Precision machining method for ultrathin-wall beryllium pipe part

Abstract

The invention discloses a precision machining method for ultrathin-wall beryllium pipe parts, and belongs to the technical field of pipe part machining. The method specifically comprises the steps of rough turning of a first outer circular face and an inner hole, first time of aging treatment, semi-finish turning of the first outer circular face, semi-finish milling of a second outer circular face, second time of aging treatment, finish milling of the second outer circular face and an arc transition face, finish turning of the inner hole and an end face, finish turning of the first outer circular face and chemical milling. According to the machining method, the special tool is designed, and the outer circle face of the beryllium pipe is machined in a regional mode, so that surface cracking or cracking and deformation of the ultra-thin-wall beryllium pipe are avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of tube parts processing, and in particular relates to a precision processing method for ultra-thin wall beryllium tube parts. Background Art

[0002] As a part made of rare and lightweight beryllium metal materials with high elastic modulus, high melting point, high specific stiffness, ultra-thin wall beryllium tube parts are the core components of major testing machine equipment and are the heart of this type of equipment.

[0003] Beryllium is a brittle metal material, which is prone to surface damage, cracks, and broken edges and corners during machining. Due to the thin wall of beryllium tube parts, high precision requirements, poor structural rigidity, weak strength, strict use environment requirements, and extremely high part quality requirements, it is very easy to be subjected to force, heat, cutting, stress deformation and cracking during machining. At present, there is no corresponding precision machining technology method abroad.

[0004] The existing processing method for pipe parts is: blank → rough turning of inner hole → rough turning of outer circle → aging treatment → fine turning of inner hole → fine turning of outer circle. The brittle ultra-thin wall beryllium tube is easily cracked and scrapped by using the existing processing method for pipe parts, and the product accuracy cannot meet the use requirements. Therefore, it is urgent to develop a precision processing method for ultra-thin wall beryllium tube parts. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes a precision machining method for ultra-thin-wall beryllium tube parts, which avoids surface cracking or fissures and deformation of the ultra-thin-wall beryllium tube by designing special tooling and machining the outer cylindrical surface of the beryllium tube in different areas.

[0006] The present invention provides a precision machining method for an ultra-thin wall beryllium tube part, wherein the outer cylindrical surface of the beryllium tube comprises two first outer cylindrical surfaces, two arc transition surfaces and a second outer cylindrical surface; the two ends of the second outer cylindrical surface are respectively connected to an arc transition surface, and the other end of each of the arc transition surfaces is connected to a first outer cylindrical surface; a plurality of reinforcing ribs with equal intervals are arranged on the second outer cylindrical surface;

[0007] The method comprises the following steps:

[0008] Step S1, assembling the pre-treated beryllium tube on two first fixtures by double-center clamping, the fitting clearance between the two first fixtures and the beryllium tube is ≤0.05mm, and the perpendicularity between the two first fixtures and the outer circle of the beryllium tube is ≤0.05mm, and then rough turning the first outer circle surface and inner hole of the beryllium tube;

[0009] Wherein, the first tooling is an end cover with a center hole;

[0010] Step S2, removing the first tooling, and subjecting the beryllium tube that has been rough-turned on the first outer cylindrical surface and the inner hole to a first aging treatment;

[0011] Step S3, using the first tooling and the second tooling to fix the beryllium tube that has undergone the first aging treatment, the outer circle runout of the fixed beryllium tube is ≤0.05mm, and then the first outer circle surface of the beryllium tube is semi-finished;

[0012] Wherein, the second tooling is a mandrel with a central axis hole, one end of the mandrel is provided with a clamping platform protruding from the outer periphery of the mandrel, a first 60° conical surface is provided on a surface of the clamping platform close to the other end of the mandrel, a long step is provided at the other end of the mandrel, and an external thread is provided at a position connected to the long step and away from the end face of the mandrel;

[0013] Step S4, semi-finishing the second outer cylindrical surface of the beryllium tube after semi-finishing the first outer cylindrical surface, so as to form a plurality of reinforcing ribs with equal intervals on the second outer cylindrical surface of the beryllium tube;

[0014] Step S5, removing the first tooling and the second tooling, and subjecting the beryllium tube having the semi-finished milled second outer cylindrical surface to a second aging treatment;

