A numerical control machining method for end face ring groove

Abstract

The application provides a numerical control machining method for an end face ring groove, and relates to the field of numerical control machining.The numerical control machining method for the end face ring groove comprises the following steps: obtaining the cross-sectional shape of the end face ring groove; determining the real-time groove width of the tool shaft when feeding according to the cross-sectional shape and the real-time groove depth of the tool shaft when feeding; determining the center track radius of the tool shaft according to the real-time groove width and the width of the blade; determining a track circle which is concentric with the center of the center circle and has a radius equal to the center track radius according to the center of the center circle of the end face ring groove; coinciding the symmetric center of the inner and outer edges of the blade with the center of the center circle, coinciding the shaft center of the tool shaft with the center of the center circle, and controlling the rotation of the tool shaft to cut out the ring groove.The technical scheme of the application greatly improves the utilization rate of the tool, reduces the production cost, and covers a wide range of machining of the end face ring groove.

Description

Technical Field

[0001] This invention relates to the field of CNC machining, and more specifically, to a CNC machining method for an end face annular groove. Background Technology

[0002] Numerous annular grooves are processed in nuclear power, petrochemical, and other related equipment, including various small and medium-sized symmetrical end-face annular grooves, especially those with a diameter less than 200 mm, such as rectangular annular grooves, isosceles trapezoidal annular grooves, and U-shaped annular grooves. Existing processing methods for these types of end-face annular grooves mainly include flange machining.

[0003] Of the existing technologies mentioned above, firstly, flange processing machines are portable machines for processing flange faces, flange sealing faces, and sealing end face annular grooves. They are suitable for use in ultra-large products. However, there are several drawbacks when using flange processing machines for end face annular groove processing: they require specialized cutting tools, which need to be ground according to the groove shape, making them unsuitable for different groove widths; they are also unsuitable for processing groove shapes other than rectangular annular grooves, such as trapezoidal annular grooves and U-shaped annular grooves; furthermore, they result in high tool wear and processing costs. Therefore, this processing method is only suitable for a few processing scenarios. Summary of the Invention

[0004] The problem that this invention aims to solve is that existing machining methods require special-purpose cutting tools, which are difficult to apply to different groove widths and shapes, and have high machining costs.

[0005] To address the above problems, this invention provides a CNC machining method for end-face annular grooves, applied to the machining of end-face annular grooves by a grooving tool. The grooving tool includes a tool shaft and an insert eccentrically mounted relative to the tool shaft. The CNC machining method for the end-face annular groove includes:

[0006] Obtain the cross-sectional shape of the end face annular groove;

[0007] The real-time groove width of the cutter shaft during the feed is determined based on the cross-sectional shape and the real-time groove depth of the cutter shaft during the feed.

[0008] The center trajectory radius of the cutter shaft is determined based on the real-time slot width and the blade width.

[0009] Based on the center of the center circle of the end face annular groove, determine a trajectory circle that is concentric with the center circle and has a radius equal to the radius of the center trajectory.

[0010] The center of symmetry of the inner and outer edges of the blade is aligned with the center circle, and the axis is set coaxially with the center circle. The blade axis is controlled to rotate to cut an annular groove.

[0011] While controlling the axis to follow the circular trajectory, the tool shaft is also controlled to rotate and continuously feed along the axial direction to form a helical toolpath; or, the tool shaft is controlled to step along the axial direction to form a layered toolpath.

[0012] Optionally, before obtaining the cross-sectional shape of the end face annular groove, the method further includes:

[0013] Determine whether the groove type of the end face annular groove is a symmetrical annular groove or an asymmetrical annular groove;

[0014] When the end face annular groove is an asymmetric annular groove, the asymmetric annular groove is decomposed sequentially along the cross-sectional width direction of the asymmetric annular groove to generate multiple symmetric annular grooves.

[0015] Optionally, the symmetrical annular groove includes at least one of a rectangular annular groove, an isosceles trapezoidal annular groove, and a U-shaped annular groove.

[0016] Optionally, determining the real-time groove width of the cutter shaft during the feed based on the cross-sectional shape and the real-time groove depth of the cutter shaft during the feed includes:

[0017] Based on the cross-sectional shape, determine the relationship model between the real-time groove depth and the real-time groove width;

[0018] Based on the relationship model and the real-time groove depth of the cutter shaft during infeed, the real-time groove width of the cutter shaft during infeed is determined;

[0019] The relational model includes:

[0020] a = k + h * tan(d);

[0021] Where a represents the real-time groove width, h represents the real-time groove depth, d represents the side inclination angle of the end face annular groove, and k represents the bottom width of the end face annular groove.

[0022] Optionally, determining the center trajectory radius of the cutter axis based on the real-time slot width and the blade width includes:

[0023] Determine the relationship between the real-time slot width, the blade width, and the center trajectory radius, the relationship including:

[0024] a = s + 2b;

[0025] Where s represents the width of the blade, and b represents the radius of the center trajectory;

[0026] Substituting the given relational expression into the relational model generates the central trajectory radius, which satisfies the following formula:

[0027] b = k / 2 + h * tan(d) - s / 2.

[0028] Optionally, aligning the centers of symmetry of the inner and outer edges of the blade with the central circle, coaxializing the axis with the central circle, and controlling the rotation of the blade shaft to cut an annular groove includes:

[0029] Adjust the distance between the center of symmetry of the inner and outer edges of the blade and the axis to be equal to the radius of the central circle;

[0030] Adjust the axis to coincide with the center of the central circle so that the center of symmetry of the inner and outer edges of the blade coincides with the central circle;

[0031] Control the rotation of the cutter shaft to cut out the annular groove.

