 includes a coolant supply source 31 and a pipe 32. The coolant supply source 31 stores the temperature-controlled coolant. The coolant supply source 31 causes the coolant to flow through the pipe 32 by a drive source 31a such as a pump. The pipe 32 is routed along the bed 3 and inserted into the tool rest 5 from the −Z side surface of the tool rest 5. The pipe 32 is arranged so as to pass through the turret 50 and the holder 51, and the downstream end of the coolant in the flow direction is directed to the processed portion of the work W.

  The moving device 6 includes an X-direction guide 61, a feed base 62, and a Z-direction guide 63. The two X-direction guides 61 are arranged on the bed 3 in parallel along the X-direction. The X-direction guide 61 guides the feed base 62 in the X-direction. The feed table 62 is formed in a rectangular plate shape or a trapezoid shape, and is arranged on the X-direction guide 61. In this specification, a rectangle means a rectangle including a square.

  The feed table 62 moves in the X direction by the driving of the X direction drive unit 64. The X-direction drive unit 64 is, for example, a mechanism that uses a rotational driving force of an electric motor or the like to convert it into a linear motion by a ball screw mechanism, a mechanism that uses a rack and a pinion gear, a hydraulic or pneumatic cylinder device, or the like. To be The two Z-direction guides 63 are arranged on the feed base 62 in parallel along the Z-direction. The Z direction guide 63 guides the headstock 4 in the Z direction. The headstock 4 moves in the Z direction by the drive of the Z direction drive unit 65. The Z-direction drive unit 65 has the same configuration as the X-direction drive unit 64, such as an electric motor.

  The measuring device 7 includes a reference frame 70, a spindle side position measuring device 71, and a blade side position measuring device 72. Further, the measuring device 7 serves as a temperature measuring device such as a first temperature measuring device 73, a second temperature measuring device 74, a third temperature measuring device 79, a fourth temperature measuring device 75, and a fifth temperature measuring device 76. And. The reference frame 70 has a pillar portion 77 and a horizontal portion 78. The reference frame 70 is formed using a material having a coefficient of thermal expansion lower than that of the bed 3. Examples of such a material include alloy materials such as Invar material, ceramics, and the like. The column 77 is arranged in a state of standing upright from the bed 3 along the Y direction. The column part 77 is fixed to the bed 3 by a fixing member (not shown) or the like.

  The horizontal portion 78 is arranged such that the base end side is connected to the upper end of the column portion 77 and extends linearly in the + Z direction. The horizontal portion 78 is supported by the column portion 77 in a so-called cantilever shape. The horizontal portion 78 is supported by the reinforcing portion 78a (see FIG. 2). The horizontal portion 78 is arranged at the height of the axis AX2 of the rotating shaft of the turret 50. The + Z side end of the horizontal portion 78 is arranged at the + X side position of the tool rest 5 (that is, at the position opposite to the turret 50). A through hole for inserting a second scale 72a and a second reading device 72b, which will be described later, is formed at the + Z side end of the horizontal portion 78. The through hole is provided so as to penetrate the horizontal portion 78 in the X direction.

  The spindle side position measuring device 71 detects the displacement of the spindle axis center AX1 in the X direction. The spindle side position measuring device 71 has a first scale 71a and a first reading device 71b. The first scale 71a is, for example, a rod-shaped member having a circular cross section, an elliptical cross section, or a polygonal cross section. The first scale 71a is connected to the pillar portion 77 and is linearly arranged along the X direction. The first scale 71a is supported by the pillar portion 77 in a so-called cantilever shape. The position of the first scale 71a in the Y direction is arranged at the height position of the feed table 62. The end of the first scale 71a in the −X direction is arranged at the + Z side of the feed table 62.

  The first scale 71a has scales M1 formed side by side in the X direction. The scale M1 can be read optically or magnetically. The scale M1 may have a configuration directly formed on the first scale 71a, or may have a configuration in which a member having a scale is attached to the first scale 71a. In the present embodiment, the scale M1 has a configuration in which, for example, magnetic portions and nonmagnetic portions are alternately arranged in the X direction of the first scale 71a. The scale M1 is formed in a region including a range in which the spindle 10 moves in the X direction (a movement range of the spindle axis AX1 in the X direction). In the first scale 71a, the portion supported by the column 77 is the first reference position P1. That is, the spindle side position measuring device 71 measures the position of the spindle axis center AX1 in the radial direction of the spindle 10 with respect to the first reference position P1 in the bed 3.

  The first reading device 71b is fixed to the end surface 62a on the + Z side of the feed table 62, and has a reading reference on a plane perpendicular to the radial direction of the spindle 10 that passes through the spindle axis AX1. The reading reference is a plane shape that passes through the main axis AX1 and is parallel to the YZ plane. As the first reading device 71b, for example, a magnetic head that detects a magnetic portion and a non-magnetic portion is used. When the headstock 4 and the feed base 62 are thermally deformed, the first reading device 71b is displaced along with the deformation of the headstock 4 and the feed base 62. Therefore, the first reading device 71b can detect the displacement when it is displaced in the X direction with respect to the scale M1 (magnetic portion and nonmagnetic portion) formed on the first scale 71a. The first reading device 71b transmits the displacement in the X direction with respect to the scale M1 to the control device 2 as an electric signal.

  The blade side position measuring device 72 measures the displacement in the X direction of the end surface 50a of the turret 50 on the −X side (the blade T side or the work W side). The blade-side position measuring device 72 has a second scale 72a and a second reading device 72b. Similar to the first scale 71a, the second scale 72a is, for example, a rod-shaped member having a circular cross section, an elliptical cross section, or a polygonal cross section, and is linearly arranged along the X direction. The second scale 72a is disposed so as to penetrate the tool rest 5 and the turret 50 in the X direction with the central axis thereof aligned with the rotation axis AX2 of the turret 50, and is provided integrally with the tool rest 5 and the turret 50. To be The second scale 72a is supported on the −X side end surface 50a of the turret 50 in a so-called cantilever manner. When the tool rest 5 is thermally deformed, the second scale 72a is displaced along with the heat deformation of the tool rest 5.

