Cavitation treatment method

Abstract

To improve a grinding state of the inside of an object hole curved from an inlet side toward a depth side.SOLUTION: A work (object) 10 including a target hole 20 having a curved portion 210 curved from an inlet side to a back side, and a nozzle 102 having a nozzle hole 103 are immersed in a processing liquid 105 in which a polishing material 106 is mixed, and a jet flow C1 of the processing liquid 105 accompanied by cavitation is injected from the nozzle hole 103 along an injection axis 30, the injection axis 30 being a straight line extending from the outside to the inside of the target hole 20 and having a portion close to an inner side surface 211 which is a surface on an inner peripheral side of the curved portion 210 in a side surface 25 of the target hole 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cavitation treatment method for performing cavitation treatment on an object. [Background technology]

[0002] A cavitation surface treatment method called cavitation abrasive surface finishing (CASF) is known, in which a cavitation jet containing an abrasive is used to smooth the roughness of the workpiece surface and perform peening (US2024 / 0001509A1). Summary of the Invention [Problem to be solved by the invention]

[0003] Conventional cavitation processing methods sometimes fail to grind the inside of a curved target hole. The present invention aims to improve the grinding conditions inside a target hole that curves from the entrance side to the back side. [Means for solving the problem]

[0004] A first aspect of the present invention is A target object including a target hole having a curved portion that curves from an entrance side to a back side and a nozzle having a nozzle are immersed in a processing liquid in which an abrasive is mixed; a straight line extending from the outside to the inside of the target hole and having a portion close to an inner surface, which is a surface of the side of the target hole on the inner circumferential side of the curved portion, is set as an injection axis, and a jet of the treatment liquid accompanied by cavitation is injected from the injection port along the injection axis. This is a cavitation treatment method.

[0005] The object is made of metal. Examples of metals constituting the object include heat-resistant alloys, aluminum alloys, magnesium alloys, titanium, titanium alloys, steel, and corrosion-resistant steel. Examples of the object are machine parts, medical equipment parts, and medical instruments. Examples of machine parts include piping, valves, piping joints, and aerospace parts. Examples of medical instruments include surgical implants. Examples of aerospace parts include aircraft engine parts and other aircraft parts, rocket engine parts, spacecraft parts, satellite parts, and rocket piping.

[0006] The target hole may be a through hole, may extend linearly from an entrance and have a curved portion at the back, or may consist of only a curved portion.

[0007] The nozzle has an orifice diameter of, for example, 0.5 mm to 3 mm, and the jet pressure of the jet is, for example, 10 MPa to 200 MPa.

[0008] Both the object and the nozzle are immersed in a treatment liquid stored in a tank. A jet of the treatment liquid is sprayed from the nozzle toward the object in the treatment liquid. The treatment liquid is, for example, water. The treatment liquid may contain a rust inhibitor.

[0009] The injection axis may be tangent to the inner surface of the curved portion. The injection axis may intersect with the outer surface, which is the side surface on the outer periphery of the curved portion. The injection axis may have a portion that passes closer to the inner surface than the outer surface of the curved portion. The injection axis may extend along the inner surface at a position deeper than the inlet end of the curved portion. The injection axis may extend along the inner surface at the deep (outlet) end of the curved portion.

[0010] Cavitation treatment is performed on a part or the entire side surface of the target hole.

[0011] The abrasive is abrasive particles, such as ceramics, alumina, garnet, or zirconia.

[0012] The structure of the support structure material is, for example, a block support, an adaptive cell support, a rod support, a line support, or a tree support.

[0013] The jet may simultaneously remove the supporting structure and smooth the sides of the target hole that were being supported. [Effects of the Invention]

[0014] According to the present invention, it is possible to improve the grinding condition inside a target hole that curves from the entrance side to the back side. [Brief explanation of the drawings]

[0015] [Figure 1] 2 is a cross-sectional view of the workpiece of the first embodiment (a cross-sectional view taken along line II in FIG. 2); [Figure 2] 1 is a top view of a workpiece according to a first embodiment; [Figure 3] An explanatory diagram of additive manufacturing of a workpiece according to the first embodiment. [Figure 4] Cavitation treatment device of the first embodiment [Figure 5] Cross-sectional view of a workpiece according to a second embodiment DETAILED DESCRIPTION OF THE INVENTION

[0016] The cavitation treatment method of the first embodiment is a method in which a workpiece (object) 10 is formed by additive manufacturing (step 1), the workpiece 10 and nozzle 102 are immersed in a processing liquid 105 in which an abrasive 106 is turbid (step 2), and the support structure material 26 is removed by cavitation treatment (step 3).

