A method for expanding the application of CNC lathe cutting tools

Abstract

A method for extending the application of CNC lathe inserts involves providing insert mounting slots on a tool holder. A rhomboid insert, equipped with a rake face and a tip, is fixed within these slots by screws. A rotation center coordinate system is established with the tool holder's axis (equivalent to the machine tool spindle) as the Z-axis and the positive direction of the rake face normal as the Y-axis. The rake face is parallel to and coincides with the XZ plane of the established coordinate system. When machining a triangular internal thread hole with an angle G using a rhomboid insert with an included angle F between its two cutting edges, a CNC machining center is used. The workpiece remains stationary, and the tool rotates around the Z-axis, raising the rake face relative to the XZ plane of the coordinate system by a distance L. This raises the angle formed by the projections of the cutting edges on both sides of the rake face onto the plane formed by the tip and the Z-axis, equal to the angle G of the triangular internal thread to be machined. This method allows for the machining of triangular internal threads with other angles using rhomboid inserts with known angles, even in situations where taps, thread cutters, and thread inserts are unavailable.

Description

Technical Field

[0001] This invention relates to the field of machine cutting tools, and more particularly to a method for extending the application of CNC lathe inserts. Background Technology

[0002] In machining, when using a CNC machining center to machine triangular internal threads, taps, special thread cutters, or thread inserts are generally used. However, in special cases where taps, thread cutters, and thread inserts are unavailable, how to use a diamond-shaped CNC turning insert with a known angle (e.g., 55°) to mill triangular internal threads with other angles (e.g., 60°) is a problem that urgently needs to be solved. Summary of the Invention

[0003] The main objective of this invention is to propose a method for extending the application of CNC lathe cutting tools, aiming to solve the aforementioned technical problems.

[0004] To achieve the above objectives, this invention proposes a method for extending the application of CNC lathe inserts. An insert mounting groove is provided at the tool head position of the tool holder. A rhomboid insert is fixed in the insert mounting groove by screws. The rhomboid insert has a rake face and a tool tip. A rotation center coordinate system is established with the axis of the tool holder as the Z-axis and the positive direction of the normal to the rake face as the Y-axis. The rake face is parallel to the XZ plane of the established coordinate system. When machining a triangular internal thread hole with an angle of G using a rhomboid insert with an included angle F between its two cutting edges, a CNC machining center is used. The workpiece is fixed, and the tool rotates around the Z-axis, raising the rake face relative to the XZ plane of the coordinate system by a distance L. This raises the rake face by a distance L, ensuring that the included angle formed by the projection of the two cutting edges on the plane formed by the tool tip and the Z-axis is equal to the angle G of the triangular internal thread to be machined.

[0005] Preferably, the distance L between the rake face and the XZ plane of the coordinate system is calculated according to the following formula:

[0006] tg(F / 2) = (D / 2) ÷ A;

[0007] tg(G / 2) = (D / 2) ÷ C;

[0008] cosα = C ÷ A;

[0009] sinα = L ÷ C;

[0010] Where: A is the distance from the tool tip to the Z-axis, in mm, and this distance is less than 1 / 2 the root diameter of the thread being machined;

[0011] F is the included angle between the two cutting edges of the rhomboid insert, in degrees;

[0012] G represents the angle of the triangular internal thread to be machined, in degrees.

[0013] C is the distance from the tool tip to the Z-axis of the coordinate system when the spacing L is set between the tool tip and the XZ plane of the coordinate system, and the unit is mm;

[0014] D is the width of the blade at the center of rotation, in mm;

[0015] α is the angle between the perpendicular line from the tool tip to the Z-axis and the negative direction of the X-axis.

[0016] Preferably, the top surface of the blade mounting groove is flush with the rake face; the depth L2 of the blade mounting groove is determined according to the thickness L1 of the rhomboid blade and the height L of the rake face relative to the XZ plane of the coordinate system; then L2 = L - L1.

[0017] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0018] (1) Compared with the prior art, this method is not limited by the cutting angle of the rhombus insert. Regardless of the internal thread profile angle and the angle of the rhombus insert, the corresponding height L of the rhombus cutter face relative to the XZ plane of the coordinate system can be calculated. Then, based on the thickness of the rhombus insert and the calculated distance L, a tool bar with insert mounting groove can be manufactured to install the rhombus insert and mill the required triangular internal thread.

[0019] (2) Under certain circumstances, the present invention saves the time for purchasing blades, shortens the processing time, and reduces the processing cost, and can be widely promoted and applied in the field of machining technology.

[0020] (3) By utilizing the present invention, in special cases where there are no taps, thread cutters and thread inserts, triangular internal threads of other angles can be machined using diamond inserts with known angles commonly used on CNC machining centers, such as milling triangular internal threads with a tooth angle of 60° using a 55° diamond insert. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 The principle of this invention Figure 1 ;

[0023] Figure 2 The principle of this invention Figure 2 ;

[0024] Figure 3This is a schematic diagram showing the rake face coinciding with the ZX plane of the coordinate system during cutting.

