Method for processing a metal pipe

Abstract

The present invention provides a metal pipe processing method that stably fixes a metal pipe when forming a groove in the pipe and improves productivity. The metal pipe processing method includes: a first half-cut groove forming process that exposes a first face of a quadrangular prism (8) in which an outer face of a metal pipe (2) is covered with resin in a quadrangular prism shape, forms a first half-cut groove (22a) that does not reach the center using a cutting tool while indexing in a length direction of the quadrangular prism at a prescribed interval; a second half-cut groove forming process that exposes a second face perpendicular to the first face, and forms a second half-cut groove in the center of adjacent first half-cut grooves; a third half-cut groove forming process that exposes a third face on an opposite side of the first face, and forms a third half-cut groove on the opposite side corresponding to the first half-cut groove; and a fourth half-cut groove forming process that exposes a fourth face on an opposite side of the second face, and forms a fourth half-cut groove on the opposite side corresponding to the second half-cut groove.

Description

Technical Field

[0001] This invention relates to a processing method for shaping metal tubes into bendable metal tubes. Background Technology

[0002] A technique has been proposed to process a metal tube into a bendable form by forming multiple circumferentially extending grooves on the outer periphery of a slender, cylindrical metal tube (e.g., made of titanium alloy). The bendable metal tube is then used for medical catheters, etc. (see, for example, Patent Document 1).

[0003] Patent Document 1: Japanese Patent Publication No. 2006-507073

[0004] However, when the metal tube is rotated intermittently at 90-degree intervals while a groove of approximately 20 μm width is formed on the metal tube at intervals of approximately 50 μm across the entire circumference, there are problems with unstable fixation of the metal tube and poor productivity. Summary of the Invention

[0005] In view of the above facts, the objective of the present invention is to provide a method for processing metal tubes, which can stably fix the metal tube when a groove is formed on it, thereby improving productivity.

[0006] According to the present invention, a method for processing a metal tube is provided to solve the above-mentioned problems. Specifically, a method for processing a metal tube that can be bent is provided, wherein the method includes the following steps: a fixture preparation step, in which a fixture having a straight rectangular groove for receiving the metal tube is prepared; an embedding step, in which the metal tube is received in the rectangular groove and liquid resin is injected to embed the metal tube using the liquid resin; a removal step, in which the liquid resin is hardened and a prism obtained by covering the outer surface of the metal tube with resin in a prism shape is removed from the fixture; a first half-cut groove forming step, in which the first face of the prism is exposed, and a first half-cut groove that does not reach the center is formed using a cutting tool while indexing and feeding at predetermined intervals along the length direction of the prism; and a second half-cut groove forming step, in which the second face perpendicular to the first face is exposed, and a second half-cut groove is formed. In the process of forming a second half-cut groove, a cutting tool is used to form a second half-cut groove that does not reach the center while the first half-cut groove is indexed at predetermined intervals along the length of the quadrangular prism. In the process of forming a third half-cut groove, the third face located on the opposite side of the first face is exposed. On the opposite side of the first half-cut groove, a cutting tool is used to form a third half-cut groove that does not reach the center while the cutting tool is indexed at predetermined intervals along the length of the quadrangular prism. In the process of forming a fourth half-cut groove, the fourth face located on the opposite side of the second face is exposed. On the opposite side of the second half-cut groove, a cutting tool is used to form a fourth half-cut groove that does not reach the center while the cutting tool is indexed at predetermined intervals along the length of the quadrangular prism.

[0007] Preferably, the third half-cut groove forming process is performed immediately after the first half-cut groove forming process, and the fourth half-cut groove forming process is performed immediately after the second half-cut groove forming process.