[0015] Step S6, using the first tool and the second tool to fix the beryllium tube that has undergone the second aging treatment, the outer circle runout of the fixed beryllium tube is ≤0.03mm, and the second outer circle surface and the arc transition surface of the beryllium tube that has undergone the second aging treatment are finely milled;

[0016] Step S7, putting the third tooling set on the outer circumference of the beryllium tube fixed by the first tooling and the second tooling and assembling them by bonding, injecting wax into the gap between the third tooling and the beryllium tube through the wax injection port of the third tooling, removing the first tooling and the second tooling after the wax solidifies, obtaining the beryllium tube fixed by the third tooling, and then fine turning the inner hole and end face of the beryllium tube;

[0017] Wherein, the third tooling is a cylindrical ring without clamping force, the inner hole surfaces of the two ports of the cylindrical ring are both provided with steps protruding from the inner hole surface of the cylindrical ring to form a step inner hole, the step is provided with a plurality of first grooves with equal intervals, the depth of each first groove is less than the height of the step, and the side surface of the cylindrical ring is provided with a plurality of wax injection ports penetrating the side surface of the cylindrical ring; the fitting clearance between the inner hole surface of the cylindrical ring and the beryllium tube is ≥0.05mm, and the aperture of the step inner hole is equal to the outer diameter of the beryllium tube;

[0018] Step S8, remove the third tooling, and then embed the fourth tooling into the inner hole of the beryllium tube whose inner hole and end face have been precision-turned, the matching clearance between the fourth tooling and the beryllium tube is ≤0.05mm, and wax is injected into the gap between the fourth tooling and the beryllium tube through one end of the second groove of the fourth tooling, and after the wax solidifies, one end of the long step of the second tooling is inserted into the central axis hole of the fourth tooling from one end of the 60° tapered hole of the fourth tooling, and the other end of the beryllium tube is fixed by the first tooling, so as to obtain the beryllium tube fixed by the first tooling, the second tooling and the fourth tooling, and then precision-turn the first outer cylindrical surface of the beryllium tube;

[0019] The fourth tooling is a cylinder with a central axis hole, the inner surface of one end of the fourth tooling is provided with a second 60° conical surface matching the first 60° conical surface to form a 60° conical hole, and the outer periphery of the fourth tooling is provided with a plurality of second grooves at equal intervals, and the depth of each of the second grooves is less than half of the difference between the outer diameter and the inner diameter of the fourth tooling;

[0020] Step S9, removing the first tooling, the second tooling and the fourth tooling, and subjecting the beryllium tube having the first outer cylindrical surface finely turned to chemical milling.

[0021] According to the method for precision machining of ultra-thin-wall beryllium tube parts of the present invention, in step S1, the process parameters for rough machining the first outer cylindrical surface of the beryllium tube are as follows:

[0022] The tool tip arc is R0.1mm~R0.3mm, the cutting depth is 0.05~0.2mm, the rotation speed is 200~500r / min, the feed speed is 0.01~0.03mm / r, and the reserved processing allowance is 0.1~0.3mm.

[0023] According to the method for precision machining of ultra-thin-wall beryllium tube parts of the present invention, in step S1, the process parameters for rough turning the inner hole of the beryllium tube are as follows:

[0024] The tool tip arc is R0.1mm~R0.3mm, the cutting depth is 0.05~0.2mm, the rotation speed is 200~500r / min, the feed speed is 0.01~0.03mm / r, and the reserved processing allowance is 0.05~0.15mm.

[0025] According to the method for precision machining of ultra-thin-wall beryllium tube parts of the present invention, in step S3, the process parameters for semi-finishing the first outer cylindrical surface of the beryllium tube are as follows:

[0026] The tool tip arc is R0.1mm~R0.2mm, the cutting depth is 0.05~0.15mm, the rotation speed is 200~300r / min, the feed speed is 0.01~0.03mm / r, and the reserved processing allowance is 0.05~0.2mm.