  The second scale 72a is arranged such that the end portion on the + X side penetrates the horizontal portion 78 in the X direction and projects toward the + X side. The 2nd scale 72a has the scale M2 arrange | positioned along with the X direction similarly to the 1st scale 71a. The scale M2 can be read optically or magnetically. The scale M2 is arranged in a region of the second scale 72a to be inserted inside the horizontal portion 78. The position of the horizontal portion 78 through which the second scale 72a penetrates becomes the second reference position P2.

  The −X side end surface 72c of the second scale 72a is arranged so as to match the −X side end surface 50a of the turret 50. The position of the end surface 72c in the X direction coincides with the end surface 50a of the turret 50. The end surface 50a is the third reference position P3 of the tool rest 5. Therefore, the end surface 72c of the second scale 72a is arranged at the third reference position P3. That is, the blade-side position measuring device 72 measures the position of the third reference position P3 with respect to the second reference position P2 of the bed 3. The first reference position P1 and the second reference position P2 are positions where the thermal displacement amounts are equal to each other in the radial direction of the main axis, and are coincident with each other. Further, since the first reference position P1 and the second reference position P2 are respectively set to the Invar material or the like having a low coefficient of thermal expansion, it is possible to prevent the both from moving relatively. However, the first reference position P1 and the second reference position P2 may be arranged in different reference frames or the like.

  The second reading device 72b is fixed to the second reference position P2 of the horizontal portion 78. The second reference position P2 is a position inside the horizontal portion 78 that overlaps the axis AX2 of the turret 50. As the second reading device 72b, for example, a magnetic head that detects a magnetic portion and a non-magnetic portion is used. The second reading device 72b can detect displacement when the scale M2 (magnetic portion and non-magnetic portion) is displaced in the X direction. When the scale M2 is displaced in the X direction, the second reading device 72b transmits this displacement to the control device 2 as an electric signal. As described above, in the blade-side position measuring device 72 of the present embodiment, the second reading device 72b is arranged at the fixed position and the second scale 72a is displaced, but the structure is not limited to this. For example, the second scale 72a may be fixed to the horizontal portion 78, and the second reading device 72b may be arranged on the end surface 50a of the turret 50.

  The first temperature measuring device 73 is arranged, for example, on the −Z side end surface of the tool rest 5. The first temperature measuring device 73 measures the first temperature t1 of the tool rest 5 or the vicinity thereof. The first temperature measuring device 73 measures the temperature of the pipe 32 to measure the temperature of the coolant flowing through the pipe 32. Since the coolant is discharged toward the blade T during cutting, the temperature of the pipe 32 through which the coolant flows is substantially equal to the temperature of the blade T and its surroundings during cutting. Therefore, by measuring the temperature of the coolant in the pipe 32, the first temperature t1 of the tool rest 5 at the time of cutting or the vicinity thereof can be measured.

  The second temperature measuring device 74 measures one or more second temperatures which are temperatures of the headstock 4 (or the spindle 10) and / or its vicinity. The second temperature measuring device 74 may have any attachment position as long as it can measure the second temperature t2 of the headstock 4, and may be attached, for example, in the vicinity of the main spindle 10, or the headstock 4 or the main spindle 10. May be placed inside. Further, the second temperature measuring device 74 may not be arranged. In the present embodiment, the second temperature measuring device 74 is attached to the + X side surface of the headstock 4. The second temperature t2 detected by the second temperature measuring device 74 is, for example, the same or almost the same temperature as the area TEM1 (area surrounded by a broken line) near the main shaft 10 shown in FIG.

  The third temperature measuring device 79 is provided inside the cover C. The third temperature measuring device 79 measures the third temperature t3 inside the cover C. In the present embodiment, the third temperature t3 inside the cover C corresponds to the outside air temperature around the tool rest 5 and the headstock 4. Therefore, the third temperature measuring device 79 can measure the temperature corresponding to the outside air temperature around the tool rest 5 and the headstock 4 by measuring the third temperature t3. The third temperature measuring device 79 is not limited to being inside the cover C, but may be arranged outside the cover C. The third temperature measuring device 79 is not limited to the inside of the cover C, and may be arranged, for example, outside the cover C, or provided apart from the outside of the cover C (away from the main body 1). May be.

  The fourth temperature measuring device 75 measures the fourth temperature t4 which is the temperature of the feed table 62. The fourth temperature measuring device 75 is attached to the surface of the feed base 62, for example, and can measure the temperature of the feed base 62. The fourth temperature measuring device 75 may be arranged inside the feed base 62. In the present embodiment, the fourth temperature measuring instrument 75 is attached to the + Y-side surface of the corner of the feed base 62 on the + X side and the −Z side. The fourth temperature t4 detected by the fourth temperature measuring device 75 is, for example, the same or almost the same temperature as the −X side region TEM2 (region surrounded by a broken line) of the feed table 62 shown in FIG. .

  The fifth temperature measuring device 76 is arranged on the + Y side surface of the bed 3 and in the −Z side region of the tool rest 5. The fifth temperature measuring device 76 measures the temperature (fifth temperature) t5 of the region of the bed 3 on the −Z side of the tool rest 5. The fifth temperature t5 detected by the fifth temperature measuring device 76 is, for example, the same or substantially the same as the temperature of the region TEM3 on the + Z side end surface of the tool rest 5 shown in FIG. Note that one or both of the fourth temperature measuring device 75 and the fifth temperature measuring device 76 may not be arranged.