[0008] The metal tube processing method of the present invention includes the following steps: a fixture preparation step, in which a fixture with a straight rectangular groove for receiving the metal tube is prepared; an embedding step, in which the metal tube is received in the rectangular groove and liquid resin is injected to embed the metal tube using the liquid resin; a removal step, in which the liquid resin is hardened and a prism obtained by covering the outer surface of the metal tube with resin in a prism shape is removed from the fixture; a first half-cut groove forming step, in which the first face of the prism is exposed and a first half-cut groove is formed by indexing at predetermined intervals along the length direction of the prism using a cutting tool; and a second half-cut groove forming step, in which the second face perpendicular to the first face is exposed and a second half-cut groove is formed at the center of adjacent first half-cut grooves along the prism. In the process of forming a second half-cut groove, the material is fed at predetermined intervals along the length of the prism while using a cutting tool to form a groove that does not reach the center. In the process of forming a third half-cut groove, the third surface located on the opposite side of the first surface is exposed. On the opposite side of the first half-cut groove, the third half-cut groove is formed on the opposite side of the prism along the length of the prism while using a cutting tool to form a groove that does not reach the center. In the process of forming a fourth half-cut groove, the fourth surface located on the opposite side of the second surface is exposed. On the opposite side of the second half-cut groove, the fourth half-cut groove is formed on the opposite side of the prism along the length of the prism while using a cutting tool to form a groove that does not reach the center. Therefore, when grooves are formed on a metal tube, the metal tube can be stably fixed, and productivity can be improved. Attached Figure Description

[0009] Figure 1 It is a three-dimensional diagram of metal tubing and fixtures.

[0010] Figure 2 It is a three-dimensional view showing the state of the burial process.

[0011] Figure 3 (a) is a perspective view showing the state of liquid resin hardening under ultraviolet light. Figure 3 (b) is a three-dimensional view of a quadrangular prism formed by covering the outer surface of a metal tube with resin in a quadrangular prism shape.

[0012] Figure 4 (a) is shown Figure 3 (b) is a three-dimensional view of a tetrahedron supported on a ring frame by means of a slitting strip. Figure 4 (b) is Figure 4 (a) BB view.

[0013] Figure 5 This is a perspective view showing the state of the first half-cut groove forming process.

[0014] Figure 6 This is the front view of a quadrangular prism with the first half-cut groove.

[0015] Figure 7 This is the front view of a quadrangular prism with the first and third semi-cut grooves.

[0016] Figure 8 This is the front view of a quadrangular prism with the first, second, and third semi-cut grooves.

[0017] Figure 9 (a) is a front view of a tetrahedron with the first to fourth half-cut grooves. Figure 9 (b) is from Figure 9 (a) is a three-dimensional view of a metal tube made of a tetrahedron after the resin has been removed.

[0018] Label Explanation

[0019] 2: Metal tube; 4: Fixture; 4a: Rectangular groove; 6: Liquid resin; 6': Hardened resin; 8: Quadrangular prism; 8a: First face; 8b: Second face; 8c: Third face; 8d: Fourth face; 20: Cutting tool; 22a: First half-cutting groove; 22b: Second half-cutting groove; 22c: Third half-cutting groove; 22d: Fourth half-cutting groove. Detailed Implementation

[0020] Hereinafter, a preferred embodiment of a processing method for processing a metal tube into a bendable metal tube will be described with reference to the accompanying drawings.

[0021] Reference Figure 1 To explain, in this embodiment, the first step is to prepare a fixture 4, which has a straight rectangular groove 4a for receiving the metal tube 2. For example, a slender medical catheter used in vascular treatment and examination can be used as the metal tube 2. When using the metal tube 2 as a catheter, the material of the metal tube 2 can be titanium alloy. Furthermore, regarding the dimensions of the metal tube 2, for example, an outer diameter of 0.4 mm, an inner diameter of 0.35 mm, and a length of approximately 300 mm are acceptable.

[0022] Regarding the material of jig 4, a material that transmits ultraviolet light (such as glass) can be used. The jig 4 as a whole can be... Figure 1As shown, the rectangular groove 4a of the fixture 4 has a slender cuboid shape, and the cross-section (the face that cuts off the length of the fixture 4) can be square. Furthermore, the width and depth of the rectangular groove 4a are slightly larger than the outer diameter of the metal tube 2, and the length of the rectangular groove 4a is slightly longer than the length of the metal tube 2, allowing the entire metal tube 2 to be housed within the rectangular groove 4a. Additionally, in the accompanying drawings, for ease of understanding, an example is shown where there is no wall at the length end of the rectangular groove 4a, i.e., the length end of the rectangular groove 4a is open. However, a wall can be provided at the length end of the rectangular groove 4a of the fixture 4 to prevent the liquid resin (described later) from flowing out.

