Method for grinding a flank face of a helical drill tip and a numerical control device

Abstract

The application relates to a flank surface grinding method of a helical drill point and numerical control equipment. The method comprises the following steps: obtaining each curve point on a three-dimensional helical curve; wherein the radial curvature of the three-dimensional helical curve decreases from the first curve point and extends in the opposite direction of the drill bit axis; determining each circumferential point on the outer cylindrical surface of the drill bit corresponding to each curve point; wherein the inclination of the trajectory line segment between the curve point and the corresponding circumferential point increases relative to the drill bit axis from the first curve point; the straight line where the trajectory line segment is located intersects with the drill bit axis; determining the grinding posture of the grinding wheel when the conical surface generatrix of the grinding wheel is parallel to the trajectory line segment; and controlling the grinding wheel to perform flank surface grinding according to the grinding posture and the trajectory line segment. The method can improve the flank surface grinding efficiency of the helical drill point.

Description

Technical Field

[0001] This application relates to the field of machining technology, and in particular to a method and CNC equipment for grinding the back face of a helical drill tip. Background Technology

[0002] With the development of machining technology, helical drill tips with good centering and stable entry have emerged. The flank face of the helical drill tip directly affects its drilling performance, lifespan, and machining quality. Therefore, flank face grinding is crucial in the manufacturing process of helical drill tips.

[0003] In traditional techniques, the grinding of the flank face of a helical drill tip relies primarily on the operator's experience and is done manually on a tool grinder. However, this method is very limited and cannot avoid the problem of low grinding efficiency. Summary of the Invention

[0004] Therefore, it is necessary to provide a method and CNC equipment for grinding the back face of a helical drill tip that can improve grinding efficiency, in order to address the above-mentioned technical problems.

[0005] In a first aspect, this application provides a method for grinding the back face of a helical drill tip, comprising:

[0006] Obtain each curve point on the three-dimensional spiral curve; wherein, starting from the first curve point, the radial curvature of the three-dimensional spiral curve decreases and extends in the opposite direction to the drill bit axis;

[0007] Determine the circumferential points on the outer cylindrical surface of the drill bit that correspond to each of the curve points; wherein, starting from the first curve point, the inclination of the trajectory line segment between the curve point and the corresponding circumferential point relative to the drill bit axis increases; the straight line containing the trajectory line segment intersects the drill bit axis;

[0008] Determine the grinding posture of the grinding wheel when the generatrix of the conical surface of the grinding wheel is parallel to the trajectory line segment;

[0009] The grinding wheel is controlled to perform back face grinding based on the grinding posture and the trajectory line segment.

[0010] Secondly, this application also provides a numerical control device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method.

[0011] Thirdly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the above-described method.

[0012] Fourthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps in the above-described method.

[0013] The aforementioned grinding method, CNC equipment, storage medium, and computer program product for the flank face of a helical drill tip, in order to ensure that the chip channel of the helical drill tip has an expanding tendency in the chip removal direction and to avoid the risk of chip clogging or accumulation, designs its flank face as a helical surface structure that rotates around the drill bit axis and gradually contracts in the opposite direction of the drill bit axis. This is achieved by obtaining each curve point on a three-dimensional helical curve; where, starting from the first curve point, the radial curvature of the three-dimensional helical curve decreases and extends in the opposite direction of the drill bit axis. Circumferential points on the outer cylindrical surface of the drill bit, corresponding to each curve point, are determined; where, starting from the first curve point, the inclination of the trajectory line segment between the curve point and the corresponding circumferential point relative to the drill bit axis increases; the straight line containing the trajectory line segment intersects the drill bit axis. The trajectory line segments between different curve points and their corresponding circumferential points collectively constitute a helical surface structure that rotates around the drill bit axis and gradually contracts in the opposite direction of the drill bit axis. Furthermore, the grinding posture of the grinding wheel is determined when its conical generatrix is ​​parallel to the trajectory segment. Under this grinding posture, when the grinding point on the conical generatrix passes through the trajectory segment, the grinding wheel can grind the trajectory segment on the helical drill tip. Thus, the grinding wheel is controlled to perform flank grinding based on the grinding posture and the trajectory segment. The trajectory segment ground by the grinding wheel on the helical drill tip together constitutes a helical surface structure that rotates in the opposite direction and gradually contracts along the drill bit's axis, forming the flank. Compared to manual grinding on a tool grinder, this significantly improves the flank grinding efficiency of the helical drill tip. Attached Figure Description

[0014] Figure 1 This is a schematic flowchart illustrating a method for grinding the back face of a helical drill tip, as provided in an embodiment of this application.

[0015] Figure 2 This is a schematic diagram of a grinding wheel provided in an embodiment of this application.

[0016] Figure 3A This is a schematic diagram of the back face in a workpiece coordinate system provided in an embodiment of this application.

[0017] Figure 3B This is a schematic diagram of an Archimedean spiral in a workpiece coordinate system provided in an embodiment of this application.

[0018] Figure 4A This is a schematic diagram of the starting tilt angle in a reference coordinate system corresponding to the starting central angle provided in an embodiment of this application.

[0019] Figure 4BThis is a schematic diagram of the ending tilt angle in a reference coordinate system corresponding to the central angle of the endpoint, provided in an embodiment of this application.

[0020] Figure 4C This is a schematic diagram of the initial tilt angle in a reference coordinate system corresponding to the central angle of the endpoint, provided in an embodiment of this application.

[0021] Figure 5 This application provides an embodiment of a swing angle in a reference coordinate system corresponding to a reference central angle.

[0022] Figure 6 This is a schematic diagram of the intermediate radial direction in a reference coordinate system corresponding to a reference central angle, provided in an embodiment of this application.

[0023] Figure 7 This is a schematic diagram of the grinding radial direction in a reference coordinate system corresponding to a reference central angle, provided in an embodiment of this application.

[0024] Figure 8 This is a schematic diagram of another grinding wheel provided in an embodiment of this application.

[0025] Figure 9A This is a schematic diagram of the grinding position of a grinding wheel provided in an embodiment of this application.

[0026] Figure 9B This is a schematic diagram illustrating the relative positional relationship between the center of the second end face and a curve point when the grinding wheel is in the grinding position, as provided in an embodiment of this application.

[0027] Figure 10 This is a schematic diagram of a rake face parameter provided in an embodiment of this application.

[0028] Figure 11 This is a schematic diagram of the simulation results of the flank face provided in an embodiment of this application.

[0029] Figure 12 This is an internal structural diagram of a CNC device provided in an embodiment of this application. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0031] In one exemplary embodiment, such as Figure 1 As shown, a flowchart of a method for grinding the back face of a helical drill tip is provided. Taking the application of this method to a CNC machine as an example, the method includes the following steps 102 to 108.

[0032] Step 102: Obtain each curve point on the three-dimensional spiral curve; wherein, starting from the first curve point, the radial curvature of the three-dimensional spiral curve decreases and extends in the opposite direction to the drill bit axis.

[0033] In this context, radial curvature refers to the projected curvature of the three-dimensional helical curve on a projection plane perpendicular to the drill bit axis. It can be understood that the three-dimensional helical curve has a radial curvature at each curve point, and the radial curvature at each curve point is smaller than the radial curvature at the previous curve point. The drill bit axis refers to the direction along the drill bit axis towards the drill tip. The opposite direction of the drill bit axis refers to the direction along the drill bit axis towards the drill shank.

[0034] For example, the CNC equipment can acquire the flank face parameters. The flank face parameters may include helical curve parameters. Based on the helical curve parameters and the helical curve model, each curve point on the three-dimensional helical curve is determined. The helical curve model is used to describe the mathematical relationship between the three-dimensional helical curve and the helical curve parameters. It is understood that this embodiment does not specifically limit the mathematical modeling method of the helical curve model, as long as it satisfies the characteristic that the radial curvature of the three-dimensional helical curve decreases from the first curve point and extends in the opposite direction to the drill bit axis.

[0035] In some embodiments, the CNC equipment can acquire each curve point on the input three-dimensional spiral curve.

