CN108544041A - Inner screw thread milling processing method - Google Patents

Abstract

The embodiment of the present invention discloses a method for internal thread milling, which is used for machining internal threads by a multi-axis, for example, three-axis CNC machine tool. The internal thread milling method includes: installing a turntable on the three-axis CNC machine tool; The angle head is installed on the main shaft of the three-axis CNC machine tool, and the axis of the angle head is adjusted according to the type of the internal thread to form a preset swing angle with the axis of the main shaft and the angle head is locked; the workpiece to be processed is clamped and made The axis of the bottom hole on the workpiece to be processed coincides with the axis of the turntable; a thread milling cutter is installed on the angle head; the turntable is controlled to rotate at a constant speed, and the main shaft is started; the thread milling cutter is controlled to pre- The feed speed is set to process the internal thread on the bottom hole according to the preset feed path. The internal thread milling processing method provided by the embodiment of the present invention can improve the processing accuracy of the internal thread and the surface finish of the thread, reduce the processing cost of the internal thread, and have obvious economic benefits.

Description

Internal thread milling method

technical field

The invention relates to the technical field of numerical control processing, in particular to an internal thread milling processing method.

Background technique

Traditional thread processing methods include: turning, tapping, etc. However, these processing methods all have the disadvantages of low thread processing accuracy and poor thread surface finish. In addition, the turning process also has the problem that it is not easy to break chips, the chips are easy to wrap around the tool, or stay in the threaded hole, which will greatly reduce the processing quality of the threaded hole, and also increase the wear of the tool, especially turning. It is suitable for the processing of asymmetric parts and large parts. Tapping also has the disadvantages of easy breakage of the tap, low processing efficiency, and large cutting force, and is not suitable for processing difficult-to-machine materials. At present, turning is still the main processing method for the conical thread whose thread profile angle bisector is perpendicular to the cone generatrix. In addition, some manufacturers use five-axis CNC machine tools to mill internal threads, which can well overcome the shortcomings of traditional processing methods. Thread milling has high processing accuracy, good thread surface finish, and is not limited by thread direction and size. Processing versatility Well, the cutting force is small, the tool life is long, etc., but the cost of milling threads with a five-axis CNC machine tool is very high.

Contents of the invention

In view of the above problems, an embodiment of the present invention provides a method for milling an internal thread, so as to improve the processing quality of the internal thread and reduce the processing cost.

Specifically, an embodiment of the present invention provides an internal thread milling method for machining internal threads on a three-axis CNC machine tool. The internal thread milling method includes: installing a turntable on the three-axis CNC machine tool; An angle head is installed on the main shaft of the CNC machine tool, and the axis of the angle head is adjusted to a preset swing angle with the axis of the main shaft according to the type of the internal thread, and the angle head is locked, wherein, when the internal thread When the type is a conical internal thread whose tooth profile angle bisector is perpendicular to the generatrix of the cone, the preset swing angle θ and the taper half angle of the internal thread equal, when the type of the internal thread is a conical internal thread whose tooth profile angle bisector is perpendicular to the thread axis or a cylindrical internal thread, the preset swing angle θ is zero; the workpiece to be processed is clamped so that it is located at the The axis of the bottom hole on the workpiece to be processed coincides with the axis of the turntable; a thread milling cutter is installed on the angle head; the turntable is controlled to rotate at a constant speed, and the main shaft is started; the thread milling cutter is controlled to preset feed The internal thread is machined on the bottom hole according to the preset feed path.

On the other hand, an embodiment of the present invention also provides an internal thread milling method for machining internal threads on a multi-axis machine tool. The multi-axis machine tool includes a spindle and is equipped with a turntable. It is characterized in that the internal thread milling method It includes: installing an angle head on the main shaft, adjusting the axis of the angle head and the axis of the main shaft to form a preset swing angle and locking the angle head; clamping the workpiece to be processed so that it is located on the workpiece to be processed The axis of the bottom hole coincides with the axis of the turntable; install a thread milling cutter on the angle head; control the turntable to rotate at a constant speed, and start the main shaft; control the thread milling cutter to follow the preset feed rate The feed path processes the internal thread on the bottom hole.