[0023] After the fixture preparation process is completed, such as Figure 2 As shown, the installation process is as follows: a metal tube 2 is placed in a rectangular groove 4a and liquid resin 6 is injected, and the metal tube 2 is installed using the liquid resin 6. The liquid resin 6 can be a UV-curing type liquid resin that hardens upon exposure to ultraviolet light.

[0024] After the installation process, a removal process is performed: the liquid resin 6 is hardened, and the quadrangular prism formed by covering the outer surface of the metal tube 2 with resin in a quadrangular shape is removed from the fixture 4. During the removal process, when the liquid resin 6 is hardened, for example, if the fixture 4 is made of a material that transmits ultraviolet light and an ultraviolet-curing liquid resin is used as the liquid resin 6, such as... Figure 3 As shown in (a), ultraviolet light (UV) is irradiated from around the fixture 4, thereby easily hardening the liquid resin 6. If the liquid resin 6 is hardened, then as... Figure 3 As shown in (b), a quadrangular prism 8, formed by covering the outer surface of the metal tube 2 with resin 6' in a quadrangular prism shape, is removed from the fixture 4. Additionally, in Figure 3 In (b), the resin obtained by curing the liquid resin 6 is indicated by reference numeral 6'.

[0025] After the removal process is performed, the first half-cut groove forming process is performed: the first face of the quadrangular prism 8 is exposed, and the first half-cut groove that has not reached the center is formed by indexing and feeding at specified intervals along the length of the quadrangular prism 8 using a cutting tool.

[0026] In the first half-cut groove forming process, firstly as follows Figure 4 As shown in (a), a quadrangular prism 8 is attached to a scribe strip 12 that is fixed to the periphery of the annular frame 10, and the quadrangular prism 8 is supported by the scribe strip 12. Thus, in the illustrated embodiment, by attaching the quadrangular prism 8 to the scribe strip 12 and supporting the quadrangular prism 8 with the surface of the scribe strip 12, the metal tube 2 can be stably fixed.

[0027] In the first half-groove forming process, when the quadrangular prism 8 is attached to the scribe strip 12, the groove has not yet been formed on the quadrangular prism 8, and there is no difference on the four faces other than the two axial end faces. Therefore, the first face exposed (facing upward) in the first half-groove forming process can be arbitrarily selected from the four faces other than the two axial end faces. In the illustrated embodiment, as... Figure 4 As shown in (b), the upward-facing face is designated as the first face 8a, and a face perpendicular to the first face 8a is designated as the second face. Figure 4 The right side of (b) is taken as the second side 8b, and the side located on the opposite side of the first side 8a is taken as the second side 8b. Figure 4 The lower surface of (b) is taken as the third surface 8c, and another surface perpendicular to the first surface 8a is taken as the third surface 8c. Figure 4 (b) The left side) is the fourth side 8d.

[0028] When forming the first half-cut groove on the quadrangular prism 8 supported by the dicing strip 12 on the annular frame 10, for example, the following can be used: Figure 5 The cutting device 14 shown is used to perform this action. Furthermore, the cutting device 14 can also be used to form the second to fourth half-cut grooves, which will be described later.

[0029] The cutting device 14 includes: a chuck table (not shown) for holding a workpiece; a cutting unit 16 for cutting the workpiece held by the chuck table; and an imaging unit (not shown) for imaging the workpiece held by the chuck table and detecting the area to be cut. The cutting unit 16 includes: a spindle 18 configured to... Figure 5 The Y-axis, indicated by the middle arrow Y, is the axis of rotation; and a ring-shaped cutting tool 20 is fixed to the front end of the spindle 18. Additionally, Figure 5 The X-axis direction indicated by the middle arrow X is perpendicular to the Y-axis direction. The XY plane defined by the X-axis and Y-axis directions is actually horizontal.

[0030] Reference Figure 5 Continuing the explanation, in the first half-cutting groove forming process, the quadrangular prism 8, supported by the dicing belt 12 and resting on the annular frame 10, is first held on the chuck worktable. Next, the quadrangular prism 8 is photographed using the imaging unit. Based on the image of the quadrangular prism 8 captured by the imaging unit, the length direction of the quadrangular prism 8 is aligned with the Y-axis direction, and the end of the quadrangular prism 8 along its length direction is used as a reference to align the quadrangular prism 8 with the cutting tool 20 along the Y-axis direction.