[0036] In some embodiments, the CNC equipment may be, but is not limited to, a five-axis CNC machine.

[0037] Step 104: Determine the circumferential points on the outer cylindrical surface of the drill bit that correspond to each curve point; wherein, starting from the first curve point, the inclination of the trajectory line segment between the curve point and the corresponding circumferential point relative to the drill bit axis increases; the straight line containing the trajectory line segment intersects the drill bit axis.

[0038] For example, a CNC machine can determine the circumferential intersection line corresponding to a three-dimensional helical curve from the outer cylindrical surface of the drill bit. The circumferential intersection line is the intersection line between the flank face and the outer cylindrical surface of the drill bit. A circumferential point corresponding to a curve point is determined from the circumferential intersection line. In some embodiments, for each curve point, a corresponding reference inclination angle is determined. The reference inclination angle reflects the inclination of the trajectory segment containing the curve point relative to the drill bit axis. It can be understood that a trajectory segment passing through a curve point, intersecting the drill bit axis, and whose inclination relative to the drill bit axis matches the reference inclination angle, will intersect the outer cylindrical surface of the drill bit at the circumferential point corresponding to that curve point. Therefore, the CNC machine can determine the circumferential point corresponding to the curve point from the circumferential intersection line based on the reference inclination angle.

[0039] In some embodiments, the CNC equipment can acquire the circumferential points on the outer cylindrical surface of the drill bit that correspond to each curve point.

[0040] Step 106: Determine the grinding posture of the grinding wheel when the generatrix of the conical surface of the grinding wheel is parallel to the trajectory line segment.

[0041] Among them, the generatrix of the conical surface is one of the generatrixes of the grinding wheel's conical surface. The radial direction of the grinding wheel corresponding to the generatrix of the conical surface is used to characterize the direction of each grinding point on that generatrix of the conical surface relative to the axis of the grinding wheel. It can be understood that none of the generatrixes of the grinding wheel's conical surface are parallel; there will only be one generatrix of the conical surface that is parallel to the trajectory line segment.

[0042] In some embodiments, such as Figure 2 The diagram shown illustrates the grinding wheel. The grinding wheel thickness H... g This is the distance between the first and second end faces. Grinding wheel cone angle μ g It is the angle between the generatrix of the grinding wheel's conical surface and the first end face. Grinding wheel radius R g This is the distance from the outer edge of the grinding wheel to its axis. The first fillet radius r1 is the radius of the circle containing the first fillet. The second fillet radius r2 is the radius of the circle containing the second fillet. The grinding wheel conical surface is the conical surface on the grinding wheel located between the first and second fillets. The generatrix of the conical surface is the generatrix of the grinding wheel conical surface. The grinding wheel conical surface can be considered as the conical surface formed by rotating the generatrix of the conical surface around the grinding wheel axis.

[0043] It can be understood that a grinding wheel includes a first end face, a second end face, a conical surface, a first fillet, and a second fillet. The first fillet is the fillet between the first end face and the conical surface. The second fillet is the fillet between the second end face and the conical surface. The diameter of the first end face is larger than that of the second end face.

[0044] In some embodiments, the grinding posture includes a grinding axial direction and a grinding radial direction. The grinding axial direction is used to characterize the axial direction of the grinding wheel when the generatrix of the conical surface of the grinding wheel is parallel to the trajectory line segment. The grinding radial direction is used to characterize the radial direction of the grinding wheel corresponding to the generatrix of the conical surface. It can be understood that the grinding wheel is in a grinding posture when the axial direction of the grinding wheel is the grinding axial direction and the radial direction of the grinding wheel corresponding to the generatrix of the conical surface parallel to the trajectory line segment is the grinding radial direction.

[0045] CNC equipment can determine the grinding axis of the grinding wheel when the generatrix of the grinding wheel's conical surface is parallel to the trajectory line segment. A reference normal perpendicular to the drill bit axis and the trajectory line segment is determined. Based on the initial radial direction perpendicular to the reference normal and the grinding axis, the grinding radial direction is determined.

[0046] In some embodiments, to ensure that the ground structure matches the structural requirements of the helical drill tip when the grinding point on the generatrix of the grinding wheel in the grinding posture passes through the trajectory segment, while minimizing the risk of grinding wheel interference, attitude constraint conditions can be adaptively set to constrain the radial direction of the grinding wheel corresponding to the generatrix of the conical surface. The CNC equipment can determine the grinding axis of the grinding wheel when the generatrix of the grinding wheel is parallel to the trajectory segment, and the grinding radial direction that satisfies the attitude constraint conditions.

[0047] In some embodiments, the attitude constraint can be that the grinding radial direction is parallel to the reference plane containing the drill bit axis and the trajectory line segment. The reference normal is the normal to the reference plane. Specifically, the CNC machine can use an initial radial direction perpendicular to both the reference normal and the grinding axis as the grinding radial direction.

[0048] In some embodiments, the flank parameters may include at least one of a clearance angle or a chip flute angle. The attitude constraint may be, but is not limited to, matching the inclination of the grinding radial direction relative to the reference plane with at least one of the clearance angle or the chip flute angle. Specifically, the CNC machine may determine an initial radial direction perpendicular to the reference normal and the grinding axis. A grinding radial direction satisfying the attitude constraint is determined based on the initial radial direction and at least one of the clearance angle or the chip flute angle.

[0049] Step 108: Control the grinding wheel to perform back face grinding according to the grinding posture and trajectory line segment.

[0050] For example, the trajectory segment is used to characterize the trajectory of the grinding point on the generatrix of the conical surface of the grinding wheel. The CNC equipment can control the movement of the grinding wheel so that the grinding point on the generatrix of the conical surface of the grinding wheel in the grinding posture passes through the trajectory segment, so as to realize the back face grinding of the helical drill tip.

[0051] In the aforementioned method for grinding the flank face of a helical drill tip, to ensure that the chip channel of the helical drill tip tends to expand in the chip removal direction and to avoid the risk of chip clogging or accumulation, its flank face is designed as a helical surface structure that rotates around the drill bit axis and gradually contracts in the opposite direction of the drill bit axis. This is achieved by obtaining various curve points on a three-dimensional helical curve; where, starting from the first curve point, the radial curvature of the three-dimensional helical curve decreases and extends in the opposite direction of the drill bit axis. Circumferential points on the outer cylindrical surface of the drill bit, corresponding to each curve point, are determined; where, starting from the first curve point, the inclination of the trajectory line segment between the curve point and the corresponding circumferential point relative to the drill bit axis increases; the straight line containing the trajectory line segment intersects the drill bit axis. The trajectory line segments between different curve points and their corresponding circumferential points collectively constitute a helical surface structure that rotates around the drill bit axis and gradually contracts in the opposite direction of the drill bit axis. Furthermore, the grinding posture of the grinding wheel is determined when its conical generatrix is ​​parallel to the trajectory segment. Under this grinding posture, when the grinding point on the conical generatrix passes through the trajectory segment, the grinding wheel can grind the trajectory segment on the helical drill tip. Thus, the grinding wheel is controlled to perform flank grinding based on the grinding posture and the trajectory segment. The trajectory segment ground by the grinding wheel on the helical drill tip together constitutes a helical surface structure that rotates in the opposite direction and gradually contracts along the drill bit's axis, forming the flank. Compared to manual grinding on a tool grinder, this significantly improves the flank grinding efficiency of the helical drill tip.

[0052] In some embodiments, the projection of the three-dimensional helical curve onto a projection plane perpendicular to the drill bit axis is an Archimedean spiral; the pole of the Archimedean spiral is located on the drill bit axis; the inclination angle of the line connecting the pole and the curve point relative to the drill bit axis is related to the drill tip angle of the helical surface; obtaining each curve point on the three-dimensional helical curve includes: obtaining the spiral start parameter, the spiral end parameter, and the drill tip angle; determining the Archimedean spiral based on the spiral start parameter and the spiral end parameter; and determining each curve point on the three-dimensional helical curve according to the Archimedean spiral and the drill tip angle.