  As shown in FIG. 1, the control device 2 is, for example, a computer and has a numerical control function and a programmable controller. The control device 2 includes a movement control unit 21, a calculation unit 22, an operation execution unit 23, a coefficient adjustment unit 24, a storage unit 25, an input unit 26, and a display unit 27. The movement control unit 21 controls the X-direction driving unit 64 and the Z-direction driving unit 65 of the moving device 6 to relatively move the work W and the blade T in the X and Z directions. When controlling the relative movement in the X direction between the work W and the blade T, the movement control unit 21 controls the distance L in the X direction between the spindle axis AX1 of the spindle 10 and the cutting edge Ta of the blade T.

  This distance L is determined by the position of the headstock 4 in the X direction and the mounting dimensions in the X direction of the turret 50, the holder 51 and the tool T which are mounted on the tool rest 5. The distance L may be measured, for example, by abutting (or actually cutting) the blade T on a test piece held on the main shaft 10. Further, the control device 2 corrects the processing data (for example, the coordinate value) of the work W based on each thermal displacement amount described later, and the movement control unit 21 controls the X-direction drive unit 64 and The Z direction drive unit 65 is controlled.

  The calculation unit 22 performs various calculations based on, for example, the programs and data stored in the storage unit 25. The calculation unit 22 calculates the headstock thermal displacement amount ΔS based on the displacement (position) in the X direction of the spindle axis AX1 measured by the spindle side position measuring device 71. The headstock thermal displacement amount ΔS is a thermal displacement amount of the headstock 4 caused by heat. Further, the calculation unit 22 calculates the tool post thermal displacement amount ΔT based on the displacement (position) in the X direction of the third reference position P3 measured by the tool side position measurement device 72. The tool post thermal displacement amount ΔT is a thermal displacement amount of the tool post 5 caused by heat.

  The calculation unit 22 estimates the blade thermal displacement amount ΔH based on the first temperature t1 measured by the first temperature measuring device 73. The blade thermal displacement amount ΔH is the thermal displacement amount in the X direction of the portion (the holder 51 and the blade T) from the third reference position P3 to the blade tip Ta of the blade T. There is a predetermined correlation between the first temperature t1 and the blade thermal displacement amount ΔH. The correlation between the first temperature t1 and the thermal displacement amount ΔH of the blade is obtained in advance by experiments or simulations. This correlation is stored in the storage unit 25, for example, as function data of the blade thermal displacement amount ΔH having the value of the first temperature t1 as a variable. In this case, the calculation unit 22 uses the function data stored in the storage unit 25 to calculate the blade thermal displacement amount ΔH corresponding to the value of the first temperature t1.

  Further, the calculation unit 22 may estimate the spindle shaft thermal displacement amount Δθs based on the temperature (second temperature) t2 of the spindle 10 measured by the second temperature measuring device 74. As shown in FIG. 4, the spindle shaft center thermal displacement amount Δθs is the thermal displacement amount of the spindle shaft center AX1 with respect to the reading reference. For example, the thermal displacement amount Δθs of the spindle shaft center is a value obtained by extracting a component in the X direction from the thermal displacement amounts around the Z axis of the headstock 4 centered around the first reading device 71b or the first reading device 71b. Is. The thermal displacement amount Δθs of the spindle shaft center includes, for example, the thermal displacement amount of the spindle shaft center AX1 caused by the thermal displacement of the gap formed between the headstock 4 and the Z-direction guide 63.

  There is a predetermined correlation between the second temperature t2 and the spindle shaft center thermal displacement amount Δθs. The main axis thermal displacement amount Δθs increases in absolute value on the + (plus) side as the temperature difference between the second temperature t2 and the fourth temperature t4 increases. If there is a correlation between the second temperature and the fourth temperature t4, the temperature of the fourth temperature t4 is calculated from the value of the second temperature t2, and the temperature difference is calculated based on the calculation result. Good. Such a correlation between the temperature difference between the second temperature t2 and the fourth temperature t4 and the spindle shaft center thermal displacement amount Δθs is obtained in advance by experiments or simulations. This correlation is stored in the storage unit 25, for example, as function data of the thermal displacement amount Δθs of the spindle shaft center with the value of the temperature difference as a variable. In this case, the calculation unit 22 uses the function data stored in the storage unit 25 to calculate the spindle shaft center thermal displacement amount Δθs corresponding to the value of the second temperature t2.

  In the control device 2, the movement control unit 21 and the calculation unit 22 may be realized by software. Further, the control device 2 may be configured by the movement control unit 21 and the calculation unit 22 by different control devices. Further, as the storage unit 25, for example, a hard disk built in the control device 2, a portable CD-ROM, a USB memory, or the like may be used.

  Further, the calculation unit 22 estimates the mounting position thermal displacement amount Δθt from the temperature (first temperature) t1 of the pipe 32 measured by the first temperature measuring device 73. The mounting position thermal displacement amount Δθt is the thermal displacement amount of the blade mounting position of the turret 50 with respect to the −X side end surface 72c of the second scale 72a (or the rotation center of the turret 50), as shown in FIG. The attachment position thermal displacement amount Δθt is a value obtained by extracting the component in the X direction from the thermal displacement amount around the X axis of the tool rest 5 centered on the end face 72c.

  There is a predetermined correlation between the first temperature t1 and the mounting position thermal displacement amount Δθt. The attachment position thermal displacement amount Δθt increases in absolute value on the − (minus) side as the temperature difference between the first temperature t1 and the fifth temperature t5 increases. Such a correlation between the temperature difference between the first temperature t1 and the fifth temperature t5 and the mounting position thermal displacement amount Δθt is obtained in advance by experiments or simulations. This correlation is stored in the storage unit 25 as, for example, function data of the attachment position thermal displacement amount Δθt having a variable of the temperature difference between the first temperature t1 and the fifth temperature t5. In this case, the calculation unit 22 uses the function data stored in the storage unit 25 to calculate the mounting position thermal displacement amount Δθt corresponding to the temperature difference between the first temperature t1 and the fifth temperature t5.

