A CBN oil pipe thread combing cutter processing technology

Abstract

The present invention discloses a CBN oil pipe thread combing cutter processing technology, which relates to the technical field of tool processing. Specifically, it includes: preforming, in which a conductive integral CBN blank is roughly cut to form the outline of the thread combing cutter tool; rough machining, in which the upper and lower surfaces of the CBN blank are ground and polished, and the surrounding of the CBN blank is ground; primary finishing, in which all cutting edges of the CBN blank are precisely formed using slow-speed wire cutting to form the thread tooth profile; and secondary finishing, in which all cutting edges of the CBN blank that have undergone primary finishing are sequentially passivated and polished to strengthen them. In the present invention, because the tool is made of CBN material, the tool life, dimensional retention, and surface roughness are significantly improved. The service life is increased by 2 to 10 times compared to cemented carbide. The CBN tool does not change size with use, and the grinding process is reduced during processing, which avoids tool chipping and reduces the tool scrap rate.

Description

Technical Field

[0001] The invention relates to the technical field of tool processing, in particular to a CBN petroleum pipe thread combing tool processing technology. Background Art

[0002] Because carbide offers superior heat and wear resistance compared to high-speed steel, carbide cutting tools are primarily used in CNC machining centers and CNC engraving machines. They can also be installed on conventional milling machines to process relatively hard, less complex heat-treated materials. Currently, the majority of cutting tools used on the market for composite materials, industrial plastics, organic glass, and non-ferrous metals are carbide tools, capable of cutting hard materials up to around 50HRC.

[0003] Cubic Boron Nitride (CBN) is a synthetic material created by converting soft hexagonal boron nitride into a catalyst under ultra-high temperature and high pressure conditions. Its hardness is second only to diamond, but its thermal stability is far superior to diamond. Therefore, it and diamond are collectively referred to as superhard materials. It possesses high hardness, thermal stability, and strong chemical stability to iron-based metal elements. Therefore, CBN is a new type of inorganic superhard material that has been widely used in processing fields across various industries. It is typically used to make superhard cutting tools, of which solid CBN tools are a type. CBN tools can reach a hardness of 3000 to 4500 HV, and their wear resistance is 50 times that of carbide tools when cutting wear-resistant materials. CBN tools can be used to cut high-temperature alloys and hardened steel at speeds 3 to 5 times higher than carbide tools.

[0004] However, due to the extremely high overall hardness of CBN tools and the complex dimensions of oil pipe thread comb blades, traditional machining requires grinding, which is prone to chipping and results in a CBN tool scrap rate exceeding 50%. Current research on CBN tool grinding primarily focuses on machining special-shaped surfaces and grinding equipment, with no specific improvements to CBN comb tool machining processes being developed. Summary of the Invention

[0005] The purpose of the present invention is to provide a CBN oil pipe thread combing cutter processing technology to solve the problems existing in the above-mentioned prior art, so that the service life, dimensional retention and surface roughness of the oil pipe thread combing cutter are greatly improved, the tool chipping phenomenon is avoided, and the tool scrap rate is reduced.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a CBN petroleum pipe thread combing tool processing process, which specifically includes the following steps:

[0008] S1. Preforming: Roughly cut the CBN blank to form the outline of the thread comb tool to form a CBN tool blank;

[0009] S2 roughing, the upper and lower surfaces of the CBN blade blank are ground and polished, and the CBN blade blank is ground around;

[0010] S3 a finishing, the CBN blade blank by pulsed spark discharge method to process the thread profile of the cutting edge;

[0011] S4. Secondary finishing, passivating and polishing all cutting edges of the CBN blade blank that has undergone primary finishing in sequence.

[0012] Preferably, in S1, the CBN blank is processed by laser cutting to form the contour line of the thread comb tool.

[0013] Preferably, the CBN blank is a conductive integral CBN material.

[0014] Preferably, in S1, a machining allowance of 0.4 mm to 1 mm is reserved for the CBN blade blank.

[0015] Preferably, in S2, the total grinding allowance of the upper surface or the lower surface of the CBN blade blank is 0.2 mm, and the number of grinding times is 2-5 times.

[0016] Preferably, in S2, the polishing time of the upper surface and the lower surface of the CBN blade blank is 20 min-120 min.

[0017] Preferably, in S2, the roughness of the upper and lower surfaces of the CBN blade blank after polishing is Ra≤0.4 μm.