[0053] For example, such as Figure 3A The diagram shown illustrates the flank face in the workpiece coordinate system. The flank face includes a three-dimensional helical curve P. s P e Intersection with the circle Q s Q e The spiral surface structure between the points is decomposed into trajectory segments P and Q. The curve point P of each trajectory segment lies on the three-dimensional spiral surface, and the circumferential point Q of the trajectory segment lies on the circumferential intersection line. The workpiece coordinate system O... w -X w Y w Z w In the middle, O w Located at the first curve point P s and the corresponding circumferential point Q s The trajectory line segment P between s Q s The intersection with the drill bit axis, Z w The axis is located on the drill bit axis and its direction is consistent with the drill bit axis. X w The axis is the polar axis of the Archimedean spiral, X w Axis, Y w Axis and Z w The axes conform to the rules of the right-hand coordinate system.

[0054] The projection plane can be X w O w Y w .like Figure 3B The diagram shows a schematic of an Archimedean spiral in the workpiece coordinate system. The flank parameters can include the spiral start parameter, the spiral end parameter, the drill radius R, and the drill tip angle. The spiral start parameter includes the starting central angle θ. s and the starting edge distance coefficient Y f The starting central angle characterizes the angle of inclination of the line connecting the starting point and the pole of the Archimedean spiral relative to the polar axis of the spiral. The starting distance coefficient characterizes the ratio of the starting polar diameter L1 between the starting point and the pole of the Archimedean spiral to the drill bit diameter. The spiral endpoint parameters include the angular deviation L and the endpoint distance coefficient S. fThe difference between the starting central angle and the angle deviation is the ending central angle θ. e The terminal central angle is used to characterize the angle of inclination of the line connecting the terminal point and the pole of the Archimedean spiral relative to the polar axis. The terminal distance coefficient is used to characterize the ratio of the terminal polar diameter L2 between the terminal point and the pole of the Archimedean spiral to the drill bit diameter.

[0055] The CNC equipment can determine the starting point extreme diameter based on the starting point edge distance coefficient and the drill bit radius. Specifically, the CNC equipment can calculate the starting point extreme diameter using formula (1).

[0056] L1 = 2·R·Y f (1).

[0057] Where L1 is the starting extreme diameter. R is the drill bit radius. Y f This is the starting edge distance coefficient.

[0058] The CNC equipment can determine the endpoint extreme diameter based on the endpoint distance coefficient and the drill bit radius. Specifically, the CNC equipment can calculate the endpoint extreme diameter using formula (2).

[0059] L2=-2·R·S f (2).

[0060] Where L1 is the endpoint polar diameter. R is the drill bit radius. S f This is the endpoint distance coefficient. It can be understood that the polar radius of a point on the Archimedean spiral can be negative; a negative polar radius indicates that the point is at the polar angle. The opposite direction.

[0061] The CNC equipment can determine the starting polar angle and the ending polar angle based on the starting central angle and the ending central angle. The helical coefficient is determined based on the starting polar diameter, the ending polar diameter, the starting polar angle, and the ending polar angle. The helical offset is determined based on the starting polar diameter, the starting polar angle, and the helical coefficient. Specifically, the CNC equipment can calculate the helical coefficient and the helical offset using formula (3).

[0062]

[0063] Where a is the helical coefficient, L1 is the starting radius, and L2 is the ending radius. θ is the starting polar angle. s The central angle is the starting point. θ is the polar angle at the endpoint. e denoted as the central angle at the endpoint. b represents the spiral offset.

[0064] CNC equipment can determine the Archimedean spiral based on the spiral coefficient, spiral offset, and drill tip angle. Specifically, CNC equipment can determine the Archimedean spiral using formula (4).

[0065]

[0066] in, It is the extreme radius of a point on the Archimedean spiral. θ is the polar angle at a point on the Archimedean spiral. a is the spiral coefficient. b is the spiral offset. s θ is the central angle at the starting point. e The central angle of the endpoint.

[0067] The CNC equipment can determine the three-dimensional helical curve in the workpiece coordinate system based on the Archimedean spiral and the drill tip angle. Specifically, the helical curve model can include formula (5). The CNC equipment can use formula (5) to determine the coordinates of each curve point corresponding to the reference central angle in the workpiece coordinate system from the three-dimensional helical curve in the workpiece coordinate system based on the Archimedean spiral and the drill tip angle.

[0068]

[0069] Where P is the coordinate of a point on the three-dimensional helical curve in the workpiece coordinate system. p For P in X w The coordinate values ​​on the axis. y p For P in Y w The coordinate values ​​on the axis. p For P in Z w The coordinate values ​​on the axis. Let θ be the polar angle of the projection point of P onto the Archimedean spiral. a is the spiral coefficient. b is the spiral offset. s θ is the central angle at the starting point. e ψ is the central angle at the endpoint. ψ is the drill tip angle.

[0070] It is understandable that the first curve point P s and the last curve point P e The coordinates in the workpiece coordinate system are as follows:

[0071]

[0072] In some embodiments, the helical curve model may include formulas (1) to (5). The helical curve parameters may include drill bit radius, drill tip angle, starting center angle, starting edge distance coefficient, ending center angle, and ending edge distance coefficient.

[0073] In some embodiments, the CNC equipment can use formula (5) to determine the coordinates of the curve points on the three-dimensional helical curve in the workpiece coordinate system based on the reference central angle, helix coefficient, helix offset, drill radius and drill tip angle.

[0074] In this embodiment, the projection of the three-dimensional helical curve onto a projection plane perpendicular to the drill bit axis is an Archimedean spiral; the pole of the Archimedean spiral is located on the drill bit axis; the inclination angle of the line connecting the pole and the curve point relative to the drill bit axis is related to the drill tip angle of the helical surface; by obtaining the spiral start parameter, spiral end parameter, and drill tip angle; the Archimedean spiral is determined based on the spiral start parameter and spiral end parameter; and then, based on the Archimedean spiral and the drill tip angle, each curve point on the three-dimensional helical curve can be automatically determined, which is more convenient and efficient than manually marking each curve point on the three-dimensional helical curve.

[0075] In some embodiments, the inclination of the line connecting the pole and the curve point relative to the drill bit axis is related to the drill tip angle and the clearance angle; determining each curve point on the three-dimensional spiral curve based on the Archimedean spiral and the drill tip angle includes: determining each curve point on the three-dimensional spiral curve based on the Archimedean spiral, the drill tip angle, and the clearance angle.

[0076] For example, depending on the structural requirements of the helical drill tip, it is possible to adaptively choose whether to introduce a clearance angle. The CNC equipment can determine each curve point on the three-dimensional helical curve based on the Archimedean spiral and the drill tip angle, even when the clearance angle is not included in the rake face parameters. Specifically, the CNC equipment can use formula (5) to determine the coordinates of each curve point corresponding to each reference central angle in the workpiece coordinate system from the three-dimensional helical curve in the workpiece coordinate system.

[0077] It is understandable that the clearance angle directly affects the sharpness, strength, chip removal, heat dissipation, and lifespan of the drill bit. The clearance angle is not constant; it varies along the cutting edge, i.e., from the center of the drill tip to the outer edge and at different radii. The clearance angle in this application may be, but is not limited to, the clearance angle at the outer edge of the drill bit. When there is a clearance angle, the three-dimensional helical curve needs to be adjusted so that the circumferential intersection line corresponding to the three-dimensional helical curve can meet the structural requirements of the clearance angle of the helical drill tip. The CNC equipment can determine each curve point on the three-dimensional helical curve based on the Archimedean spiral, the drill tip angle, and the clearance angle when the clearance face parameters include the clearance angle. Specifically, the CNC equipment can use formula (6) to determine the coordinates of each curve point corresponding to each reference central angle in the workpiece coordinate system from the three-dimensional helical curve in the workpiece coordinate system based on the Archimedean spiral, the drill tip angle, the starting central angle, and the clearance angle.

