JP2021003799A - In-machine measurement correction method of processor - Google Patents

Abstract

To suppress occurrence of an error of a correction value of a calculated dimension by a simple constitution.SOLUTION: An in-machine measurement correction method of a processor having a jig 11 installed in the processor 1, a position detection probe 13 attached to a spindle which is driven by a feed mechanism including a ball screw, and a control device, there are provided: a master guide 14 fixed to the jig 11; and a master plate 15 formed of a raw material which is the same as that of a processed product 12, and having a thermal expansion coefficient similar to that of the processed product, and fixed to the jig so as to progress along the master guide 14. The master plate 15 is fixed so that displacement of the ball screw in a feed direction is not hindered, and the control device corrects a measurement value of displacement of the processed product 12 which is measured by the position detection probe 13 by using a ratio of a reference dimension and a dimension of the expanded master plate 15.SELECTED DRAWING: Figure 1

Description

The present invention relates to an in-machine measurement correction method of a processing machine for processing an workpiece.

Conventionally, Japanese Patent Application Laid-Open No. 2006-212765 is available as a technique in such a field. The in-machine measurement correction method described in this publication discloses a configuration in which the thermal displacement of a ball screw in a processing machine is calculated with reference to an Invar material which is a low expansion material. As a result, the thermal displacement of both the machine tool and the workpiece is comprehensively measured and corrected.

Japanese Unexamined Patent Publication No. 2006-21765

However, in the conventional in-flight measurement correction method described above, the reference thermal displacement may not be small due to the distortion of the device used as the reference for the dimensions. In other words, the thermal displacement of the equipment itself used as the dimensional (position) reference is extremely small, but the processing table provided in the processing machine is usually made of iron-based metal and is affected by the coolant liquid and atmospheric temperature. Because of the thermal displacement, an error may occur in the reference depending on how the equipment used as the reference for the dimensions is attached to the processing table. Therefore, an error may occur in the entire processing machine, and in particular, in the correction value of the dimensions calculated for correcting the ball screw used for the feed mechanism in the processing machine.

In addition, it is necessary to use a plurality of temperature detectors for temperature measurement. This is because the temperature difference between the workpiece to be machined and the reference temperature is measured and the correction value is calculated using the coefficient of linear expansion, so that it is necessary to use a plurality of temperature detectors.

Furthermore, calibration may be performed with a dimensional standard in a larger range than the workpiece to be actually measured and corrected. This is because in a positioning drive device that uses a ball screw or the like, when there is a bias in the parts used such as a machining machine, the thermal expansion of the parts that are frequently used may increase, and the amount of thermal displacement may differ depending on the part. Can be mentioned.

For example, as shown in FIG. 6, in the temperature distribution of the ball screw, heat is accumulated around the center of the operating region and the temperature rises. Further, as shown in FIG. 7, when heat displacement occurs due to heat storage in the ball screw shown in FIG. 6 and heat elongation of the ball screw is generated, the elongation method differs depending on the position of the ball screw. Therefore, it is desirable to use a part having a thermal displacement amount almost equal to the part to be measured as a reference.
The present invention provides an in-machine measurement correction method for a processing machine having a simple structure and suppressing the occurrence of an error in the calculated correction value of dimensions.

The in-machine measurement correction method of the processing machine according to the present invention includes a jig installed in the processing machine, a position detection probe attached to a spindle driven by a feed mechanism including a ball screw, and a control device. This is an in-flight measurement correction method of the above method, in which the master guide fixed to the jig and the material having the same material or the same thermal expansion coefficient as the workpiece and follow the master guide. A master plate fixed to the jig is provided, the master plate is fixed so as not to hinder the displacement of the ball screw in the feeding direction, and the control device is the machine to be processed as measured by the position detection probe. The measured value of the displacement of the object is corrected by using the ratio of the reference dimension and the dimension of the master plate after expansion.
As a result, the thermal displacement of the ball screw can be calculated using the measured value of the corrected position detection probe, and the correction of the processing machine can be executed.

As a result, it is possible to provide an in-machine measurement correction method for a processing machine having a simple configuration and suppressing the occurrence of an error in the calculated correction value of the dimensions.

