A direct-formed LC-SM ceramic ferrule and its manufacturing process

Abstract

This invention discloses an LC-SM (Liquid Crystal Socket) ceramic ferrule with direct inner hole forming and its manufacturing process, relating to the field of core optical communication devices. Addressing the problems of low precision, long lead times, high cost, and poor reliability in existing products, the ferrule of this invention employs a rounded end chamfer, achieving an inner hole diameter tolerance of ±0.0002μm, ellipticity ≤0.0003μm, and concentricity ≤0.6μm, reaching nanometer-level precision. The innovative manufacturing process integrates composite-coated variable-diameter PIN pins and staged degreasing sintering technology, enabling direct forming of the inner hole without grinding. The product exhibits a low assembly breakage rate and high yield, balancing high precision, low cost, and high reliability, making it suitable for the needs of 5G communication, data centers, and fiber-to-the-home scenarios.

Description

Technical Field

[0001] This invention relates to the field of core optical communication devices, and in particular to an LC-SM direct-formed ceramic ferrule and its manufacturing process. Background Technology

[0002] In optical communication systems, ceramic ferrules are core components of fiber optic connections, and their precision, stability, and lifespan directly affect the transmission quality of optical signals. Currently, zirconia ceramics are widely used as ferrule substrates in the industry due to their excellent wear resistance, corrosion resistance, and high and low temperature stability, which meet the requirements for long-term stable operation of optical communication equipment. However, existing ceramic ferrule manufacturing processes still suffer from many problems that urgently need to be solved, such as long processing cycles, high costs, difficulty in precision control, and high defect rates at the tail end, which seriously restrict the performance improvement and cost optimization of optical communication systems.

[0003] The traditional production process for LC-SM ceramic ferrules generally follows the pattern of "injection molding blank → degreasing and sintering → internal hole fine grinding → outer diameter trimming → chamfering." Among these steps, internal hole fine grinding is a key bottleneck restricting production efficiency and cost. Due to the high Mohs hardness of zirconia ceramics, internal hole fine grinding requires imported high-precision diamond grinding wheels and specialized grinding machines, resulting in high equipment maintenance costs. More importantly, the internal hole fine grinding process is extremely time-consuming, leading to a long production cycle for the entire ferrule. Furthermore, the need for specialized technicians to operate the equipment and the requirement for a large cleanroom ultimately results in a persistently high production cost per ferrule, making it difficult to meet the demands of large-scale, low-cost applications such as Fiber to the Home (FTTH).

[0004] Some manufacturers are attempting to use a "direct inner hole forming" process, controlling the inner hole size of the blank through PIN pins to eliminate the grinding process. However, this still doesn't solve the core problem of unstable precision. On one hand, traditional PIN pins are mostly made of pure tungsten steel, which is prone to micro-deformation under the high pressure of injection molding and oxidation wear under the high temperature of debinding and sintering. This results in a large fluctuation range in the inner hole diameter after sintering, far exceeding the precision threshold required by LC-SM ferrules. On the other hand, traditional sintering processes often use a crude "single heating rate + constant temperature holding" approach, which cannot adapt to the binder decomposition during the debinding stage and the densification process during the sintering stage of zirconia powder. This leads to large fluctuations in the powder shrinkage ratio, which in turn causes problems such as excessive inner hole ellipticity and large concentricity deviation, seriously affecting the accuracy of fiber optic splicing and the stability of optical signal transmission.

[0005] Therefore, developing a direct-forming ceramic ferrule for LC-SM inner holes that combines short cycle time, low cost, high precision, and high reliability, as well as its manufacturing process, has become a technical challenge that the industry urgently needs to solve. Summary of the Invention

[0006] To address the technical bottlenecks of existing LC-SM ceramic ferrules, such as low inner hole precision, long production cycle, high assembly breakage rate, short insertion / removal life, high connection loss, and difficulty in cost control, this invention provides an ultra-high precision, long-life LC-SM ceramic ferrule with directly formed inner hole and its manufacturing process. Through an innovative integrated technical solution of "composite coating variable diameter PIN + staged atmosphere sintering + double arc sealing chamfer," it achieves the technical effects of direct forming of the inner hole without grinding, nanometer-level dimensional accuracy, zero assembly breakage, long insertion / removal life, and low connection loss, while simultaneously reducing production costs and resolving the core contradiction of existing technologies where "precision, cost, and reliability" cannot be simultaneously achieved.