[0032] Optionally, controlling the axis to rotate around the trajectory circle while simultaneously controlling the cutter shaft to rotate, and simultaneously controlling the cutter shaft to continuously feed axially to form a helical toolpath, or simultaneously controlling the cutter shaft to step feed axially to form a layered toolpath includes:

[0033] After each time the cutter axis is controlled to advance an axial step by a preset increment, the cutter axis is returned to the center of the central circle;

[0034] Determine whether the accumulated value of the preset increment is equal to the total groove depth;

[0035] If not, then based on the preset increment, control the cutter shaft to continue stepping feed along the axial direction;

[0036] If so, control the cutter axis to stop its axial step feed.

[0037] Optionally, the helical toolpath includes at least one of a cylindrical helical toolpath, a conical helical toolpath, and a spherical helical toolpath.

[0038] Optionally, controlling the axis to rotate around the trajectory circle while simultaneously controlling the cutter shaft to rotate, and simultaneously controlling the cutter shaft to continuously feed axially to form a helical toolpath, or simultaneously controlling the cutter shaft to step feed axially to form a layered toolpath includes:

[0039] Based on the initial center position of the cutter shaft and the helical parameters of the helical toolpath, the coordinates of the center point of the cutter shaft are determined. Multiple center point coordinates constitute the helical toolpath. The helical parameters include the direction of rotation, pitch, and incremental angle. The helical toolpath is the running path of the shaft center.

[0040] Optionally, the grooving tool further includes:

[0041] The tool holder includes a tool seat that is fixedly connected to the tool shaft;

[0042] The blade body is mounted on the blade holder. The blade body includes a first cutting head and a second cutting head, which are set at an angle to each other. The blade is mounted on the second cutting head.

[0043] Compared with the prior art, the CNC machining method for end face annular grooves of the present invention has the following beneficial effects: By obtaining the cross-sectional shape of the end face annular groove, the real-time groove width of the cutter shaft at the time of tool feed is determined according to the cross-sectional shape and the real-time groove depth of the cutter shaft at the time of tool feed; the center trajectory radius of the cutter shaft is determined according to the real-time groove width and the width of the cutting tool; a trajectory circle concentric with the center of the center circle of the end face annular groove and with a radius equal to the radius of the center trajectory is determined according to the center of the center circle of the end face annular groove; after determining the groove depth h, it can be applied to machining end face annular grooves with different groove widths and different groove shapes, greatly improving the machining coverage of end face annular grooves; the symmetry center of the inner and outer edges of the cutting tool is aligned with the center circle, the axis of the cutter shaft is aligned with the center circle, and the rotation of the cutter shaft is controlled to cut out the annular groove, the circle in the middle of the annular groove is also the center circle; while controlling the axis to follow the circular trajectory along the trajectory circle, the rotation of the cutter shaft is controlled, and after passing through the annular groove of the grooving tool, it rotates by a certain angle (e.g., circumference). After turning, the tool travels in a circular path with a radius of b, offset from the center of the end face annular groove. This can quickly widen the range of the target groove shape and improve the grooving efficiency. Simultaneously, the tool axis can be controlled to feed continuously along the axial direction, forming a helical toolpath. Alternatively, the tool axis can be controlled to feed in a stepwise manner along the axial direction, forming a layered toolpath. Layered toolpaths are simple to implement and easy to program, and can be applied to the machining of all groove shapes. However, they require repeated tool advances and retractions, resulting in relatively low machining efficiency and faster tool wear. Helical toolpaths are continuous, especially conical helical or spherical helical toolpaths. While their programming involves complex calculations, they are continuous without intermediate tool advances or retractions, ensuring stable and reliable cutting with slower tool wear. Only one tool is needed for the entire annular groove machining, reducing the risk of tool failure after tool changes. These different toolpaths can be selected based on different actual machining scenarios, improving practical operability. Attached Figure Description

[0044] Figure 1 A flowchart illustrating a CNC machining method for an end face annular groove according to an embodiment of the present invention is shown.

[0045] Figure 2 A flowchart illustrating the process of determining whether to stop the layered machining toolpath feed in an embodiment of the present invention is shown;

[0046] Figure 3 A schematic diagram of the rectangular annular groove in an embodiment of the present invention is shown;

[0047] Figure 4 A schematic diagram of the U-shaped annular groove in an embodiment of the present invention is shown;

[0048] Figure 5 A schematic diagram of the trapezoidal annular groove in an embodiment of the present invention is shown;

[0049] Figure 6 A schematic diagram of the structure of the open U-shaped annular groove in an embodiment of the present invention is shown;

[0050] Figure 7 An exploded structural diagram of the asymmetric annular groove in an embodiment of the present invention is shown;

[0051] Figure 8 This diagram illustrates grooving in an embodiment of the present invention when the groove width is equal to the blade width.

[0052] Figure 9 This diagram illustrates the grooving process performed when the cutter axis is translated a distance b along the +X axis in an embodiment of the present invention.

[0053] Figure 10 This diagram illustrates how the slot width increases by 2b after the cutter shaft is translated a distance b along the +X axis in an embodiment of the present invention.

[0054] Figure 11 A schematic diagram of the mating structure of the grooving tool and the tool holder in an embodiment of the present invention is shown;

[0055] Figure 12 A schematic diagram of the grooving tool in an embodiment of the present invention is shown;

[0056] Figure 13 A schematic diagram of parameter calculation using a trapezoidal annular groove as an example in an embodiment of the present invention is shown;

[0057] Figure 14 This diagram illustrates the parameter calculation for an arc-shaped annular groove, as an example, in an embodiment of the present invention.

[0058] Explanation of reference numerals in the attached figures:

[0059] 1-End face annular groove; 2-Tool holder; 21-Tool shaft; 22-Tool holder; 3-Tool body; 31-First cutting head; 32-Second cutting head; 33-Insert tool. Detailed Implementation

[0060] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0061] It should be noted that relational terms such as "first" and "second" in this invention are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0062] In the description of this specification, references to terms such as "embodiment," "one embodiment," and "one implementation" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or implementation is included in at least one embodiment or illustrative implementation of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or implementation. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or implementations.