It is a figure which showed an example of the whole structure of the processing machine which concerns on Embodiment 1. FIG. It is a figure which shows the state which the master plate and the master guide are arranged on the side surface of the jig which concerns on Embodiment 1. FIG. It is a figure which shows an example of the procedure of measurement and correction in the processing machine which concerns on Embodiment 1. FIG. It is a figure which shows the example which fixed the master plate by abutting the master fixing spring from above which concerns on Embodiment 1. FIG. FIG. 5 is a diagram showing an example in which a master fixing screw is inserted from below into the lower center of the master plate according to the first embodiment to fix the master plate. It is a figure which shows an example of the temperature distribution for each position in the heating state of the related ball screw. It is a figure which shows an example of the heat elongation distribution for each position in the heating state of the related ball screw. It is a figure which showed an example of the whole structure of the processing machine 2 which concerns on Embodiment 2. FIG. It is a figure which showed typically an example of the positional relationship between the fixing part and the knock pin which concerns on Embodiment 2. FIG.

Embodiment 1.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the processing machine 1 includes a jig 11, a work piece 12 mounted on the jig 11, a position detection probe 13 for measuring the position of the work piece 12, and a jig. The master guide 14 is provided so as to project from the side surface of the eleven, and the master plate 15 is arranged along the master guide 14.

The jig 11 will be described as being a substantially rectangular parallelepiped formed long in the X direction and the Y direction. Here, it is assumed that the X direction and the Y direction are substantially horizontal, and the upper surface in the Z direction is a plane extending in the XY direction and extending in the substantially horizontal direction.

Further, it is assumed that two master guides 14a and 14b are used as the master guide 14 in the processing machine 1, and two master plates 15a and 15b are used as the master plate 15.

The workpiece 12 is placed on the upper surface 11a of the jig 11 in the Z direction. Further, a master guide 14a having a shape extending in the X direction is formed on the side surface 11b on the Y direction side of the jig 11 so as to project from the side surface 11b. Similarly, on the side surface 11c of the jig 11 on the X direction side, a master guide 14b having a shape extending in the Y direction is formed as well as being formed so as to protrude from the side surface 11c.

The master guide 14a and the master guide 14b are formed on the lower side of the side surfaces 11b and 11c of the jig 11, respectively. For example, the position of the master guide 14a in the Z direction is such that the upper surface of the master plate 15a having a substantially rectangular parallelepiped shape is the upper surface 11a of the jig 11 in the Z direction when the master plate 15a is arranged above the master guide 14a. It is formed so as to be approximately the same as or lower than the height. The same applies to the master guide 14b.

The master guide 14a and the master guide 14b are low thermal expansion materials having a small displacement due to expansion with respect to heat, respectively.

The position detection probe 13 detects the position of the workpiece 12. The position detection probe 13 is attached to a spindle driven by a feed mechanism having a ball screw.

For example, the position detection probe 13 is installed in place of the machining tool used when machining the workpiece using the machining machine 1, and measures the machining accuracy of the machining machine 1.

The master plates 15a and 15b are plates having predetermined dimensions, and the ratio of the reference dimension, which is the dimension before thermal expansion, and the dimension after thermal expansion is calculated. The position detection probe 13 detects the position of the workpiece 12.

The control device (not shown) is a calculation that corrects and calculates the measured value measured by the position detection by the position detection probe 13 by using the ratio of the reference dimension and the dimensions of the master plates 15a and 15b after thermal expansion. It is a device. As a result, the control device can calculate the amount of displacement due to heat of the ball screw of the feed mechanism in which the position detection probe 13 is installed.

Here, the master plate 15a will be described. The master plate 15a is arranged above the master guide 14a. The master plate 15a is a material having the same material as the workpiece 12 or a material having the same coefficient of thermal expansion.

Further, the master plate 15a is arranged along the master guide 14a and is fixed to the jig 11. More specifically, the master plate 15a is a plate extending in the X direction, and is above the master guide 14a provided on the side surface 11b on the Y direction side of the jig 11 and formed so as to extend in the X direction. Placed in. Typically, the master plate 15a is formed to have a shorter length in the extending direction (X direction) than the master guide 14a.

Further, as shown in FIG. 2, the master plate 15a is fixed to the jig 11 by a master fixing screw 16 penetrating in the Y direction at the central portion of the master plate 15a in the X direction. For example, the master plate 15a is fixed to the jig 11 by a plurality of master fixing screws 16 continuously provided in the Z direction. Since the master plate 15a is fixed at the central portion, it is in a state where the thermal displacement in both ends in the X direction is not hindered. Further, the master plate 15a is prevented from rotating by a master guide 14a arranged along the lower side thereof, and the same posture is maintained.