In one embodiment of the present invention, the internal thread is a conical internal thread, and the coordinates of the feed point L on the preset feed path satisfy:

Among them, X _L is the X-axis coordinate of the described feed point L, Y _L is the Y-axis coordinate of the described feed point L, Z _L is the Z-axis coordinate of the described feed point L, and D is the internal thread The reference diameter of the large end face, a is the distance from the feed point L to the large end face of the internal thread, is the taper half angle of the internal thread;

The coordinates of the retraction point M on the preset feed path satisfy:

Wherein, X _M is the X-axis coordinate of the retraction point M, Y _M is the Y-axis coordinate of the retraction point M, Z _M is the Z-axis coordinate of the retraction point M, and H is the internal thread the thread depth.

In one embodiment of the present invention, the internal thread is a conical internal thread whose profile angle bisector is perpendicular to the generatrix of the cone, and the preset swing angle θ is the same as the taper half angle of the internal thread equal.

In one embodiment of the present invention, the internal thread is a conical internal thread whose profile angle bisector is perpendicular to the thread axis, and the preset swing angle θ is zero.

In one embodiment of the present invention, the internal thread is a cylindrical internal thread, the preset swing angle θ is zero, and the coordinates of the feed point L on the preset feed path satisfy:

Among them, X _L is the X-axis coordinate of the described feed point L, Y _L is the Y-axis coordinate of the described feed point L, Z _L is the Z-axis coordinate of the described feed point L, and D is the internal thread The nominal diameter, a is the distance from the feed point L to the end face of the internal thread;

The coordinates of the retraction point M on the preset feed path satisfy:

Wherein, X _M is the X-axis coordinate of the retraction point M, Y _M is the Y-axis coordinate of the retraction point M, Z _M is the Z-axis coordinate of the retraction point M, and H is the internal thread the thread depth.

In one embodiment of the present invention, the rotation speed n of the turntable and the preset feed speed f satisfy:

Wherein, p is the pitch of the internal thread.

In one embodiment of the present invention, the internal thread milling method further includes: controlling the thread milling cutter to return to the machine zero point of the multi-axis machine tool according to a preset tool retraction path, wherein the preset tool retraction path includes from The tool retraction point M is retracted to the axis of the internal thread in the radial direction, retracted from the axis of the internal thread to the outside of the end face of the internal thread along the axis, and then retracted to the machine zero point of the multi-axis machine tool .

In yet another aspect, the embodiment of the present invention also provides a method for internal thread milling, which is applied to a multi-axis numerical control machine tool, comprising the steps of: controlling the turntable to rotate at a uniform speed and starting the main shaft, wherein the workpiece to be processed is clamped on the turntable, and the to-be-processed The axis of the bottom hole on the workpiece coincides with the axis of the turntable, and a thread milling cutter is installed on the main shaft through an angle head, the axis of the angle head and the axis of the main shaft form a preset swing angle θ, and the The preset swing angle θ is determined by the type of internal thread to be formed on the bottom hole; the thread milling cutter is controlled to process the bottom hole on the bottom hole at a preset feed speed according to a preset feed path. Internal thread, wherein the preset feed path includes a straight path from the feed point L to the retraction point M; and controlling the thread milling cutter to return to the machine zero point of the multi-axis machine tool according to the preset retraction path, Wherein the preset tool withdrawal path includes withdrawing from the tool withdrawal point M in the radial direction to the axis of the internal thread, and withdrawing from the axis of the internal thread to the outside of the end surface of the internal thread along the axis , and then return to the machine zero point of the multi-axis machine tool.