[0027] According to the method for precision machining of ultra-thin-wall beryllium tube parts of the present invention, in step S4, the process parameters for semi-finishing the second outer cylindrical surface of the beryllium tube after semi-finishing the first outer cylindrical surface are as follows:

[0028] The cutting depth is 0.05-0.15 mm, the rotation speed is 500-800 r / min, the feed speed is 100-300 mm / min, and the processing is performed layer by layer until the reserved processing allowance is 0.1-0.3 mm.

[0029] According to the method for precision machining of ultra-thin-wall beryllium tube parts of the present invention, in step S6, the process parameters for fine milling the second outer cylindrical surface and the arc transition surface of the beryllium tube that has undergone the second aging treatment are as follows:

[0030] The cutting depth is 0.05~0.1mm, the rotation speed is 600~1500r / min, and the feed speed is 50~200mm / min.

[0031] According to the method for precision machining of ultra-thin-wall beryllium tube parts of the present invention, in step S7, the process parameters for precision machining the inner hole and end face of the beryllium tube are as follows:

[0032] The tool tip arc is ≤R0.1mm, the cutting depth is 0.05~0.1mm, the rotation speed is 600~1500r / min, and the feed speed is 50~200mm / min.

[0033] According to the method for precision machining of ultra-thin-wall beryllium tube parts of the present invention, in step S8, the process parameters for fine turning the first outer cylindrical surface of the beryllium tube are as follows:

[0034] The tool tip arc is ≤R0.1mm, the cutting depth is 0.05~0.1mm, the rotation speed is 500~1000r / min, and the feed speed is 50~200mm / min.

[0035] According to the method for precision machining of ultra-thin-wall beryllium tube parts of the present invention, in step S9, the beryllium tube with the first outer cylindrical surface finely turned is subjected to chemical milling for 1-3 minutes.

[0036] The solution proposed by the present invention has the following technical effects:

[0037] The invention avoids cracking or fissures and deformation on the surface of the ultra-thin-wall beryllium tube by designing a special tool and processing the outer cylindrical surface of the beryllium tube in different areas.

[0038] In addition, the ultra-thin wall beryllium tube obtained by the method of the present invention has a wall thickness of ≤0.8mm, a shape and position accuracy of ≤0.02mm, and a dimensional accuracy of ≤0.03mm, which meets the high-precision requirements of the ultra-thin wall beryllium tube and achieves an overall total leakage rate of ≤0.5 to 2.5×10-11Pa.m 3 / s, the ultimate vacuum degree is ≤3~8×10-8Pa, which is required for product application in strict environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 It is a structural schematic diagram of a beryllium tube obtained by a precision machining method for an ultra-thin-wall beryllium tube part in one embodiment of the present invention.

[0041] Figure 2 yes Figure 1 Enlarged schematic diagram of the middle reinforcement rib.

[0042] Figure 3 It is a structural schematic diagram of a first tool in a method for precision machining of an ultra-thin-wall beryllium tube part in one embodiment of the present invention.

[0043] Figure 4 The present invention is a schematic structural diagram of a method for precision machining of an ultra-thin-wall beryllium tube part in one embodiment of the present invention after assembling a first tool and a beryllium tube to be machined.

[0044] Figure 5 It is a structural schematic diagram of a second tool in a method for precision machining of an ultra-thin-wall beryllium tube part in one embodiment of the present invention.

[0045] Figure 6 The present invention is a schematic structural diagram of a method for precision machining of an ultra-thin-wall beryllium tube part in one embodiment of the present invention, wherein a first tool and a second tool are simultaneously assembled with the beryllium tube to be machined.

[0046] Figure 7 It is a structural schematic diagram of a third tool in a method for precision machining of an ultra-thin-wall beryllium tube part in one embodiment of the present invention.

[0047] Figure 8 The present invention is a schematic structural diagram of a method for precision machining of an ultra-thin-wall beryllium tube part in one embodiment of the present invention, wherein a first tool, a second tool and a third tool are simultaneously assembled with the beryllium tube to be machined.

[0048] Fig. 9 The present invention is a schematic structural diagram of a method for precision machining of an ultra-thin-wall beryllium tube part in one embodiment of the present invention after the third tool is assembled with the beryllium tube to be machined.

[0049] Fig.10It is a structural schematic diagram of a fourth tool in a method for precision machining of an ultra-thin-wall beryllium tube part in one embodiment of the present invention.