Similarly, the master plate 15b is arranged above the master guide 14b and is arranged so as to extend in the Y direction along the master guide 14b extending in the Y direction. Further, the master plate 15b is fixed to the jig 11 by a plurality of master fixing screws 16 penetrating in the X direction at the central portion in the Y direction. As a result, the master plate 15b is in a state in which the displacement in the thermal direction is not hindered in both ends in the X direction. Further, the master plate 15b is prevented from rotating by the master guide 14b arranged below the master plate 15b, and the same posture is maintained.

Next, with reference to FIG. 3, a procedure for performing measurement for performing position correction of the processing machine 1 and performing correction will be described.

The workpiece 12 is placed on the upper surface 11a of the jig 11 (step S1). Further, the position detection probe 13 is set on the work piece 12 (step S2) so that the displacement of the work piece 12 due to thermal expansion can be measured. Typically, it is possible to measure the displacement of the position of the workpiece 12 in the X and Y directions due to thermal expansion. The X direction and the Y direction correspond to the displacement direction of the ball screw feeding direction.

The master plate 15a is set on the side surface 11b of the jig 11, and the master plate 15b is set on the side surface 11c (step S3). The master plates 15a and 15b are fixed to the jig 11 at the central portion in the extending direction of the plates, respectively. Further, below the master plate 15a, a master guide 14a extending in the same direction as the extending direction of the master plate 15a is arranged, and the master plate 15a is arranged along the master guide 14a. The same applies to the arrangement of the master plate 15b and the master guide 14b.

The displacement amount is measured by measuring the position of the work piece 12 that has been thermally displaced by the position detection probe 13 (step S4). At this time, the thermal displacements of the master plates 15a and 15b in the extending direction in both ends are measured. Here, both ends in the extending direction are displacements in the feeding direction of the ball screw, and the master plates 15a and 15b are fixed in a state where the displacement in the feeding direction of the ball screw is not hindered.

The control device calculates the ratio of the reference dimension and the measured value after thermal expansion for the master plates 15a and 15b (step S5). Further, in the control device, regarding the measured value of the displacement of the workpiece 12 measured by the position detection probe 13, the reference dimension which is the dimension of the master plates 15a and 15b before thermal expansion and the measured value after thermal expansion are set. Correction is performed using the ratio (step S6).

Here, the master plates 15a and 15b use the same material as the workpiece 12 or a material having the same coefficient of thermal expansion. Therefore, by using the ratio of the thermal displacements of the master plates 15a and 15b to the reference dimensions to correct the displacement amount of the workpiece 12 measured by the position detection probe 13, it is possible to make it difficult to include an error. .. That is, the correction for the expansion of the workpiece 12 can be performed more accurately than the case where the correction is performed using an article that does not expand as the reference material. Therefore, the thermal displacement applied to the ball screw can be measured more accurately, and the processing machine 1 can be corrected.

Since the correction value is calculated not by the temperature but by the dimension at the time of measurement in this method, it is not necessary to install a thermometer for the correction, and the cost can be reduced.

As described above, in the processing machine 1 having the feed mechanism including the ball screw, the thermal displacement of the ball screw can be measured in a state where the occurrence of error is reduced by a simple configuration without using a thermometer. Further, the correction of the processing machine 1 can be executed based on the measured value.

Further, for example, as shown in FIG. 4, the master plates 15a and 15b may have a structure in which master guides are provided above and below. For example, the master plate 15a is placed on a first master guide 17a provided below and is fixed by a master fixing spring 19 connected to a second master guide 18a provided above. ..

Further, for example, on the upper surface of the master plate 15a, the force fixed by the master fixing spring 19 may be formed so as to be applied substantially evenly in the extending direction of the master plate 15a. Typically, a plurality of master fixing springs 19 are provided between the second master guide 18a and the master plate 15a.

Here, the master plate 15a is fixed by the master fixing spring 19 without using the master fixing screw 16. As a result, the stress of the master plate 15a is lower than that of the case where the master fixing screw 16 is used, and the master plate 15a is in a state where the thermal displacement in the extending direction is not hindered while maintaining the same posture.