In one embodiment of the present invention, the step of responding to the user's operation and controlling the thread milling cutter to process the internal thread on the bottom hole at a preset feed speed according to a preset feed path includes: obtaining The thread diameter D of the internal thread, the pitch p, the distance a from the feed point L to the thread end surface, the thread depth H, and the taper half angle The preset feed speed f is calculated according to the pitch p of the internal thread and the rotation speed n of the turntable, wherein the preset feed speed f satisfies: Determine the taper half angle is zero when the taper half-angle When it is non-zero, calculate the coordinates of the entry point L and the retraction point M according to the first formula set to determine the preset entry path, when the taper half-angle When it is zero, calculate the coordinates of the feed point L and the retraction point M in a second manner to determine the preset feed path; and control the thread milling cutter to advance according to the preset feed speed The tool path processes the internal thread.

The above technical solution may have the following advantages: In the embodiment of the present invention, a turntable and an angle head are configured on a three-axis or four-axis CNC machine tool, and then the corresponding preset swing angle θ of the angle head is set according to the type of internal thread to be processed and related parameters , and cooperate with the turntable to complete the machining of internal threads according to the preset feed path. The internal thread milling processing method provided by the embodiment of the present invention can improve the processing accuracy of the internal thread and the surface finish of the thread, reduce the processing cost of the internal thread, and have obvious economic benefits.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings without making creative efforts.

Fig. 1 is a schematic flow chart of an internal thread milling method provided by an embodiment of the present invention;

Fig. 2 is a schematic structural view of a multi-axis machine tool according to an embodiment of the present invention;

3 is a schematic structural view of a turntable according to an embodiment of the present invention;

Figure 4a and Figure 4b are the front view and the axonometric view of an angle head of an embodiment of the present invention, respectively;

Fig. 5 a and Fig. 5 b are the tooth form schematic diagrams of two kinds of conical internal threads of the embodiment of the present invention, wherein Fig. 5 a is the conical internal thread whose tooth form angle bisector is perpendicular to the cone generatrix, and Fig. 5 b is the tooth form angle bisector perpendicular to Conical internal thread of the axis;

Figure 6a and Figure 6b are schematic diagrams of the structure of the bottom hole on the workpiece to be processed according to the embodiment of the present invention, wherein the bottom hole in Figure 6a is a bottom hole of a conical internal thread, and the bottom hole in Figure 6b is a bottom hole of a cylindrical internal thread ;

Fig. 7a, Fig. 7b and Fig. 7c are respectively the processing schematic diagrams of the conical internal thread with the tooth profile angle bisector perpendicular to the cone generatrix, the conical internal thread with the tooth profile angle bisector perpendicular to the thread axis, and the cylindrical thread of the embodiment of the present invention ;

Fig. 8 is a schematic flowchart of another internal thread milling method provided by an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Referring to Fig. 1, Fig. 2 and Fig. 3, Fig. 1 is a schematic flow chart of an internal thread milling method provided by an embodiment of the present invention, Fig. 2 is a schematic structural view 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 processing method provided by the embodiment of the present invention is suitable for machining internal threads by a multi-axis machine tool. The multi-axis machine tool 1 (see FIG. 2 ) here can be, for example, a three-axis (X-Y-Z) CNC machine tool but a turntable 2 (see FIG. 3 ) needs to be installed on the workbench 11 of the multi-axis machine tool 1 (see FIG. 3 ), or, for example, a self-contained Four-axis (X-Y-Z-C) machine tool with rotary table 2. The turntable 2 can be, for example, a numerically controlled turntable. The numerical control turntable is connected with the multi-axis machine tool 1 and controlled by a servo system (not shown in the figure). The turntable 2 can be linked with the three axes (X-Y-Z) of the multi-axis machine tool 1 . The workpiece 3 to be processed can be clamped on the turntable 2 . The workpiece 3 to be processed can be symmetrical rotary parts and small parts, or asymmetrical parts and large parts. Before the thread is processed, the bottom hole 31 has been processed in advance on the workpiece 3 to be processed (see FIG. 6 a ). The internal thread milling method provided by the embodiment of the present invention is to process the internal thread on the inner wall of the bottom hole 31 . Furthermore, a spindle 12 is provided on the multi-spindle machine tool 1 .