[0017] A workpiece (object) 10 in this embodiment will be described with reference to Figures 1 and 2. In Figures 1 and 2, the X and Y directions are horizontal, and the Z direction is vertical. The description will be based on the posture of the workpiece 10 when cavitation treatment is performed.

[0018] The workpiece 10 has an upper surface 21, a lower surface 22, and one target hole 20. The upper surface 21 faces upward. The lower surface 22 faces downward. The upper surface 21 and the lower surface 22 may be parallel. The target hole 20 has an entrance 23, an exit 24, and a side surface 25. The target hole 20 penetrates from the upper surface 21 to the lower surface 22. The entrance 23 is formed in the upper surface 21. The exit 24 is formed in the lower surface 22. The exit 24 side is on the back side of the entrance 23 side. The side surface 25 extends from the entrance 23 to the exit 24. As shown in FIG. 2, the target hole 20 extends long in the X direction when viewed from above. As shown in FIG. 1, the target hole 20 has a curved portion 210. The curved portion 210 curves from the entrance 23 side to the exit 24 side (back side). The entire target hole 20 is the curved portion 210. The curved portion 210 is curved to such an extent that a line of sight is visible from the entrance 23 to the exit 24. The curved portion 210 has an inner surface 211 and an outer surface 212. The inner surface 211 is on the inner circumferential side of the curved portion 210 (the right side in FIG. 1). The outer surface 212 is on the outer circumferential side of the curved portion 210 (the left side in FIG. 1). As shown in FIG. 1, on a plane perpendicular to the X direction, a tangent T passing through a point at the end of the inner surface 211 on the exit 24 side extends in the vertical direction.

[0019] In the target hole 20, the injection axis 30 is defined as follows. However, the injection axis 30 is defined in a cross section of the target hole 20 perpendicular to the X direction. As shown in FIG. 1 , the injection axis 30 is a straight line that passes from the outside of the target hole 20 through the inlet 23 toward the inside, and has a portion that is close to the inner surface 211. At least at the end of the target hole 20 (curved portion 210) on the outlet 24 side, the injection axis 30 passes closer to the inner surface 211 than to the outer surface 212. At the end of the target hole 20 (curved portion 210) on the outlet 24 side, the injection axis 30 extends along the inner surface 211. The injection axis 30 extends vertically downward.

[0020] In step 1, the workpiece 10 is formed by additive manufacturing. As shown in FIG. 3 , material is layered from below on the base surface 300, with the lower surface 22 in contact with the base surface 300. During the forming process, the upward-facing surface of the side surface 25 of the target hole 20 is called the upskin surface 250, and the downward-facing surface is called the downskin surface 260. The upskin surface 250 is made up of the inner surface 211. The downskin surface 260 is made up of the outer surface 212. The inclination angle α of the downskin surface 260 relative to the horizontal direction is smallest at the end of the inlet 23. The inclination angle α is 45 degrees or greater. During the forming process, a support structure 26 is formed inside the target hole 20. The support structure 26 is a long, thin rod extending vertically. The support structure 26 extends from the base surface 300 or the upskin surface 250 to the downskin surface 260.

[0021] A cavitation treatment apparatus for cavitation treatment will now be described. As shown in Fig. 4, a cavitation treatment apparatus 100 includes a tank 101, a nozzle 102, a fixing base 104, and a high-pressure fluid supply source (not shown).

[0022] The tank 101 stores a processing liquid 105. The processing liquid 105 is, for example, water. The processing liquid 105 is a turbid abrasive 106. The tank 101 may include a device for circulating the stored processing liquid 105.

