CN118219001A - Method for calibrating a rotational center axis and five-axis machining center - Google Patents

Abstract

The invention relates to the technical field of detection and calibration of a finish machining machine tool, and discloses a method for calibrating a rotation central axis and a five-axis machining center, wherein the method for calibrating the rotation central axis comprises the following steps: adsorbing the dial indicator on a main shaft of a five-shaft machining center; the method comprises the steps of (1) marking a dial indicator on a first bus of a core rod, and moving a main shaft along the extending direction of the first bus to detect a deviation error d1 from a fixed end to a free end of the core rod in a direction parallel to a C axis; adjusting the core rod to reduce the offset error d1 to be smaller than a first preset precision value; the dial indicator is arranged on a second bus of the core rod, and the main shaft is moved along the extending direction of the second bus to detect the offset error d2 from the fixed end to the free end of the core rod in the direction parallel to the C axis, wherein the radian between the second bus and the first bus is not less than pi/4 and not more than 3 pi/4; the mandrel is adjusted to reduce the offset error d2 to less than a first predetermined precision value. The scheme of the invention can ensure that the assembly precision of the core rod is higher, and the detection and correction efficiency is higher.

Description

Method for calibrating rotation center axis and five-axis machining center

Technical Field

The invention relates to the technical field of detection and calibration of finishing machine tools, and in particular to a method for calibrating a rotation center axis and a five-axis machining center.

Background technique

The five-axis machining center needs to be calibrated before processing the core rod to keep the axis of the core rod always in a straight line with the C axis. The existing method of calibrating the center axis of the core rod rotation is: adsorb the micrometer on the spindle, first pull the meter in the X and Y directions to ensure that the worktable surface is parallel to the X and Y directions, set the mechanical zero point of the A and C rotation axes to zero, then put the micrometer on the wall of the center hole of the worktable, move the worktable by the handwheel, and rotate the spindle at a low speed to calibrate the center position of the worktable. When the swing amount of the needle is basically zero, record the current mechanical coordinates, which are the mechanical coordinate values of the center of the worktable, and then input the mechanical coordinate values into the system variables for storage.

Since the spindle table and the mandrel are in an assembly relationship, there are assembly errors. After the mandrel is installed on the table, the two are not in an ideal vertical relationship. The larger the table, the greater the flatness error. Therefore, when using a micrometer to pull the table surface in the X and Y directions, it cannot be guaranteed that the axis of the C axis is 90 degrees perpendicular to the table, so the spindle axis and the C axis axis are not in an ideal parallel relationship. The calculation principle of RTCP (Rotation Tool Center Point" in the CNC system requires an orthogonal intersection. The verticality error of the machine tool axis is not conducive to detecting and adjusting the relationship between the turntable axis and the spindle axis, which will lead to a decrease in the accuracy of RTCP.

Summary of the invention

The main purpose of the invention is to provide a method for calibrating the rotation center axis, aiming at improving the core rod assembly accuracy.

To achieve the above-mentioned purpose, the present invention proposes a method for calibrating the rotation center axis, which is used for calibrating the rotation center axis of a core rod installed on a five-axis machining center. The five-axis machining center includes a bed and a cradle mechanism and a milling mechanism installed on the bed. The cradle mechanism includes an A-axis cradle and a C-axis turntable. The A-axis cradle is rotatably installed on the bed and can rotate around the A-axis. The C-axis turntable is rotatably installed on the A-axis cradle and can rotate around the C-axis. The C-axis turntable is used to install the core rod to be processed; the milling mechanism has a spindle, and the milling mechanism can drive the spindle to move along the X, Y, and Z directions. The method for calibrating the rotation center axis includes the following steps:

Adsorbing a micrometer onto the spindle of the five-axis machining center;

Place the micrometer on the first generatrix of the mandrel and move the spindle along the extension direction of the first generatrix to detect the offset error d1 from the fixed end to the free end of the mandrel in the direction parallel to the C-axis;

Adjusting the mandrel to reduce the offset error d1 to less than a first preset accuracy value;

Place the micrometer on the second generatrix of the mandrel and move the spindle along the extension direction of the second generatrix to detect the offset error d2 from the fixed end to the free end of the mandrel in the direction parallel to the C-axis, and the arc between the second generatrix and the first generatrix is not less than π/4 and not more than 3π/4;

The mandrel is adjusted to reduce the offset error d2 to be less than a first preset accuracy value.

Preferably, after the step of adjusting the mandrel to reduce the offset error d2 to less than the first preset accuracy value, the method further comprises:

Place the micrometer on the side of the mandrel and rotate the C axis of the five-axis machining center to detect the offset error d3 between the mandrel axis and the C axis in the direction perpendicular to the C axis.