[0007] To achieve the above objectives, this invention provides an LC-SM direct-formed ceramic insert, comprising an insert body, a front chamfer at the front end of the insert body, an inner hole penetrating the insert body, V-grooves symmetrically arranged on the sides of the insert body, and a tail chamfer at the tail end of the insert body; the tail chamfer is an arc structure; the inner hole diameter is 0.1256±0.0004μm, and the inner hole ellipticity is ≤0.0003μm; the insert length is 6.5±0.02mm, the insert outer diameter is 1.249±0.0005mm, and the insert concentricity is ≤0.6μm; the inner hole surface roughness Ra is ≤0.02μm; the surface roughness Ra of the front chamfer and the tail chamfer is ≤0.03μm, and the clearance with the metal flange is ≤0.002mm.

[0008] Another object of the present invention is to provide a manufacturing process for the LC-SM inner hole direct forming ceramic ferrule, comprising the following steps: Step S1, Mold and PIN preparation: The mold is made of S136H steel by vacuum quenching + deep cryogenic treatment + aging tempering. The surface of the mold cavity is polished with diamond to Ra≤0.005μm. Three sets of temperature sensors are installed in the cavity to monitor the molding temperature in real time. The PIN is a WC-Co alloy variable diameter structure with a TiN-AlN composite coating deposited on the surface. Step S2, Raw material modification: After uniformly mixing high-purity zirconia powder, stabilizing phase, sintering aid, binder and plasticizer, the mixture is ball-milled and spray-dried to obtain granulated powder; Step S3, Precision Injection Molding: Add the granulated powder to the injection molding machine for injection molding; after molding, a ceramic ferrule blank is obtained, and the inner diameter of the blank is consistent with the diameter of the middle section of the PIN pin; Step S4, staged degreasing treatment: Place the blank into a degreasing oven, heat it from room temperature to 250℃ at a heating rate of 1℃ / min, and hold it for 4 hours; then heat it to 450℃ at a heating rate of 0.5℃ / min and hold it for 6 hours; finally cool it down to room temperature at a cooling rate of 1℃ / min. Step S5, staged sintering treatment: First, the temperature is raised from room temperature to 700℃ at a rate of 2℃ / min and held in air for 3 hours; then, the temperature is raised from 700℃ to 950℃ at a rate of 1℃ / min and held in air for 4 hours; subsequently, the temperature is raised from 950℃ to 1345-1350℃ at a rate of 0.6℃ / min and held in air for 4 hours; finally, the temperature is lowered to room temperature at a rate of 0.8℃ / min. Step S6, High-precision post-processing: Precision grinding with diamond grinding wheels to control the length at 6.5±0.02mm and the end face parallelism at ≤0.001mm; machining with a centerless grinder to achieve an outer diameter of 1.249±0.0005mm and a roundness at ≤0.0003mm; using a diamond micro-grinding tool, with the outer diameter as the reference, making minor corrections along the deviation direction of the inner hole axis to ensure concentricity at ≤0.6μm; using a CNC diamond brush machine, first machining the inner arc, then machining the outer arc, and removing burrs from the chamfered surface by ultrasonic cleaning; Step S7, Finished Product Inspection and Assembly: Inspect the inner diameter, concentricity, length, outer diameter and other dimensional parameters according to relevant national standards. After passing the inspection, assemble with the metal flange to complete the finished product preparation.

[0009] Preferably, the vacuum quenching temperature in step S1 is 1050-1080℃, and the holding time is 2-3 hours; the cryogenic treatment temperature is -196±4℃, and the holding time is 3.5-4.5 hours; the aging tempering temperature is approximately 515-525℃, and the holding time is 2.5-3.5 hours.

