CN108544041B - Internal thread milling method - Google Patents
Internal thread milling method Download PDFInfo
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- CN108544041B CN108544041B CN201810728211.5A CN201810728211A CN108544041B CN 108544041 B CN108544041 B CN 108544041B CN 201810728211 A CN201810728211 A CN 201810728211A CN 108544041 B CN108544041 B CN 108544041B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
- B23G1/00—Thread cutting; Automatic machines specially designed therefor
- B23G1/32—Thread cutting; Automatic machines specially designed therefor by milling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
- B23G1/00—Thread cutting; Automatic machines specially designed therefor
- B23G1/44—Equipment or accessories specially designed for machines or devices for thread cutting
Abstract
The embodiment of the invention discloses an internal thread milling method, which is used for processing internal threads by a multi-axis numerical control machine tool such as a three-axis numerical control machine tool, and comprises the following steps: a rotary table is arranged on the three-axis numerical control machine tool; installing an angle head on a main shaft of the three-shaft numerical control machine tool, adjusting the axis of the angle head to form a preset swing angle with the axis of the main shaft according to the type of the internal thread, and locking the angle head; clamping a workpiece to be machined and enabling the axis of a bottom hole on the workpiece to be machined to coincide with the axis of the rotary table; installing a thread milling cutter on the angle head; controlling the rotary table to rotate at a constant speed and starting the main shaft; and controlling the thread milling cutter to machine the internal thread on the bottom hole at a preset feed speed according to a preset feed path. The internal thread milling method provided by the embodiment of the invention can improve the processing precision and the surface finish of the internal thread, reduce the processing cost of the internal thread and has obvious economic benefit.
Description
Technical Field
The invention relates to the technical field of numerical control machining, in particular to an internal thread milling method.
Background
The traditional thread processing mode comprises the following steps: turning, tapping, etc. However, these machining methods have disadvantages of low thread machining accuracy and poor thread surface finish. In addition, the turning process also has the problems that chips are not easy to break, chips are easy to wind around the tool, or the chips are left in the threaded hole, the processing quality of the threaded hole is greatly reduced, meanwhile, the abrasion of the tool is also increased, and particularly, the turning process is not suitable for processing asymmetric parts and large parts. The tapping process also has the defects of easy breakage of a screw tap, low processing efficiency, large cutting force and the like, and is not suitable for processing difficult-to-process materials. At present, the machining of the conical thread with the thread tooth form angle bisector perpendicular to the cone generatrix is mainly turned. In addition, some manufacturers adopt a five-axis numerical control machine tool to mill internal threads, the defects of the traditional machining method can be well overcome, the thread milling has the advantages of high machining precision, good thread surface smoothness, no limitation of thread turning direction and size, good machining universality, small cutting force, long service life of a cutter and the like, but the cost of milling the threads by adopting the five-axis numerical control machine tool is very high.
Disclosure of Invention
In view of the above problems, embodiments of the present invention provide an internal thread milling method to improve the processing quality of internal threads and reduce the processing cost.
Specifically, the embodiment of the invention provides an internal thread milling method, which is used for machining an internal thread by a three-axis numerical control machine tool, and the internal thread milling method comprises the following steps: a rotary table is arranged on the three-axis numerical control machine tool; installing an angle head on a main shaft of the three-axis numerical control machine tool, adjusting the axis of the angle head and the axis of the main shaft to form a preset swing angle according to the type of the internal thread and locking the angle head, wherein when the type of the internal thread is a conical internal thread with a tooth-shaped angle bisector perpendicular to a cone bus, the preset swing angle theta and the conical half angle of the internal thread
When the type of the internal thread is a conical internal thread or a cylindrical internal thread, the tooth form angle bisector of which is vertical to the thread axis, the preset swing angle theta is zero; clamping a workpiece to be machined and enabling the axis of a bottom hole on the workpiece to be machined to coincide with the axis of the rotary table; installing a thread milling cutter on the angle head; controlling the rotary table to rotate at a constant speed and starting the main shaft; and controlling the thread milling cutter to machine the internal thread on the bottom hole at a preset feed speed according to a preset feed path.