  Further, the calculation unit 22 calculates the outside air factor thermal displacement amount ΔG which is the thermal displacement amount between the spindle axis AX1 and the blade tip (machining tip) blade tip Ta of the tool T from the third temperature t3 measured by the third temperature measuring device 79. presume. The outside air factor thermal displacement amount ΔG is a thermal displacement amount due to the outside air temperature among the thermal displacement amounts of the blade mounting position of the turret 50 with respect to the −X side end surface 72c (or the rotation center of the turret 50) of the second scale 72a. is there. The outside air factor thermal displacement amount ΔG is a value obtained by extracting a component in the X direction of the thermal displacement amount around the X axis of the tool rest 5 centered on the end surface 72c.

  There is a predetermined correlation between the third temperature t3 and the outside air factor thermal displacement amount ΔG. The correlation between the third temperature t3 and the outside air factor thermal displacement amount ΔG is obtained in advance by experiments or simulations. This correlation is stored in the storage unit 25 as, for example, function data of the outside air factor thermal displacement amount ΔG having the value of the third temperature t3 as a variable. In this case, the calculation unit 22 uses the function data stored in the storage unit 25 to calculate the outside air factor thermal displacement amount ΔG corresponding to the third temperature t3. Further, the third temperature measuring device 79 may not be arranged. In this case, the outside air factor thermal displacement amount ΔG based on the third temperature t3 is excluded from the predetermined correction formula described later.

  The calculation unit 22 calculates the headstock thermal displacement amount ΔS, the tool post thermal displacement amount ΔT, the tool blade thermal displacement amount ΔH, the spindle shaft center thermal displacement amount Δθs, the mounting position thermal displacement amount Δθt, and the outside air factor thermal displacement amount ΔG. The relative movement amount between the headstock 4 and the tool rest 5 can be calculated by including it in the correction value. In this case, the correction value ΔX is expressed by the following predetermined correction formula.

ΔX = ΔS + ΔT + ΔH + Δθs + Δθt + ΔG
Of these, for Δθs, Δθt, and ΔG,
Δθs = K1 · Δt2 + K2 · Δt4
Δθt = K3 · Δt1 + K4 · Δt5
ΔG = K5 · Δt3
It is represented by. It should be noted that each of Δt1 to Δt5 is a displacement amount of the first temperature t1 to the fifth temperature t5 in a predetermined period. Further, each of K1 to K5 is a coefficient.

  The operation execution unit 23 causes the machine tool 100 to perform a normal operation and a measurement operation. The normal operation is an operation in which a plurality of works W are sequentially processed by the blade T. In the measurement operation, at least one of the unprocessed workpieces W is taken out as a measurement workpiece Wm while performing the normal operation, and the workpiece Wm is the same as or substantially equal to the blade T with respect to the measurement workpiece Wm. The operation is performed by the same measuring blade Tm under the same or almost the same conditions as the processing of the workpiece by the blade T.

  FIG. 5 is a time table that schematically shows the processing status of the work W in the normal operation and the measurement operation. In FIG. 5, a case where the measurement operation is performed and a case where the normal operation is performed after the measurement operation is described as an example. As illustrated in FIG. 5, the operation execution unit 23 processes the plurality of works W during the measurement operation, and takes out the work Wm for measurement from the plurality of works W at a predetermined time interval and processes the work Wm. The operation execution unit 23 processes the measurement work Wm using the above-described measurement blade Tm. Therefore, in the measurement operation, the operation execution unit 23 switches the cutting tool between the blade T and the blade Tm for measurement during processing of the work W and during processing of the measurement work Wm. Between the processing of the measurement work Wm and the processing of the measurement work Wm, the work W is processed by the blade Tm. Further, as shown in FIG. 5, the operation execution unit 23 executes the normal operation after the measurement operation and processes the plurality of works W with the blade T.

  In the measurement operation shown in FIG. 5, one workpiece Wm for measurement is processed by the blade Tm for measurement after processing two workpieces W by the blade T, but the present invention is not limited to this form. Since the measurement work Wm is processed at the above-mentioned predetermined time intervals, the number of works W to be processed by the blade T is increased or decreased by the predetermined time. Further, the above-mentioned predetermined time is not limited to the same time, and may be different times. For example, the predetermined time may be set shorter at the beginning of the measurement operation, and the predetermined time may be sequentially set longer.

  The operation execution unit 23 causes the measuring workpiece Tm to be machined by the measuring blade Tm with or without using a preset predetermined correction formula. In this case, since the preset predetermined correction formula is corrected based on the deviation from the design value when the predetermined correction formula is used or the deviation from the design value when the predetermined correction formula is not used, the work W Can be processed with higher precision.

  The coefficient adjusting unit 24 determines, based on the dimensions of the measurement work Wm after machining, the amount of displacement which is a deviation from the design value, and the first temperature t1 to the fifth temperature t5 at the timing of machining the measurement work Wm. The coefficient used for estimating the predetermined thermal displacement amount of the predetermined correction formula is adjusted so as to reduce the displacement amount. In the present embodiment, the coefficient adjusting unit 24 determines the coefficients K1 and K2 used for estimating the spindle axial thermal displacement amount Δθs, the coefficients K3 and K4 used for estimating the mounting position thermal displacement amount Δθt, and the outside air factor thermal displacement amount. Each coefficient K5 used for estimation is adjusted. The adjustment of the coefficients K1 to K5 is performed, for example, by substituting previously prepared values for the coefficients K1 to K5 and selecting the combination of the coefficients K1 to K5 that minimizes the displacement amount.

  The input unit 26 can input the dimensions of the measurement work Wm after machining during the measurement operation. As the input unit 26, for example, an input interface such as a keyboard, a mouse, a touch panel can be used. The input result of the input unit 26 is transmitted to the coefficient adjusting unit 24 of the control device 2. When the size of the measurement work Wm is input by the input unit 26, the coefficient adjusting unit 24 determines the above-mentioned predetermined correction formula based on the size of the measurement work Wm input by the input unit 26. The coefficients K1 to K5 are adjusted to the coefficients K1 to K5, respectively.