Specifically, referring to Fig. 1 to Fig. 7, the internal thread milling processing method provided by the embodiment of the present invention includes:

Step S11, install the angle head 13 on the main shaft 12, adjust the axis of the angle head 13 and the axis of the main shaft 12 to form a preset swing angle θ, and then lock the angle head 13 (see Fig. 4a and Fig. 4b). Specifically, the axis of the spindle 12 is parallel to the axis of the turntable 2 . The value of the preset swing angle θ is determined according to the parameters of the internal thread, such as the thread type of the internal thread. The internal thread includes conical internal thread and cylindrical internal thread. The conical internal thread includes the conical internal thread whose tooth profile angle bisector is perpendicular to the cone generatrix (see Figure 5a) and the conical internal thread whose tooth profile angle bisector is perpendicular to the axis (see Figure 5b).

As shown in Figure 5a, when the internal thread is a conical internal thread whose profile angle bisector is perpendicular to the generatrix of the cone, the preset swing angle θ of the angle head 13 satisfies:

Among them, the taper half angle is the angle between the generatrix of the cone of the internal thread and the axis of the internal thread hole.

As shown in Figure 5b, when the internal thread is a conical internal thread whose profile angle bisector is perpendicular to the thread axis, the preset swing angle θ of the angle head 13 is zero, that is, the axis of the angle head 13 and the axis of the main shaft 12 coincide.

When the internal thread is a cylindrical thread, its profile angle bisector is also perpendicular to the axis of the internal thread, therefore, the preset swing angle θ of the angle head 13 is zero, that is, the axis of the angle head 13 and the axis of the main shaft 12 The axes coincide.

Step S13 , clamping the workpiece 3 to be processed so that the axis of the bottom hole 31 on the workpiece 3 coincides with the axis of the turntable 2 . Specifically, the workpiece 3 to be processed is clamped on the turntable 2 , and the position of the workpiece 3 to be processed is adjusted so that the axis of the bottom hole 31 on the workpiece 3 to be processed coincides with the axis of the turntable 2 . As shown in FIG. 6 a , when the internal thread is a conical thread such as a conical thread whose thread profile angle bisector is perpendicular to the generatrix of the cone, the bottom hole 31 is a conical hole. As shown in Figure 6b, when the internal thread is a cylindrical thread, the bottom hole 31 is a round hole.

Step S15 , installing the thread milling cutter 14 on the angle head 13 . Of course, after the thread milling cutter 14 is installed, the tool setting work needs to be completed.

Step S17 , rotating the turntable 2 at a constant speed, and starting the main shaft 12 .

Step S19, controlling the thread milling cutter 14 to process the internal thread on the bottom hole 31 at a preset feed rate f and according to a preset feed path. Controlling the movement of the thread milling cutter 14 here can be understood as controlling the relative movement of the workpiece 3 to be processed relative to the thread milling cutter 14 . The preset feed rate f satisfies:

Wherein, p is the pitch of the internal thread, and n is the rotation speed of the turntable 2 .

The preset cutting path may, for example, include a path from the zero point of the machine tool to the cutting point L and a path from the cutting point L to the retracting point M.

The machine zero point is the origin of the machine tool specified by the machine tool manufacturer, which is the origin of the machine tool coordinate system. The zero point of the machine tool is not only the reference point for establishing the workpiece coordinate system on the machine tool, but also the reference point for machine tool debugging and part processing.

The path from the zero point of the machine tool to the tool entry point L may be, for example, a straight line path, and of course may also be a curved path or other paths.

The path from the entry point L to the exit point M is typically a straight path. The coordinates of the entry point L and the exit point M are different due to the type and parameters of the internal thread to be processed. Usually, the center O of the upper end surface of the bottom hole 31 is used as the programming coordinate origin (see Fig. 7a, Fig. 7b, Fig. 7c). Of course, other points can also be used as the programming coordinate origin, and the present invention is not limited thereto.