[0078]

[0079] Where P is the coordinate of a point on the three-dimensional helical curve in the workpiece coordinate system. p For P in X w The coordinate values ​​on the axis. y p For P in Y w The coordinate values ​​on the axis. p For P in Zw The coordinate values ​​on the axis. Let θ be the polar angle of the projection point of P onto the Archimedean spiral. a is the spiral coefficient. b is the spiral offset. s θ is the central angle at the starting point. e The endpoint is the central angle. ψ is the drill tip angle. R is the drill bit radius. α is the clearance angle.

[0080] In some embodiments, the attitude constraint may be, but is not limited to, matching the tilt angle of the grinding wheel radial direction relative to the reference plane with the clearance angle, corresponding to the generatrix of the conical surface. The CNC machine can determine the grinding radial direction based on the initial radial direction and the clearance angle.

[0081] In some embodiments, the CNC equipment can use formula (6) to determine the coordinates of the curve point in the workpiece coordinate system based on the reference central angle, helix coefficient, helix offset, drill radius, drill tip angle, back angle and starting central angle.

[0082] In this embodiment, the inclination of the line connecting the pole and the curve point relative to the drill bit axis is related to the drill tip angle and the clearance angle. Based on the Archimedean spiral, the drill tip angle, and the clearance angle, each curve point on the three-dimensional spiral curve is determined to ensure that each curve point on the three-dimensional spiral curve simultaneously meets the structural requirements of the clearance angle and the drill tip angle of the spiral surface drill tip, thereby improving adaptability.

[0083] In some embodiments, the spiral start-point parameter includes a start-point central angle; the start-point central angle is used to characterize the angle of inclination of the line connecting the start-point and pole of the Archimedean spiral relative to the polar axis of the Archimedean spiral; the spiral end-point parameter includes an angular deviation; the angular deviation is used to characterize the angle of deviation of the line connecting the end-point and pole of the Archimedean spiral relative to the line connecting the start-point and pole; the Archimedean spiral has projection points corresponding to curve points; determining each curve point on the three-dimensional helical curve based on the Archimedean spiral and the drill tip angle includes: determining the end-point central angle based on the start-point central angle and the angular deviation; the end-point central angle is used to characterize the angle of inclination of the line connecting the end-point and pole relative to the polar axis; determining the range of central angles formed by the start-point central angle and the end-point central angle; determining each reference central angle from the range of central angles; each reference central angle is used to characterize the angle of inclination of the line connecting the projection point corresponding to the curve point and the pole relative to the polar axis; determining the curve point corresponding to the reference central angle from the three-dimensional helical curve based on the Archimedean spiral and the drill tip angle.

[0084] For example, the CNC equipment can determine the end point central angle by the angle difference between the starting point central angle and the angle deviation. Specifically, the CNC equipment can use formula (7) to determine the end point central angle.

[0085] θ e =θ s -L (7).

[0086] Where, θ e Let θ be the central angle at the endpoint. s Let θ be the starting central angle, and L be the angular deviation. Obtain the range of the central angle formed by the ending central angle and the starting central angle. It can be understood that θ in formulas (4) and (5)... e ≤θ≤θ s It refers to the range of the central angle.

[0087] The CNC equipment can discretize the range of central angles to obtain each reference central angle. This embodiment does not limit the specific method of discretization. The coordinates of the curve point corresponding to the reference central angle in the workpiece coordinate system are determined from the three-dimensional spiral curve in the workpiece coordinate system based on the Archimedean spiral and the drill tip angle. Specifically, formula (5) or (6) can be used to determine the coordinates of the curve point corresponding to the reference central angle in the workpiece coordinate system from the three-dimensional spiral curve in the workpiece coordinate system.

[0088] In some embodiments, the CNC equipment can discretize the range of central angles based on the number of discrete points to obtain each reference central angle. The number of discrete points is used to characterize the total number of each reference central angle.

[0089] In this embodiment, the ending central angle is determined based on the starting central angle and the angular deviation; the range of central angles formed by the starting and ending central angles is determined; each reference central angle is determined from the range of central angles; each reference central angle is used to characterize the inclination angle of the line connecting the projection point and the pole corresponding to the curve point relative to the polar axis; the curve point corresponding to the reference central angle is determined from the three-dimensional spiral curve according to the Archimedean spiral and the drill tip angle, without the need for manual specification of the curve point, which is more efficient and convenient.

[0090] In some embodiments, determining each circumferential point on the outer cylindrical surface of the drill bit corresponding to each curve point includes: determining a reference inclination angle corresponding to a reference central angle; wherein, the reference inclination angle corresponding to the reference central angle is used to characterize the line-plane angle between the trajectory line segment between the curve point corresponding to the reference central angle and the corresponding circumferential point relative to the projection plane; and determining the circumferential point corresponding to the curve point from the outer cylindrical surface of the drill bit based on the curve point corresponding to the reference central angle and the reference inclination angle.

[0091] For example, a CNC machine can linearly map a reference central angle to a range of inclination angles to obtain an initial inclination angle corresponding to the reference central angle. Depending on the structural requirements of the helical drill tip, whether or not to introduce a target rake angle can be adaptively selected. When the flank parameters include the target rake angle, the reference inclination angle corresponding to the reference central angle is determined based on the target rake angle and the initial inclination angle. When the flank parameters do not include the target rake angle, the initial inclination angle is determined as the reference inclination angle corresponding to the reference central angle.

[0092] The CNC equipment can determine the circumferential point corresponding to the curve point from the outer cylindrical surface of the drill bit based on the curve point corresponding to the reference central angle, the reference inclination angle, and the intersection model. Specifically, the intersection model can include formula (8). The CNC equipment can use formula (8) to determine the coordinates of the circumferential point corresponding to the reference central angle in the workpiece coordinate system from the circumferential intersection line in the workpiece coordinate system based on the drill bit radius, the coordinates of the curve point in the workpiece coordinate system, and the reference inclination angle. It can be understood that the corresponding curve point and circumferential point also correspond to the same reference central angle.

[0093]

[0094] Where Q is the coordinate of the circumferential point in the workpiece coordinate system. q For Q in X w The coordinate values ​​on the axis. y q For Q in Y w The coordinate values ​​on the axis. q For Q in Z w The coordinate value on the axis. x p For P in X w The coordinate values ​​on the axis. y p For P in Y w The coordinate values ​​on the axis. p For P in Z w The coordinates on the axis. θ is the reference central angle. η is the reference tilt angle.

[0095] In some embodiments, the CNC equipment can use formula (8) to determine the coordinates of the corresponding circumferential point in the workpiece coordinate system based on the drill bit radius, the coordinates of the curve point in the workpiece coordinate system, the reference tilt angle and the reference central angle.

[0096] In this embodiment, a reference inclination angle corresponding to a reference central angle is determined; wherein, the reference inclination angle corresponding to the reference central angle is used to characterize the line-plane angle of the trajectory line segment between the curve point and the corresponding circumferential point corresponding to the reference central angle relative to the projection plane; the circumferential point corresponding to the curve point is determined from the outer cylindrical surface of the drill bit based on the curve point corresponding to the reference central angle and the reference inclination angle, which eliminates the need for manually specifying the circumferential point corresponding to the curve point, making it more efficient and convenient.

[0097] In some embodiments, determining the reference inclination angle corresponding to the reference central angle includes: determining a starting inclination angle matching the drill tip angle and a ending inclination angle matching the grinding wheel cone angle; linearly mapping the reference central angle to the inclination angle range formed by the starting and ending inclination angles to obtain the initial inclination angle corresponding to the reference central angle; linearly mapping the reference central angle to the rake angle range to obtain the reference rake angle corresponding to the reference central angle; and superimposing the initial inclination angle and the reference rake angle corresponding to the reference central angle to obtain the reference inclination angle corresponding to the reference central angle.

