Cavitation Treatment Method

Abstract

To improve the grinding condition inside a target hole that curves from the entrance side to the back side. [Solution] A workpiece (target object) 10 including a target hole 20 having a curved portion 210 that curves from the entrance side to the back side, and a nozzle 102 having a nozzle hole 103 are immersed in a processing liquid 105 in which an abrasive 106 is mixed, and a jet C1 of the processing liquid 105 accompanied by cavitation is sprayed from the nozzle hole 103 along the spray axis 30, which is a straight line that runs from the outside to the inside of the target hole 20 and has a portion of the side 25 of the target hole 20 that is close to the inner surface 211, which is the inner surface of the curved portion 210.

Description

[Technical field]

[0001] The present invention relates to a cavitation processing method for performing cavitation processing 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] According to conventional cavitation processing methods, there are cases where the inside of a curved target hole cannot be ground. An object of the present invention is 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] The first aspect of the present invention is A target object including a target hole having a curved portion that curves from the entrance side to the back side This is then shaped using additive manufacturing. The object and a nozzle having a nozzle hole is immersed in a processing liquid in which the abrasive is mixed, A straight line extending from the outside to the inside of the target hole, 、 The inner surface of the side of the target hole, which is the surface on the inner periphery side of the curved portion On the other hand, the hole is more inward than the entrance side of the target hole. A straight line having adjacent portions 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. death, The inside of the target hole is subjected to cavitation treatment by the jet. do, A cavitation treatment method.

[0005] The object is made of a 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 the machine parts include piping, valves, piping joints, and aerospace parts. Examples of the medical instruments include surgical implants. Examples of the 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. The target hole may extend linearly from an entrance and have a curved portion on the inner side. The target hole may be composed only of 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] The object and the nozzle are both immersed in a treatment liquid stored in a tank. In the treatment liquid, a jet of the treatment liquid is sprayed from the nozzle toward the object. 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 side surface of the curved portion. The injection axis may intersect with the outer side 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 side surface than the outer side surface of the curved portion. The injection axis may extend along the inner side surface at a position deeper than the inlet end of the curved portion. The injection axis may extend along the inner side surface at the deep (outlet) end of the curved portion.

[0010] A cavitation treatment is performed on a part or the entire surface of the side 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, and a tree support.

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

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

[0016] The cavitation treatment method of the first embodiment is a method in which a workpiece (object) 10 is shaped by additive manufacturing (step 1), the workpiece 10 and nozzle 102 are immersed in a processing liquid 105 in which an abrasive 106 is clouded (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 directions, and the Z direction is vertical. The description will be based on the posture of the workpiece 10 when the 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 is a surface facing upward. The lower surface 22 is a surface facing 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 the back side with respect to 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 can pass 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 periphery side of the curved portion 210 (the right side in FIG. 1). The outer surface 212 is on the outer periphery 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 line T passing through a point at the end point on the exit 24 side of the inner surface 211 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 through the inlet 23 from the outside of the target hole 20 toward the inside, and has a portion close to the inner side 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 side surface 211 than to the outer side 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 side surface 211. The injection axis 30 extends vertically downward.

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

[0021] The cavitation treatment device for cavitation treatment will now be described. As shown in Fig. 4, the cavitation treatment device 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 liquid obtained by mixing an 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: the horizontal direction (front-back and left-right directions) and the up-down direction. 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 by 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 onto 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 an abrasive 106 is muddied. 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 as to be immersed in the processing liquid 105, and the jet direction of the jet C1 is aligned with the jet 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 jet a jet C1 along the jet axis 30 from the nozzle 103 of the nozzle 102, as shown in Fig. 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 support structure 26 is broken off or scraped off by the abrasive material 106 contained in the jet C1. After the support structure 26 is removed, the side surface 25 is smoothed by the abrasive material 106 contained in the jet C1. The side surface 25 is peened by the impact force when the cavities contained in the jet C1 collapse. The peening process imparts compressive residual stress to the side surface 25. 2, while jet flow C1 is being ejected, 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 area of ​​the target hole 20. Preferably, the nozzle 102 is moved while jet flow C1 is being ejected, as shown by the arrow A1. In this manner, the jet C1 removes the support structure 26 from the entire interior of the target hole 20. At the same time, the jet C1 smoothes and peens the side surface 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 the process is removed by cavitation processing to produce a product. During the cavitation processing, by bringing the jet axis 30 close to the inner surface 211 of the curved portion 210, the area where the jet C1 acts (the area where the abrasive 106 reaches) is not biased toward the outer periphery of the curved portion 210, and the entire interior area 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 the breakage and removal of the support structure 26. Because the jet C1 is straight rod-shaped, the side surface 25 is less likely to deform.

[0030] A cavitation processing method according to the second embodiment will be described. In this embodiment, the shape of the workpiece 10a is different from that of the first embodiment. 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 side surface 211a and an outer side surface 212a. The lower straight portion 230 has a lower inner side surface 231. The lower inner side surface 231 is a surface that connects to the inner side 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 than the outer surface 212a of the curved portion 210a. The injection axis 30a extends along the inner surface 211a on the inner side (outlet 24a side) of the inlet 23a side end of the curved portion 210a. 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 to 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 embodiment, and various modifications are possible without departing from the gist of the present invention, and all technical matters included in the technical ideas described in the claims are the subject of the present invention. The above-described embodiment shows a preferred example, 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 attached claims. [Explanation of symbols]

[0034] 10, 10a Work (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 the entrance side to the back side is manufactured by additive manufacturing; The object and a nozzle having a nozzle hole are immersed in a processing liquid in which the abrasive is mixed; a straight line extending from the outside to the inside of the target hole, the straight line having a portion closer to an inner surface of the side of the target hole, which is the inner peripheral surface of the curved portion, on the inner side of the side of the target hole, than on the inlet side of the target hole, 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; The inside of the target hole is subjected to cavitation treatment by the jet. Cavitation treatment methods.

2. The injection axis extends along the inner side of the inner surface. The method for treating cavitation 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 claim 1 or 2.

5. A support structure for supporting the side surface of the target hole is formed inside the target hole; removing the support structure with the jet; The cavitation treatment method according to claim 1 or 2.

6. When the target object is formed, a minimum inclination angle of a downwardly facing surface among the side surfaces of the target hole with respect to a horizontal direction is 45 degrees or more. The cavitation treatment method according to claim 1 or 2.

Images