The mandrel is adjusted to reduce the offset error d3 to be less than a second preset accuracy value.

Preferably, after the step of adjusting the mandrel to reduce the offset error d3 to less than the second preset accuracy value, the method further comprises:

Rotate the A-axis of the five-axis machining center to a preset angle;

Repeat the steps of placing the micrometer on the first generatrix of the mandrel and moving the spindle along the extension direction of the first generatrix to detect the offset error d1 from the fixed end to the free end of the mandrel and the subsequent steps.

Preferably, the preset angle of the A-axis in the step of rotating the A-axis of the five-axis machining center is 90 degrees.

Preferably, the C-axis turntable includes a base body and a column protruding from one side of the base body, the pitch adjustment bolt is installed on the base body, the column is clearance-matched with the assembly groove of the end face of the mandrel, the cradle mechanism also includes a radial adjustment bolt, the radial adjustment bolt is used to screw into the mounting through hole of the mandrel and abut against the column, and the step of adjusting the mandrel to reduce the offset error d3 to less than the second preset accuracy value is:

The position of the mandrel is adjusted by tightening or loosening the radial adjustment bolt.

Preferably, before the step of adsorbing the micrometer onto the spindle of the five-axis machining center, the method further comprises:

The five-axis machining center is adjusted so that the C axis is in a vertical state.

Preferably, the cradle mechanism further includes a pitch adjustment bolt, the pitch adjustment bolt is mounted on the C-axis turntable, the pitch adjustment bolt is used to connect the mandrel to the C-axis turntable, and the step of adjusting the mandrel to reduce the offset error d1 to less than the first preset accuracy value is:

The pitch angle of the mandrel is adjusted by tightening or loosening the pitch adjustment bolt.

The present invention also proposes a five-axis machining center, comprising a bed, a cradle mechanism, a milling mechanism and a controller installed on the bed; wherein:

The cradle mechanism includes an A-axis cradle and a C-axis turntable, wherein the A-axis cradle is rotatably mounted on the bed and can rotate around the A-axis, and the C-axis turntable is rotatably mounted on the A-axis cradle and can rotate around the C-axis, and the C-axis turntable is used to mount the mandrel to be processed;

The milling mechanism has a main shaft, and the milling mechanism can drive the main shaft to move along the X, Y, and Z directions;

The controller stores a control program capable of implementing any one of the methods for calibrating the rotation center axis.

Preferably, the C-axis turntable includes a base body and a column protruding from one side of the base body, the cradle mechanism also includes a pitch adjustment bolt, the pitch adjustment bolt is installed on the base body, the column is clearance-matched with the assembly groove on the end face of the core rod, and the cradle mechanism also includes a radial adjustment bolt, the radial adjustment bolt is used to screw into the mounting through hole of the core rod and press against the column.

Preferably, the column is provided with an assembly hole in the radial direction, and the cradle mechanism further comprises a core shaft, the core shaft passes through the assembly hole, and the two ends of the core shaft exposed outside the column are gap-matched with the positioning hole of the core rod.

In the scheme of the present invention, before detection with a micrometer, the mandrel is pre-installed on the cradle mechanism. At this time, the flatness error of the C-axis worktable surface and the assembly error of the mandrel are superimposed. The first busbar and the second busbar of the mandrel installed on the cradle mechanism are measured in turn by the micrometer, and adjustments are made to reduce the offset error. The mandrel assembly accuracy is higher and the detection and correction efficiency is higher.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

FIG1 is a schematic structural diagram of an embodiment of a five-axis machining center provided by the present invention;

FIG2 is a schematic structural diagram of another perspective of an embodiment of a five-axis machining center provided by the present invention;

FIG3 is a partial structural schematic diagram of a five-axis machining center provided by the present invention;

FIG4 is a schematic diagram of a partial structure of the five-axis machining center provided by the present invention from another perspective;

Fig. 5 is a cross-sectional view of the A-A position in Fig. 4;

Fig. 6 is a cross-sectional view of the B-B portion in Fig. 4;

FIG. 7 is a flow chart of a method for calibrating a rotation center axis according to the present invention.

Description of Figure Numbers:

100. Five-axis machining center; 1. Cradle mechanism; 10. C-axis turntable; 121. Base; 1211. Positioning groove; 122. Column; 1221. Assembly hole; 123. Mandrel; 13. Pitch adjustment bolt; 15. A-axis cradle; 16. Radial adjustment bolt; 2. Bed; 200. Mandrel; 201. First busbar; 202. Second busbar; 203. Mounting through hole; 204. Positioning hole; 205. Shaft; 206. Flange; 207. Assembly groove; 208. Positioning rib.