[0031] Next, lower the spindle 18 so that... Figure 5The cutting tool 20, rotating at high speed in the direction indicated by the middle arrow A, cuts into the first face 8a of the quadrangular prism 8 to a depth that does not reach the radial center of the metal tube 2. While providing cutting water to the portion cut by the cutting tool 20, the chuck table is fed relative to the cutting unit 16 in the X-axis direction at a predetermined feed rate. This allows the formation of a first semi-cut groove 22a that does not reach the radial center of the metal tube 2.

[0032] Furthermore, while indexing feed is performed at predetermined intervals along the length direction of the quadrangular prism 8 (the Y-axis direction in the illustrated embodiment), the formation of the first half-cutting groove 22a is repeated. Thus, as... Figure 6 As shown, multiple first half-cut grooves 22a can be formed by spacing them at predetermined intervals along the length of the quadrangular prism 8. Furthermore, in Figure 6 The dimensions of the quadrangular prism 8 and the first half-cut groove 22a are shown, but these dimensions are for reference only.

[0033] In this embodiment, after the first half-cut groove forming process is performed, the third half-cut groove forming process is performed: the third surface 8c located on the opposite side of the first surface 8a is exposed (facing upwards), and on the opposite side corresponding to the first half-cut groove 22a, the third half-cut groove that does not reach the center is formed by using the cutting tool 20 while indexing feed at predetermined intervals in the length direction of the quadrangular prism 8.

[0034] In the third half-cut groove forming process, the quadrangular prism 8, supported by the scribe strip 12 on the annular frame 10, is first removed from the chuck table, and the scribe strip 12 is temporarily peeled off from the quadrangular prism 8. Next, with the third face 8c facing upward, the quadrangular prism 8 is reattached to the scribe strip 12, and the quadrangular prism 8, supported by the scribe strip 12 on the annular frame 10, is once again held on the chuck table.

[0035] Next, the imaging unit takes an image of the quadrangular prism 8 with its third face 8c facing upwards. Based on the image of the quadrangular prism 8 taken by the imaging unit, the length direction of the quadrangular prism 8 is aligned with the Y-axis direction, and the end of the quadrangular prism 8 along its length direction is used as a reference to align the quadrangular prism 8 with the cutting tool 20 along the Y-axis direction. At this time, the cutting tool 20 is positioned directly above the first half-cutting groove 22a located at the end of one of the plurality of first half-cutting grooves 22a.

[0036] Furthermore, similarly to the formation of the first half-cut groove 22a, the cutting tip of the cutting tool 20 is driven into the metal tube 2 from the third surface 8c to a depth not reaching the radial center, and the chuck table is fed in the X-axis direction to form the third half-cut groove 22c (see reference). Figure 7Furthermore, while indexing and feeding along the length of the quadrangular prism 8 at intervals identical to those of the first half-cutting groove 22a, the formation of the third half-cutting groove 22c is repeated. Thus, as... Figure 7 As shown, multiple third half-cut grooves 22c that do not reach the radial center of the metal tube 2 can be formed on the opposite side corresponding to the multiple first half-cut grooves 22a respectively.

[0037] Reference Figure 7 It is understandable that the Y-axis position of the third half-cut groove 22c is the same as that of the first half-cut groove 22a. However, both the first and third half-cut grooves 22a and 22c are at depths that do not reach the radial center of the metal tube 2. Therefore, the first half-cut groove 22a and the third half-cut groove 22c will not be connected, and the metal tube 2 will not be broken by the first and third half-cut grooves 22a and 22c.

[0038] After the third half-cut groove forming process is performed, the second half-cut groove forming process is performed, so that the second surface 8b, which is perpendicular to the first surface 8a, is exposed. At the center of the adjacent first half-cut groove 22a, the second half-cut groove that does not reach the center is formed by the cutting tool 20 while the indexing feed is performed at a predetermined interval in the length direction of the quadrangular prism 8.