[0018] Preferably, in S3, the one-time finishing includes one cutting and at least two finishing operations, and the one-time finishing is performed using a wire cutting machine with a total machining allowance of 1 mm.

[0019] Preferably, in S3, the machining allowance of the one-time cutting is 0.8 mm, the fine trimming is performed twice, and the machining allowances of the two fine trimmings are ≤0.15 mm and ≤0.05 mm respectively.

[0020] Preferably, in S4, the passivation and strengthening time of the secondary finishing is at least 30 minutes, and the total amount of repeated passivation and strengthening is 0.01 mm to 0.06 mm.

[0021] Preferably, in S4, the roughness of all cutting edges of the CBN blade blank after polishing and strengthening is Ra≤0.4 μm.

[0022] Compared with the prior art, the present invention has achieved the following technical effects:

[0023] In the present invention, since the tool uses conductive integral CBN material, the tool size retention and surface roughness are greatly improved, and the service life is increased by 2 to 10 times compared with cemented carbide. The CBN tool will not change in size with use, the grinding process is reduced during the processing process, the tool chipping phenomenon is avoided, and the tool scrap rate is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 Schematic diagram of the processing flow of the first CBN blade according to an embodiment of the present invention;

[0026] Figure 2 Schematic diagram of the processing flow of the second CBN blade according to an embodiment of the present invention;

[0027] Figure 3 Schematic diagram of the structure of the CBN blade blank formed in an embodiment of the present invention;

[0028] Figure 4 Schematic diagram of the structure of the CBN insert after passivation, polishing and strengthening in the embodiment of the present invention;

[0029] Figure 5 This is a partial enlarged schematic diagram of the cutting edge after passivation and strengthening in an embodiment of the present invention;

[0030] Among them: 1-CBN blank, 2-CBN tool blank, 3-CBN blade. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention 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.

[0032] The purpose of the present invention is to provide a CBN oil pipe thread combing cutter processing technology to solve the problems existing in the prior art, so that the service life, dimensional retention and surface roughness of the oil pipe thread combing cutter are greatly improved, the tool chipping phenomenon is avoided, and the tool scrap rate is reduced.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] like Figures 1 to 5 As shown: This embodiment provides a CBN oil pipe thread combing tool processing process, which specifically includes the following steps:

[0035] S1. Preforming: Roughly cut the outline of the thread comb tool from the CBN blank 1 to form a CBN tool blank 2.

[0036] In S1, preferably, the CBN blank 1 is laser-cut to form the outline of the thread comb cutter tool; the CBN blank is a conductive, solid CBN material. Preferably, a machining allowance of approximately 1 mm is reserved for the CBN blade blank 2 to facilitate finishing. Conventional solid CBN materials, which use AlN as a binder, are not conductive and cannot be processed for electrical discharge machining (EDM). However, in this embodiment, a conductive material is added as a binder, making the solid CBN material conductive and suitable for electro-erosion machining.

[0037] S2. Rough machining: grinding and polishing the upper and lower surfaces of the CBN blade blank 2, and grinding the surrounding of the CBN blade blank 2 to reduce the phenomenon of blade chipping during CBN machining.

[0038] In S2, preferably, the total grinding allowance of the upper or lower surface of the CBN blade blank 2 is 0.2 mm, and the number of grinding passes is 2-5. Preferably, the polishing time of the upper and lower surfaces of the CBN blade blank 2 is 20-120 minutes. Preferably, the roughness Ra of the upper and lower surfaces of the CBN blade blank 2 after polishing is ≤ 0.4 μm.

[0039] S3. A finishing operation is performed in which the CBN tool blank 2 is processed into a threaded cutting edge by pulsed spark discharge, and the contour of the CBN tool blank 2 is finally completed. The conductive integral CBN material is used in combination with a pulsed spark discharge etching process, and direct grinding is no longer performed, which can effectively avoid tool chipping.

[0040] In S3, preferably, one finishing process includes one cutting and at least two finishing processes, one finishing process uses a slow wire cutting machine and the total machining allowance is 1mm, and the finished thread profile can meet the accuracy required by the API thread profile standard, and the surface roughness Ra ≤ Preferably, the machining allowance for one cutting is 0.8 mm, and the finishing is performed twice, with the machining allowances for the two finishings being ≤0.15 mm and ≤0.05 mm respectively. Preferably, a conductive adhesive is added to the material of the CBN blade blank 2 to improve its conductivity so that it can be processed by electro-erosion.