On the other hand, an embodiment of the present invention further provides an internal thread milling method, which is used for a multi-axis machine tool to machine an internal thread, where the multi-axis machine tool includes a spindle and is provided with a turntable, and the internal thread milling method includes: installing an angle head on the main shaft, adjusting the axis of the angle head to form a preset swing angle with the axis of the main shaft, and locking the angle head; clamping a workpiece to be machined and enabling the axis of a bottom hole on the workpiece to be machined to coincide with the axis of the rotary table; installing a thread milling cutter on the angle head; controlling the rotary table to rotate at a constant speed and starting the main shaft; and controlling the thread milling cutter to machine the internal thread on the bottom hole at a preset feed speed according to a preset feed path.
In an embodiment of the present invention, the internal thread is a conical internal thread, and the coordinate of the feed point L on the preset feed path satisfies:
wherein, XLIs the X-axis coordinate, Y, of the feed point LLIs the Y-axis coordinate, Z, of the feed point LLIs the Z-axis coordinate of the feed point L, D is the reference diameter of the large end face of the internal thread, a is the distance from the feed point L to the large end face of the internal thread,
the taper half angle of the internal thread;
the coordinates of a tool retracting point M on the preset tool feeding path meet the following conditions:
wherein, XMIs the X-axis coordinate, Y, of the tool retracting point MMIs the Y-axis coordinate, Z, of said tool retracting point MMAnd H is the thread depth of the internal thread.
In one embodiment of the invention, the internal thread is a conical internal thread with a tooth-shaped angle bisector perpendicular to a cone generatrix, and the preset swing angle theta and the taper half angle of the internal thread
Are equal.
In one embodiment of the invention, the internal thread is a conical internal thread with a thread form angle bisector perpendicular to the thread axis, and the preset swing angle theta is zero.
In an embodiment of the present invention, the internal thread is a cylindrical internal thread, the preset swing angle θ is zero, and the coordinate of the feed point L on the preset feed path satisfies:
wherein, XLIs the X-axis coordinate, Y, of the feed point LLIs the Y-axis coordinate, Z, of the feed point LLThe Z-axis coordinate of the feed point L is shown, D is the nominal diameter of the internal thread, and a is the distance from the feed point L to the end face of the internal thread;
the coordinates of a tool retracting point M on the preset tool feeding path meet the following conditions:
wherein, XMIs the X-axis coordinate, Y, of the tool retracting point MMIs the Y-axis coordinate, Z, of said tool retracting point MMAnd H is the thread depth of the internal thread.
In one embodiment of the present invention, the rotation speed n of the turntable and the preset feeding speed f satisfy:
wherein p is the pitch of the internal thread.
In an embodiment of the present invention, the internal thread milling method further includes: and controlling the thread milling cutter to retreat to the zero point of the machine tool of the multi-axis machine tool according to a preset cutter retreating path, wherein the preset cutter retreating path comprises retreating from a cutter retreating point M to the axis of the internal thread along the radial direction, retreating from the axis of the internal thread to the outer side of the end surface of the internal thread along the axial direction, and retreating to the zero point of the machine tool of the multi-axis machine tool.
In another aspect, an embodiment of the present invention further provides an internal thread milling method, which is applied to a multi-axis numerical control machine tool, and includes the steps of: controlling a rotary table to rotate at a constant speed and starting a main shaft, wherein a workpiece to be machined is clamped on the rotary table, the axis of a bottom hole in the workpiece to be machined is overlapped with the axis of the rotary table, a thread milling cutter is mounted on the main shaft through an angle head, a preset swing angle theta is formed between the axis of the angle head and the axis of the main shaft, and the preset swing angle theta is determined by the type of an internal thread to be machined in the bottom hole; controlling the thread milling cutter to machine the internal thread on the bottom hole at a preset feed speed according to a preset feed path, wherein the preset feed path comprises a straight path from a feed point L to a tool withdrawal point M; and controlling the thread milling cutter to retreat to a machine tool zero point of the multi-axis machine tool according to a preset cutter retreating path, wherein the preset cutter retreating path comprises retreating from the cutter retreating point M to the axis of the internal thread along the radial direction, retreating from the axis of the internal thread to the outer side of the end surface of the internal thread along the axial direction, and retreating to the machine tool zero point of the multi-axis machine tool.
In an embodiment of the present invention, the step of responding to the user operation and controlling the thread milling cutter to machine the internal thread on the bottom hole at a preset feed speed according to a preset feed path comprises: obtaining the thread diameter D, the thread pitch p, the distance a from the feed point L to the thread end surface, the thread depth H and the taper half angle of the internal thread
Calculating the preset feeding speed f according to the pitch p of the internal thread and the rotating speed n of the rotary table, wherein the preset feeding speed f meets the following requirements:
judging the taper half angle
Whether or not it is zero when the taper half angle is
When the value is non-zero, the coordinates of the feed point L and the retreat point M are calculated according to a first formula set to determine the pre-advanceSetting a feed path when the taper half angle
When the preset cutting path is zero, calculating the coordinates of the cutting feed point L and the retreating point M in a second mode to determine the preset cutting feed path; and controlling the thread milling cutter to process the internal thread at a preset feed speed according to a preset feed path.