[0098] For example, a CNC machine can acquire an initial tilt angle complementary to half the angle of the drill tip. For example... Figure 4A The diagram shows the initial tilt angle in the reference coordinate system corresponding to the starting central angle. It should be noted that the calculations in this application are primarily performed in the workpiece coordinate system; the reference coordinate system is introduced mainly for ease of illustration in the diagram. The reference coordinate system corresponding to the starting central angle is obtained by rotating the workpiece coordinate system around the drill bit axis by the starting central angle. It can be understood that the reference coordinate system O corresponding to the starting central angle... m -X m Y m Z m Relative to the workpiece coordinate system O w -X w Y w Z w , origin O m and Z m The axes are respectively with respect to the origin O w and Z w Keep the axes consistent, plane X m O m Y m With plane X w O w Y w Both are projection planes, but X m axis and Y m The axes are respectively with X w axis and Y w The axis difference is the initial central angle. Plane X m O m Z m The reference plane, Y m The axial direction of the shaft is the reference normal. η s This is the initial tilt angle. F g0 For the grinding axis. F r0 The initial radial direction is O. g0 It is the center of the second end face of the grinding wheel.

[0099] Specifically, the CNC equipment can use formula (9) to determine the initial tilt angle.

[0100]

[0101] Where, η s ψ is the initial tilt angle. ψ is the drill tip angle.

[0102] CNC equipment can obtain a finishing angle that is complementary to the grinding wheel taper angle. For example... Figure 4B The diagram shows the ending tilt angle in the reference coordinate system corresponding to the ending central angle. The reference coordinate system O corresponding to the ending central angle... m -X m Y m Zm , is the workpiece coordinate system O w -X w Y w Z w η is obtained after rotating the drill bit around its axis to the central angle at the endpoint. e To end the tilt angle.

[0103] Specifically, the CNC equipment can use formula (10) to determine the end tilt angle.

[0104]

[0105] Where, η e The final tilt angle. μ g The cone angle of the grinding wheel.

[0106] The CNC equipment can determine the first mapping relationship based on the starting central angle, the ending central angle, the starting tilt angle, and the ending tilt angle. The first mapping relationship is a linear mapping relationship between the range of central angles and the range of tilt angles. Specifically, the first mapping relationship can be, but is not limited to, the mapping relationship described by formula (11).

[0107]

[0108] Where θ is the reference central angle. η(θ) is the initial tilt angle corresponding to the reference central angle. s θ is the central angle at the starting point. e η is the central angle at the endpoint. s η is the initial tilt angle. e To end the tilt angle.

[0109] like Figure 4C The diagram shows the initial tilt angle in the reference coordinate system corresponding to the endpoint central angle. The CNC machine can linearly map the reference central angle to the tilt angle range based on the first mapping relationship to obtain the initial tilt angle corresponding to the reference central angle.

[0110] The front angle range refers to the range that is not less than 0 and not greater than the target front angle. The CNC equipment can determine the second mapping relationship based on the starting central angle, the ending central angle, and the target front angle. The second mapping relationship is a linear mapping relationship between the central angle range and the front angle range. Specifically, the second mapping relationship can be, but is not limited to, the mapping relationship described by formula (12).

[0111]

[0112] Where θ is the reference central angle. γ(θ) is the reference front angle corresponding to the reference central angle. s θ is the central angle at the starting point. e γ is the central angle at the endpoint. e The front angle of the target.

[0113] The CNC equipment can linearly map the reference central angle to the range of the front angle based on the second mapping relationship to obtain the reference front angle corresponding to the reference central angle.

[0114] The CNC equipment can sum the initial tilt angle and the reference rake angle corresponding to the reference central angle to obtain the reference tilt angle corresponding to the reference central angle. Specifically, the CNC equipment can use formula (13) to determine the reference tilt angle corresponding to the reference central angle.

[0115] η′(θ)=η(θ)+γ(θ) θ e ≤θ≤θ s (13).

[0116] Where θ is the reference central angle. η′(θ) is the reference inclination angle corresponding to the reference central angle. η(θ) is the initial inclination angle corresponding to the reference central angle. γ(θ) is the reference rake angle corresponding to the reference central angle. s θ is the central angle at the starting point. e The central angle of the endpoint.

[0117] The rake angle of a helical drill tip has a significant impact on cutting force, cutting heat, and tool wear during the cutting process. Based on the structural requirements of the helical drill tip, the rake angle can be adaptively selected and introduced. In this embodiment, by determining the initial tilt angle matching the drill tip angle and the final tilt angle matching the grinding wheel cone angle, a reference central angle is linearly mapped to the tilt angle range formed by the initial and final tilt angles to obtain the initial tilt angle corresponding to the reference central angle. The reference central angle is then linearly mapped to the rake angle range to obtain the reference rake angle corresponding to the reference central angle. The initial tilt angle and the reference rake angle corresponding to the reference central angle are then superimposed to obtain the reference tilt angle corresponding to the reference central angle. This ensures that the reference tilt angle meets the structural requirements of the helical drill tip's rake angle and drill tip angle, while also matching the grinding conditions of the grinding wheel, thus improving adaptability.

[0118] In some embodiments, the grinding posture includes a grinding axial direction and a grinding radial direction; the grinding axial direction is used to characterize the axial direction of the grinding wheel when the generatrix of the grinding wheel's conical surface is parallel to the trajectory line segment; the grinding radial direction is used to characterize the radial direction of the grinding wheel corresponding to the generatrix of the conical surface; determining the grinding posture of the grinding wheel when the generatrix of the grinding wheel's conical surface is parallel to the trajectory line segment includes: determining an oscillation angle based on the grinding wheel's cone angle and a reference tilt angle; the oscillation angle is used to characterize the angle of the grinding axial direction relative to the projection plane; determining a reference normal perpendicular to the drill bit axis and the trajectory line segment; determining the projection vector of the trajectory line segment in the projection plane; rotating the projection vector around the reference normal by an oscillation angle to obtain the grinding axial direction; and determining the grinding radial direction perpendicular to the grinding axial direction.

[0119] For example, such as Figure 5 As shown, the swing angle in the reference coordinate system corresponding to the reference central angle is provided. The reference coordinate system O corresponding to the reference central angle...m -X m Y m Z m , is obtained by rotating the workpiece coordinate system around the drill bit axis by a reference central angle. λ represents the oscillation angle. F g0 For the grinding axis. F r0 P is the initial radial direction. P'Q' is the projection vector. PQ is the trajectory segment. s P e It is a three-dimensional spiral curve. Q s Q e The circumferential intersection line is η, which is the reference tilt angle. The angle difference between the reference tilt angle and the oscillation angle is consistent with the complementary angle of the grinding wheel cone angle.

[0120] The CNC equipment can determine the swing angle based on the angle difference between the reference tilt angle and the complementary angle of the grinding wheel cone angle. The swing angle is used to characterize the angle of the grinding wheel's axis relative to the projection plane when the generatrix of the grinding wheel's cone surface is parallel to the trajectory line segment. Specifically, the CNC equipment can determine the swing angle using formula (14).

[0121]

[0122] Where λ is the oscillation angle, and η′(θ) is the reference tilt angle corresponding to the reference central angle. g θ is the cone angle of the grinding wheel. s θ is the central angle at the starting point. e The central angle of the endpoint.

[0123] The CNC equipment can perform a cross product of the direction vectors of the drill bit axis and the trajectory line segment to obtain the reference normal. The direction vector of the trajectory line segment is used to characterize the direction from the curve point to the corresponding circumferential point. The projection vector is determined based on the coordinates of the curve point and the corresponding circumferential point in the workpiece coordinate system. The projection vector is rotated around the reference normal by an angle using the rotation matrix formula to obtain the grinding axis. Specifically, the CNC equipment can determine the grinding axis using formula (15).

[0124]

[0125] Among them, F g0 This refers to the grinding axis. Z is the direction vector of the trajectory line segment. w λ represents the drill bit's axial direction. λ represents the oscillation angle. x is the projection vector. q Let the point on the circle be X w The coordinate values ​​on the axis. y q For a point on the circumference in Y w The coordinate value on the axis. x p For the curve point at X w The coordinate values ​​on the axis. y p For the curve point in Yw The coordinate values ​​on the axis. Represents the reference normal The rotation matrix for rotation angle λ.