[0025] Figure 4 This is a schematic diagram showing the height difference L of the rake face relative to the XZ plane of the coordinate system during cutting.

[0026] Figure 5 This is a schematic diagram illustrating the calculation principle of the lifting distance L of the rake face relative to the XZ plane of the coordinate system in this invention.

[0027] Figure 6 This is a schematic diagram of the blade mounting groove in the present invention;

[0028] Figure 7 This is a schematic diagram of the tool holder in this invention;

[0029] Figure 8 This is a schematic diagram of the rhomboid blade in this invention;

[0030] Figure 9 This is a schematic diagram showing the rhomboid blade installed after the tool holder in this invention.

[0031] The following are the symbols in the attached diagram: 1. Tool holder; 101. Insert mounting slot; 102. Threaded hole; 2. Rhomboid insert; 201. Tool tip; 202. Rake face; 3. Screw; 4. Workpiece. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0034] Normally, CNC machining centers use taps, thread cutters, or thread inserts to machine internal threads. However, in special cases where taps, thread cutters, and thread inserts are unavailable, to save time on purchasing inserts, shorten the machining cycle, and deliver products on time, the application of CNC lathe inserts is expanded to allow the use of 55° (or other angle) rhomboid inserts on CNC machining centers to mill triangular internal thread holes with a thread angle of 60° (or other angle).

[0035] Combination Figure 1 , Figure 2The diagram shows the processing principle of this invention. A rhombus with an included angle of 55° is projected at 25.618° to obtain a rhombus with an included angle of 60°. Based on this principle, this invention allows cutting angles different from the included angle of the 55° rhombus blade by installing the blade in a certain manner.

[0036] Therefore, this embodiment provides a method for extending the application of CNC lathe cutting tools.

[0037] Combination Figures 6 to 9 As shown, a blade mounting groove 101 is provided at the blade head position of the blade holder 1, and a threaded hole 102 is provided on the blade mounting groove 101. The rhomboid blade 2 is fixed in the blade mounting groove 101 by a screw 3. The rhomboid blade 2 has a rake face 202 and a blade tip 201.

[0038] Combination Figure 3 and Figure 4 As shown, when machining triangular internal thread holes using a CNC machining center, a rotation center coordinate system is established with the axis of the tool holder 1 as the Z-axis and the positive direction of the normal to the rake face 202 as the Y-axis; then the rake face 202 is parallel to the XZ plane of the established coordinate system. When the rake face 202 coincides with the XZ plane, the rhomboid insert 2 with an included angle of F on both sides will produce a triangular internal thread hole with a thread angle of F.

[0039] When it is necessary to use a rhomboid insert 2 with an included angle of F on both sides to machine a triangular internal thread hole with an angle of G, a CNC machining center is used for machining. The workpiece 4 is fixed and the tool rotates around the Z-axis, raising the rake face 202 relative to the XZ plane of the coordinate system by a distance L. This makes the included angle formed by the projection of the cutting edges on both sides of the rake face 202 onto the plane formed by the tool tip 201 and the Z-axis equal to the angle G of the triangular internal thread to be machined.

[0040] In this embodiment, to raise the rake face 202 relative to the XZ plane of the coordinate system by a distance L, a specific insert mounting groove 101 needs to be machined on the tool holder 1. In this embodiment, the tool holder 1 is modified from a conventional straight shank round tool holder. The insert mounting groove 101 is manufactured according to the shape and thickness of the rhomboid insert 2. To facilitate the machining and depth calculation of the insert mounting groove 101, the top surface of the insert mounting groove 101 is set to be flush with the rake face 202. Therefore, the depth L2 of the insert mounting groove 101 can be determined according to the thickness L1 of the rhomboid insert 2 and the raising distance L of the rake face 202 relative to the XZ plane of the coordinate system; then L2 = L - L1. The screw 3 is a common screw. After the tool holder 1 and the rhomboid insert 2 are fastened with screw 3, they are mounted on the spindle of the CNC machining center for milling.

[0041] The key to this embodiment lies in determining the distance L between the cutting edge rake face 202 and the XZ plane of the coordinate system, combined with... Figure 1 . Figure 2 as well as Figure 5 As shown, the spacing L is calculated according to the following formula:

[0042] tg(F / 2) = (D / 2) ÷ A;

[0043] tg(G / 2) = (D / 2) ÷ C;

[0044] cosα = C ÷ A;

[0045] sinα = L ÷ C;

[0046] Where: A is the distance from the tool tip to the Z-axis, in mm, and this distance is less than 1 / 2 the root diameter of the thread being machined;

[0047] F is the included angle between the two cutting edges of the rhomboid insert 2, in degrees;

[0048] G represents the angle of the triangular internal thread to be machined, in degrees.