The technical scheme has the following advantages: according to the embodiment of the invention, the rotary table and the angle head are configured on the three-axis or four-axis numerical control machine tool, then the corresponding preset swing angle theta of the angle head is set according to the type and relevant parameters of the internal thread to be processed, and the swing angle theta is matched with the rotary table to complete the processing of the internal thread according to the preset feed path. The internal thread milling method provided by the embodiment of the invention can improve the processing precision and the surface finish of the internal thread, reduce the processing cost of the internal thread and has obvious economic benefit.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic flow chart of a milling method for internal threads according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a multi-axis machine tool according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a turntable according to an embodiment of the present invention;
FIGS. 4a and 4b are a front view and an isometric view, respectively, of an angle head in accordance with an embodiment of the present invention;
FIGS. 5a and 5b are schematic views showing two types of thread forms of the conical internal thread according to the embodiment of the present invention, wherein FIG. 5a is the conical internal thread with a thread form angle bisector perpendicular to a cone generatrix, and FIG. 5b is the conical internal thread with a thread form angle bisector perpendicular to an axis;
fig. 6a and 6b are schematic structural diagrams of a bottom hole on a workpiece to be processed according to an embodiment of the present invention, where the bottom hole in fig. 6a is a bottom hole with a conical internal thread, and the bottom hole in fig. 6b is a bottom hole with a cylindrical internal thread;
FIGS. 7a, 7b and 7c are schematic views of the machining of a conical internal thread with a profile angle bisector perpendicular to a cone generatrix, a conical internal thread with a profile angle bisector perpendicular to a thread axis and a cylindrical thread, respectively, according to an embodiment of the invention;
fig. 8 is a schematic flow chart of another internal thread milling method according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the scope of the present invention.
Referring to fig. 1, fig. 2 and fig. 3, in which fig. 1 is a schematic flow chart of a milling method for internal threads according to an embodiment of the present invention, fig. 2 is a schematic structural diagram of a multi-axis machine tool according to an embodiment of the present invention, and fig. 3 is a schematic structural diagram of a turntable according to an embodiment of the present invention. The internal thread milling method provided by the embodiment of the invention is suitable for machining internal threads by a multi-axis machine tool. The multi-axis machine tool 1 (see fig. 2) can be, for example, a three-axis (X-Y-Z) numerical control machine tool but with a turntable 2 (see fig. 3) mounted on the table 11 of the multi-axis machine tool 1, or, for example, a four-axis (X-Y-Z-C) machine tool with a turntable 2. The turntable 2 may for example be a numerically controlled turntable. The numerical control turntable is connected with the multi-axis machine tool 1 and is controlled by a servo system (not shown in the figure). The turret 2 may be coupled to three axes (X-Y-Z) of the multi-axis machine 1. The turntable 2 can be loaded with a workpiece 3 to be machined. The workpiece 3 to be machined can be a symmetrical rotary part and a small part, and can also be an asymmetrical part and a large part. Before the thread is machined, a bottom hole 31 (see fig. 6a) has already been machined in advance in the workpiece 3 to be machined. The internal thread milling method provided by the embodiment of the invention is to process the internal thread on the inner wall of the bottom hole 31. Further, the multi-axis machine tool 1 is provided with a spindle 12.
Specifically, referring to fig. 1 to 7, the internal thread milling method according to the embodiment of the present invention includes:
in step S11, the angle head 13 is mounted on the main shaft 12, and after the axis of the angle head 13 is adjusted to the preset swing angle θ with respect to the axis of the main shaft 12, the angle head 13 is locked (see fig. 4a and 4 b). Specifically, the axis of the spindle 12 is parallel to the axis of the turntable 2. The value of the preset swing angle theta is determined according to parameters of the internal thread, such as the thread type of the internal thread. The internal threads include conical internal threads and cylindrical internal threads. The conical internal threads include conical internal threads with a profile angle bisector perpendicular to the cone generatrix (see fig. 5a) and conical internal threads with a profile angle bisector perpendicular to the axis (see fig. 5 b).