  The display unit 27 can display predetermined information output from the control device 2. As the display unit 27, for example, a display device such as a liquid crystal panel or an organic electroluminescence panel is used. For example, the coefficient adjusting unit 24 outputs the input result from the input unit 26 to the display unit 27, so that the display unit 27 can display the input result in the input unit 26. When the operation execution unit 23 executes the measurement operation, the display unit 27 can display that the measurement operation is being executed.

  FIG. 6 is a diagram showing an example of a display screen displayed on the display unit 27. In the example shown in FIG. 6, the display screen G of the display unit 27 displays an operation status display area 27a, a work diameter display area 27b, a coefficient display area 27c, and an operation button display area 27d. In the present embodiment, a case where a touch panel is used as the input unit 26 on the display screen G of the display unit 27 will be described as an example. By using a touch panel as the input unit 26, a worker can easily input data in each area.

  In the operation status display area 27a, for example, information indicating the progress of the measurement operation and the status of the work W after the measurement operation is displayed. In the work diameter display area 27b, when the size of the measurement work Wm during the measurement operation is input by the input unit 26, each input result is displayed. The coefficients K1 to K5 before and after the measuring operation are displayed in the coefficient display area 27c. The operation button display area 27d includes operation buttons such as a button for starting a measurement operation, a button for inputting a work diameter, and a button for displaying information indicating the status of the work W after the measurement operation. Is displayed. When a worker or the like touches the area where the operation button is displayed on the display screen of the display unit 27, a predetermined input signal corresponding to the operation button is transmitted to the driving execution unit 23.

  In the control device 2, the movement control unit 21, the calculation unit 22, the operation execution unit 23, and the coefficient adjustment unit 24 may be realized by software. Further, in the control device 2, at least one of the movement control unit 21, the calculation unit 22, the operation execution unit 23, and the coefficient adjustment unit 24 may be configured by another control device. Further, as the storage unit 25, for example, a hard disk built in the control device 2, a portable CD-ROM, a USB memory, or the like may be used.

  Next, the operation of the machine tool 100 configured as above will be described. First, a case where the machine tool 100 performs a normal operation will be described. In this case, the control device 2 causes the work spindle W to be processed to be held on the spindle 10 by the grip claws 11a. After holding the workpiece W on the spindle 10, the control device 2 rotates the spindle 10 in the axial direction (θZ direction) of the spindle axis AX1 to rotate the workpiece W in the axial direction of the spindle axis AX1. Let

  Subsequently, the control device 2 controls the X-direction driving unit 64 and the Z-direction driving unit 65 by the movement control unit 21 to relatively move the work W and the cutting tool T, so that the work W is moved at the cutting edge Ta of the cutting tool T. To cut. The processing data relating to the relative movement amount and speed of the work W and the blade T are stored in the storage unit 25 or the like by, for example, transmission from a host controller or input by a worker. The processing data is, for example, coordinate data of a trajectory along which the cutting edge Ta of the cutting tool T should move. The movement control unit 21 drives the X-direction drive unit 64 and the Z-direction drive unit 65 based on the processing data of the storage unit 25 and the like.

  When the work W is cut, the headstock 4, the tool rest 5, the spindle 10, the turret 50, the tool T, due to a change in environmental temperature, cutting heat generated when the work W is cut, heat generated in each part during operation, and the like. The holder 51, the bed 3, and the like are thermally deformed, and the distance in the X direction between the spindle axis AX1 and the blade tip Ta of the blade T changes. Due to this variation in the distance, an initially set reference position or reference distance (for example, a distance L in the X direction between the spindle axis AX1 and the cutting edge Ta, etc.) changes, and the cutting edge Ta of the cutting tool T with respect to the workpiece W changes. The position deviates from the expected value (set value based on the processed data). Therefore, in the present embodiment, the calculation unit 22 calculates or estimates the thermal displacement amount, calculates the correction value ΔX that is the relative movement amount between the spindle 10 and the cutting tool T, and corrects the machining data.

  FIG. 7 is a flowchart showing an example of processing for calculating the correction value of the distance L. As shown in FIG. 7, the calculation unit 22 calculates the headstock thermal displacement amount ΔS based on the displacement (position) in the X direction of the spindle axis AX1 measured by the spindle side position measuring device 71 (step). S01). Further, the calculation unit 22 calculates the tool post thermal displacement amount ΔT based on the displacement (position) in the X direction of the third reference position P3 measured by the tool side position measurement device 72 (step S02). Further, the calculation unit 22 estimates the blade thermal displacement amount ΔH based on the temperature of the pipe 32 (first temperature) measured by the first temperature measuring device 73 (step S03).

  As described above, the calculation unit 22 estimates the spindle shaft center thermal displacement amount Δθs based on the temperature of the headstock 4 (second temperature) measured by the second temperature measuring device 74 (step S04). Further, the calculation unit 22 estimates the mounting position thermal displacement amount Δθt from the temperature of the pipe 32 (first temperature) measured by the first temperature measuring device 73 (step S05). Further, the calculation unit 22 estimates the outside air factor thermal displacement amount ΔG based on the temperature inside the cover C (third temperature) measured by the third temperature measuring device 79 (step S06).

  The calculation unit 22 calculates or estimates the headstock thermal displacement amount ΔS, the tool post thermal displacement amount ΔT, the blade tool thermal displacement amount ΔH, the spindle shaft center thermal displacement amount Δθs, the attachment position thermal displacement amount Δθt, and the outside air factor thermal displacement amount ΔG. Based on the above, the correction value ΔX which is the relative movement amount between the spindle axis AX1 of the spindle 10 and the cutting edge Ta of the tool T is calculated by a predetermined correction formula (ΔX = ΔS + ΔT + ΔH + Δθs + Δθt + ΔG) (step S07).