[0126] The specific formula for the rotation matrix is ​​as follows:

[0127]

[0128] It can be understood that rot(N,ξ) represents a vector revolving around any unit vector N(N) x N y N z The rotation matrix of the rotation angle ξ.

[0129] The CNC equipment can determine the initial radial direction perpendicular to the grinding axis and the reference normal. The grinding radial direction is then determined based on the initial radial direction.

[0130] In this embodiment, the swing angle is determined based on the grinding wheel cone angle and the reference tilt angle; the swing angle is used to characterize the angle of the grinding axis relative to the projection plane; the reference normal perpendicular to the drill axis and the trajectory line segment is determined; the projection vector of the trajectory line segment in the projection plane is determined; the projection vector is rotated around the reference normal by the swing angle to obtain the grinding axis; the grinding radial direction perpendicular to the grinding axis is determined. The grinding point on the generatrix of the grinding wheel cone surface under the subsequent grinding posture passes through the trajectory line segment, which can grind the flank face on the helical drill tip, thereby improving the flank face grinding efficiency.

[0131] In some embodiments, the method further includes: linearly mapping a reference central angle to a chip groove angle range to obtain a reference chip groove angle corresponding to the reference central angle; wherein the reference chip groove angle is used to characterize the angle between the grinding radial direction and the reference normal; determining the grinding radial direction perpendicular to the grinding axis, including: determining an initial radial direction perpendicular to the grinding axis and the reference normal; rotating the initial radial direction about the grinding axis according to the reference chip groove angle to obtain the grinding radial direction.

[0132] For example, the flank face parameters may include the starting chip flute angle and the ending chip flute angle. The chip flute angle range is the angle range formed by the starting chip flute angle and the ending chip flute angle. It can be understood that by introducing a chip flute angle relative to the drill bit axis, the helical drill tip can more accurately control chip removal. The reference chip flute angles within the chip flute angle range enable the helical drill tip to have a constantly changing chip flute angle, which avoids chip accumulation compared to a constant chip flute angle.

[0133] The CNC equipment can determine a third mapping relationship based on the starting central angle, the ending central angle, the starting chip groove angle, and the ending chip groove angle. The third mapping relationship is a linear mapping relationship between the range of central angles and the range of chip groove angles. Specifically, the third mapping relationship can be, but is not limited to, the mapping relationship described by formula (17).

[0134]

[0135] Where δ(θ) is the reference chip groove angle corresponding to the reference central angle θ. s The starting chip groove angle is δ. e θ represents the end-point chip groove angle. s θ is the central angle at the starting point. e The central angle of the endpoint.

[0136] The CNC equipment can linearly map the reference central angle to the chip groove angle range based on the third mapping relationship to obtain the reference chip groove angle corresponding to the reference central angle.

[0137] The CNC equipment can determine the initial radial direction perpendicular to the grinding axis and the reference normal based on the reference normal, the swing angle, and the projection vector. Specifically, the CNC equipment can use formula (18) to determine the initial radial direction perpendicular to the grinding axis and the reference normal.

[0138]

[0139] Among them, F r0 The initial radial direction. Z is the direction vector of the trajectory line segment. w This refers to the drill bit's axial direction. Represents the reference normal Rotation angle The rotation matrix. λ is the swing angle. This is the projection vector.

[0140] The CNC equipment can obtain the grinding radial direction by rotating the initial radial direction around the grinding axis by the complementary angle of the reference chip groove angle. Specifically, the CNC equipment can determine the grinding radial direction using formula (18).

[0141]

[0142] Among them, F r Radial radius of the grinding process. δ is the reference chip groove angle. F g0 For the grinding axis. F r0 The initial radial direction. This is a rotation matrix for rotating the reference chip groove angle around the grinding axis.

[0143] In some embodiments, the flank face parameters include the clearance angle. The CNC equipment can determine a third mapping relationship based on the starting central angle, the ending central angle, the clearance angle, the starting chip groove angle, and the ending chip groove angle. The third mapping relationship can be, but is not limited to, the mapping relationship described by formula (20).

[0144]

[0145] Where δ(θ) is the reference chip groove angle corresponding to the reference central angle θ. s The starting chip groove angle is δ. e θ represents the end-point chip groove angle. s θ is the central angle at the starting point. e The final central angle is α. α is the rear angle.

[0146] CNC equipment can rotate the initial radial direction around the grinding axis based on the back angle to obtain the intermediate radial direction. For example... Figure 6 As shown, a schematic diagram of the intermediate radial direction in the reference coordinate system corresponding to the reference central angle is provided. It can be understood that if the flank parameters do not include the chip flute angle, then when the angle between the grinding wheel radial direction corresponding to the generatrix of the conical surface, i.e., the grinding radial direction, and the reference plane is the flank angle, the attitude constraint condition is satisfied, and the CNC equipment can directly use the intermediate radial direction as the grinding radial direction. If the flank parameters include the chip flute angle, then when the angle between the grinding wheel radial direction corresponding to the generatrix of the conical surface, i.e., the grinding radial direction, and the reference normal is the reference chip flute angle, the attitude constraint condition is satisfied. Therefore, further adjustments are needed based on the intermediate radial direction to obtain the grinding radial direction. Specifically, the CNC equipment can use formula (21) to determine the intermediate radial direction.

[0147] F r1 =rot(F g0 ,α)·F r0 (twenty one).

[0148] Among them, F r1 For the central radial direction. F g0 α is the grinding axis. α is the back angle. F r0 For the initial radial direction. rot(F) g0 ,α) is about F g0 The rotation matrix of rotation α.

[0149] CNC equipment can rotate the intermediate radial direction around the grinding axis based on the reference chip flute angle and clearance angle to obtain the grinding radial direction. For example... Figure 7 As shown, a schematic diagram of the grinding radial direction in the reference coordinate system corresponding to the reference central angle is provided. Specifically, the CNC equipment can determine the grinding radial direction using formula (22).

[0150]

[0151] Among them, F r2 For the grinding radial direction. F r1 For the central radial direction. F g0 α is the grinding axis. α is the back angle. To circle F g0 Rotation The rotation matrix. δ is the reference chip groove angle.

[0152] According to the structural requirements of the helical drill tip, the chip flute angle can be adaptively selected. In this embodiment, the reference central angle is linearly mapped to the range of chip flute angles to obtain the reference chip flute angle corresponding to the reference central angle; wherein, the reference chip flute angle is used to characterize the angle between the grinding radial direction and the reference normal direction; the initial radial direction perpendicular to the grinding axis and the reference normal direction is determined; the initial radial direction is rotated around the grinding axis according to the reference chip flute angle to obtain the grinding radial direction, ensuring that when the generatrix of the conical surface of the grinding wheel in the grinding posture passes through the trajectory line segment, a structure matching the reference chip flute angle can be ground, thus improving adaptability.

[0153] In some embodiments, controlling the grinding wheel to perform back face grinding based on the grinding posture and trajectory line segment includes: for the grinding wheel in the grinding posture, determining the grinding position of the grinding wheel when a reference straight line parallel to the drill axis and passing through the curve point is tangent to the grinding wheel fillet and the straight line containing the generatrix of the conical surface passes through the trajectory line segment; and controlling the grinding wheel to perform back face grinding based on the grinding posture and grinding position.

[0154] For example, such as Figure 8 The diagram shown illustrates a grinding wheel. CNC equipment can be configured based on the grinding wheel radius R. g First fillet radius r1 and grinding wheel cone angle μ g Determine the radius R of the first outer circle corresponding to the first end face. g_max .

[0155] Specifically, the CNC equipment can use formula (23) to determine the radius of the first outer circle.

[0156]

[0157] CNC equipment can be based on the first outer circle radius R g_max Grinding wheel thickness H g and grinding wheel cone angle μ g Determine the radius R of the second outer circle corresponding to the second end face. g_min Specifically, the CNC equipment can use formula (24) to determine the radius of the second outer circle.

[0158] R g_min =R g_max -H g / tanμ g (twenty four).

[0159] CNC equipment can be based on the second outer circle radius R g_min The second fillet radius r2 and the grinding wheel cone angle μ g Determine the radius of the second end face. Specifically, the CNC equipment can use formula (25) to determine the radius of the second end face.