The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings.

Detailed ways

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and/or" or "and/or" appears in the full text, its meaning includes three parallel schemes. Taking "A and/or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Referring to FIGS. 1 to 7 , the present invention provides a method for calibrating a rotation center axis, which is used to calibrate the rotation center axis of a core rod 200 installed on a five-axis machining center 100. The five-axis machining center 100 includes a bed 2 and a cradle mechanism 1 and a milling mechanism (not shown) installed on the bed 2. The cradle mechanism 1 includes an A-axis cradle 15 and a C-axis turntable 10. The A-axis cradle 15 is rotatably installed on the bed 2 and can rotate around the A-axis. The C-axis turntable 10 is rotatably installed on the A-axis cradle 15 and can rotate around the C-axis. The C-axis turntable 10 is used to install the core rod 200 to be processed; the milling mechanism has a spindle, and the milling mechanism can drive the spindle to move along the X, Y, and Z directions. The method for calibrating the rotation center axis includes the following steps:

S1. Attach the micrometer to the main shaft of the five-axis machining center 100;

S2, placing a micrometer on the first generatrix 201 of the mandrel 200, and moving the spindle along the extension direction of the first generatrix 201 to detect the offset error d1 from the fixed end to the free end of the mandrel 200 in the direction parallel to the C-axis;

S3, adjusting the mandrel 200 to reduce the offset error d1 to be less than a first preset accuracy value;

S4, place a micrometer on the second generatrix 202 of the mandrel 200, and move the spindle along the extension direction of the second generatrix 202 to detect the offset error d2 from the fixed end to the free end of the mandrel 200 in the direction parallel to the C-axis, and the arc between the second generatrix 202 and the first generatrix 201 is not less than π/4 and not more than 3π/4;

S5. Adjust the mandrel 200 to reduce the offset error d2 to less than a first preset accuracy value.

In the scheme of the present invention, before detection with a micrometer, the mandrel 200 is pre-installed on the cradle mechanism 1. At this time, the flatness error of the C-axis worktable surface and the assembly error of the mandrel 200 are superimposed. The first busbar 201 and the second busbar 202 of the mandrel 200 installed on the cradle mechanism 1 are measured in turn by a micrometer, and adjustments are made to reduce the offset error. The assembly accuracy of the mandrel 200 is higher, and the detection and correction efficiency is higher.

Preferably, after the step of adjusting the mandrel 200 to reduce the offset error d2 to less than the first preset accuracy value, the method further includes:

S6, placing a micrometer on the side of the mandrel 200, rotating the C axis of the five-axis machining center 100, to detect the offset error d3 between the axis of the mandrel 200 and the C axis in the direction perpendicular to the C axis;

S7, adjusting the mandrel 200 to reduce the offset error d3 to a value smaller than a second preset accuracy value.

Preferably, after the step of adjusting the mandrel 200 to reduce the offset error d3 to less than the second preset accuracy value, the method further includes:

S8, rotating the A-axis of the five-axis machining center 100 to a preset angle;

S9, repeating the steps of placing the micrometer on the first generatrix 201 of the mandrel 200 and moving the spindle along the extension direction of the first generatrix 201 to detect the offset error d1 from the fixed end to the free end of the mandrel 200 and the subsequent steps.

The arc between the second busbar 202 and the first busbar 201 is not less than π/4 and not greater than 3π/4, and can specifically be π/4, π/2, or π3/4. The A-axis of the five-axis machining center 100 is rotated to a preset angle; the preset angle here can be 30 degrees, 45 degrees, 60 degrees, or 90 degrees; preferably, the preset angle of the A-axis in the step of rotating the A-axis of the five-axis machining center 100 is 90 degrees to facilitate calibration.

Through the above solution, the error caused by the core rod 200 rotating around the A axis can be reduced. The number of repeated rotations of the A axis can be once, 2 times, 3 times or more times, which is not limited here.

Preferably, the C-axis turntable 10 includes a base body 121 and a column 122 protruding from one side of the base body 121, the column 122 is clearance-matched with the assembly groove 207 on the end face of the core rod 200, and the cradle mechanism 1 also includes a radial adjustment bolt 16, the radial adjustment bolt 16 is used to screw into the mounting through hole of the core rod 200 and press against the column 122, and the step of adjusting the core rod 200 to reduce the offset error d3 to less than the second preset accuracy value is: adjusting the position of the core rod 200 by tightening or loosening the radial adjustment bolt 16.