[0050] Fig.11 It is a structural schematic diagram of a method for precision machining of an ultra-thin-wall beryllium tube part in one embodiment of the present invention after a first tool, a second tool and a fourth tool are simultaneously assembled with the beryllium tube to be machined.

[0051] Among them, 1-first outer cylindrical surface, 2-arc transition surface, 3-second outer cylindrical surface, 4-reinforcing ribs, 5-first tooling, 6-second tooling, 7-clamping table, 8-first 60° conical surface, 9-long step, 10-external thread, 11-third tooling, 12-step inner hole, 13-first groove, 14-wax injection port, 15-fourth tooling, 16-second 60° conical surface, 17-second groove, 18-water flow groove, 19-nut. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] The purpose of this embodiment is to propose a processing method for high-precision ultra-thin wall tube parts made of rare, lightweight, brittle metal beryllium material with a length ≥ L00mm, a wall thickness ≤0.8mm, a shape and position accuracy ≤0.02mm, and a dimensional accuracy ≤0.03mm, so as to achieve precision processing of ultra-thin wall high-precision beryllium tube parts, meet the high-precision requirements of ultra-thin wall beryllium tubes and the overall total leakage rate: ≤0.5~2.5×10-11Pa.m 3 / s, ultimate vacuum degree: ≤3~8×10-8Pa, strict environmental application requirements.

[0054] like Figure 1 As shown, the outer cylindrical surface of the target ultra-thin-wall beryllium tube includes two first outer cylindrical surfaces 1, two arc transition surfaces 2 and a second outer cylindrical surface 3; the two ends of the second outer cylindrical surface 3 are respectively connected to an arc transition surface 2, and the other end of each of the arc transition surfaces 2 is connected to a first outer cylindrical surface 1; a plurality of reinforcing ribs 4 with equal intervals are arranged on the second outer cylindrical surface 3.

[0055] Specifically, the wall thickness of the first outer cylindrical surface 1 of the target ultra-thin wall beryllium tube is ≤1.6 mm, the wall thickness of the second outer cylindrical surface 3 is ≤0.8 mm, the target ultra-thin wall beryllium tube has 6 reinforcing ribs 4, and the thickness of each reinforcing rib 4 is ≤0.8 mm (such as Figure 2 shown).

[0056] This embodiment provides a precision machining method for an ultra-thin-wall beryllium tube part, and the overall machining process is: rough turning the first outer cylindrical surface and inner hole → first aging treatment → semi-finishing turning the first outer cylindrical surface → semi-finishing milling the second outer cylindrical surface → second aging treatment → finishing milling the second outer cylindrical surface and arc transition surface → finishing turning the inner hole and end face → finishing turning the first outer cylindrical surface → chemical milling.

[0057] The specific processing method includes the following steps:

[0058] Step S1, assembling the pre-treated beryllium tube on two first fixtures by double-center clamping, the fitting clearance between the two first fixtures and the beryllium tube is ≤0.05mm, the perpendicularity between the two first fixtures and the outer circle of the beryllium tube is ≤0.05mm, and then the first outer circle surface and inner hole of the beryllium tube are rough-turned.

[0059] Preferably, when rough turning the inner hole of the beryllium tube, the beryllium tube is fixed with copper claws whose inner diameter is equal to the outer diameter of the beryllium tube, so that the clamping force is evenly distributed on the surface of the beryllium tube, changing the linear contact to full surface contact, increasing the contact area, reducing the clamping force per unit area, and thus avoiding clamping deformation and cracking of the beryllium tube during the rough turning process.

[0060] This embodiment uses a double-center clamping method to assemble the pre-treated beryllium tube on two first fixtures to avoid deformation caused by directly clamping the beryllium tube and ensure that the two end surfaces of the beryllium tube are perpendicular to the outer cylindrical surface when rough turning the first outer cylindrical surface.

[0061] Among them, Figure 3 As shown in FIG. 1 , the first fixture 5 is an end cap with a central hole. The structure of the beryllium tube assembled on the two first fixtures 5 is as shown in FIG. Figure 4 shown.