As shown in Figure 7a, when the internal thread is a conical internal thread whose profile angle bisector is perpendicular to the generatrix of the cone, the preset swing angle θ of the angle head 13 is related to the taper half angle equal, therefore, the angle between the axis of the thread milling cutter 14 and the axis of the internal thread (that is, the Z axis) is equal to The path from the entry point L to the exit 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 generatrix of the cone of the internal thread in the XOZ plane.

The coordinates of the tool entry point L satisfy:

Among them, X _L is the X-axis coordinate of the described feed point L, Y _L is the Y-axis coordinate of the described feed point L, Z _L is the Z-axis coordinate of the described feed point L, and D is the internal thread The reference diameter (the basic major diameter of the large end surface of the internal thread), a is the distance from the feed point L to the large end surface (also called the reference plane) of the internal thread.

The coordinates of tool withdrawal point M satisfy:

Wherein, X _M is the X-axis coordinate of the retraction point M, Y _M is the Y-axis coordinate of the retraction point M, Z _M is the Z-axis coordinate of the retraction point M, and H is the internal thread the thread depth.

As shown in Figure 7b, when the internal thread is a conical internal thread whose profile angle bisector is perpendicular to the thread axis, the preset swing angle θ of the angle head 13 is zero, so the axis of the thread milling cutter 14 is in line with the internal thread The axes of the threads (ie the Z axis) are parallel. The path from the entry point L to the exit point M is parallel to the generatrix of the cone of the internal thread in the XOZ plane. The coordinates of the tool entry point L satisfy the formula (3), and the coordinates of the tool withdrawal point M satisfy the formula (4).

As shown in Figure 7c, when the internal thread is a cylindrical internal thread, the preset swing angle θ of the angle head 13 is zero, so the axis of the thread milling cutter 14 is parallel to the axis of the internal thread (that is, the Z axis) . The path from the entry point L to the exit point M is parallel to the axial direction of the thread milling cutter 14 .

The coordinates of the tool entry point L satisfy:

Wherein, 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 tool withdrawal point M satisfy:

Wherein, H is the thread depth of the internal thread.

First control the thread milling cutter 14 to move from the zero point of the machine tool to the feed point L, and then control the thread milling cutter 14 to process on the bottom hole 31 according to the path from the feed point L to the retraction point M at a preset feed speed f out the internal thread.

Of course, the internal thread milling method provided in this embodiment also includes a tool retracting step. Specifically, the tool retracting step includes controlling the thread milling cutter 14 to retract to the machine zero point according to a preset tool retracting path. The preset tool retraction path may, for example, include retracting from the tool retraction point M in the radial direction to the axis of the internal thread, and from the axis of the internal thread along the axial direction (in Fig. 7a, Fig. 7b, Fig. 7c). positive direction of the Z axis) to the outside of the end face of the internal thread and to the zero point of the machine tool. Here, retracting from the tool retraction point M to the axis of the internal thread in the radial direction can be understood as the thread milling cutter does not move, but the workpiece to be processed moves relative to the thread milling cutter; from the axis of the internal thread along the Retreating in the axial direction to the outside of the end face of the internal thread can be understood as the thread milling cutter moves along the axial direction of the internal thread with the spindle, while the workpiece to be processed does not move; retreating to the machine zero point of the multi-axis machine tool can also be understood The thread milling cutter does not move, but the workpiece to be processed moves relative to the thread milling cutter. Of course, other control methods that can realize the same function are also possible.

It is worth mentioning here that the preset feed path and the preset retract path can be obtained through manual planning, or can be obtained through CAD/CAM software planning. In addition, multi-axis machine tools are typically multi-axis linkage CNC machine tools, and all machining actions are controlled by CNC machining programs. In addition, the planning of the preset feed path and the preset retract path needs to consider the cutter radius of the thread milling cutter 14 and the profile height of the internal thread. Furthermore, the preset feed path and the preset retract path can be a single processing path or multiple processing paths, which can be determined according to specific thread parameters and processing conditions.

In order to facilitate a better understanding of the embodiment of the present invention, an example of processing a PZ39 right-handed conical thread with a thread depth H of 40mm will be used as an example to describe the internal thread milling method provided by the embodiment of the present invention.