As shown in fig. 5a, when the internal thread is a conical internal thread with a thread-type angle bisector perpendicular to a cone generatrix, the preset swing angle θ of the angle head 13 satisfies:
wherein, the taper half angle
The included angle is an included angle between the cone generatrix of the internal thread and the axis of the internal thread hole.
When the internal thread is a conical internal thread with a thread form angle bisector perpendicular to the thread axis, the preset oscillation angle theta of the angle head 13 is zero, i.e. the axis of the angle head 13 coincides with the axis of the main shaft 12, as shown in fig. 5 b.
When the internal thread is a cylindrical thread, the bisector of the profile angle thereof is also perpendicular to the axis of the internal thread, so that the preset oscillation angle θ of the angle head 13 is zero, i.e. the axis of the angle head 13 coincides with the axis of the main shaft 12.
Step S13, the workpiece 3 to be machined is clamped so that the axis of the bottom hole 31 on the workpiece 3 to be machined coincides with the axis of the turntable 2. Specifically, the workpiece 3 to be machined is clamped onto the turntable 2, and the position of the workpiece 3 to be machined is adjusted so that the axis of the bottom hole 31 in the workpiece 3 to be machined coincides with the axis of the turntable 2. As shown in fig. 6a, the bottom hole 31 is a conical hole when the internal thread is a conical thread, such as a conical thread having a thread profile angle bisector perpendicular to the cone generatrix. As shown in fig. 6b, the bottom hole 31 is a circular hole when the internal thread is a cylindrical thread.
In step S15, the thread milling cutter 14 is mounted on the angle head 13. Of course, after the thread milling cutter 14 is installed, the tool setting work needs to be completed.
In step S17, the turntable 2 is rotated at a constant speed to start the spindle 12.
In step S19, the thread milling cutter 14 is controlled to machine the internal thread on the bottom hole 31 at the preset feed speed f according to the preset feed path. The control of the movement of the thread milling cutter 14 is understood here to mean the control of the relative movement of the workpiece 3 to be machined with respect to the thread milling cutter 14. The preset feeding speed f satisfies:
wherein p is the pitch of the internal thread and n is the rotation speed of the turntable 2.
The preset feed path may include, for example, a path from a machine zero point to a feed point L and a path from the feed point L to a retract point M.
The machine zero point is a machine origin point specified by a machine manufacturer, and is an origin point of a machine coordinate system. The machine zero point is not only a reference point for establishing a workpiece coordinate system on the machine tool, but also a reference point for machine tool debugging and part machining.
The path from the machine zero point to the cutting feed point L may be, for example, a straight path, but may be a curved path or other path.
The path from the feed point L to the retract point M is typically a straight path. The coordinates of the feed point L and the relief point M are different depending on the type and parameters of the internal thread to be machined. Usually, the center O of the upper end surface of the bottom hole 31 is used as the origin of the programmed coordinate (see fig. 7a, 7b, 7 c). Of course, other points may be used as the programmed coordinate origin, and the invention is not limited thereto.
When the internal thread is a conical internal thread with a thread-type angle bisector perpendicular to a cone generatrix, the preset swing angle theta and the taper half angle of the angle head 13 are as shown in fig. 7a
Equal, the angle between the axis of the thread milling cutter 14 and the axis of said internal thread (i.e. the Z-axis) is therefore equal to
The path from the feed point L to the relief point M is parallel to the axial direction of the thread milling cutter 14 (as shown in fig. 7 a) and also parallel to the taper generatrix of said internal thread in the XOZ plane.
The coordinates of the feed point L satisfy:
wherein, XLIs the X-axis coordinate, Y, of the feed point LLIs the Y-axis coordinate, Z, of the feed point LLThe Z-axis coordinate of the feed point L, D is a reference diameter of the internal thread (a basic major diameter of a major end surface of the internal thread), and a is a distance from the feed point L to the major end surface of the internal thread (also referred to as a reference plane).
The coordinates of the tool retracting point M satisfy:
wherein, XMIs the X-axis coordinate, Y, of the tool retracting point MMIs the Y-axis coordinate, Z, of said tool retracting point MMAnd H is the thread depth of the internal thread.
As shown in fig. 7b, when the internal thread is a conical internal thread having a profile angle bisector perpendicular to the thread axis, the preset swing angle θ of the angle head 13 is zero, and thus the axis of the thread mill 14 is parallel to the axis (i.e., Z-axis) of the internal thread. The path from the feed point L to the withdrawal point M is parallel to the conical generatrix of the internal thread in the XOZ plane. The coordinate of the feed point L satisfies formula (3), and the coordinate of the retract point M satisfies formula (4).