[0023] The nozzle 102 is connected to a high-pressure fluid supply source. The nozzle 102 has an orifice 103. The orifice 103 faces vertically downward. The nozzle 102 sprays a jet C1 of the processing liquid 105 vertically downward from the orifice 103. The jet C1 is a straight rod-shaped jet. The jet C1 contains many cavities. The nozzle 102 can move in three axial directions: horizontally (front-back and left-right), and up-down. The spray speed (pressure) of the jet C1 and the movement of the nozzle 102 in the three axial directions are controlled by a control device (not shown).

[0024] The fixed table 104 fixes the workpiece 10. The workpiece 10 is fixed to the fixed table 104 with fasteners (not shown) such as bolts and clamps. The fixed table 104 can move in the vertical direction. The workpiece 10 is put in and taken out of the tank 101 by the vertical movement of the fixed table 104. The vertical movement of the fixed table 104 is controlled by a control device (not shown).

[0025] The cavitation treatment device 100 can inject the jet C1 at any location on the workpiece 10 from any distance.

[0026] In step 2, the workpiece 10 and the nozzle 102 are immersed in a processing liquid 105 in which the abrasive 106 is turbid. First, the workpiece 10 is fixed to the fixing table 104. The workpiece 10 is fixed in a position in which the entrance 23 of the target hole 20 faces upward and the end of the inner surface 211 on the exit 24 side is parallel to the vertical direction. Next, the fixing table 104 is moved downward, and the workpiece 10 (fixing table 104 ) is immersed in the processing liquid 105 stored in the tank 101 . Next, the nozzle 102 is moved so that it is immersed in the processing liquid 105, and the spray direction of the jet C1 is aligned with the spray axis 30. The nozzle 102 is positioned above the target hole 20. The position of the nozzle 102 in the X direction is set to a position facing the end of the target hole 20 in the X direction.

[0027] In step 3, the support structure 26 is removed by a cavitation process. First, the high-pressure fluid supply source is activated to eject a jet C1 along the ejection axis 30 from the nozzle 103 of the nozzle 102, as shown in Figure 1. Preferably, the jet C1 is a straight rod-shaped jet. The jet C1 contains many cavities. The jet C1 entrains abrasive material 106 and collides with the support structure 26 and the side surface 25 of the target hole 20. The abrasive material 106 contained in the jet C1 breaks off or scrapes off the support structure 26. After the support structure 26 is removed, the abrasive material 106 contained in the jet C1 smoothes the side surface 25. The impact force caused by the collapse of cavities contained in the jet C1 causes the side surface 25 to be peened. The peening process imparts compressive residual stress to the side surface 25. Next, while jet flow C1 is being ejected, as shown in Fig. 2, the nozzle 102 is moved in the X direction along the shape of the target hole 20. By moving the nozzle 102, the jet flow C1 is allowed to reach the entire interior of the target hole 20. Preferably, the nozzle 102 is moved while jet flow C1 is being ejected, as shown by arrow A1. In this way, the jet C1 removes the support structure 26 throughout the interior of the target hole 20. At the same time, the jet C1 smooths and peens the side surfaces 25 (the inner surface 211 and the outer surface 212) of the target hole 20.

[0028] In this manner, in this embodiment, the workpiece 10 is formed by additive manufacturing, and the support structure 26 formed during this process is removed by cavitation processing to form a finished product. During cavitation processing, by bringing the jet axis 30 close to the inner surface 211 of the curved portion 210, the area acted upon by the jet C1 (the area reached by the abrasive 106) is not biased toward the outer periphery of the curved portion 210, and the entire interior of the target hole 20 can be appropriately processed.

[0029] In this embodiment, the injection axis 30 is aligned with the inner surface 211 at the end of the target hole 20 (curved portion 210) on the outlet 24 side. This promotes peening of the inner peripheral region of the curved portion 210. If the injection axis 30 is oriented vertically downward, it is not affected by gravity and the jet C1 can easily reach the target position. When the jet C1 is a straight rod-shaped jet, the dynamic pressure of the jet C1 increases. This promotes fracture and removal of the support structure material 26. Because the jet C1 is a straight rod-shaped jet, the side surface 25 is less likely to deform.