The PZ39 thread is a conical internal thread whose tooth angle bisector is perpendicular to the cone generatrix. The major diameter of the thread on the reference plane is D=39mm, the middle diameter is 37.643mm, the minor diameter is 36.286mm, the pitch P=2mm, and the taper half angle The milling method of PZ39 thread includes:

1) Install and fix the turntable on the workbench of the three-axis CNC machine tool.

2) Install the angle head on the main shaft, adjust the axis of the angle head and the axis of the main shaft to form a preset swing angle After the included angle, lock the angle head.

3) Clamp the workpiece to be processed so that the axis of the bottom hole on the workpiece to be processed coincides with the axis of the turntable.

4) Install the thread milling cutter on the angle head.

5) Turn the CNC turntable at a constant speed and start the spindle. The CNC turntable rotates counterclockwise at a speed of n=60r/min. The spindle speed is 600~700r/min.

6) The feed rate f of the thread milling cutter is:

7) Take the distance a=5mm from the tool entry point L to the reference plane of the internal thread. The L coordinate value of the tool entry point is:

That is, the coordinates of the tool entry point L are (19.800, 0, 5).

The M coordinate value of the tool retraction point is:

Y _M =0

Z _M = -H = -40

That is, the coordinates of the tool retraction point M are (17.103, 0, -40).

Control the thread milling cutter to feed from the zero point of the machine tool to the feed point L(19.800, 0, 5) according to the preset feed path at the feed speed f=2.5mm/s, and then from the feed point L(19.800, 0, 5) Run the tool in a straight line to the retract point M (17.103, 0, -40) to process the PZ39 internal thread on the bottom hole.

8) Control the thread milling cutter to retract from the retract point M (17.103, 0, -40) in the radial direction to the point (0, 0, -40) on the axis of the PZ39 internal thread according to the preset retract path, and then from Point (0, 0, -40) retracts along the PZ39 internal thread axis direction (Z positive direction) to the point (0, 0, 100) outside the end face of the PZ39 internal thread, and finally returns to the machine zero to complete the PZ39 internal thread milling process.

In summary, the embodiment of the present invention configures a turntable and an angle head on a multi-axis CNC machine tool, and then sets the corresponding angle head preset swing angle θ according to the type of internal thread to be processed and related parameters, and cooperates with the turntable according to The preset feed path completes the machining of internal threads. The internal thread milling processing method provided by the embodiment of the present invention can also improve the processing quality of the internal thread, such as processing accuracy, thread surface finish, and the like. In addition, compared with the method of milling internal threads using a five-axis machine tool, the internal thread milling method provided by the embodiment of the present invention greatly reduces the processing cost of internal threads, and has obvious economic benefits. Furthermore, the internal thread milling method provided by the embodiment of the present invention can not only process cylindrical internal threads and conical internal threads on symmetrical parts and small parts, but also process cylindrical internal threads and conical internal threads on asymmetrical parts and large parts. Internal thread, wide processing range.

In addition, the embodiment of the present invention also provides another internal thread milling method. The internal thread milling method is suitable for multi-axis machine tools. 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 the preset feed speed and preset feed path according to the user operation and the relevant parameters input by the user, and complete the internal thread according to the preset feed speed and the preset feed path Milling. In this way, while improving the quality of internal thread processing, the internal thread processing operation is simplified and the processing efficiency is improved. As shown in Figure 8, the steps of the internal thread milling method include:

1) Control the turntable to rotate at a constant speed and start the spindle. The multi-axis machine tool, for example, controls the turntable to rotate at a constant speed and starts the spindle by responding to user operations such as triggering an operation button. Wherein, a workpiece to be processed is clamped on the turntable on the multi-axis machine tool, and the axis of the bottom hole on the workpiece to be processed coincides with the axis of the turntable, and a thread milling cutter is installed on the main shaft through an angle head, so The axis of the angle head and the axis of the main shaft form a preset swing angle θ, and the preset swing angle θ is determined by the type of internal thread to be formed on the bottom hole.