As shown in fig. 7c, when the internal thread is a cylindrical internal thread, the preset swing angle θ of the angle head 13 is zero, and thus the axis of the thread mill 14 is parallel to the axis (i.e., Z-axis) of the internal thread. The path from the feed point L to the retract point M is parallel to the axial direction of the thread milling cutter 14.
The coordinates of the feed point L satisfy:
and D is the nominal diameter of the internal thread, and a is the distance from the feed point L to the end face of the internal thread.
The coordinates of the tool retracting point M satisfy:
and H is the thread depth of the internal thread.
The thread milling cutter 14 is controlled to move from the zero point of the machine tool to the feed point L, and then the thread milling cutter 14 is controlled to machine the internal thread on the bottom hole 31 at the preset feed speed f according to the path from the feed point L to the retracting point M.
Of course, the internal thread milling method provided by this embodiment further includes a tool retracting step. Specifically, the tool retracting step includes controlling the thread milling cutter 14 to retract to the zero point of the machine tool according to a preset tool retracting path. The preset tool retracting path may, for example, include retracting from a tool retracting point M to the axis of the internal thread in the radial direction, retracting from the axis of the internal thread to the outside of the end face of the internal thread in the axial direction (positive Z-axis direction in fig. 7a, 7b, 7c), and retracting to the zero point of the machine tool. Here, the receding from the receding point M in the radial direction to the axis of the internal thread can be understood as the thread milling cutter being stationary, but the workpiece to be machined moving relative to the thread milling cutter; the thread milling cutter retreats from the axis of the internal thread to the outer side of the end face of the internal thread along the axis direction, so that the thread milling cutter moves along the axis direction of the internal thread along with the main shaft, and a workpiece to be machined is not moved; a machine zero point of the multi-axis machine tool can also be understood as meaning that the thread milling cutter is not moving, but the workpiece to be machined is moving relative to the thread milling cutter. Of course, other control schemes that achieve the same function are possible.
It should be noted here that the preset cutting feed path and the preset cutting retract path may be obtained through manual planning, or may be obtained through CAD/CAM software planning. In addition, the multi-axis machine tool is typically a multi-axis linked numerical control machine tool, and all machining operations are controlled by a numerical control machining program. In addition, the preset feed path and the preset retracting path are planned in consideration of the tool radius of the thread milling cutter 14 and the profile height of the internal thread. Furthermore, the preset feed path and the preset retracting path may be a single machining path or a multiple machining path, which may be determined according to specific thread parameters and machining conditions.
In order to better understand the embodiment of the invention, the internal thread milling method provided by the embodiment of the invention is exemplified by machining a right-handed conical thread of PZ39 with a thread depth H of 40 mm.
The PZ39 thread is a conical internal thread with a tooth-type angular bisector perpendicular to a cone generatrix, the major diameter D of the thread on a reference plane is 39mm, the middle diameter is 37.643mm, the minor diameter is 36.286mm, the thread pitch P is 2mm, and the taper half angle
The milling method of the PZ39 thread comprises the following steps:
1) and a rotary table is well installed and fixed on a workbench of the three-axis numerical control machine tool.
2) An angle head is arranged on the main shaft, and the axis of the angle head is adjusted to form a preset swing angle with the axis of the main shaft
After the included angle is formed, the angle head is locked.
3) And clamping the workpiece to be machined and enabling the axis of the bottom hole on the workpiece to be machined to coincide with the axis of the rotary table.
4) And a thread milling cutter is arranged on the angle head.
5) And rotating the numerical control turntable at a constant speed and starting the main shaft. The numerical control rotary table rotates anticlockwise at the rotating speed of n-60 r/min. The rotating speed of the main shaft is 600-700 r/min.
6) The feed speed f of the thread milling cutter is:
7) the distance a from the cutting point L to the reference plane of the internal thread is 5 mm. The coordinate value of the feed point L is as follows:
that is, the coordinate of the cutting feed point L is (19.800, 0, 5).
The tool retracting point M has the coordinate value:
YM＝0
ZM＝-H＝-40
i.e. the coordinates of the tool retracting point M are (17.103, 0, -40).