[0063] Reference Figure 1 As shown, this embodiment of the invention proposes a CNC machining method for an end face annular groove 1, applied to the machining of the end face annular groove 1 by a grooving tool. The grooving tool includes a tool shaft 21 and an insert 33 eccentrically mounted relative to the axis of the tool shaft 21. Before machining, the insert 33 is first mounted on the tool shaft (the eccentricity between the two will be described later). Figure 11 As shown, the blade 33 is installed at the end of the cutter shaft 21, and it is not on the axis of the cutter shaft 21, that is, the blade 33 is installed eccentrically.

[0064] The CNC machining method for the end face annular groove includes:

[0065] S10: Obtain the cross-sectional shape of the end face annular groove 1.

[0066] This invention is mainly applicable to the processing of various small and medium-sized symmetrical end face annular grooves 1, especially annular grooves with a diameter of less than 200mm, such as rectangular annular grooves, isosceles trapezoidal annular grooves, U-shaped annular grooves and other groove types.

[0067] S11: Determine the real-time groove width of the cutter shaft 21 during the feed based on the cross-sectional shape and the real-time groove depth of the cutter shaft 21 during the feed.

[0068] The rectangular annular groove, isosceles trapezoidal annular groove, and U-shaped annular groove described above all describe the cross-sectional shape of the end face annular groove 1. Determining the cross-sectional shape is equivalent to determining the groove type. Furthermore, the cross-sectional shape of the end face annular groove 1 also includes its dimensional information. For example, the cross-sectional shape of the isosceles trapezoidal annular groove is an isosceles trapezoid, and the dimensions of its upper and lower bases, as well as its height, are given. Since the cross-sectional shape is determined, the real-time groove depth of the tool shaft 21 during machining is variable. At different real-time groove depths, the tool shaft 21 feeds to different positions of the cross-sectional shape, corresponding to different real-time groove widths. The real-time groove width is the groove width that should be formed when the tool shaft 21 feeds to different groove depths. That is, by determining the groove depth h, it can be applied to machining end face annular grooves 1 with different groove widths and groove types.

[0069] After a special grooving cutter is installed on the cutter shaft 21, the blade 33 can be fed and rotated under the drive of the cutter shaft 21; the specific types of feed motion are explained below.

[0070] S12: Determine the center trajectory radius of the cutter shaft 21 based on the real-time slot width and the width of the blade 33.

[0071] S13: Based on the center of the center circle of the end face annular groove 1, determine a trajectory circle that is concentric with the center circle and has a radius equal to the radius of the center trajectory.

[0072] S14: Align the center of symmetry of the inner and outer edges of the blade 33 with the center circle, set the axis coaxially with the center circle, and control the blade shaft 21 to rotate to cut out an annular groove; the circle in the middle of the annular groove is also the center circle.

[0073] See Figure 8 and Figure 10 , Figure 8 and Figure 10 In the diagram, the circle represented by the dashed line at the center of the annular groove is the central circle;

[0074] For S12-S14, specifically, the following refers to... Figure 8 , Figure 9 and Figure 10 The three steps are further explained, and the basic cutting principles of the present invention are uniformly described.

[0075] First, the machine tool uses the aforementioned tool clamping device and grooving tool to cut a groove along the axial direction. The center circle of the resulting groove coincides with the rotation circle of the center of symmetry of the inner and outer edges of the insert, and the groove width a1 is equal to the width s of the insert 33, i.e., a1 = s. See [link to documentation]. Figure 8 This results in an annular groove.

[0076] For a given end face annular groove 1, the center circle of the end face annular groove 1 is fixed and determined, so the center of the center circle is also determined. When determining the trajectory circle, that is, taking the center of the center circle as the new center and drawing a circle with a radius equal to the center trajectory as the new center radius, the trajectory circle can be obtained. When executing S13, the tool moves along the axial direction to cut the groove, and the center circle of the resulting groove coincides with the rotation circle of the blade's center of symmetry, thus obtaining the annular groove. The circle in the middle of the annular groove is also the center circle.

[0077] Then, the tool axis 21 is moved a distance (b) along the +X axis. Because the tool rotates continuously, the groove width at the intersection of the outer edge of the groove and the +X axis increases by b, and the groove width at the intersection of the inner edge of the groove and the -X axis also increases by b. (See...) Figure 9 .

[0078] Secondly, the tool axis 21 moves around a circle with the center circle and a radius of b (i.e., the trajectory circle) for one revolution. At this time, the opening widths of the inner and outer sides of the symmetrical annular groove are simultaneously increased by b, forming a groove that is consistent with... Figure 1 A groove with the same center as the center, but with a width increased by 2*b, such as... Figure 10 As shown, the groove width is a = s + 2 * b; that is, when the target groove width is a, the target groove width can be obtained without changing the grooving tool by changing the translation distance b.

[0079] It should be noted that once the cross-sectional shape and groove type are determined, the real-time groove depth h is the independent variable. The real-time groove width a can be calculated using the trigonometric functions related to the cross-sectional shape. With the help of a = s + 2 * b, the relevant function b = F(h) can be obtained, that is, the radius b of the center trajectory circle is the dependent variable.

[0080] The radius b of the central trajectory circle can be calculated from a = s + 2 * b.

[0081] S15: Control the axis to rotate around the trajectory circle while controlling the tool shaft 21 to rotate, and simultaneously control the tool shaft 21 to feed in axial steps to form a layered toolpath.

[0082] That is, combining the above Figure 8 , Figure 9 and Figure 10 The principle explains that the cutter shaft 21 travels one revolution along a circle with a radius of b centered on the central circle (i.e., the trajectory circle). During this revolution, the cutter shaft 21 maintains a high-speed rotation, simultaneously expanding the width b of the openings on both the inner and outer sides of the symmetrical annular groove, forming a shape that... Figure 1 The central groove is the same as the circle, but the groove width is increased by 2*b.