A part of the first master guide 17a has a shape that protrudes upward. As a result, the master plate 15a is placed in contact with or close to the side surface 11b without being separated from the side surface 11b of the jig 11.

The structure for fixing the master plate 15b can be the same as that for the master plate 15a. As a result, the master plate 15b can be fixed in a reduced stress state.

Further, for example, as shown in FIG. 5, instead of fixing the master plate 15a to the jig 11 with the master fixing screw 16 penetrating in the Y direction, the master fixing screw 20 is passed through from below to above the master guide 14a. , The master plate 15a can be fixed by inserting it into the lower center of the master plate 15a. That is, the master plate 15a is fixed to the master guide 14a fixed to the jig 11.

As a result, the master plate 15a can maintain the same posture in a state in which the thermal displacement in the extending direction (X direction) in both end directions is not hindered and in a state in which the thermal displacement in the upward direction is not hindered. ..

The structure for fixing the master plate 15b can be the same as that for the master plate 15a. As a result, the master plate 15b can maintain the same posture in a state in which the thermal displacement in the extending direction (Y direction) in both end directions is not hindered and in a state in which the thermal displacement in the upward direction is not hindered. ..

Embodiment 2.
Next, a processing machine 2 using a fixing portion 21 for fixing the master plates 15a and 15b and a knock pin 22 for fixing the workpiece 12 will be described. In the following, the constituent articles having the same functions as the constituent articles of the processing machine 1 shown in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The processing machine 2 is provided with a jig 11, a work piece 12 mounted on the jig 11, a position detection probe 13 for measuring the position of the work piece 12, and a protrusion from the side surface of the jig 11. The master guide 14 provided, the master plate 15 arranged along the master guide 14, the fixing portion 21, and the knock pin 22 are provided.

As shown in FIG. 8, the knock pin 22 is a plurality of pins provided so as to project upward from the upper surface of the jig 11. Here, it is assumed that the two knock pins 22 are arranged so as to be continuous in the X direction with a predetermined distance. In FIG. 8, the pin on the left side in the X direction is referred to as a knock pin 22a, and the pin on the right side is referred to as a knock pin 22b.

As shown in FIGS. 8 and 9, the fixing portion 21 has two fixing portions 21a and 21b for fixing the master plate 15a and a fixing portion 21c for fixing the master plate 15b.

The fixing portions 21a and 21b fix a predetermined portion of the master plate 15a to the master guide 14a. Specifically, pins provided so as to project upward from the upper surface of the master guide 14a are used for the fixing portions 21a and 21b, respectively. That is, the master plate 15a is fixed to the master guide 14a by inserting a pin into the lower part of the master plate 15a.

Here, as shown in FIG. 9, the positions where the two fixing portions 21a and 21b are provided are the positions where the two knock pins 22a and 22b are aligned with each other in the X direction. In other words, the fixed portion 21a is arranged so that the straight line drawn so as to be orthogonal to the fixed portion 21a with respect to the straight line connecting the knock pins 22a and 22b, that is, the straight line drawn in the Y direction intersects at the position of the knock pin 22a. ing. Similarly, the fixing portion 21b is arranged so that a straight line drawn so as to be orthogonal to the fixing portion 21b intersects the straight line connecting the knock pins 22a and 22b at the position of the knock pin 22b.

For example, the positions of the fixing portions 21a and 21b are set inside the X direction with respect to the measurement points set on the master plate 15b. Here, the position of the measurement point on the master plates 15a and 15b can be determined according to the shape of the workpiece 12 and the position of the object to be processed on the workpiece 12, but typically the extension of the master plates 15a and 15b. It is near the end in the direction of presence.

The fixing portion 21c fixes a predetermined portion of the master plate 15b to the master guide 14b. Specifically, a pin provided so as to project upward from the upper surface of the master guide 14b is used for the fixing portion 21c. That is, the master plate 15b is fixed to the master guide 14b by inserting a pin from the lower part of the master plate 15b.

Here, as shown in FIG. 9, the position where the fixing portion 21c is provided is a position on a straight line connecting the two knock pins 22a and 22b. In other words, the knock pins 22a and 22b and the fixing portion 21c are arranged so as to be aligned in the Y direction and continuous in the X direction.

Here, in the processing machine 2 provided with the fixing portion 21 and the knock pin 22, master plates 15a and 15b whose dimensions are known and made of a member equivalent to the coefficient of thermal expansion of the workpiece 12 are attached to the side surface of the jig 11. , The operation when measuring the dimension of the workpiece 12 using these expansion ratios will be described.