[0039] In the second half-groove forming process, similar to the third half-groove forming process, the annular frame 10 supporting the quadrangular prism 8 is first removed from the chuck table, and the scribe strip 12 is temporarily peeled off from the quadrangular prism 8. Next, with the second face 8b facing upward, the quadrangular prism 8 is reattached to the scribe strip 12, and the quadrangular prism 8, supported by the annular frame 10 with the aid of the scribe strip 12, is once again held on the chuck table.

[0040] Next, the imaging unit takes a picture of the quadrangular prism 8 with its second face 8b facing upwards. Based on the image of the quadrangular prism 8 taken by the imaging unit, the length direction of the quadrangular prism 8 is aligned with the Y-axis direction, and the end of the quadrangular prism 8 along its length direction is used as a reference to align the quadrangular prism 8 with the cutting tool 20 along the Y-axis direction. At this time, the cutting tool 20 is positioned at the center of the adjacent first half-cutting groove 22a.

[0041] Furthermore, similar to the formation of the first and third semi-cutting grooves 22a and 22c, the cutting tip of the cutting tool 20 is driven into the metal tube 2 from the second surface 8b to a depth not reaching the radial center, and the chuck table is fed in the X-axis direction to form the second semi-cutting groove 22b (see reference). Figure 8Furthermore, while indexing and feeding along the length of the quadrangular prism 8 at the same intervals as the first and third half-cut grooves 22a and 22c, the formation of the second half-cut groove 22b is repeated. Thus, multiple second half-cut grooves 22b that do not reach the radial center of the metal tube 2 can be formed between adjacent first half-cut grooves 22a (and also between adjacent third half-cut grooves 22c).

[0042] After the second half-cut groove forming process is performed, the fourth half-cut groove forming process is performed, so that the fourth surface 8d located on the opposite side of the second surface 8b is exposed. On the opposite side corresponding to the second half-cut groove 22b, while indexing feed is performed at predetermined intervals in the length direction of the quadrangular prism 8, the fourth half-cut groove that has not reached the center is formed by the cutting tool 20.

[0043] In the fourth half-groove forming process, similar to the second and third half-groove forming processes, the annular frame 10 supporting the quadrangular prism 8 is removed from the chuck table, and the scribe strip 12 is temporarily peeled off from the quadrangular prism 8. Then, with the fourth face 8d facing upward, the quadrangular prism 8 is reattached to the scribe strip 12, and the quadrangular prism 8, supported by the annular frame 10 with the aid of the scribe strip 12, is once again held on the chuck table.

[0044] Next, the imaging unit takes an image of the quadrangular prism 8 with its fourth face 8d facing upwards. Based on the image of the quadrangular prism 8 taken by the imaging unit, the length direction of the quadrangular prism 8 is aligned with the Y-axis direction, and the end of the quadrangular prism 8 along its length direction is used as a reference to align the quadrangular prism 8 with the cutting tool 20 along the Y-axis direction. At this time, the cutting tool 20 is positioned directly above the second half-cutting groove 22b located at the end of one of the plurality of second half-cutting grooves 22b.

[0045] Furthermore, similarly to the formation of the first to third semi-cutting grooves 22a to 22c, the cutting tip of the cutting tool 20 is driven into the metal tube 2 from the fourth face 8d to a depth not reaching the radial center, and the chuck table is fed in the X-axis direction to form the fourth semi-cutting groove 22d (see reference). Figure 9 (a)). In addition, the fourth half-cut groove 22d is repeatedly formed while being indexed and fed in the longitudinal direction of the quadrangular prism 8 at the same interval as the second half-cut groove 22b. As a result, a plurality of fourth half-cut grooves 22d that do not reach the radial center of the metal tube 2 can be formed on the opposite side corresponding to the plurality of second half-cut grooves 22b respectively.

[0046] Reference Figure 9As can be understood in (a), the Y-axis position of the fourth half-cut groove 22d is the same as that of the second half-cut groove 22b. However, both the second and fourth half-cut grooves 22b and 22d are at depths that do not reach the radial center of the metal tube 2. Therefore, the second half-cut groove 22b and the fourth half-cut groove 22d will not be connected, and the metal tube 2 will not be disconnected by the second and fourth half-cut grooves 22b and 22d.

[0047] Such a process of forming the first to fourth half-cut grooves can be carried out, for example, under the following processing conditions.