[0041] S4. Secondary finishing, all cutting edges of the CBN blade blank 2 that have undergone primary finishing are passivated, polished and strengthened in turn, the chamfered part of the thread profile is passivated, and the entire cutting edge is polished. In S4, preferably, the passivation and strengthening time of the secondary finishing is at least 30 minutes, and the total amount of repeated passivation and strengthening is 0.01mm to 0.06mm. The service life of the tool is increased by performing multiple passivation and polishing strengthening treatments on the cutting edge. Preferably, the roughness of all cutting edges of the CBN blade blank 2 after polishing and strengthening is Ra≤0.4μm. After the secondary finishing, the processing of the formed CBN blade 3 is completed, as shown in FIG. Figure 3 As shown, the thread profile after finishing needs to meet the accuracy requirements of API profile standard, and the surface roughness Ra ≤ 0.4μm.

[0042] The tool in this embodiment uses conductive integral CBN material, which greatly improves its service life, dimensional retention, and surface roughness. The high hardness, high thermal conductivity, and high heat resistance of the conductive integral CBN material, as well as the chemical inertness, conductivity, and impact toughness of the conductive integral CBN material and ferrous metal (the workpiece to be processed by the tool), meet the dimensional retention and high processing efficiency of the precision thread processing of the oil pipe thread combing tool. The service life is increased by 2 to 10 times compared with cemented carbide. In terms of dimensional retention, the size of cemented carbide will gradually change with use of the tool, while the CBN blade 3 will not change in size with use. The roughness of the cemented carbide blade can generally reach Ra1.6, and the surface roughness of the CBN blade after processing generally reaches Ra≤0.4μm.

[0043] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A CBN oil pipe thread combing tool processing technology, characterized in that: The specific steps include: S1. Preforming: Roughly cut the CBN blank to form the outline of the thread comb tool to form a CBN tool blank; S2 roughing, the upper and lower surfaces of the CBN blade blank are ground and polished, and the CBN blade blank is ground around; S3 a finishing, the CBN blade blank by pulsed spark discharge method to process the thread profile of the cutting edge; S4. Secondary finishing, passivating and polishing all cutting edges of the CBN blade blank that has undergone primary finishing in sequence.

2. The CBN oil pipe thread combing cutter processing technology according to claim 1 is characterized in that: In S1, the CBN blank is processed by laser cutting to form the outline of the thread comb cutter tool; the CBN blank is a conductive integral CBN material.

3. The CBN oil pipe thread combing tool processing process according to claim 1 is characterized in that: In S1, a machining allowance of 0.4 mm to 1 mm is reserved for the CBN blade blank.

4. The CBN oil pipe thread combing tool processing process according to claim 1 is characterized in that: In S2, the total grinding allowance of the upper surface or the lower surface of the CBN blade blank is 0.2 mm, and the number of grinding times is 2-5 times.

5. The CBN oil pipe thread combing tool processing process according to claim 1 is characterized in that: In S2, the polishing time of the upper surface and the lower surface of the CBN blade blank is 20 min-120 min.

6. The CBN oil pipe thread combing tool processing process according to claim 1 is characterized in that: In S2, the roughness of the upper and lower surfaces of the CBN blade blank after polishing is Ra≤0.4 μm.

7. The CBN oil pipe thread combing tool processing process according to claim 1 is characterized in that: In S3, the one-time finishing includes one-time cutting and at least two-time finishing. The one-time finishing is performed using a wire cutting machine with a total machining allowance of 1 mm.

8. The CBN oil pipe thread combing tool processing process according to claim 7 is characterized in that: In S3, the machining allowance of the one-time cutting is 0.8 mm, the fine trimming is performed twice, and the machining allowances of the two fine trimmings are ≤0.15 mm and ≤0.05 mm respectively.

9. The CBN oil pipe thread combing tool processing process according to claim 1 is characterized in that: In S4, the passivation and strengthening time of the secondary finishing is at least 30 minutes, and the total amount of repeated passivation and strengthening is 0.01 mm to 0.06 mm.

10. The CBN oil pipe thread combing tool processing process according to claim 1 is characterized in that: In S4, the roughness of all cutting edges of the CBN blade blank after polishing and strengthening is Ra≤0.4 μm.

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