[0062] Preferably, the outer cylindrical surface and end surface of the first tooling 5 in contact with the inner hole surface of the beryllium tube are both provided with a plurality of water flow grooves 18 with equal intervals, which are used for the circulation of adhesive when the beryllium tube is bonded to the first tooling to ensure that the beryllium tube and the first tooling are firmly bonded, and are also used for the circulation of debonding agent when the beryllium tube is separated from the tooling to ensure that the beryllium tube and the first tooling are easily separated without damaging each other.

[0063] Step S2, removing the first tooling, and subjecting the beryllium tube that has been rough-turned on the first outer cylindrical surface and the inner hole to a first aging treatment.

[0064] Preferably, the beryllium tube that has been rough-turned on the first outer cylindrical surface and the inner hole is subjected to multiple first aging treatments to fully release the internal stress and processing stress of the beryllium tube part, thereby avoiding deformation of the beryllium tube part caused by the internal stress.

[0065] Step S3, using the first tooling and the second tooling to fix the beryllium tube that has undergone the first aging treatment, the outer circle runout of the fixed beryllium tube is ≤0.05mm, and then the first outer circle surface of the beryllium tube is semi-finished.

[0066] Among them, Figure 5 As shown, the second tooling 6 is a core shaft with a central axis hole, one end of the core shaft is provided with a clamping platform 7 protruding from the outer circumference of the core shaft, a first 60° conical surface 8 is provided on a side of the clamping platform 7 close to the other end of the core shaft, a long step 9 is provided at the other end of the core shaft, and an external thread 10 is provided at a position connected to the long step 9 and away from the end face of the core shaft.

[0067] Step S4, semi-finishing milling the second outer cylindrical surface of the beryllium tube that has been semi-finished on the first outer cylindrical surface, so as to form a plurality of reinforcing ribs with equal intervals on the second outer cylindrical surface of the beryllium tube.

[0068] Step S5, removing the first tooling and the second tooling, and subjecting the beryllium tube having the semi-finished milled second outer cylindrical surface to a second aging treatment.

[0069] Preferably, the beryllium tube with the semi-finished second outer cylindrical surface is subjected to multiple second aging treatments to fully release the internal stress and processing stress of the beryllium tube part, thereby avoiding deformation of the beryllium tube part caused by the internal stress.

[0070] Step S6, using the first tool and the second tool to fix the beryllium tube after the second aging treatment, the outer circle runout of the fixed beryllium tube is ≤0.03mm, and the second outer circle surface and the arc transition surface of the beryllium tube after the second aging treatment are finely milled.

[0071] Preferably, the second outer cylindrical surface 3 is firstly processed layer by layer and angle by angle to a preset size to ensure that the symmetry accuracy is ≤ 0.02 mm, and then a Φ6mm-Φ10mm ball-end milling cutter is used to complete the processing of the 6 reinforcing ribs at each angle.

[0072] Step S7, put the third tooling set on the outer circumference of the beryllium tube fixed by the first tooling and the second tooling and assemble them by bonding, inject wax into the gap between the third tooling and the beryllium tube through the wax injection port of the third tooling, remove the first tooling and the second tooling after the wax solidifies, obtain the beryllium tube fixed by the third tooling, and then fine-turn the inner hole and end face of the beryllium tube.

[0073] Among them, the third tooling 11 is a cylindrical ring without clamping force, and the inner hole surfaces of the two ports of the cylindrical ring are both provided with steps protruding from the inner hole surface of the cylindrical ring to form a step inner hole 12, and the step is provided with a plurality of first grooves 13 with equal intervals, and the depth of each first groove 13 is less than the height of the step, and the side of the cylindrical ring is provided with a plurality of wax injection ports 14 that penetrate the side of the cylindrical ring; the fitting clearance between the inner hole surface of the cylindrical ring and the beryllium tube is ≥0.05mm, and the aperture of the step inner hole 12 is equal to the outer diameter of the beryllium tube.

[0074] In this embodiment, after the third tooling is mounted on the outer periphery of the beryllium tube fixed by the first tooling and the second tooling, the first groove is used as a flow path for glue, and the third tooling and the beryllium tube are bonded and fixed by pouring glue into the first groove. Preferably, the depth of the first groove is 3 mm, and the height of the step is 5 mm.