The cooperation between the column 122 and the assembly groove 207 can play a role in rough positioning of the assembly. The gap between the column 122 and the groove wall of the assembly groove 207 can meet the needs of core rod pitch angle adjustment and position adjustment, and is set according to specific circumstances.

Preferably, before the step of attaching the micrometer to the main shaft of the five-axis machining center 100, the process further includes: adjusting the five-axis machining center 100 to a vertical position of the C axis, so that the operator can calibrate the initial position conveniently.

Preferably, the cradle mechanism 1 also includes a pitch adjustment bolt 13, which is installed on the C-axis turntable 10. The pitch adjustment bolt 13 is used to connect the mandrel 200 to the C-axis turntable 10. The step of adjusting the mandrel 200 to reduce the offset error d1 to less than the first preset accuracy value is: adjusting the pitch angle of the mandrel 200 by tightening or loosening the pitch adjustment bolt 13.

In the above solution, the position or angle is adjusted by the radial adjustment bolt 16 and the pitch adjustment bolt 13 respectively, which is quick and convenient to operate and has high adjustment accuracy.

The present invention also proposes a five-axis machining center 100, including a bed 2 and a cradle mechanism 1, a milling mechanism and a controller installed on the bed 2; wherein the cradle mechanism 1 includes an A-axis cradle 15 and a C-axis turntable 10, the A-axis cradle 15 is rotatably installed on the bed 2 and can rotate around the A-axis, the C-axis turntable 10 is rotatably installed on the A-axis cradle 15 and can rotate around the C-axis, and the C-axis turntable 10 is used to install a core rod 200 to be processed; the milling mechanism has a spindle, and the milling mechanism can drive the spindle to move along the X, Y, and Z directions; the controller stores a control program, which can implement any method of calibrating the center axis of rotation.

Preferably, the C-axis turntable 10 includes a base 121 and a column 122 protruding from one side of the base 121, the cradle mechanism 1 also includes a pitch adjustment bolt 13, the pitch adjustment bolt 13 is installed on the base 121, the column 122 is clearance-matched with the assembly groove 207 on the end face of the mandrel 200, and the cradle mechanism 1 also includes a radial adjustment bolt 16, the radial adjustment bolt 16 is used to be screwed into the mounting through hole of the mandrel 200 and abut the column 122. In this way, when the radial adjustment bolt 16 is rotated, the distance between the groove wall of the assembly groove 207 of the mandrel 200 and the outer surface of the column 122 changes, and the position of the mandrel 200 moves relative to the column 122.

Preferably, the column 122 is provided with an assembly hole in the radial direction, and the cradle mechanism 1 further comprises a mandrel 123, the mandrel 123 passes through the assembly hole, and the two ends of the mandrel 123 exposed outside the column 122 are in clearance fit with the positioning hole 204 of the mandrel 200. The mandrel 123 has a certain elasticity, and can produce a certain deformation when the position or pitch angle of the mandrel 200 is adjusted by adjusting the bolt, and can ensure the connection stability between the mandrel 200 and the seat 121. The mandrel 200 comprises a shaft 205 and a flange 206, one end of the shaft 205 is formed with an assembly groove 207, and the outer edge of the end is convex to form the flange 206, the installation through hole of the mandrel 200 is arranged on the flange 206, and the positioning hole 204 is arranged on the groove wall of the assembly groove 207 and is spaced from the flange 206.

In some embodiments of the present invention, two positioning grooves 1211 are provided on the seat body 121, and the extension directions of the two positioning grooves 1211 are perpendicular to each other. The core rod 200 is provided with two positioning ribs 208 on one side where the assembly groove 207 is provided. The two positioning ribs are used to cooperate with the two positioning grooves 1211 to achieve rough positioning, thereby facilitating the preparation work before calibration.

The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly/indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims (10)

1. A method for calibrating a rotation central axis, which is used for calibrating the rotation central axis of a core rod installed on a five-axis machining center, wherein the five-axis machining center comprises a lathe bed, a cradle mechanism and a milling mechanism, wherein the cradle mechanism is installed on the lathe bed and comprises an A-axis cradle and a C-axis turntable, the A-axis cradle is rotatably installed on the lathe bed and can rotate around the A-axis, the C-axis turntable is rotatably installed on the A-axis cradle and can rotate around the C-axis, and the C-axis turntable is used for installing the core rod to be machined; the milling mechanism is provided with a main shaft, and the milling mechanism can drive the main shaft to move along the direction X, Y, Z, and the method for calibrating the rotation central axis is characterized by comprising the following steps of:

Adsorbing a dial indicator on a main shaft of the five-shaft machining center;

The dial indicator is arranged on a first bus of the core rod, and the main shaft is moved along the extending direction of the first bus to detect the offset error d1 from the fixed end to the free end of the core rod in the direction parallel to the C axis;

adjusting the core rod to reduce the offset error d1 to be smaller than a first preset precision value;

The dial indicator is arranged on a second bus of the core rod, and the main shaft is moved along the extending direction of the second bus to detect the offset error d2 from the fixed end to the free end of the core rod in the direction parallel to the C axis, wherein the radian between the second bus and the first bus is not less than pi/4 and not more than 3 pi/4;

And adjusting the core rod to reduce the offset error d2 to be smaller than a first preset precision value.

2. The method of calibrating a center axis of rotation of claim 1, wherein after the step of adjusting the mandrel to reduce the offset error d2 to less than a first predetermined precision value, further comprising:

The dial indicator is arranged on the side surface of the core rod, and the C shaft of the five-shaft machining center is rotated to detect the offset error d3 of the axis of the core rod and the C shaft in the direction vertical to the C shaft;

And adjusting the core rod to reduce the offset error d3 to be smaller than a second preset precision value.

3. The method of calibrating a center axis of rotation of claim 2, wherein after the step of adjusting the mandrel to reduce the offset error d3 to less than a second predetermined precision value, further comprising:

rotating the A axis of the five-axis machining center to a preset angle;

Repeating the step of marking the dial indicator on the first bus of the core rod, and moving the main shaft along the extending direction of the first bus to detect the offset error d1 from the fixed end to the free end of the core rod and the subsequent steps.

4. A method of calibrating a center axis of rotation according to claim 3, wherein the predetermined angle of the a-axis in the step of rotating the a-axis of the five-axis machining center to the predetermined angle is 90 degrees.

5. The method of calibrating a rotation center axis according to claim 2, wherein the C-axis turntable includes a base and a post protruding from one side of the base, the post being clearance-fitted with an assembly groove of the end surface of the mandrel, the cradle mechanism further includes a radial adjustment bolt for screwing into an installation through hole of the mandrel and abutting against the post, the step of adjusting the mandrel to reduce the offset error d3 to be smaller than a second preset precision value is:

The position of the core rod is adjusted by screwing or unscrewing the radial adjustment bolt.

6. The method of calibrating a central axis of rotation of claim 1, wherein prior to the step of attaching a dial gauge to a spindle of the five-axis machining center, further comprising:

and adjusting the five-axis machining center until the C axis is in a vertical state.

7. The method of calibrating a center axis of rotation of claim 1, wherein the cradle mechanism further comprises a pitch adjustment bolt mounted to the C-axis turntable, the pitch adjustment bolt for connecting the mandrel to the C-axis turntable, the step of adjusting the mandrel to reduce the offset error d1 to less than a first predetermined accuracy value is:

the pitch angle of the mandrel is adjusted by screwing or unscrewing the pitch adjustment bolt.

8. The five-axis machining center is characterized by comprising a lathe bed, a cradle mechanism, a milling mechanism and a controller, wherein the cradle mechanism, the milling mechanism and the controller are arranged on the lathe bed; wherein,

The cradle mechanism comprises an A-axis cradle and a C-axis turntable, the A-axis cradle is rotatably arranged on the lathe bed and can rotate around the A-axis, the C-axis turntable is rotatably arranged on the A-axis cradle and can rotate around the C-axis, and the C-axis turntable is used for mounting a core rod to be processed;

the milling mechanism is provided with a main shaft, and can drive the main shaft to move along the X, Y, Z direction;

the controller stores a control program capable of realizing the method of calibrating a rotation center axis according to any one of claims 1 to 7.

9. The five-axis machining center according to claim 8, wherein the C-axis turntable comprises a base and a stand column protruding from one side of the base, the cradle mechanism further comprises a pitching adjusting bolt, the pitching adjusting bolt is mounted on the base, the stand column is in clearance fit with an assembly groove on the end face of the core rod, and the cradle mechanism further comprises a radial adjusting bolt, and the radial adjusting bolt is used for being screwed into an installation through hole of the core rod and propped against the stand column.

10. The five-axis machining center according to claim 9, wherein the upright is provided with an assembly hole along the radial direction, the cradle mechanism further comprises a mandrel, the mandrel penetrates through the assembly hole, and two ends of the mandrel exposed out of the upright are in clearance fit with the positioning hole of the mandrel.