[0083] Considering the axial feed, the so-called layered toolpath, also known as the stepping toolpath, means that the annular groove is cut layer by layer along the axial direction. Each layer includes the steps of controlling the axis to move along the trajectory circle while controlling the rotation of the cutter shaft 21. For example, a rectangular annular groove with a height of 20mm is cut in 3 steps, that is, in 3 layers, to cut depths of 6mm, 7mm and 7mm respectively. Since different depths can determine different radii b of the center trajectory circle, the real-time groove width corresponding to different depths can be cut; thus, groove shapes such as trapezoidal annular grooves can be cut.

[0084] Based on the above description, after the grooving cutter cuts into the annular groove and rotates at a certain angle (such as turning around), it takes the center of the central circle as the new center and the deviation distance as the radius of the central trajectory. That is, it moves the cutter in a circle with a radius of b, for example, 360 degrees. This realizes that the opening width of the inner and outer sides of the symmetrical annular groove is simultaneously expanded by b, which can quickly widen the range of the target groove shape and improve the grooving efficiency.

[0085] Alternatively, (while controlling the axis to rotate around the trajectory circle, the cutter shaft 21 can be rotated), and the cutter shaft 21 can be continuously fed along the axial direction to form a spiral cutter path.

[0086] Specifically, if the grooving tool moves in a circular path along the tool axis 21 while also having axial feed, according to the law of motion synthesis, this path is a helical trajectory. This trajectory will produce a rectangular annular groove with a width of a = s + 2 * b and a depth equal to the helical lead. Different annular grooves can be machined by the tool axis 21 following different helical trajectories. For example, a cylindrical helical toolpath can machine a rectangular end-face annular groove; a conical helical toolpath can machine a trapezoidal end-face annular groove; and a spherical helical toolpath can machine an arc-shaped end-face annular groove, etc. The helical toolpath along the inner wall of the end-face annular groove 1 is a continuous helical trajectory (i.e., a continuous helical toolpath).

[0087] When deciding between layered toolpaths and helical toolpaths, the choice can be made based on the actual situation. For example, if the calculation of the initial helical toolpath is more complex, a layered toolpath can be used, while the calculation of the subsequent helical toolpath is simpler, so a helical toolpath can be used. The helical toolpath is continuous, with no tool entry or exit process in between. Furthermore, the entire annular groove machining only requires one tool, reducing the risk of tool failure after tool change. The choice can be made based on different actual machining scenarios.

[0088] In practical application, this embodiment obtains the cross-sectional shape of the end face annular groove 1, and determines the real-time groove width of the cutter shaft 21 during infeed based on the cross-sectional shape and the real-time groove depth of the cutter shaft 21 during infeed. Based on the real-time groove width and the width of the insert 33, the radius of the center trajectory of the cutter shaft 21 is determined. Based on the center of the center circle of the end face annular groove 1, a trajectory circle concentric with the center circle and with a radius equal to the radius of the center trajectory is determined. After determining the groove depth h, it can be applied to machining end face annular grooves 1 with different groove widths and shapes, greatly improving the utilization rate of the tool and the machining coverage of the end face annular groove 1. The symmetry center of the inner and outer edges of the insert 33 is controlled to coincide with the center circle, and the axis of the cutter shaft 21 is controlled to coincide with the center circle. The cutter shaft 21 is controlled to rotate to cut out the annular groove, the circle in the middle of the annular groove being the center circle. While controlling the axis to rotate around the trajectory circle, the cutter shaft 21 is also controlled to rotate, and after passing through the annular groove, it rotates by a certain angle (e.g., circumference). After turning, the center of the central circle of the end face annular groove 1 is used as the new center, and the deviation distance is the radius of the central trajectory. That is, the tool moves in a circle with radius b as the trajectory, for example, 360 degrees. This can quickly widen the range of the target groove shape and improve the grooving efficiency. At the same time, the tool axis 21 is controlled to feed continuously along the axial direction to form a helical toolpath, or the tool axis 21 is controlled to feed stepwise along the axial direction to form a layered toolpath. Since the machining toolpath of the layered toolpath is simple and easy to implement, the programming difficulty is small, and it can be applied to the machining of all groove shapes. However, it requires repeated tool entry and exit, and the machining efficiency is relatively low, and the tool wear is relatively fast. The helical toolpath is continuous, especially the conical helical toolpath or the spherical helical toolpath. Its programming requires complex calculations, but its toolpath is continuous without the middle of the tool entry and exit process, the cutting is stable and reliable, and the tool wear is slow. It can be achieved that only one tool is needed for the entire annular groove machining, reducing the risk of tool failure after tool change. The above different toolpaths can be selected according to different actual machining scenarios, improving the actual operability.

[0089] As an optional embodiment of the present invention, before obtaining the cross-sectional shape of the end face annular groove 1, the method further includes:

[0090] Step: Determine whether the groove type of the end face annular groove 1 is a symmetrical annular groove or an asymmetrical annular groove.

[0091] Asymmetric annular grooves are those whose cross-sectional shape cannot find a central axis, meaning their cross-sectional shape is not symmetrical about the axis. Symmetrical annular grooves are the opposite of symmetrical annular grooves, and will not be described further here.

[0092] Step: When the end face annular groove 1 is the asymmetric annular groove, the asymmetric annular groove is decomposed sequentially along the cross-sectional width direction of the asymmetric annular groove to generate multiple symmetric annular grooves.

[0093] Specifically, when the end face annular groove 1 is the asymmetric annular groove, along the cross-sectional width direction of the asymmetric annular groove, based on the cross-sectional shape, a symmetry line is found along the cross-sectional width. If it is found, it indicates that the groove type corresponding to the partial shape is a symmetric annular groove. This process continues, and the asymmetric annular groove is decomposed sequentially to generate multiple symmetric annular grooves.

[0094] Specifically, in dealing with the processing of various small and medium-sized symmetrical end face annular grooves 1, such as rectangular annular grooves (e.g. Figure 3 As shown), isosceles trapezoidal annular groove (such as...) Figure 5 As shown), U-shaped annular groove (such as) Figure 4 As shown), open U-shaped annular groove (such as...) Figure 6 As shown in the figure, this invention is particularly applicable to CNC machining methods.