  The movement control unit 21 corrects the processing data based on the relative movement amount (correction value ΔX) calculated by the calculation unit 22, and controls the X-direction driving unit 64 and the Z-direction driving unit 65 based on the corrected processing data. The workpiece W is driven to cut the workpiece W (step S08). In step S08, since the work W is cut based on the corrected working data, the heat of the machine tool 100 (main body 1) is cut in the X direction (cut amount of the work W) and the Z direction (feed amount of the cutting edge Ta). The work W is processed by eliminating the influence of deformation, and the work W can be accurately cut to a desired dimension.

  When the cutting of the work W is completed, the holding by the grip claws 11 a is released and the work W is taken out from the spindle 10. The work W may be loaded into or unloaded from the spindle 10 by a work transfer device (not shown). The series of operations from the loading and unloading of the work W by the work transporting device may be performed, for example, by an instruction from the control device 2 or may be performed manually by an operator. Since the control device 2 performs a series of operations from the loading and unloading of the work W by the work transfer device, the work W can be processed automatically.

  Next, a case where the machine tool 100 performs a measurement operation will be described. FIG. 8 is a flowchart showing an example of processing for performing the measurement operation. The operation execution unit 23 executes the machining of the work W, similarly to step S08 described above (step S11). In the machining operation of this work, the operation execution unit 23 determines whether or not to execute the measurement operation (step S12). In step S12, the operation execution unit 23 determines whether or not there is a flag for performing measurement operation, for example. Examples of such a flag include a case where a predetermined period has elapsed since the machine tool 100 was operated, or a case where there was an input from the input unit 26 to perform a measurement operation. For example, the operation executing unit 23 may execute the measurement operation at the first operation after a holiday or holiday for stopping the operation of the factory or the like, or the timing when the workpiece W to be processed is changed, or the blade T. It may be executed at the timing of replacement.

  FIG. 9 is a diagram showing an example of the display screen G displayed on the display unit 27, and shows the display screen G before performing the measurement operation. As shown in FIG. 9, the operation execution unit 23 displays a confirmation message as to whether or not to start the measurement operation in the operation status display area 27a of the display screen G. The operation execution unit 23 also displays an operation button for starting the measurement operation in the operation button display area 27d. When a signal to start the measurement operation is input on the display screen G of FIG. 9, the operation execution unit 23 determines that there is a flag for performing the measurement operation.

  As shown in FIG. 8, when there is no input to perform the measurement operation, the operation execution unit 23 determines not to perform the measurement operation (NO in step S12), and repeats the processing in steps S11 and S12. Do it. Further, when there is an input to perform the measurement operation, the operation execution unit 23 determines to execute the measurement operation (YES in step S12) and processes the measurement work Wm (step S13). In step S13, the operation execution unit 23 takes out at least one unprocessed work W and sets it as the measurement work Wm. The measurement work Wm is, for example, one of the unprocessed works W arranged in the processing order on the mounting table of the work W or the like.

  Further, the operation executing unit 23, after taking out the measurement work Wm, processes the measurement work Wm by the measurement blade Tm under the same or almost the same condition as the processing of the work W by the blade T. In this case, the operation execution unit 23 uses, for example, a machining program for machining the work W with the blade T. The operation execution unit 23 rotates the turret 50 in the θX direction so that the measuring blade Tm is arranged at a predetermined processing position. Then, the operation execution unit 23 controls the operations of the spindle 10, the headstock 4, and the tool rest 5 by the above-described machining program so that the machining amount is set in advance.

  10: is a figure which shows an example of the display screen G displayed on the display part 27, and has shown the display screen G when the driving | operation for measurement is started. When the measurement operation is started, the operation execution unit 23 causes the operation status display area 27a on the display screen G of the display unit 27 to display that the measurement operation is being executed, as illustrated in FIG. 10. This display can easily inform the operator that the machine tool 100 is in the measurement operation. The operation executing unit 23 may display the coefficients K1 to K5 before the adjustment in the coefficient display area 27c in the correction low correction formula for calculating the correction value.

  In the measurement operation, the operation executing unit 23 takes out the measurement work Wm from the plurality of works W at predetermined time intervals and causes the measurement blade Tm to process each measurement work Wm. The predetermined time and the number of the measurement works Wm taken out can be set by storing them in the storage unit 25 in advance. The operation execution unit 23 causes the blade T to process the normal work W until the next work Wm for measurement is processed after processing one work Wm for measurement. In other words, the operation executing unit 23 switches the blade T to the blade Tm for measurement every time a predetermined time elapses during a normal processing operation of processing the plurality of workpieces W with the blade T, and sets it as the workpiece Wm for measurement. The set unprocessed work W is processed. After processing the measurement work Wm, the operation execution unit 23 switches the measurement tool Tm to the tool T again and executes the normal work W processing until a predetermined time elapses.

  As shown in FIG. 8, the operation executing unit 23 processes one measurement work Wm, and then determines whether or not the processed measurement work Wm has reached a predetermined number (step S14). When the operation execution unit 23 determines that the processed measurement work Wm has not reached the predetermined number (NO in step S14), the operation execution unit 23 waits until the processed measurement work Wm reaches the predetermined number. , And control is performed so that the operation of step S13 and subsequent steps is repeated. In other words, the operation execution unit 23 determines whether or not a predetermined time has elapsed (step S15), and when the predetermined time has elapsed (YES in step S15), the next part of the unworked workpiece W for measurement is measured. The work Wm is set, and processing is performed with the measuring blade Tm. The driving | operation execution part 23 repeats the determination of step S15, when predetermined time has not passed (NO of step S15).

  When it is determined that the number of processed measurement works Wm has reached the predetermined number (YES in step S14), the operation execution unit 23 displays the dimension of the processed measurement work Wm on the display screen G of the display unit 27. FIG. 11 is a diagram showing an example of a display screen G displayed on the display unit 27, and shows the display screen G for inputting the dimension (diameter) of the processed measurement work Wm. The operation execution unit 23 displays the work diameter input area 27e on the display screen G of the display unit 27. The operator operates the touch panel as the input unit 26 to input the dimension (diameter) of the measurement work Wm into each of the work diameter input areas 27e (step S16).