[0075] Step S8, remove the third tooling, and then embed the fourth tooling into the inner hole of the beryllium tube whose inner hole and end face have been precision-turned, the matching clearance between the fourth tooling and the beryllium tube is ≤0.05mm, and wax is injected into the gap between the fourth tooling and the beryllium tube through one end of the second groove of the fourth tooling. After the wax solidifies, one end of the long step of the second tooling is inserted into the central axis hole of the fourth tooling from one end of the 60° tapered hole of the fourth tooling, and the other end of the beryllium tube is fixed by the first tooling, so as to obtain the beryllium tube fixed by the first tooling, the second tooling and the fourth tooling, and then the first outer cylindrical surface of the beryllium tube is precision-turned.

[0076] Among them, the fourth tooling 15 is a cylinder with a central axis hole, and the inner surface of one end of the fourth tooling is provided with a second 60° conical surface 16 matching the first 60° conical surface to form a 60° conical hole, and the outer periphery of the fourth tooling is provided with a plurality of second grooves 17 with equal intervals, and the depth of each of the second grooves 17 is less than half of the difference between the outer diameter and the inner diameter of the fourth tooling.

[0077] In this embodiment, the first 60° conical surface and the second 60° conical surface are completely matched, so that the second tooling and the fourth tooling can be automatically centered.

[0078] Step S9, removing the first tooling, the second tooling and the fourth tooling, and subjecting the beryllium tube having the first outer cylindrical surface finely turned to chemical milling treatment to remove micro cracks on the surface of the beryllium tube.

[0079] In some embodiments, in step S1, the process parameters for rough turning the first outer cylindrical surface of the beryllium tube are as follows:

[0080] The tool tip arc is R0.1mm~R0.3mm, the cutting depth is 0.05~0.2mm, the rotation speed is 200~500r / min, the feed speed is 0.01~0.03mm / r, and the reserved processing allowance is 0.1~0.3mm.

[0081] In some embodiments, in step S1, the process parameters for rough turning the inner hole of the beryllium tube are as follows:

[0082] The tool tip arc is R0.1mm~R0.3mm, the cutting depth is 0.05~0.2mm, the rotation speed is 200~500r / min, the feed speed is 0.01~0.03mm / r, and the reserved processing allowance is 0.05~0.15mm.

[0083] In some embodiments, in step S3, the process parameters for semi-finishing the first outer cylindrical surface of the beryllium tube are as follows:

[0084] The tool tip arc is R0.1mm~R0.2mm, the cutting depth is 0.05~0.15mm, the rotation speed is 200~300r / min, the feed speed is 0.01~0.03mm / r, and the reserved processing allowance is 0.05~0.2mm.

[0085] In some embodiments, in step S4, the process parameters for semi-finishing the second outer cylindrical surface of the beryllium tube after semi-finishing the first outer cylindrical surface are as follows:

[0086] The cutting depth is 0.05-0.15 mm, the rotation speed is 500-800 r / min, the feed speed is 100-300 mm / min, and the processing is performed layer by layer until the reserved processing allowance is 0.1-0.3 mm.

[0087] In some embodiments, in step S6, the process parameters for fine milling the second outer cylindrical surface and the arc transition surface of the beryllium tube that has undergone the second aging treatment are as follows:

[0088] The cutting depth is 0.05~0.1mm, the rotation speed is 600~1500r / min, and the feed speed is 50~200mm / min.

[0089] In some embodiments, in step S7, the process parameters for finishing the inner hole and end surface of the beryllium tube are as follows:

[0090] The tool tip arc is ≤R0.1mm, the cutting depth is 0.05~0.1mm, the rotation speed is 600~1500r / min, and the feed speed is 50~200mm / min.

[0091] In some embodiments, in step S8, the process parameters for finishing the first outer cylindrical surface of the beryllium tube are as follows:

[0092] The tool tip arc is ≤R0.1mm, the cutting depth is 0.05~0.1mm, the rotation speed is 500~1000r / min, and the feed speed is 50~200mm / min.

[0093] In some embodiments, in step S9, the beryllium tube having the first outer cylindrical surface finely turned is subjected to chemical milling for 1-3 minutes.

[0094] In summary, the solution proposed by the present invention has the following technical effects:

[0095] The invention avoids cracking or fissures and deformation on the surface of the ultra-thin-wall beryllium tube by designing a special tool and processing the outer cylindrical surface of the beryllium tube in different areas.