[0095] Specifically, such as Figure 7 As shown, the CNC machining method in this invention can also be applied to the machining of certain specific asymmetrical ring grooves. However, this type of groove can be decomposed into several symmetrical ring grooves (U-shaped ring grooves, two-open U-shaped ring grooves). In this case, the cross-section of the asymmetrical ring groove is determined to include multiple symmetrical ring grooves (the symmetrical ring groove can be a part of a complete symmetrical ring groove, such as half, 2 / 3, etc.). Along the width direction of the cross-section of the asymmetrical ring groove, the symmetry line is found along the width of the cross-section, and the asymmetrical ring groove is decomposed sequentially. During machining, the machining of the asymmetrical ring groove can be achieved through multiple tool adjustments and multiple programming. This can broaden the coverage of groove types and improve the practical application range of grooving.

[0096] As an optional embodiment of the present invention, determining the real-time groove width of the cutter shaft 21 during tool feed based on the cross-sectional shape and the real-time groove depth of the cutter shaft 21 during tool feed includes:

[0097] Step: Determine the relationship model between the real-time groove depth and the real-time groove width based on the cross-sectional shape.

[0098] The rectangular annular groove, isosceles trapezoidal annular groove, U-shaped annular groove, etc. described above are all descriptions of the cross-sectional shape of the end face annular groove 1. Determining the cross-sectional shape is equivalent to determining the groove type. Furthermore, the cross-sectional shape of the end face annular groove 1 also includes its dimensional information. For example, the cross-sectional shape of the isosceles trapezoidal annular groove is an isosceles trapezoid, and the dimensions of its upper and lower bases, as well as its height, are given. The cross-sectional shape has been determined.

[0099] Step: Determine the real-time groove width of the tool axis during tool feed based on the relationship model and the real-time groove depth of the tool axis during tool feed.

[0100] The relational model includes:

[0101] a = k + 2h * tan(d);

[0102] Where a represents the real-time groove width, h represents the real-time groove depth, d represents the side inclination angle of the end face annular groove 1, and k represents the bottom width of the end face annular groove 1. (A typical calculation example here is...) Figure 13 (Middle trapezoidal annular groove).

[0103] When d = 0 degrees, the trapezoidal annular groove becomes a rectangular annular groove; for the circular arc annular groove, the same calculation can be performed by using the relationship between R and h.

[0104] Specifically, during the machining process of the tool shaft 21, the real-time groove depth of the tool shaft is variable. At different real-time groove depths, the tool shaft 21 feeds to different positions of the cross-sectional shape, corresponding to different real-time groove widths. The real-time groove width is the groove width that the tool shaft 21 should form when machining to different groove depths. By determining the groove depth h, it can be applied to machining end face annular grooves 1 with different groove widths and groove shapes, greatly improving the applicability of the tool.

[0105] Furthermore, in conjunction with the above embodiments, as an optional embodiment of the present invention, determining the center trajectory radius of the cutter shaft 21 based on the real-time slot width and the width of the blade 33 includes:

[0106] Step: Determine the relationship between the real-time slot width, the width of the blade 33, and the center trajectory radius, wherein the relationship includes:

[0107] a = s + 2b;

[0108] Where s represents the width of the blade 33, and b represents the radius of the center trajectory.

[0109] Based on the aforementioned fundamental principles, the tool axis 21 moves around a circle with the center circle and a radius of b (i.e., the trajectory circle) for one revolution. This simultaneously expands the width of the openings on both the inner and outer sides of the symmetrical annular groove by b, forming a shape that is consistent with... Figure 1 A groove with the same center as the center, but with a width increased by 2*b, such as... Figure 10 As shown, the groove width is a = s + 2 * b.

[0110] Step: Substitute the given relation into the relation model to generate the central trajectory radius, which satisfies the following formula:

[0111] b = k / 2 + h * tan(d) - s / 2.

[0112] Where b represents the center trajectory radius and s represents the width of the grooving tool.

[0113] Based on the aforementioned basic principles, for a groove type that can be mathematically modeled (represented by a mathematical formula), the width value a (width s of blade 33) of the groove at different depths can be calculated according to the mathematical formula. Then, according to the formula: b = (as) / 2, the radius of the center trajectory circle of the cutter shaft 21 can be obtained.

[0114] Substituting a = k + 2h * tan(d) into b = (as) / 2, we get b = k / 2 + h * tan(d) - s / 2;

[0115] Specifically: After the program starts, the machine tool computer obtains the relevant parameters of the groove type by assigning the R parameter in the program, and sets the groove depth (h) as the independent variable and the radius of the center trajectory circle (b) as the dependent variable. Through the knowledge of trigonometric functions, the relevant function b = F(h) can be obtained. That is, after the grooving tool cuts into the annular groove and rotates at a certain angle (such as turning around), the center of the center circle of the end face annular groove 1 is taken as the new center, and the deviation distance is the radius of the center trajectory. That is, the tool moves in a circle with a radius of b as the trajectory, for example, 360 degrees. This realizes that the opening width of the inner and outer sides of the symmetrical annular groove is simultaneously expanded by b. The above can quickly widen the range of the target groove type and improve the grooving efficiency.

[0116] As an optional embodiment of the present invention, the step of aligning the center of symmetry of the inner and outer edges of the blade 33 with the central circle, setting the axis coaxially with the central circle, and controlling the rotation of the blade shaft 21 to cut an annular groove includes:

[0117] Step: Adjust the distance between the center of symmetry of the inner and outer edges of the blade 33 and the axis to be equal to the radius of the central circle.

[0118] Step: Adjust the axis to coincide with the center of the central circle so that the center of symmetry of the inner and outer edges of the blade coincides with the central circle.

[0119] Specifically, the distance between the blade 33 and the axis is adjusted so that when the axis coincides with the center of the central circle, the distance between the center of symmetry of the inner and outer edges of the blade 33 and the axis is equal to the radius of the central circle.