[0049] C is the distance from the tip 201 to the Z-axis of the coordinate system when the spacing L is set between the cutting face 202 of the insert and the XZ plane of the coordinate system, in mm;

[0050] D is the width of the blade at the center of rotation, in mm;

[0051] α is the angle between the perpendicular line from the tool tip 201 to the Z-axis and the negative direction of the X-axis.

[0052] Combination Figure 2 , Figure 5 As shown, taking a diamond-shaped insert 2 with an included angle of F = 55° on both sides and a triangular internal thread hole with an angle of G = 60° as an example, based on the distance A from the tip of the diamond-shaped insert 2 to the Z-axis (this distance is less than 1 / 2 of the bottom diameter of the thread being machined) and the included angle F = 55° of the diamond-shaped insert 2, when the negative direction projection along the cutting direction on the diamond-shaped insert 2 is calculated, when the two cutting edges form a 60° cutting angle on the plane formed by the tip 201 and the Z-axis, and the angle α between the perpendicular line of the tip 201 and the Z-axis and the negative direction of the rotation center X, the height L of the rake face 202 relative to the coordinate system XZ plane can be calculated. Then, combined with the thickness L1 of the diamond-shaped insert 2, the depth L2 of the insert mounting groove 101 can be calculated.

[0053] Assuming the angle of the triangular internal thread to be machined is G = 60°, the included angle F = 55° between the two cutting edges of the rhombus insert 2, and the distance A from the tip of the rhombus insert 2 to the Z-axis is 16mm, the calculation method for the lifting distance L of the rake face 202 relative to the XZ plane of the coordinate system includes the following steps:

[0054] S1. Calculate the width D of the rhomboid blade 2 at the center of rotation: According to tg(F / 2)=(D / 2)÷A, that is, tg55 / 2°=D / 2÷A=D / 2÷16, then D=16.658mm;

[0055] S2. Calculate the distance C between the tool tip 201 and the Z-axis of the coordinate system: According to tg(G / 2)=(D / 2)÷C, that is, tg60 / 2°=D / 2÷C, then C=14.427mm;

[0056] S3. Calculate the angle α between the perpendicular line from the tool tip 201 to the Z-axis and the negative direction of the X-axis: based on cosα=C÷A, α=25.618°.

[0057] S4. Calculate the height difference L of the rake face 202 relative to the XZ plane of the coordinate system: Calculate the value of L based on C = 14.427 mm and α = 25.618°: sinα = L ÷ C, which gives L = 6.238 mm.

[0058] The above calculations are rounded to three decimal places.

[0059] Using the above method, when machining triangular internal thread holes, the required thread is obtained by cutting layer by layer from the inside out according to the procedure.

[0060] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for extending the application of CNC lathe inserts, wherein an insert mounting groove (101) is provided at the tool head position of a tool holder (1), and a rhomboid insert (2) is fixed in the insert mounting groove (101) by screws (3), the rhomboid insert (2) having a rake face (202) and a tool tip (201), characterized in that: A rotation center coordinate system is established with the axis of the tool holder (1) as the Z-axis and the positive direction of the normal of the front tool face (202) as the Y-axis. The front tool face (202) is parallel to the XZ plane of the established coordinate system. When machining a triangular internal thread hole with an angle of G using a rhomboid insert (2) with an angle of F between the cutting edges on both sides, a CNC machining center is used. The workpiece (4) is fixed and the tool rotates around the Z-axis, raising the front tool face (202) relative to the XZ plane of the coordinate system by a distance L. This makes the angle formed by the projection of the cutting edges on both sides of the front tool face (202) onto the plane formed by the tool tip (201) and the Z-axis equal to the angle G of the triangular internal thread to be machined. The distance L between the cutting edge rake face (202) and the XZ plane of the coordinate system is calculated according to the following formula: tg(F / 2) = (D / 2) ÷ A; tg(G / 2) = (D / 2) ÷ C; cosα = C ÷ A; sinα = L ÷ C; Where: A is the distance from the tool tip to the Z-axis, in mm, and this distance is less than 1 / 2 the root diameter of the thread being machined; F is the included angle between the two cutting edges of the rhomboid blade (2), in degrees; G represents the angle of the triangular internal thread to be machined, in degrees. C is the distance from the tip (201) to the Z-axis of the coordinate system when the spacing L is set between the cutting face (202) of the insert and the XZ plane of the coordinate system, in mm; D is the width of the blade at the center of rotation, in mm; α is the angle between the perpendicular line from the tool tip (201) to the Z-axis and the negative direction of the X-axis.

2. The method for extending the application of CNC lathe cutting tools as described in claim 1, characterized in that, The top surface of the blade mounting groove (101) is flush with the front cutting face (202); the depth L2 of the blade mounting groove (101) is determined according to the thickness L1 of the rhomboid blade (2) and the height L of the front cutting face (202) relative to the XZ plane of the coordinate system; then L2 = L - L1.

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