[0096] In addition, the ultra-thin wall beryllium tube obtained by the method of the present invention has a wall thickness of ≤0.8mm, a shape and position accuracy of ≤0.02mm, and a dimensional accuracy of ≤0.03mm, which meets the high-precision requirements of the ultra-thin wall beryllium tube and achieves an overall total leakage rate of ≤0.5 to 2.5×10-11Pa.m 3 / s, the ultimate vacuum degree is ≤3~8×10-8Pa, which is required for product application in strict environment.

[0097] Please note that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not 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. The above embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all belong to the scope of protection of the present application. Therefore, the scope of protection of the patent in this application shall be based on the attached claims.

Claims

1. A method for precision machining of ultra-thin wall beryllium tube parts, characterized in that: The outer cylindrical surface of the beryllium tube includes two first outer cylindrical surfaces, two arc transition surfaces and a second outer cylindrical surface; the two ends of the second outer cylindrical surface are respectively connected to an arc transition surface, and the other end of each of the arc transition surfaces is connected to a first outer cylindrical surface; a plurality of reinforcing ribs with equal intervals are arranged on the second outer cylindrical surface; The method comprises the following steps: Step S1, assembling the pre-treated beryllium tube on two first fixtures by double-center clamping, the fitting clearance between the two first fixtures and the beryllium tube is ≤0.05mm, and the perpendicularity between the two first fixtures and the outer circle of the beryllium tube is ≤0.05mm, and then rough turning the first outer circle surface and inner hole of the beryllium tube; Wherein, the first tooling is an end cover with a center hole; Step S2, removing the first tooling, and subjecting the beryllium tube that has been rough-turned on the first outer cylindrical surface and the inner hole to a first aging treatment; Step S3, using the first tooling and the second tooling to fix the beryllium tube that has undergone the first aging treatment, the outer circle runout of the fixed beryllium tube is ≤0.05mm, and then the first outer circle surface of the beryllium tube is semi-finished; Wherein, the second tooling is a mandrel with a central axis hole, one end of the mandrel is provided with a clamping platform protruding from the outer periphery of the mandrel, a first 60° conical surface is provided on a surface of the clamping platform close to the other end of the mandrel, a long step is provided at the other end of the mandrel, and an external thread is provided at a position connected to the long step and away from the end face of the mandrel; Step S4, semi-finishing the second outer cylindrical surface of the beryllium tube after semi-finishing the first outer cylindrical surface, so as to form a plurality of reinforcing ribs with equal intervals on the second outer cylindrical surface of the beryllium tube; Step S5, removing the first tooling and the second tooling, and subjecting the beryllium tube having the semi-finished milled second outer cylindrical surface to a second aging treatment; Step S6, using the first tool and the second tool to fix the beryllium tube that has undergone the second aging treatment, the outer circle runout of the fixed beryllium tube is ≤0.03mm, and the second outer circle surface and the arc transition surface of the beryllium tube that has undergone the second aging treatment are finely milled; Step S7, putting the third tooling set on the outer circumference of the beryllium tube fixed by the first tooling and the second tooling and assembling them by bonding, injecting wax into the gap between the third tooling and the beryllium tube through the wax injection port of the third tooling, removing the first tooling and the second tooling after the wax solidifies, obtaining the beryllium tube fixed by the third tooling, and then fine turning the inner hole and end face of the beryllium tube; Wherein, the third tooling is a cylindrical ring without clamping force, the inner hole surfaces of the two ports of the cylindrical ring are both provided with steps protruding from the inner hole surface of the cylindrical ring to form a step inner hole, the step is provided with a plurality of first grooves with equal intervals, the depth of each first groove is less than the height of the step, and the side surface of the cylindrical ring is provided with a plurality of wax injection ports penetrating the side surface of the cylindrical ring; the fitting clearance between the inner hole surface of the cylindrical ring and the beryllium tube is ≥0.05mm, and the aperture of the step inner hole is equal to the outer diameter of the beryllium tube; Step S8, remove the third tooling, and then embed the fourth tooling into the inner hole of the beryllium tube whose inner hole and end face have been precision-turned, the matching clearance between the fourth tooling and the beryllium tube is ≤0.05mm, and wax is injected into the gap between the fourth tooling and the beryllium tube through one end of the second groove of the fourth tooling, and after the wax solidifies, one end of the long step of the second tooling is inserted into the central axis hole of the fourth tooling from one end of the 60° tapered hole of the fourth tooling, and the other end of the beryllium tube is fixed by the first tooling, so as to obtain the beryllium tube fixed by the first tooling, the second tooling and the fourth tooling, and then precision-turn the first outer cylindrical surface of the beryllium tube; The fourth tooling is a cylinder with a central axis hole, the inner surface of one end of the fourth tooling is provided with a second 60° conical surface matching the first 60° conical surface to form a 60° conical hole, and the outer periphery of the fourth tooling is provided with a plurality of second grooves at equal intervals, and the depth of each of the second grooves is less than half of the difference between the outer diameter and the inner diameter of the fourth tooling; Step S9, removing the first tooling, the second tooling and the fourth tooling, and subjecting the beryllium tube having the first outer cylindrical surface finely turned to chemical milling.