[0160]

[0161] Among them, O g2 N is the radius of the second end face. O g2 The center of the second end face is N. N is located at the boundary of the second end face.

[0162] The fillet of a grinding wheel can be, but is not limited to, a second fillet. For example... Figure 9A The diagram illustrates the grinding position of a grinding wheel. When the grinding wheel is in the grinding position, a reference line parallel to the drill bit axis and passing through the curve point is tangent to the second fillet, and the line containing the generatrix of the conical surface passes through the trajectory segment. It should be noted that this diagram is for ease of illustrating the grinding position of the grinding wheel. Figure 9A The grinding wheel is relatively small. In reality, the length of the generatrix of the grinding wheel's conical surface is generally not less than the length of the trajectory segment. Therefore, when the grinding wheel is in the grinding position in the grinding posture, the generatrix of the conical surface can grind the trajectory segment on the helical drill tip in one go. It can be understood that if the length of the generatrix of the grinding wheel's conical surface is less than the length of the trajectory segment, then when the grinding wheel is in the grinding position in the grinding posture, the generatrix of the conical surface cannot grind the trajectory segment on the helical drill tip in one go, and the grinding wheel needs to travel a further distance along the trajectory segment.

[0163] CNC equipment can determine the grinding position of the center of the second end face when the reference straight line parallel to the drill bit axis and passing through the curve point is tangent to the second fillet and the straight line containing the generatrix of the conical surface passes through the trajectory line segment for the grinding wheel in the grinding posture.

[0164] CNC equipment can adjust the attitude of the grinding wheel to the grinding attitude and adjust the center of the second end face to the grinding position, so that the grinding point on the generatrix of the conical surface passes through the trajectory line segment, thereby grinding the back face on the helical drill tip.

[0165] In some embodiments, the CNC equipment can determine the grinding position of the center of the second end face based on the grinding wheel cone angle, swing angle, second fillet radius, curve point, grinding radial direction, and grinding axial direction.

[0166] like Figure 9B As shown, a schematic diagram illustrates the relative positional relationship between the center of the second end face and the curve point when the grinding wheel is in the grinding position. rIt is the center of the circle containing the second fillet. T is the point of tangency between the circle containing the second fillet and the trajectory line segment. N is located at the boundary of the second end face, that is, the intersection of the second end face and the second fillet. M is the distance from curve point P to O. r The perpendicular point is obtained by drawing a perpendicular line from N. The angle between the reference line and the grinding radial direction is the oscillation angle. Based on Figure 9B Based on the relative positional relationship, the CNC equipment can use formulas (26) and (27) to determine the grinding position of the grinding wheel.

[0167] O g2 =P+F r2 ·(O g2 N+MP)-F g0 ·MN (26).

[0168]

[0169] Among them, O g2 The center of the second end face. P is the curve point. F r2 For the grinding radial direction. O g2 N is the radius of the second end face. MP is O r The perpendicular segment of N, O g2 N+MP is the distance of curve point P relative to the center of the second end face in the grinding radial direction. F g0 MN is the distance of curve point P along the grinding axis relative to the center of the second end face. r2 is the radius of the second fillet. λ is the oscillation angle. g The cone angle of the grinding wheel.

[0170] In some embodiments, the CNC equipment can determine the grinding path of the grinding wheel based on the grinding posture, grinding position, and trajectory segment. The grinding wheel is then controlled to perform flank grinding based on the grinding path.

[0171] In this embodiment, for the grinding wheel in the grinding posture, the grinding position of the grinding wheel is determined when the reference straight line parallel to the drill axis and passing through the curve point is tangent to the rounded corner of the grinding wheel, and the straight line containing the generatrix of the conical surface passes through the trajectory line segment; the grinding wheel is controlled to perform back face grinding according to the grinding posture and grinding position, eliminating the need for manual grinding and improving the back face grinding efficiency.

[0172] In some embodiments, the CNC equipment can acquire the flank face parameters. For example... Figure 10 The diagram shown illustrates the back face parameters. These parameters may include the drill radius R, drill tip angle ψ, clearance angle α, angular deviation L, and starting edge distance coefficient Y. f Endpoint distance coefficient S f θ, the central angle at the starting point s δ, the angle of the chip groove at the starting point s End point chip groove angle δ e and the target's front angle γe . Figure 10 δ is at the starting point of the chip groove angle δ s and the end chip groove angle δ e Within the angle range of the formed chip groove.

[0173] The CNC equipment can use formula (1) to determine the starting extreme diameter based on the drill bit radius and the starting edge distance coefficient. Formula (2) can be used to determine the ending extreme diameter based on the ending edge distance coefficient and the drill bit radius. Formula (3) can be used to determine the helical coefficient based on the starting extreme diameter, ending extreme diameter, starting polar angle, and ending polar angle, and the helical offset based on the starting extreme diameter, starting polar angle, and helical coefficient. The range of central angles formed by the starting and ending central angles is discretized to obtain each reference central angle. Formula (6) can be used to determine the coordinates of the curve point in the workpiece coordinate system based on the reference central angle, helical coefficient, helical offset, drill bit radius, drill tip angle, clearance angle, and starting central angle.

[0174] The CNC equipment can use formula (9) to determine the starting tilt angle based on the drill tip angle. Formula (10) is used to determine the ending tilt angle based on the grinding wheel cone angle. Formula (11) is used to determine the first mapping relationship based on the starting central angle, the ending central angle, the starting tilt angle, and the ending tilt angle. Formula (12) is used to determine the second mapping relationship based on the starting central angle, the ending central angle, and the target front angle. Based on the second mapping relationship, the reference central angle is linearly mapped to the range of the front angle to obtain the reference front angle corresponding to the reference central angle. Formula (13) is used to determine the reference tilt angle corresponding to the reference central angle based on the initial tilt angle and the reference front angle. Formula (8) is used to determine the coordinates of the corresponding circumferential point in the workpiece coordinate system based on the drill radius, the coordinates of the curve point in the workpiece coordinate system, the reference tilt angle, and the reference central angle.

[0175] Based on the coordinates of the curve points and corresponding circumferential points in the workpiece coordinate system, determine the direction vector and projection vector of the trajectory line segment. Using formula (14), determine the oscillation angle based on the reference tilt angle and the grinding wheel cone angle. Using formula (15), determine the grinding axis based on the drill bit axis, the direction vector of the trajectory line segment, the oscillation angle, and the projection vector. Using formula (18), determine the initial radial direction based on the drill bit axis, the direction vector of the trajectory line segment, the oscillation angle, and the projection vector. Using formula (21), determine the intermediate radial direction based on the grinding axis, the back angle, and the initial radial direction. Using formula (20), determine the third mapping relationship based on the starting central angle, the ending central angle, the back angle, the starting chip flute angle, and the ending chip flute angle. Based on the third mapping relationship, linearly map the reference central angle to the chip flute angle range to obtain the reference chip flute angle corresponding to the reference central angle. Using formula (22), determine the grinding radial direction based on the grinding axis, the back angle, the reference chip flute angle, and the intermediate radial direction.

[0176] CNC equipment can acquire grinding wheel parameters. For example... Figure 8 As shown, the grinding wheel parameters include the grinding wheel radius R. g Grinding wheel thickness H g First fillet radius r1, second fillet radius r2, and grinding wheel cone angle μ g .

[0177] The CNC equipment can use formula (23) to determine the first outer circle radius based on the grinding wheel radius, the first fillet radius, and the grinding wheel cone angle. Using formula (24), the second outer circle radius corresponding to the second end face can be determined based on the first outer circle radius, the grinding wheel thickness, and the grinding wheel cone angle. Using formula (25), the radius of the second end face can be determined based on the second outer circle radius, the second fillet radius, and the grinding wheel cone angle. Using formulas (26) and (27), the grinding position of the grinding wheel can be determined based on the coordinates of the curve point in the workpiece coordinate system, the grinding radial direction, the radius of the second end face, the second fillet radius, the grinding wheel cone angle, the oscillation angle, and the grinding axial direction.