[0120] Step: Control the rotation of the cutter shaft 21 to cut out the annular groove.

[0121] Specifically, the blade 33 is eccentrically mounted and can be adjusted in a direction away from or towards the axis. Therefore, adjusting the distance between the blade 33 and the axis, that is, the distance between the center of symmetry of the inner and outer edges of the blade 33 and the axis, equals the radius of the central circle, so that after controlling the rotation of the cutter shaft 21, the circle in the middle of the annular groove is also the central circle. For different central circles, the distance between the blade 33 and the axis can be adjusted to meet the requirements of cutting the annular groove.

[0122] like Figure 2 As shown, in an optional embodiment of the present invention, simultaneously controlling the tool shaft 21 to step feed along the axial direction includes:

[0123] S20: After each time the cutter shaft 21 is controlled to advance an axial step by a preset increment, the cutter shaft 21 is returned to the center of the central circle.

[0124] S21: Determine whether the accumulated value of the preset increment is equal to the total groove depth.

[0125] S22: If not, then based on the preset increment, control the cutter shaft 21 to continue axial step feed.

[0126] S23: If so, control the cutter shaft 21 to stop the axial step feed.

[0127] It is understandable that the tool rotates at a set speed, and then... Figure 10 The process described above completes the machining of the relevant groove depth position. After completing the machining of a single layer, the tool axis 21 quickly returns to the center of the groove's center circle. Next, relevant logical operations are performed to determine whether the cutting is complete. If complete, the loop is exited and the program ends; if not complete, the preset groove depth increment changes incrementally, jumps to the position for calculating the b value, and the loop process is executed again. Finally, the groove is machined through a layer-by-layer generating method.

[0128] Specifically, if the total groove depth is 22mm and the cutting groove height is 4mm, then at least 6 layers (22 / 4 results in more than 5) should be used for cutting, and the preset increment should be less than or equal to 4mm. It's important to understand that since different groove depths determine different center trajectory circle radii b, real-time groove widths corresponding to different depths can be cut; thus, trapezoidal annular grooves and other groove types can be cut; and the relevant function b = F(h) can be obtained.

[0129] Although the layered toolpath machining path implemented above requires repeated tool advances and retractions, resulting in relatively low machining efficiency, it is simple to implement, has low programming difficulty, and can be applied to the machining of all groove types.

[0130] As an optional embodiment of the present invention, controlling the axis to rotate around the trajectory circle while simultaneously controlling the cutter shaft 21 to rotate, and simultaneously controlling the cutter shaft 21 to continuously feed axially to form a helical toolpath, or simultaneously controlling the cutter shaft 21 to step feed axially to form a layered toolpath includes:

[0131] Step: Determine the center point coordinates of the cutter shaft 21 based on the initial center position of the cutter shaft and the helical parameters of the helical toolpath. Multiple center point coordinates constitute the helical toolpath. The helical parameters include the direction of rotation, pitch, and incremental angle. The helical toolpath is the running path of the shaft center.

[0132] Specifically, the initial center position of the tool axis 21 is obtained, which is the starting point of the helical toolpath. The helical parameters of the helical toolpath are obtained, including the direction of rotation, pitch, and incremental angle. The incremental angle is obtained, and the coordinates of the center point of the tool axis 21 are determined according to the helical parameters using the incremental angle as the independent variable. The coordinates of the center point are the dependent variable corresponding to the independent variable. Multiple coordinates of the center point constitute the helical toolpath.

[0133] Correspondingly, the helical toolpath includes at least one of cylindrical helical toolpath, conical helical toolpath, and spherical helical toolpath.

[0134] The following description, in conjunction with detailed embodiments, provides further details.

[0135] In this embodiment, when several helical toolpaths exist, the cutting method of "continuous helical trajectory machining using the differential method of CNC macro program" is adopted. As can be seen from the aforementioned basic principle: when the grooving tool rotates at high speed, the tool shaft 21 follows a circular trajectory with radius b of the central trajectory circle, resulting in a groove with a width of a = s + 2 * b. If there is also axial feed while the tool shaft 21 is moving in a circular path, according to the law of motion synthesis, this path is a helical trajectory, and a rectangular annular groove with a width of a = s + 2 * b and a groove depth equal to the helical lead will be obtained under this trajectory.

[0136] Therefore, it can be concluded that different annular grooves can be machined by the center of the cutter shaft 21 following different helical trajectories. A cylindrical helical cutter path can machine rectangular end-face annular grooves; a conical helical cutter path can machine trapezoidal end-face annular grooves; and a spherical helical cutter path can machine arc-shaped end-face annular grooves. Figure 4 , Figure 6 and Figure 7 The rounded corners at the bottom of the groove can be machined using a spherical helical toolpath.

[0137] like Figure 13 As shown, this section will take the "numerical control macro program differential method continuous spiral trajectory machining" of the trapezoidal end face annular groove 1 as an example to explain in detail the process of generating the conical spiral toolpath.

[0138] The bottom width of the trapezoidal thread in the figure is k (note: k ≥ s must be satisfied, that is, the bottom width of the groove is not less than the width of the cutting tool), the depth of the groove is h, and the angle of the side is d°.

[0139] Depend on Figure 13 It can be seen that b = k / 2 + h * tan(d) - s / 2 (where s is the width of the grooving insert 33). Assuming the end face annular groove 1 is an annular groove within G17 (the XY plane on a certain machine tool), and the starting point height of the trajectory is H (H > h), the starting point of the conical helix is ​​located on the +X axis (with right and upward directions as the +X and +Y axes respectively), the orientation, the helical trajectory is a left-hand thread, the pitch is e, and the incremental angle Δt = n0.01°; the incremental angle is the angle that changes each time relative to 360 degrees, that is, it increases by 0.01° each time, n = 1, 2, 3...; the initial coordinates of the center position of the tool axis 21 at the starting point can be obtained as:

[0140]

[0141] Setting the incremental angle Δt as the independent variable and the coordinates of the center point of the tool axis 21 as the dependent variable, the next target position of the tool can be calculated using the following formula. A loop mode can be used to calculate the tool travel coordinates. Finally, multiple curve segments are connected to form a continuous conical thread curve. The calculation formula is as follows:

[0142]

[0143] It is necessary to explain that when d = 0, that is, when the trapezoidal end face annular groove 1 becomes a rectangular annular groove, the above formula is still applicable to the specific calculation process.