And controlling the thread milling cutter to process a PZ39 internal thread on the bottom hole from zero point feed of the machine tool to a feed point L (19.800, 0, 5) and then from the feed point L (19.800, 0, 5) to a tool withdrawal point M (17.103, 0, -40) in a straight line according to a preset feed path at a feed speed f of 2.5 mm/s.
8) And controlling the thread milling cutter to retract from a retraction point M (17.103, 0, -40) to a point (0, 0, -40) at the axis of the internal thread of the PZ39 in the radial direction according to a preset retraction path, retracting from the point (0, 0, -40) to a point (0, 0, 100) outside the end face of the internal thread of the PZ39 in the axis direction (Z positive direction) of the internal thread of the PZ39, and finally retracting to the zero point of the machine tool to finish the milling process of the internal thread of the PZ 39.
In summary, in the embodiment of the present invention, the turntable and the angle head are configured on the multi-axis numerical control machine, then the corresponding preset swing angle θ of the angle head is set according to the type of the internal thread to be processed and the related parameters, and the internal thread is processed according to the preset feed path in cooperation with the turntable. The internal thread milling method provided by the embodiment of the invention can also improve the processing quality of the internal thread, such as processing precision, thread surface finish and the like. In addition, compared with a method for milling the internal thread by adopting a five-axis machine tool, the internal thread milling method provided by the embodiment of the invention greatly reduces the processing cost of the internal thread, and has obvious economic benefit. Moreover, the internal thread milling method provided by the embodiment of the invention can be used for processing cylindrical internal threads and conical internal threads on symmetrical parts and small parts, and can also be used for processing cylindrical internal threads and conical internal threads on asymmetrical parts and large parts, and the processing range is wide.
In addition, the embodiment of the invention also provides another internal thread milling method. The internal thread milling method is suitable for a multi-axis machine tool. The multi-axis machine tool is provided with a controller and a numerical control system corresponding to the controller. The multi-axis machine tool can calculate a preset feed speed, a preset feed path and the like according to user operation and relevant parameters input by a user, and finish internal thread milling according to the preset feed speed and the preset feed path. Therefore, the processing quality of the internal thread can be improved, the processing operation of the internal thread is simplified, and the processing efficiency is improved. As shown in fig. 8, the internal thread milling method includes the steps of:
1) controlling the turntable to rotate at a constant speed and starting the main shaft. The multi-axis machine tool controls the turntable to rotate at a constant speed and starts the spindle, for example, by responding to user operations such as triggering an operation button. The machining tool comprises a spindle, a turntable, a spindle, a thread milling cutter, an angle head, a preset swinging angle theta and a preset swinging angle theta, wherein the workpiece to be machined is clamped on the turntable on the multi-spindle machine tool, the axis of a bottom hole in the workpiece to be machined is overlapped with the axis of the turntable, the spindle is provided with the thread milling cutter through the angle head, the axis of the angle head and the axis of the spindle form the preset swinging angle theta, and the preset swinging angle theta is determined by the type of an internal thread to be machined in the bottom.
2) And controlling the thread milling cutter to machine the internal thread on the bottom hole at a preset feed speed according to a preset feed path. The preset feed path comprises a straight path from a feed point L to a tool withdrawal point M. Specifically, first, the multi-axis machine tool acquires relevant parameters such as the thread diameter D of the internal thread, the thread pitch p, the distance a from the feed point L to the end face of the internal thread, the thread depth H, and the taper half angle, for example, by responding to a user input operation
And the like. Then, a preset feed speed f is calculated according to formula (2) based on the pitch p of the internal thread and the rotation speed n of the turn table. Then, the taper half angle is judged
Whether it is zero or not, when the taper half angle
When the distance a from the feed point L to the inner thread end surface is the distance from the feed point L to the inner thread end surface, the coordinates of the feed point L and the retreat point M are calculated in a first mode, for example, according to a formula (3) and a formula (4), so as to determine the preset feed path; when taper half angle
And zero, the internal thread is a cylindrical internal thread, the thread diameter D is the nominal diameter of the internal thread, the distance a from the feed point L to the end face of the internal thread is the distance from the feed point L to the end face of the internal thread, and the coordinates of the feed point L and the retreat point M are calculated in a second way, for example, according to formula (5) and formula (6), to determine the preset feed path. And finally, controlling the thread milling cutter to process the internal thread at a preset feed speed according to a preset feed path.