[0030] A cavitation treatment method according to a second embodiment will be described. This embodiment differs from the first embodiment in the shape of the workpiece 10a. As shown in FIG. 5, the workpiece 10a according to this embodiment has one target hole 20a. The target hole 20a has a circular cross section. The target hole 20a has an inlet 23a, an outlet 24a, and a side surface 25a. The target hole 20a has an upper straight portion 220, a curved portion 210a, and a lower straight portion 230. The upper straight portion 220 extends linearly from the inlet 23a in a diagonally downward direction inclined toward one side in the Y direction (toward the lower left in FIG. 5). The curved portion 210a curves from the lower end of the upper straight portion 220 in a diagonally downward direction inclined toward the other side in the Y direction (toward the lower right in FIG. 5). The lower straight portion 230 extends in a straight line from the lower end of the curved portion 210a to the outlet 24a in a diagonally downward direction inclined toward the other side of the Y direction (toward the lower right in FIG. 5). In FIG. 5, line segment L1 indicates the boundary between the upper straight portion 220 and the curved portion 210a. Line segment L2 indicates the boundary between the curved portion 210a and the lower straight portion 230. The curved portion 210a has an inner surface 211a and an outer surface 212a. The lower straight portion 230 has a lower inner surface 231. The lower inner surface 231 is a surface that connects to the inner surface 211a.

[0031] As shown in FIG. 5 , the injection axis 30a is defined in a cross section passing through the central axis of the target hole 20a. The injection axis 30a has at least a portion closer to the inner surface 211a of the curved portion 210a than the outer surface 212a. The injection axis 30a extends along the inner surface 211a on the far side (toward the outlet 24a) of the end of the curved portion 210a on the inlet 23a side. The injection axis 30a passes through the inlet 23a. The angle β between the injection axis 30a and the lower inner surface 231 is made as small as possible. The injection axis 30a may be a straight line that enters the target hole 20a from the inlet 23a and exits through the outlet 24a. The injection axis 30a may be a straight line that enters the target hole 20a from the inlet 23a and intersects with the side surface 25 of the target hole 20a.

[0032] In this embodiment, substantially the same cavitation treatment device 100 as in the first embodiment is used. The steps of the cavitation treatment method in this embodiment differ from those in the first embodiment only in that the nozzle 102 is not moved in the X direction.

[0033] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention, and all technical matters included in the technical ideas described in the claims are subject to the present invention. The above-described embodiments are preferred examples, but a person skilled in the art can realize various alternatives, modifications, variations, or improvements from the contents disclosed in this specification, and these are included in the technical scope described in the appended claims. [Explanation of symbols]

[0034] 10, 10a Workpiece (object) 20,20a Target hole 25,25a side 30,30a injection axis 102 nozzle 103 spout 105 Processing liquid 106 Abrasives 210,210a Curved section 211,211a inner surface C1 Jet

Claims

1. A target object including a target hole having a curved portion that curves from an entrance side to a back side and a nozzle having a nozzle are immersed in a processing liquid in which an abrasive is mixed; a straight line extending from the outside to the inside of the target hole and having a portion close to an inner surface, which is a surface of the side of the target hole on the inner circumferential side of the curved portion, is set as an injection axis, and a jet of the treatment liquid accompanied by cavitation is injected from the injection port along the injection axis. Cavitation treatment method.

2. The injection axis extends along the deep side of the inner surface. The cavitation treatment method according to claim 1 .

3. The jet is a straight rod-shaped jet. The cavitation treatment method according to claim 1 or 2.

4. The injection axis extends vertically downward. The cavitation treatment method according to any one of claims 1 to 3.

5. The object is an object manufactured by additive manufacturing. The cavitation treatment method according to any one of claims 1 to 4.

6. shaping the object by additive manufacturing; The cavitation treatment method according to any one of claims 1 to 5.

7. forming a support structure inside the target hole to support the side surface of the target hole; removing the support structure with the jet; The cavitation treatment method according to claim 6.

8. When forming the target object, the minimum inclination angle of a downward-facing surface of the side surface of the target hole with respect to the horizontal direction is 45 degrees or more. The cavitation treatment method according to any one of claims 5 to 7.

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