[0178] CNC equipment can grind the back face on the helical drill tip by adjusting the attitude of the grinding wheel to the grinding attitude and adjusting the center of the second end face to the grinding position.

[0179] In some embodiments, to verify the back face grinding method for the helical drill tip proposed in this application, the steps in the above-described method embodiments are performed in a simulation environment using the back face parameters in Table 1 and the grinding wheel parameters in Table 2. The grinding wheel used is a 1V1 grinding wheel with rounded corners.

[0180] Table 1:

[0181]

[0182] Table 2:

[0183]

[0184] Through simulation, the following results were obtained: Figure 11 The diagram shows the simulation results of the flank face. An "S"-shaped chisel edge is formed between the two flank faces on the helical drill tip. It can be understood that the two sides of the "S"-shaped chisel edge of the helical drill tip are the two flank faces. Further details can be found later. Figure 11 Further grinding of the helical drill tip structure is performed based on the back face shown.

[0185] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0186] In one exemplary embodiment, a CNC device is provided, which may be a terminal, and its internal structure diagram may be as follows. Figure 12 As shown, the CNC equipment includes a processor, memory, input / output interface, communication interface, display unit, and input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor provides computational and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores the operating system and computer programs. The internal memory provides the environment for the operation of the operating system and computer programs in the non-volatile storage medium. The input / output interface is used for exchanging information between the processor and external devices. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements a method for grinding the back face of a helical drill tip. The display unit of the CNC equipment is used to form a visually visible image and can be a display screen, projection device, or virtual reality imaging device. The display screen can be an LCD screen or an e-ink screen. The input device of the CNC equipment can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the housing of the CNC equipment, or external keyboards, touchpads, or mice, etc.

[0187] Those skilled in the art will understand that Figure 12 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the CNC equipment to which the present application is applied. Specific CNC equipment may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0188] In one embodiment, a numerical control device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0189] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above method embodiments.

[0190] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0191] 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 computer 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, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0192] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0193] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for grinding the flank face of a helical drill tip, characterized in that, The method includes: Obtain each curve point on the three-dimensional helical curve; wherein, starting from the first curve point, the radial curvature of the three-dimensional helical curve decreases and extends in the opposite direction to the drill bit axis; the radial curvature refers to the projected curvature of the three-dimensional helical curve on a projection plane perpendicular to the drill bit axis; the drill bit axis refers to the direction along the drill bit axis towards the drill tip. Determine the circumferential points on the outer cylindrical surface of the drill bit that correspond to each of the curve points; wherein, starting from the first curve point, the inclination of the trajectory line segment between the curve point and the corresponding circumferential point relative to the drill bit axis increases; the straight line containing the trajectory line segment intersects the drill bit axis; The grinding posture of the grinding wheel is determined when the generatrix of the conical surface of the grinding wheel is parallel to the trajectory line segment; the grinding posture includes the grinding axial direction and the grinding radial direction. For the grinding wheel in the grinding posture, determine the grinding position of the grinding wheel when the reference straight line parallel to the drill axis and passing through the curve point is tangent to the rounded corner of the grinding wheel, and the straight line containing the generatrix of the conical surface passes through the trajectory line segment; The grinding wheel is controlled to perform back face grinding based on the grinding posture and the grinding position.

2. The method according to claim 1, characterized in that, The projection of the three-dimensional helical curve onto a projection plane perpendicular to the drill bit axis is an Archimedean spiral; the pole of the Archimedean spiral is located on the drill bit axis; the inclination of the line connecting the pole and the curve point relative to the drill bit axis is related to the drill tip angle of the helical surface drill tip; The acquisition of each curve point on the three-dimensional spiral curve includes: Obtain the helix start-point parameters, the helix end-point parameters, and the drill tip angle; The Archimedean spiral is determined based on the spiral start parameters and the spiral end parameters; The curve points on the three-dimensional helical curve are determined based on the Archimedean spiral and the drill tip angle.

3. The method according to claim 2, characterized in that, The inclination of the line connecting the pole and the curve point relative to the drill bit axis is related to the drill tip angle and the clearance angle; determining each curve point on the three-dimensional helical curve based on the Archimedean spiral and the drill tip angle includes: The curve points on the three-dimensional helical curve are determined based on the Archimedean spiral, the drill tip angle, and the back angle.

4. The method according to claim 2, characterized in that, The starting point parameter of the spiral includes the starting central angle; the starting central angle is used to characterize the inclination angle of the line connecting the starting point and the pole of the Archimedean spiral relative to the polar axis of the Archimedean spiral; the ending point parameter of the spiral includes the angular deviation; the angular deviation is used to characterize the angle by which the line connecting the ending point and the pole of the Archimedean spiral deviates from the line connecting the starting point and the pole. The Archimedean spiral has projection points corresponding to the curve points; The step of determining the curve points on the three-dimensional helical curve based on the Archimedean spiral and the drill tip angle includes: The ending central angle is determined based on the starting central angle and the angle deviation. The endpoint central angle is used to characterize the angle of inclination of the line connecting the endpoint and the pole relative to the polar axis; Determine the range of the central angle formed by the starting central angle and the ending central angle; Each reference central angle is determined from the range of the central angles; each reference central angle is used to characterize the inclination angle of the line connecting the projection point corresponding to the curve point and the pole relative to the polar axis; The curve point corresponding to the reference central angle is determined from the three-dimensional helical curve based on the Archimedean spiral and the drill tip angle.

5. The method according to claim 4, characterized in that, The determination of the circumferential points on the outer cylindrical surface of the drill bit corresponding to each curve point includes: Determine the reference tilt angle corresponding to the reference central angle; wherein, the reference tilt angle corresponding to the reference central angle is used to characterize the line-plane angle of the trajectory line segment between the curve point and the corresponding circumferential point corresponding to the reference central angle relative to the projection plane; The circumferential point corresponding to the curve point is determined from the outer cylindrical surface of the drill bit based on the curve point corresponding to the reference central angle and the reference inclination angle.

6. The method according to claim 5, characterized in that, Determining the reference tilt angle corresponding to the reference central angle includes: Determine the starting inclination angle that matches the drill tip angle, and the ending inclination angle that matches the grinding wheel cone angle; The reference central angle is linearly mapped to the inclination range formed by the initial inclination angle and the final inclination angle to obtain the initial inclination angle corresponding to the reference central angle; The reference central angle is linearly mapped to the range of the front angle to obtain the reference front angle corresponding to the reference central angle. The initial tilt angle and the reference rake angle corresponding to the reference central angle are superimposed to obtain the reference tilt angle corresponding to the reference central angle.

7. The method according to claim 5, characterized in that, The grinding axial direction is used to characterize the axial direction of the grinding wheel when the generatrix of the conical surface of the grinding wheel is parallel to the trajectory line segment; the grinding radial direction is used to characterize the radial direction of the grinding wheel corresponding to the generatrix of the conical surface. Determining the grinding posture of the grinding wheel when the generatrix of the conical surface of the grinding wheel is parallel to the trajectory line segment includes: The oscillation angle is determined based on the grinding wheel cone angle and the reference tilt angle; the oscillation angle is used to characterize the angle of the grinding axis relative to the projection plane. Determine a reference normal perpendicular to the drill bit axis and the trajectory line segment; Determine the projection vector of the trajectory line segment in the projection plane; The grinding axis is obtained by rotating the projection vector around the reference normal by the swing angle; Determine the grinding radial direction perpendicular to the grinding axis.

8. The method according to claim 7, characterized in that, The method further includes: The reference central angle is linearly mapped to the chip groove angle range to obtain the reference chip groove angle corresponding to the reference central angle; wherein, the reference chip groove angle is used to characterize the angle between the grinding radial direction and the reference normal. Determining the grinding radial direction perpendicular to the grinding axis includes: Determine an initial radial direction perpendicular to the grinding axis and the reference normal; The initial radial direction is rotated about the grinding axis according to the reference chip groove angle to obtain the grinding radial direction.

9. A numerical control device, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 8.

Images