[0144] like Figure 14 As shown, the process of generating the spherical helical toolpath will be described below.

[0145] The bottom width of the groove in the figure is k (note: k ≥ s must be satisfied, that is, the bottom width of the groove is not less than the width of the blade), and the depth of the groove is h (h = R).

[0146] At the end face of the groove, b = k / 2 + Rs / 2 (where s is the width of the grooving insert 33). Similarly, the starting point of the spherical helix is ​​set to the +X axis. To ensure the surface quality of each part of the curved surface during spherical cutting, the pitch of the spherical helix toolpath is changed to an increment of angle d° per revolution, Δd. The starting angle of the helix is ​​D. Therefore, the initial coordinates of the center of the tool axis 21 at the starting point are:

[0147]

[0148] Setting the incremental angle Δt as the independent variable, the helical trajectory as a left-hand thread, the incremental angle Δt = Δt = n0.01°, the initial angle as T, and the coordinates of the center point of the tool axis 21 as the dependent variable, the next target position of the tool can be calculated using the following formula. A loop mode can be used to calculate the tool travel coordinates. Finally, multiple curve segments are connected to form a continuous spherical helical curve, the calculation formula of which is:

[0149]

[0150] The following is an example of machining a trapezoidal annular groove using a Siemens 840D machine tool system. The program code can be written as follows:

[0151] N05 G00 G54 G64 G17 G90 F100 S300 M Tool Body 3

[0152] R1 = k; width of the groove bottom

[0153] R2 = H; Starting height

[0154] R3 = d; Trapezoid angle

[0155] R4 = e; pitch of tapered thread

[0156] R5 = 0.01; Δt, incremental angle; the smaller its absolute value, the better the fit between the trajectory and the tapered thread;

[0157] R6 = s; width of blade 33

[0158] R7 = 0; Starting angle

[0159] R8 = R4 / (360 / R5); Increase depth

[0160] R9 = R1 / 2 + R2 * TAN(R3) - R6 / 2

[0161] N10 G00 X=R9 Y0

[0162] N15 Z=R2

[0163] Start:

[0164] N20 R2=R2-R8

[0165] N25 IF R2<=0GOTOF AA

[0166] R7 = R7 + R5

[0167] R10 = R1 / 2 + R2 * TAN(R3) - R6 / 2

[0168] R11=R10*COS(R7)R12=R10*SIN(R7)

[0169] N30 G01 X=R11 Y=R12 Z=R2

[0170] N35 GOTOB Start

[0171] AA:G00 X0 Y0

[0172] N40 G01 Z0

[0173] N45 G01 X=R1 / 2-R6 / 2Y0

[0174] N50 G03 I=-(R1 / 2-R6 / 2)J0

[0175] N55 G00 Z200; Lifting knife

[0176] N60 M30.

[0177] like Figure 11 and Figure 12 As shown, a grooving tool applied to the CNC machining method described in the above embodiments further includes:

[0178] The tool holder 2 includes a tool seat 22 that is fixedly connected to the tool shaft 21 and the tool holder 22.

[0179] The blade body 3 is mounted on the blade holder 22. The blade body 3 includes a first blade head 31 and a second blade head 32. The first blade head 31 and the second blade head 32 are set at an angle to each other. The blade 33 is mounted on the second blade head 32.

[0180] Specifically, the tool holder 22 is installed at the bottom of the tool shaft 21. The tool holder 22 has a mounting groove for the first cutting head 31 of the tool body 3 to be installed, and can be fastened by clamping bolts. The main part of the grooving tool is the tool body 3. When the groove depth of the end face annular groove 1 is small, suitable cutting tools can usually be purchased on the market. When the groove depth is large, a 0° end face annular groove 1 cutting tool with a larger machining depth is purchased and modified to transform it into an end face grooving tool with an angle (that is, the first cutting head 31 and the second cutting head 32 are set at an angle). The following uses an angle of 90° as an example to illustrate the tool modification process, as follows: First, the cutting head (cutting square) is sawn off to obtain the first cutting head 31 and the second cutting head 32. Then, the second cutting head 32 is welded to the first cutting head 31 along the 90° direction. The welded second cutting head 32 may have problems such as deformation. The cutting square should be re-machined on a machine tool to ensure the centering of the tool. If there is interference at the tail of the grooving tool, a grinding wheel should be used to remove part of the cutting tail. The above grooving tool can be converted into a nested end mill, which can simultaneously machine the side and bottom of the end face annular groove 11, making the subsequent cutting process simpler.

[0181] After the tool is modified, it needs to be adjusted. The tool adjustment process is described in detail below: In the absence of a tool setter and when the precision requirement of the annular groove 1 to be machined is not high, the tool holder 2 of the entire tool can be installed on the spindle of the machine tool. Find a piece of test material, first pre-adjust the position of the groove tool according to the reference axis (that is, adjust the installation position of the first cutter head 31 on the tool holder 22), then make a test cut on the test material, measure the diameter of the center circle of the rotary groove, and adjust the tool position again according to the measurement data. After the adjustment is appropriate, make another test cut on the test material and measure. Repeat this process. Usually, 2-3 times are enough to adjust the diameter of the rotary groove of the tool to be the same as the center diameter of the annular groove 1 to be machined, that is, the diameter of the rotary groove is twice the base radius.

[0182] The entire process can be summarized as "rough adjustment - trial cut - measurement - adjustment - trial cut - measurement".

[0183] During the "digital model establishment" process, the process of drawing a simplified end face annular groove 1 model and a tool model using SIEMENS NX CAD / CAM software has been completed. After the CNC program code is written, it is necessary to perform simulation using VERICUT software to ensure program accuracy and avoid problems such as overcutting and collisions.