  The work diameter input area 27e is provided with a plurality of entry fields above and below the display screen G. When the operator touches this entry field, for example, a ten-key is displayed on the display screen G, and the operator operates the ten-key to input the dimension (diameter) of the measurement work Wm. For example, the operator inputs the dimensions (diameter) of the measurement work Wm in the order in which the measurement work Wm is processed, starting from the upper column. Note that step S16 is not limited to input by the operator. For example, when measuring the dimension (diameter) of the measurement work Wm by the measurement device, the measurement result from this measurement device is sent to the control device 2, and the size of the measurement work Wm is automatically input. May be.

  When the work diameter is input through the work diameter input area 27e, the operation execution unit 23 displays the input result in the work diameter display area 27b as shown in FIG. When the dimension of the measuring workpiece Wm is input to the workpiece diameter input area 27e, the coefficient adjusting unit 24 determines, based on the dimension of the measured workpiece Wm after machining during the measuring operation and the displacement amount between the design value and The coefficients K1 to K5 used for estimating the predetermined thermal displacement amount of the predetermined correction formula are adjusted so as to reduce the displacement amount (step S17).

  FIG. 12 is a flowchart showing an example of the adjustment processing in step S17. As shown in FIG. 12, the coefficient adjusting unit 24 calculates the headstock thermal displacement amount ΔS (step S21), the tool post thermal displacement amount ΔT (step S22), and estimates the tool post thermal displacement amount ΔH (step S23). The main axis thermal displacement amount Δθs is estimated (step S24), the mounting position thermal displacement amount Δθt is estimated (step S25), and the outside air factor thermal displacement amount ΔG is estimated (step S26). These steps S21 to S26 are the same processes as steps S01 to S06 shown in FIG. 7, and description thereof will be omitted. The coefficient adjusting unit 24 makes a predetermined correction from the headstock thermal displacement amount ΔS, the tool post thermal displacement amount ΔT, the blade tool thermal displacement amount ΔH, the spindle shaft center thermal displacement amount Δθs, the mounting position thermal displacement amount Δθt, and the outside air factor thermal displacement amount ΔG. The predetermined correction equation is corrected (or updated) by calculating the coefficients K1 to K5 in the equation and adjusting the previously set predetermined correction equation coefficients K1 to K5 to new coefficients K1 to K5 (step S27). .

  FIG. 13 is a diagram showing an example of the display screen G displayed on the display unit 27, and shows the display screen G regarding the situation after the coefficient adjustment. After the coefficients K1 to K5 are adjusted, the operation executing unit 23 displays a graph for comparing the correction value after the coefficient adjustment and the correction value before the coefficient adjustment in the operation status display area 27a of the display screen G. Can be made. With this graph, it is possible to easily notify the operator of the change in the correction value before and after the coefficient adjustment. In addition, after the coefficients K1 to K5 are adjusted, the control device 2 may perform control so as to perform new cutting using the correction value according to the predetermined correction formula after the coefficient adjustment.

  In this way, the machine tool 100 according to the embodiment sequentially processes the plurality of workpieces W by the blade T, while using the measuring blade Tm for the measuring workpiece Wm, which is one of the plurality of workpieces W. A measurement operation for machining is executed, and based on the amount of displacement of the measured workpiece Wm after machining and the design value, it is used to estimate a predetermined thermal displacement amount of a predetermined correction formula so as to reduce this displacement amount. Since the coefficients K1 to K5 that have been adjusted are adjusted, the predetermined correction formula can be corrected without stopping the production by the machine tool 100 (processing of the work W), and the machine tool 100 can process the work W with high accuracy. It is possible to suppress a decrease in production efficiency (working efficiency of the work W).

  The measurement work Wm processed during the measurement operation may be treated as the processed work W, like the work W processed by the blade T. Further, the above-described measurement operation may be performed when machining is performed in which the allowable value of the dimensional error of the workpiece W after machining is large. In this case, it becomes possible to correct the predetermined correction formula while machining the workpiece W having a large allowable value of the dimensional error, and thereafter, it is possible to process the workpiece W having a small allowable value of the dimensional error. Become.

  Although the embodiment has been described above, the present invention is not limited to the above description, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, the spindle shaft center thermal displacement amount Δθs is estimated from the second temperature, but the present invention is not limited to this form. For example, the spindle shaft center thermal displacement amount Δθs may be estimated from the elapsed time from the start of operation of the machine tool. The amount of thermal displacement Δθs of the spindle axis increases from the start of operation to a predetermined value. The relationship between the time from the start of operation and the amount of thermal displacement Δθs of the spindle shaft core is stored in the storage unit 25 as, for example, function data of the amount of thermal displacement Δθs of the spindle shaft with the time from the start of operation as a variable. May be. In this case, the calculation unit 22 may use the function data stored in the storage unit 25 to calculate the spindle shaft center thermal displacement amount Δθs corresponding to the time from the start of operation.

  As described above, when the value of the thermal displacement amount Δθs of the spindle axis has a correlation with the time from the start of operation of the machine tool, the time from the start of operation is measured and Since it suffices to calculate the corresponding spindle shaft center thermal displacement amount Δθs, the second temperature measuring device 74 for measuring the second temperature becomes unnecessary. With this configuration, the device configuration of the main body 1 and the processing of the control device 2 can be simplified.

  In the above-described embodiment, the blade T and the measuring blade Tm are attached to different holders of the turret 50, but the present invention is not limited to this. For example, the blade T and the blade Tm for measurement may be attached to the same holder. Further, in the above-described embodiment, one main shaft 10 is used to hold the measurement work Wm on the main shaft 10, but the present invention is not limited to this form. For example, the machine tool may include a spindle for holding the measurement work Wm, separately from the spindle 10. Further, when the machine tool 100 is a parallel two-axis lathe, one of the two spindles is used to process the workpiece W by the blade T, while the other spindle is used for measurement by the measuring blade Tm. The work Wm may be processed. In this case, since the processing of the work W is not interrupted during the processing of the measurement work Wm, it is possible to suppress a decrease in the processing efficiency of the work.