[0048] <Workpiece>

[0049] Pipe material: Titanium alloy

[0050] Pipe outer diameter: 0.4mm

[0051] Inner diameter of the tube: 0.35mm

[0052] Pipe length: 300mm

[0053] <First to Fourth Half-Cutting Grooves>

[0054] Groove width: 0.02mm~0.05mm

[0055] Groove depth: 0.15mm~0.18mm

[0056] The spacing between the grooves is 0.10mm to 0.15mm.

[0057] <Cutting device>

[0058] Cutting tool diameter: 50mm

[0059] Width of cutting tool: 0.02mm

[0060] Cutting tool speed: 30,000 rpm

[0061] Cutting water: 1.6L / min

[0062] Machining feed rate: 3mm / s

[0063] Furthermore, after the fourth half-cut groove forming process, the resin 6' of the tetragonal prism 8 is removed using a suitable solvent, thereby obtaining... Figure 9 (b) shows a bendable metal tube 2 with first to fourth half-cut grooves 22a to 22d.

[0064] As described above, in the metal tube manufacturing method of the illustrated embodiment, after forming a quadrangular prism 8 by covering the outer surface of the metal tube 2 with resin 6', the first to fourth half-cut groove forming steps are performed while the quadrangular prism 8 is supported by a surface. Therefore, the quadrangular prism 8 will not shift when the first to fourth half-cut grooves are formed, that is, the metal tube 2 can be stably fixed, and productivity can be improved.

[0065] Unlike the illustrated embodiment, where the cylindrical metal tube 2 is directly adhered to the scribe line 12 and supported by the annular frame 10, the metal tube 2 and the scribe line 12 are in line contact, resulting in unstable fixation of the metal tube 2 and making it difficult to perform precision machining. Instead, in the illustrated embodiment, a tetrahedral prism 8, obtained by covering the outer surface of the metal tube 2 with resin 6', is adhered to the scribe line 12 and supported by the annular frame 10. The tetrahedral prism 8 and the scribe line 12 are in surface contact, resulting in surface support of the tetrahedral prism 8. Therefore, the metal tube 2 can be stably fixed, and precision machining of the metal tube 2 can be performed.

[0066] Furthermore, in the illustrated embodiment, an example is described where the third half-cut groove forming process is performed immediately after the first half-cut groove forming process and the fourth half-cut groove forming process is performed immediately after the second half-cut groove forming process. However, the order of the first to fourth half-cut groove forming processes is irrelevant; for example, they can be performed in the order of the first, second, third, and fourth half-cut groove forming processes.

Claims

1. A method of processing a metal pipe into a bendable metal pipe, wherein the method of processing a metal pipe into a bendable metal pipe comprises the following steps: a jig preparation step of preparing a jig having a linear rectangular groove for housing the metal pipe; a burying step of housing the metal pipe in the rectangular groove and injecting liquid resin to bury the metal pipe with the liquid resin; a removal step of removing a quadrangular prism in which the outer surface of the metal pipe is covered with resin in a quadrangular prism shape from the jig after hardening the liquid resin; a first half-cut groove forming step of exposing a first face of the quadrangular prism and forming a first half-cut groove that does not reach the center by using a cutting tool while indexing in a length direction of the quadrangular prism at a predetermined interval; a second half-cut groove forming step of exposing a second face perpendicular to the first face and forming a second half-cut groove that does not reach the center by using a cutting tool while indexing in the length direction of the quadrangular prism at a predetermined interval at the center of the first half-cut groove and the first half-cut groove adjacent to each other; a third half-cut groove forming step of exposing a third face on the opposite side of the first face and forming a third half-cut groove that does not reach the center by using a cutting tool while indexing in the length direction of the quadrangular prism at a predetermined interval on the opposite side corresponding to the first half-cut groove; and a fourth half-cut groove forming step of exposing a fourth face on the opposite side of the second face and forming a fourth half-cut groove that does not reach the center by using a cutting tool while indexing in the length direction of the quadrangular prism at a predetermined interval on the opposite side corresponding to the second half-cut groove.

2. The method of processing a metal pipe according to claim 1, wherein the third half-cut groove forming step is performed immediately after the first half-cut groove forming step, and the fourth half-cut groove forming step is performed immediately after the second half-cut groove forming step. ​ ​ ​ ​

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