[0184] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided by this invention can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0185] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

[0186] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A CNC machining method for an end face annular groove, applied to the machining of an end face annular groove (1) by a grooving tool, characterized in that, The grooving tool includes a cutter shaft (21) and an insert (33) eccentrically mounted relative to the cutter shaft (21). The CNC machining method for the end face annular groove includes: Obtain the cross-sectional shape of the end face annular groove (1); Based on the cross-sectional shape and the real-time groove depth of the cutter shaft (21) during the feed, the real-time groove width of the cutter shaft (21) during the feed is determined; The center trajectory radius of the cutter shaft (21) is determined based on the real-time slot width and the width of the blade (33); Based on the center circle of the end face annular groove (1), determine a trajectory circle that is concentric with the center circle and has a radius equal to the radius of the center trajectory; The center of symmetry of the inner and outer edges of the blade (33) is aligned with the center circle, the axis is set coaxially with the center circle, and the blade shaft (21) is controlled to rotate to cut out an annular groove. While controlling the axis to rotate around the trajectory circle, the cutter shaft (21) is also controlled to rotate, and the cutter shaft (21) is controlled to feed continuously along the axial direction to form a spiral toolpath, or the cutter shaft (21) is controlled to feed stepwise along the axial direction to form a layered toolpath.

2. The CNC machining method for the end face annular groove according to claim 1, characterized in that, Before obtaining the cross-sectional shape of the end face annular groove (1), the method further includes: Determine whether the groove type of the end face annular groove (1) is a symmetrical annular groove or an asymmetrical annular groove; When the end face annular groove (1) is the asymmetric annular groove, the asymmetric annular groove is decomposed sequentially along the cross-sectional width direction of the asymmetric annular groove to generate multiple symmetric annular grooves.

3. The CNC machining method for the end face annular groove according to claim 2, characterized in that, The symmetrical annular groove includes at least one of a rectangular annular groove, an isosceles trapezoidal annular groove, and a U-shaped annular groove.

4. The CNC machining method for the end face annular groove according to claim 1, characterized in that, The step of determining the real-time groove width of the cutter shaft (21) during the infeed based on the cross-sectional shape and the real-time groove depth of the cutter shaft (21) during the infeed includes: Based on the cross-sectional shape, determine the relationship model between the real-time groove depth and the real-time groove width; Based on the relationship model and the real-time groove depth of the cutter shaft (21) during the feed, the real-time groove width of the cutter shaft (21) during the feed is determined; The relational model includes: a = k + 2h * tan(d); Where a represents the real-time groove width, h represents the real-time groove depth, d represents the side inclination angle of the end face annular groove (1), and k represents the bottom width of the end face annular groove (1).

5. The CNC machining method for the end face annular groove according to claim 4, characterized in that, The step of determining the center trajectory radius of the cutter shaft (21) based on the real-time slot width and the blade width includes: Determine the relationship between the real-time slot width, the width of the blade (33), and the center trajectory radius, the relationship including: a = s + 2b; Where s represents the width of the blade (33) and b represents the radius of the center trajectory; Substituting the given relational expression into the relational model generates the central trajectory radius, which satisfies the following formula: b = k / 2 + h * tan(d) - s / 2.

6. The CNC machining method for the end face annular groove according to claim 1, characterized in that, The step of aligning the center of symmetry of the inner and outer edges of the blade (33) with the central circle, setting the axis coaxial with the central circle, and controlling the rotation of the blade shaft (21) to cut an annular groove includes: Adjust the distance between the center of symmetry of the inner and outer edges of the blade (33) and the axis to be equal to the radius of the central circle; The axis is set coaxially with the center circle so that the center of symmetry of the inner and outer edges of the blade (33) coincides with the center circle; Control the rotation of the cutter shaft (21) to cut out the annular groove.

7. The CNC machining method for the end face annular groove according to any one of claims 1-6, characterized in that, The control of the axis center to rotate around the trajectory circle while controlling the tool shaft (21) to rotate, and the control of the tool shaft (21) to continuously feed axially to form a helical toolpath, or the control of the tool shaft (21) to step feed axially to form a layered toolpath, includes: After each time the cutter shaft (21) is controlled to advance a preset increment along the axial direction, the cutter shaft (21) is returned to the center of the central circle; Determine whether the accumulated value of the preset increment is equal to the total groove depth; If not, then based on the preset increment, control the cutter shaft (21) to continue axial step-feeding. ； The layered toolpaths are multiple and each corresponds one-to-one with one of the multiple preset increments; If so, control the cutter shaft (21) to stop the axial step feed.

8. The CNC machining method for the end face annular groove according to any one of claims 1-6, characterized in that, The spiral toolpath includes at least one of cylindrical spiral toolpath, conical spiral toolpath, and spherical spiral toolpath.

9. The CNC machining method for the end face annular groove according to claim 8, characterized in that, The control of the axis center to rotate around the trajectory circle while controlling the tool shaft (21) to rotate, and the control of the tool shaft (21) to continuously feed axially to form a helical toolpath, or the control of the tool shaft (21) to step feed axially to form a layered toolpath, includes: Based on the initial center position of the cutter shaft (21) and the helical parameters of the helical toolpath, the center point coordinates of the cutter shaft (21) are determined. Multiple center point coordinates constitute the helical toolpath. The helical parameters include the direction of rotation, pitch, and incremental angle. The helical toolpath is the running path of the shaft.

10. The CNC machining method for the end face annular groove according to any one of claims 1-6, characterized in that, The grooving tool further includes: The tool holder (2) includes a tool seat (22) fixedly connected to the tool shaft (21); The blade body (3) is mounted on the blade holder (22). The blade body (3) includes a first blade head (31) and a second blade head (32). The first blade head (31) and the second blade head (32) are set at an angle to each other. The blade (33) is mounted on the second blade head (32).

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