3) And controlling the thread milling cutter to retreat to the zero point of the machine tool of the multi-axis machine tool according to a preset cutter retreating path, wherein the preset cutter retreating path comprises retreating from a cutter retreating point M to the axis of the internal thread along the radial direction, retreating from the axis of the internal thread to the outer side of the end surface of the internal thread along the axial direction, and retreating to the zero point of the machine tool of the multi-axis machine tool.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (8)
1. An internal thread milling method is used for machining internal threads by a three-axis numerical control machine tool and is characterized by comprising the following steps:
a rotary table is arranged on the three-axis numerical control machine tool;
installing an angle head on a main shaft of the three-axis numerical control machine tool, adjusting the axis of the angle head and the axis of the main shaft to form a preset swing angle according to the type of the internal thread and locking the angle head, wherein when the type of the internal thread is a conical internal thread with a tooth-shaped angle bisector perpendicular to a cone bus, the preset swing angle theta and the conical half angle of the internal thread
When the type of the internal thread is a conical internal thread or a cylindrical internal thread, the tooth form angle bisector of which is vertical to the thread axis, the preset swing angle theta is zero;
clamping a workpiece to be machined and enabling the axis of a bottom hole on the workpiece to be machined to coincide with the axis of the rotary table;
installing a thread milling cutter on the angle head;
controlling the rotary table to rotate at a constant speed and starting the main shaft;
controlling the thread milling cutter to machine the internal thread on the bottom hole at a preset feed speed according to a preset feed path;
the three-axis numerical control machine tool further comprises a workbench, the rotary table is mounted on the workbench, and the workpiece to be machined is an asymmetric part;
the rotary table is linked with three shafts of the three-shaft numerical control machine tool, and the axis of the main shaft is parallel to the axis of the rotary table.
2. An internal thread milling method for a multi-spindle machine tool for machining an internal thread, the multi-spindle machine tool including a spindle and mounted with a turntable, the internal thread milling method comprising:
installing an angle head on the main shaft, adjusting the axis of the angle head to form a preset swing angle with the axis of the main shaft, and locking the angle head;
clamping a workpiece to be machined and enabling the axis of a bottom hole on the workpiece to be machined to coincide with the axis of the rotary table;
installing a thread milling cutter on the angle head;
controlling the rotary table to rotate at a constant speed and starting the main shaft;
controlling the thread milling cutter to machine the internal thread on the bottom hole at a preset feed speed according to a preset feed path;
the multi-axis machine tool is a three-axis or four-axis numerical control machine tool, the multi-axis machine tool further comprises a workbench, the turntable is mounted on the workbench, and the workpiece to be machined is an asymmetric part;
wherein the axis of the spindle is parallel to the axis of the turntable; the internal thread is a conical internal thread with a tooth-shaped angle bisector perpendicular to a cone generatrix, and the preset swing angle theta and the taper half angle of the internal thread
Equal; the internal thread is a conical internal thread or a cylinder with a tooth form angular bisector perpendicular to the thread axisAnd the preset swing angle theta is zero.
3. The internal thread milling method according to claim 2, wherein the internal thread is a conical internal thread, and the coordinate of the feed point L on the preset feed path satisfies:
wherein, XLIs the X-axis coordinate, Y, of the feed point LLIs the Y-axis coordinate, Z, of the feed point LLIs the Z-axis coordinate of the feed point L, D is the reference diameter of the large end face of the internal thread, a is the distance from the feed point L to the large end face of the internal thread,
the taper half angle of the internal thread;
the coordinates of a tool retracting point M on the preset tool feeding path meet the following conditions:
wherein, XMIs the X-axis coordinate, Y, of the tool retracting point MMIs the Y-axis coordinate, Z, of said tool retracting point MMAnd H is the thread depth of the internal thread.
4. The internal thread milling method according to claim 2, wherein the internal thread is a cylindrical internal thread, and the coordinate of the feed point L on the preset feed path satisfies:
wherein, XLIs the X-axis coordinate, Y, of the feed point LLIs the Y-axis coordinate, Z, of the feed point LLIs the feed pointThe Z-axis coordinate of L, D is the nominal diameter of the internal thread, and a is the distance from the feed point L to the end face of the internal thread;
the coordinates of a tool retracting point M on the preset tool feeding path meet the following conditions:
wherein, XMIs the X-axis coordinate, Y, of the tool retracting point MMIs the Y-axis coordinate, Z, of said tool retracting point MMAnd H is the thread depth of the internal thread.
5. The internal thread milling method according to claim 2, wherein the rotation speed n of the turn table and the preset feed speed f satisfy:
wherein p is the pitch of the internal thread.