The workpiece 12 is predominantly accustomed to the temperature of the coolant in order to remove heat during machining, and the master plates 15a and 15b attached to the jig 11 are also cooled to the temperature of the workpiece.

The master plates 15a and 15b are formed by fixing portions 21a, 21b and 21c provided at positions where either the Y direction or the X direction is aligned with respect to the positions of the knock pins 22a and 22b on the jig 11. It is fixed to 14b. As a result, the master plates 15a and 15b are fixed to the master guides 14a and 14b, respectively, in a state of being deformable so as to follow the thermal displacement of the workpiece 12.

The physical position of the workpiece 12 is measured using the position detection probe 13. That is, the measured value can be obtained by detecting the touch point with the position detection probe 13 while changing the position of the workpiece 12 by the drive device using the ball screw and the servomotor.

Using the results of measurement of the position of the workpiece 12 using the position detection probe 13 and the state before and after heating of the master plates 15a and 15b,
The correction value can be obtained by calculating. As a result, it is possible to correct the thermal expansion of the processing machine 2 without measuring the temperature.

Therefore, in the processing machine 2 having the feed mechanism including the ball screw, the thermal displacement of the ball screw can be measured in a state where the occurrence of error is reduced by a simple configuration without using a thermometer. Further, the correction of the processing machine 2 can be executed based on the measured value.

That is, in a positioning drive device using a ball screw or the like, when there is a bias in the parts used such as a processing machine, the coefficient of thermal expansion of the parts frequently used becomes large, and the amount of thermal displacement differs depending on the parts. Therefore, the dimensional reference is a part that is almost equal to the part to be measured, and it is possible to perform measurement and correction by installing the parts to be compared so that thermal displacement occurs in the same manner.

Specifically, the reference is set by aligning the positions of the fixing portions 21a, 21b, 21c fixing the master plates 15a, 15b with the positions of the knock pins 22a, 22b fixing the workpiece 12 to the jig 11. Can be matched. As a result, the state in which the workpiece 12 is deformed by thermal expansion and the state in which the master plates 15a and 15b are deformed by thermal expansion can be brought close to each other, and a correction value for correcting the influence of expansion can be calculated in the processing machine. When doing so, the occurrence of errors can be reduced.

For example, if one end of the master plate is fixed and heat deformed with the fixed point as the origin, the difference between the amount of change in the master plate and the amount of change in the workpiece becomes large and the correction accuracy decreases, but the master plate By performing the measurement in a state where the fixed positions of 15a and 15b are aligned with the fixed positions of the workpiece 12, it is possible to suppress a decrease in correction accuracy.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit. That is, the above description has been omitted or simplified as appropriate for the purpose of clarifying the description, and those skilled in the art can easily change, add, or convert each element of the embodiment within the scope of the present invention. It is possible.

1 Processing machine 2 Processing machine 11 Jig 11a Top surface 11b, 11c Side surface 12 Work piece 13 Position detection probe 14 Master guide 14a, 14b Master guide 15 Master plate 15a, 15b Master plate 16 Master fixing screw 17a Master guide 18a Master guide 19 Master fixing spring 20 Master fixing screw 21a, 21b, 21c Fixing part 22a, 22b Knock pin

Claims (2)

An in-machine measurement correction method for a processing machine including a jig installed in the processing machine, a position detection probe attached to a spindle driven by a feed mechanism including a ball screw, and a control device.
The master guide fixed to the jig and
A material having the same material as the work piece or a material having the same coefficient of thermal expansion, and a master plate fixed to the jig along the master guide.
The master plate is fixed so that the displacement of the ball screw in the feeding direction is not hindered.
The control device corrects the measured value of the displacement of the workpiece measured by the position detection probe by using the ratio of the reference dimension and the dimension of the master plate after expansion, which is an in-machine measurement correction method of the processing machine. .. The master plate is fixed to the jig with a fixing portion.
The workpiece is fixed to the jig with at least two knock pins.
The fixed portion is formed by a straight line connecting the knock pins or a straight line drawn so as to be orthogonal to the straight line connecting the two knock pins at any position of the two knock pins. The in-flight measurement correction method for a processing machine according to claim 1, wherein the method is provided as described above.