P1 ... First reference position P2 ... Second reference position P3 ... Third reference position T ... Blade Tm ... Measuring blade Ta ... Blade tip W ... Workpiece Wm ... Measurement work AX1 ... Spindle shaft center 1 ... Main body 2 ... Control device 3 ... Bed 4 ... Spindle head 5 ... Tool rest 5b ... Side surface 5c ... Fixed position 6 ... Moving device 7 ... Measuring device 10 ... Spindle 11 ... Chuck driving part 11a ... Gripping claw 21 ... Movement control part 22 ... Calculation part 23 ... Operation execution part 24 ... Coefficient adjusting unit 26 ... Input unit 27 ... Display unit 30 ... Cooling device 32 ... Piping 50 ... Turret 50a ... End face 70 ... Reference frame 71 ... Spindle side position measuring device 71a ... First scale 71b ... First reading device 72 ... Blade side position measuring device 7 a ... second scale 72b ... second reading device 73 ... first temperature measuring device 74 ... second temperature measuring device 79 ... third temperature measuring device 75 ... fourth temperature measuring device Device 76 ... Fifth temperature measuring device 100 ... Machine tool

Claims (7)

A spindle stock that rotatably supports a spindle having a chuck for gripping a work piece at the tip,
A turret to which a turret can be attached,
A bed in which the headstock and the tool rest are installed so as to be relatively movable in the radial direction of the main shaft,
The tool post, the spindle head, or a temperature measuring device for measuring the temperature in the vicinity thereof,
A spindle side position measuring device that measures a spindle axis center position in the spindle radial direction with respect to a first reference position in the bed;
A tool-side position measuring device that measures a third reference position of the tool rest in a radial direction of the spindle with respect to a second reference position in the bed,
A headstock thermal displacement amount, which is a thermal displacement amount of the headstock, is calculated based on the spindle shaft center position measured by the spindle-side position measuring device, and the third reference measured by the tool-side position measuring device. Calculate the amount of tool rest thermal displacement that is the amount of thermal displacement of the tool rest based on the position, and estimate the predetermined amount of thermal displacement from the workpiece to the machining tip of the tool based on the temperature measured by the temperature measuring device. Then, the headstock thermal displacement amount, the tool rest thermal displacement amount, and a calculation unit for calculating the relative movement amount of the headstock and the tool rest by a predetermined correction formula having each item of the predetermined thermal displacement amount,
While sequentially processing a plurality of workpieces by the blade, at least one of the unmachined workpieces is taken out as a measurement workpiece from the plurality of workpieces, and the measurement workpiece is the same or almost the same as the blade. An operation execution unit that executes a measurement operation for processing under the same or almost the same conditions as the processing of the work by the cutting tool,
A coefficient adjustment for adjusting the coefficient used for estimating the predetermined thermal displacement amount of the predetermined correction formula based on the displacement amount between the measured workpiece after machining and the design value so as to reduce the displacement amount. Machine tools, including parts.   The work according to claim 1, wherein the operation execution unit causes each of the plurality of measurement works to be processed by the measurement blade by taking out the plurality of works at predetermined time intervals during the measurement operation. machine. A measurement headstock that rotatably supports a measurement spindle having a chuck for gripping the measurement work at the tip,
The measuring tool is attached and includes a measuring tool rest,
The machine tool according to claim 1 or 2, wherein the measurement headstock and the measurement tool rest are installed on the bed so as to be relatively movable in a radial direction of the spindle.   The operation execution unit causes the measuring workpiece to process the measuring workpiece with the predetermined correction formula that is set in advance or without using the predetermined correction formula. The machine tool according to any one of claims.   The machine tool according to any one of claims 1 to 4, further comprising a display unit that displays that the measurement operation is being performed. Equipped with an input unit that can input the dimensions of the measurement workpiece after processing,
The machine tool according to claim 1, wherein the coefficient adjusting unit adjusts the coefficient based on a dimension of the measurement work input to the input unit. A spindle stock that rotatably supports a spindle having a chuck for gripping a work piece at the tip,
A turret to which a turret can be attached,
A bed in which the headstock and the tool rest are installed so as to be relatively movable in the radial direction of the main shaft,
The tool post, the spindle head, or a temperature measuring device for measuring the temperature in the vicinity thereof,
A spindle side position measuring device that measures a spindle axis center position in the spindle radial direction with respect to a first reference position in the bed;
A tool-side position measuring device that measures a third reference position of the tool post in the radial direction of the spindle with respect to a second reference position in the bed, a machining method using a machine tool,
Calculating a headstock thermal displacement amount, which is a thermal displacement amount of the headstock, based on the spindle shaft center position measured by the spindle-side position measuring device;
Calculating a tool post thermal displacement amount that is a thermal displacement amount of the tool post based on the third reference position measured by the tool side position measuring device;
Estimating a predetermined amount of thermal displacement from the workpiece to the processing tip of the blade based on the temperature measured by the temperature measuring device,
Calculating the relative movement amount of the headstock and the tool rest by a predetermined correction formula having the headstock thermal displacement amount, the tool rest heat displacement amount, and the predetermined heat displacement amount as items,
While sequentially processing a plurality of workpieces by the blade, at least one of the unmachined workpieces is taken out as a measurement workpiece from the plurality of workpieces, and the measurement workpiece is the same or almost the same as the blade. By using a cutting tool, performing a measurement operation for processing under the same or almost the same conditions as the processing of the workpiece by the cutting tool,
Adjusting the coefficient used to estimate the predetermined thermal displacement amount of the predetermined correction formula so as to reduce the displacement amount based on the displacement amount between the measurement work after machining and the design value. And a processing method including.

Images