6. The internal thread milling method according to claim 2, further comprising:
and controlling the thread milling cutter to retreat to the zero point of the machine tool of the multi-axis machine tool according to a preset cutter retreating path, wherein the preset cutter retreating path comprises retreating from a cutter retreating point M to the axis of the internal thread along the radial direction, retreating from the axis of the internal thread to the outer side of the end surface of the internal thread along the axial direction, and retreating to the zero point of the machine tool of the multi-axis machine tool.
7. An internal thread milling method is applied to a multi-axis numerical control machine tool and is characterized by comprising the following steps:
controlling a rotary table to rotate at a constant speed and starting a main shaft, wherein a workpiece to be machined is clamped on the rotary table, the axis of a bottom hole in the workpiece to be machined is overlapped with the axis of the rotary table, a thread milling cutter is mounted on the main shaft through an angle head, a preset swing angle theta is formed between the axis of the angle head and the axis of the main shaft, and the preset swing angle theta is determined by the type of an internal thread to be machined in the bottom hole;
controlling the thread milling cutter to machine the internal thread on the bottom hole at a preset feed speed according to a preset feed path, wherein the preset feed path comprises a straight path from a feed point L to a tool withdrawal point M; controlling the thread milling cutter to retreat to a machine tool zero point of the multi-axis machine tool according to a preset cutter retreating path, wherein the preset cutter retreating path comprises retreating from the cutter retreating point M to the axis of the internal thread along the radial direction, retreating from the axis of the internal thread to the outer side of the end surface of the internal thread along the axial direction, and retreating to the machine tool zero point of the multi-axis machine tool;
the multi-axis machine tool is a three-axis or four-axis numerical control machine tool, the multi-axis machine tool further comprises a workbench, the turntable is mounted on the workbench, and the workpiece to be machined is an asymmetric part;
the internal thread is a conical internal thread with a tooth form angle bisector perpendicular to a cone generatrix, and the preset swing angle theta is equal to the taper half angle of the internal thread; the internal thread is a conical internal thread with a tooth form angle bisector perpendicular to the thread axis, and the preset swing angle theta is zero.
8. The internal thread milling method as set forth in claim 7, wherein the step of controlling the thread milling cutter to machine the internal thread on the bottom hole at a preset feed speed according to a preset feed path comprises:
obtaining the thread diameter D and the thread pitch p of the internal thread, the distance a from the feed point L to the end face of the internal thread, the thread depth H and the taper half angle
Calculating the preset feeding speed f according to the pitch p of the internal thread and the rotating speed n of the rotary table, wherein the preset feeding speed f meets the following requirements:
judging the taper half angle
Whether or not it is zero when the taper half angle is
When the value is not zero, the coordinates of the feed point L and the retracting point M are calculated in a first mode to determine the preset feed path when the taper half angle
When the preset cutting path is zero, calculating the coordinates of the cutting feed point L and the cutting retreat point M in a second mode to determine the preset cutting feed path; and controlling the thread milling cutter to process the internal thread at a preset feed speed according to a preset feed path.
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| CN112025004B (en) * | 2020-09-01 | 2022-09-27 | 东风柳州汽车有限公司 | Internal thread milling method, equipment, storage medium and device |
| CN112247291A (en) * | 2020-10-17 | 2021-01-22 | 张喜清 | Hexagonal nut tapping device |
| CN112643294A (en) * | 2020-12-11 | 2021-04-13 | 北京星航机电装备有限公司 | Precise machining method for spiral groove in multi-wire large-lead narrow deep cavity structure |
| CN113319344B (en) * | 2021-06-04 | 2022-09-02 | 湖南南方通用航空发动机有限公司 | Method for eliminating vibration cutter lines by processing orifice chamfer |
| CN114147240B (en) * | 2021-10-26 | 2024-02-06 | 内蒙古北方重工业集团有限公司 | Non-equally divided multi-head small-pitch internal spiral surface cutting processing method |
| CN114309828A (en) * | 2022-03-07 | 2022-04-12 | 海安县恒益滑动轴承有限公司 | Device for preparing lubricating oil channel of large-sized screw-down nut |
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| US6155756A (en) * | 1998-12-30 | 2000-12-05 | Musculoskeletal Transplant Foundation | Thread forming machine for bone material |
| CN101386094A (en) * | 2008-10-16 | 2009-03-18 | 中冶陕压重工设备有限公司 | Processing method of conical tube internal thread of large diameter |
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