2. The method for precision machining of ultra-thin wall beryllium tube parts according to claim 1, characterized in that: In step S1, the process parameters for rough turning the first outer cylindrical surface of the beryllium tube are as follows: The tool tip arc is R0.1mm~R0.3mm, the cutting depth is 0.05~0.2mm, the rotation speed is 200~500r / min, the feed speed is 0.01~0.03mm / r, and the reserved processing allowance is 0.1~0.3mm.

3. The method for precision machining of ultra-thin wall beryllium tube parts according to claim 1, characterized in that: In step S1, the process parameters for rough turning the inner hole of the beryllium tube are as follows: The tool tip arc is R0.1mm~R0.3mm, the cutting depth is 0.05~0.2mm, the rotation speed is 200~500r / min, the feed speed is 0.01~0.03mm / r, and the reserved processing allowance is 0.05~0.15mm.

4. The method for precision machining of ultra-thin wall beryllium tube parts according to claim 1, characterized in that: In step S3, the process parameters for semi-finishing the first outer cylindrical surface of the beryllium tube are as follows: The tool tip arc is R0.1mm~R0.2mm, the cutting depth is 0.05~0.15mm, the rotation speed is 200~300r / min, the feed speed is 0.01~0.03mm / r, and the reserved processing allowance is 0.05~0.2mm.

5. The method for precision machining of ultra-thin wall beryllium tube parts according to claim 1, characterized in that: In step S4, the process parameters for semi-finishing the second outer cylindrical surface of the beryllium tube after semi-finishing the first outer cylindrical surface are as follows: The cutting depth is 0.05-0.15 mm, the rotation speed is 500-800 r / min, the feed speed is 100-300 mm / min, and the processing is performed layer by layer until the reserved processing allowance is 0.1-0.3 mm.

6. The method for precision machining of ultra-thin wall beryllium tube parts according to claim 1, characterized in that: In step S6, the process parameters for fine milling the second outer cylindrical surface and the arc transition surface of the beryllium tube that has undergone the second aging treatment are as follows: The cutting depth is 0.05~0.1mm, the rotation speed is 600~1500r / min, and the feed speed is 50~200mm / min.

7. The method for precision machining of ultra-thin wall beryllium tube parts according to claim 1, characterized in that: In step S7, the process parameters for finishing the inner hole and end surface of the beryllium tube are as follows: The tool tip arc is ≤R0.1mm, the cutting depth is 0.05~0.1mm, the rotation speed is 600~1500r / min, and the feed speed is 50~200mm / min.

8. The method for precision machining of ultra-thin wall beryllium tube parts according to claim 1, characterized in that: In step S8, the process parameters for finishing the first outer cylindrical surface of the beryllium tube are as follows: The tool tip arc is ≤R0.1mm, the cutting depth is 0.05~0.1mm, the rotation speed is 500~1000r / min, and the feed speed is 50~200mm / min.

9. The method for precision machining of ultra-thin wall beryllium tube parts according to claim 1, characterized in that: In the step S9, the beryllium tube having the first outer cylindrical surface finely turned is subjected to chemical milling for 1-3 minutes.

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