2) Controlling the thread milling cutter to process the internal thread on the bottom hole according to a preset feeding path at a preset feed speed. The preset cutting path includes a straight line from the cutting point L to the cutting point M. Specifically, firstly, the multi-axis machine tool obtains relevant parameters such as the thread diameter D of the internal thread, the pitch p, the distance a from the feed point L to the end surface of the internal thread, the thread depth H, and the taper half angle by, for example, responding to user input operations. Wait. Then, the preset feed speed f is calculated according to the formula (2) according to the pitch p of the internal thread and the rotation speed n of the turntable. Furthermore, to determine the taper half angle Whether it is zero, when the taper half angle When it is non-zero, it means that the internal thread is a conical internal thread, the thread diameter D is the reference diameter of the large end face of the internal thread, and the distance a from the feed point L to the end face of the internal thread is the distance a from the feed point L to the internal thread The distance of the large end face, then in the first way, for example, calculate the coordinates of the feed point L and the retreat point M to determine the preset feed path according to formula (3) and formula (4); when the taper half angle is zero, indicating that the internal thread is a cylindrical internal thread, the thread diameter D is the nominal diameter of the internal thread, and 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 , then calculate the coordinates of the entry point L and the retraction point M in a second manner, for example, according to formula (5) and formula (6) to determine the preset path of entry. Finally, the thread milling cutter is controlled to process the internal thread at a preset feed speed according to a preset feed path.

3) Control the thread milling cutter to retreat to the machine zero point of the multi-axis machine tool according to the preset tool retraction path, wherein the preset tool retraction path includes retracting from the tool retraction point M to the axis of the internal thread in the radial direction . Retreat from the axis of the internal thread to the outside of the end surface of the internal thread along the axis direction, and then return to the machine zero point of the multi-axis machine tool.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. A kind of internal thread milling processing method, is used for three-axis numerical control machine tool processing internal thread, it is characterized in that, described internal thread milling processing method comprises: A turntable is installed on the three-axis CNC machine tool; Install an angle head on the main shaft of the three-axis CNC machine tool, adjust the axis of the angle head to a preset swing angle with the axis of the main shaft according to the type of the internal thread and lock the angle head, wherein, when the The type of the internal thread is a conical internal thread whose tooth profile angle bisector is perpendicular to the generatrix of the cone. When the preset swing angle θ and the taper half angle of the internal thread Equal, when the type of the internal thread is a conical internal thread whose tooth profile angle bisector is perpendicular to the thread axis or a cylindrical internal thread, the preset swing angle θ is zero; Clamping the workpiece to be processed so that the axis of the bottom hole on the workpiece to be processed coincides with the axis of the turntable; installing a thread milling cutter on the angle head; Control the turntable to rotate at a constant speed, and start the main shaft; Controlling the thread milling cutter to process the internal thread on the bottom hole at a preset feed speed according to a preset feed path. 2. A method of internal thread milling, for multi-axis machine tool processing internal thread, said multi-axis machine tool includes a main shaft and a turntable is installed, it is characterized in that, said internal thread milling method comprises: Install an angle head on the main shaft, adjust the axis of the angle head to a preset swing angle with the axis of the main shaft and lock the angle head; Clamping the workpiece to be processed so that the axis of the bottom hole on the workpiece to be processed coincides with the axis of the turntable; installing a thread milling cutter on the angle head; Control the turntable to rotate at a constant speed, and start the main shaft; Controlling the thread milling cutter to process the internal thread on the bottom hole at a preset feed speed according to a preset feed path. 3. The internal thread milling method according to claim 2, wherein the internal thread is a conical internal thread, and the coordinates of the feed point L on the preset feed path satisfy: Among them, X _L is the X-axis coordinate of the described feed point L, Y _L is the Y-axis coordinate of the described feed point L, Z _L is the Z-axis coordinate of the described feed point L, and D is the internal thread The reference diameter of the large end face, a is the distance from the feed point L to the large end face of the internal thread, is the taper half angle of the internal thread; The coordinates of the retraction point M on the preset feed path satisfy: Wherein, X _M is the X-axis coordinate of the retraction point M, Y _M is the Y-axis coordinate of the retraction point M, Z _M is the Z-axis coordinate of the retraction point M, and H is the internal thread the thread depth. 4. The internal thread milling method according to claim 3, wherein the internal thread is a conical internal thread whose profile angle bisector is perpendicular to the generatrix of the cone, and the preset swing angle θ is the same as the internal thread. Thread taper half angle equal. 5 . The internal thread milling method according to claim 3 , wherein the internal thread is a conical internal thread whose profile angle bisector is perpendicular to the thread axis, and the preset swing angle θ is zero. 6. The internal thread milling method according to claim 2, wherein the internal thread is a cylindrical internal thread, the preset swing angle θ is zero, and the feed point on the preset feed path The coordinates of L satisfy: Among them, X _L is the X-axis coordinate of the described feed point L, Y _L is the Y-axis coordinate of the described feed point L, Z _L is the Z-axis coordinate of the described feed point L, and D is the internal thread The nominal diameter, a is the distance from the feed point L to the end face of the internal thread; The coordinates of the retraction point M on the preset feed path satisfy: Wherein, X _M is the X-axis coordinate of the retraction point M, Y _M is the Y-axis coordinate of the retraction point M, Z _M is the Z-axis coordinate of the retraction point M, and H is the internal thread the thread depth. 7. The internal thread milling method according to claim 2, wherein the rotation speed n of the turntable and the preset feed speed f satisfy: Wherein, p is the pitch of the internal thread. 8. The internal thread milling method according to claim 2, further comprising: Controlling the thread milling cutter to return to the machine zero point of the multi-axis machine tool according to the preset tool retraction path, wherein the preset tool retraction path includes retracting from the tool retraction point M to the axis of the internal thread in the radial direction, Retreat from the axis of the internal thread to the outside of the end face of the internal thread along the axis direction, and then retreat to the machine zero point of the multi-axis machine tool. 9. A method for internal thread milling, applied to a multi-axis numerical control machine tool, characterized in that it comprises the steps of: Control the turntable to rotate at a constant speed and start the main shaft, wherein the workpiece to be processed is clamped on the turntable, and the axis of the bottom hole on the workpiece to be processed coincides with the axis of the turntable, and a thread milling cutter is installed on the main shaft through an angle head , the axis of the angle head and the axis of the main shaft form a preset swing angle θ, and the preset swing angle θ is determined by the type of internal thread to be formed on the bottom hole; Controlling the thread milling cutter to process the internal thread on the bottom hole according to a preset feed path at a preset feed speed, wherein the preset feed path includes from the feed point L to the retraction point M and controlling the thread milling cutter to retreat to the machine zero point of the multi-axis machine tool according to the preset retraction path, wherein the preset retraction path includes retracting from the retraction point M in the radial direction to The axis of the internal thread retreats from the axis of the internal thread to the outside of the end surface of the internal thread along the axis direction, and then retreats to the machine zero point of the multi-axis machine tool. 10. The internal thread milling method according to claim 9, characterized in that, said controlling said thread milling cutter to process said internal thread milling cutter on said bottom hole at a preset feed speed according to a preset feed path. The threading steps include: Obtain the thread diameter D, pitch p, the distance a from the feed point L to the end face of the internal thread, thread depth H, and taper half angle of the internal thread The preset feed speed f is calculated according to the pitch p of the internal thread and the rotation speed n of the turntable, wherein the preset feed speed f satisfies: Determine the taper half angle is zero when the taper half-angle When it is non-zero, calculate the coordinates of the entry point L and the retraction point M in the first way to determine the preset entry path, when the taper half-angle When it is zero, calculate the coordinates of the feed point L and the retraction point M in a second manner to determine the preset feed path; and control the thread milling cutter to advance according to the preset feed speed The tool path processes the internal thread.