[0010] Preferably, the WC-Co alloy in step S1 has a Co content of 8% by mass.

[0011] Preferably, the diameter of the middle section of the variable diameter structure in step S1 is 166.2±0.1μm, and the diameters at both ends are 166.0±0.1μm.

[0012] Preferably, in step S1, the thickness of the bottom TiN layer of the TiN-AlN composite coating is 1.5 μm, and the thickness of the top AlN layer is 0.5 μm.

[0013] Preferably, the mass ratio of the high-purity zirconia powder, the stabilizing phase, the sintering aid, the binder, and the plasticizer in step S2 is (80-85):(3.5-4):(0.5-0.8):(7-9):(4-6).

[0014] Preferably, the high-purity zirconia powder has a particle size of 0.8 μm; the stable phase is a compound of Y₂O₃ and Sc₂O₃ in a mass ratio of (3.5-3.7):(0.3-0.35); the sintering aid is a compound of MgO and La₂O₃ in a mass ratio of (3-5):(2-3); the binder is a compound of polyvinyl butyral and hydroxypropyl methylcellulose in a mass ratio of (6-7):(0.5-0.8); the weight-average molecular weight of the polyvinyl butyral is 80,000-100,000; and the plasticizer is a compound of dibutyl phthalate, polyethylene glycol PEG-400, and tributyl citrate in a mass ratio of (1.8-2.4):(0.9-1.3):(1.3-2.6).

[0015] Preferably, the specific parameters for injection molding in step S3 are: barrel temperature of 150-180℃, injection pressure of 80-100MPa, injection speed of 50-80mm / s, holding pressure of 60-70MPa, holding time of 10-15s, and mold temperature of 40℃.

[0016] Due to the application of the above technical solution, the present invention has the following beneficial effects: (1) The LS-SM direct-formed ceramic ferrule disclosed in this invention, through the synergistic innovation of composite-coated variable-diameter PIN pins and staged atmosphere sintering, precisely controls the inner diameter tolerance to ±0.0002μm, ellipticity ≤0.0003μm, and concentricity ≤0.6μm, improving accuracy by 3-5 times. The variable-diameter PIN pins adapt to the sintering shrinkage difference of zirconia, and the TiN-AlN composite coating resists high temperature and high pressure loss, completely solving the problem of accuracy loss caused by deformation and uneven sintering shrinkage of traditional PIN pins, providing an ultimate dimensional foundation for low-loss optical signal transmission.

[0017] (2) The LS-SM direct-formed ceramic ferrule disclosed in this invention directly forms the inner hole without grinding. Combined with the triple heat treatment of mold vacuum quenching-deep cryogenic tempering and precise proportioning of composite components, the production cycle is shortened, the cost per piece is reduced, and the product qualification rate is improved. The gradient decomposition of composite binder and plasticizer avoids degreasing defects, adapts to sintering requirements in stages, and the high stability of mold and PIN reduces material consumption. It completely solves the long-standing dilemma of the industry's contradiction between precision and cost, and between efficiency and qualification rate.

[0018] (3) The LS-SM direct-formed ceramic ferrule disclosed in this invention reduces the breakage rate, improves insertion and extraction life, and stabilizes and reduces connection loss through the use of arc-shaped sealing chamfers. The arc-shaped chamfers reduce assembly stress, and the fit clearance of ≤0.002mm prevents impurities from entering.

[0019] (4) The LS-SM direct-formed ceramic ferrule disclosed in this invention uses a Y2O3-Sc2O3 composite stabilizing phase to suppress high-temperature phase transformation and a MgO-La2O3 composite sintering aid to refine grains, resulting in small variations in the inner diameter of the ferrule and small dimensional fluctuations between different batches. The stabilizing phase and the sintering aid work together to improve material stability, and the phased temperature control rate matches the material change pattern, ensuring the uniformity of product performance in large-scale production. At the same time, it enhances the reliability of operation in extreme environments and is suitable for the stringent requirements of multiple scenarios such as 5G communication and data centers.

[0020] (5) The LS-SM inner hole direct forming ceramic ferrule disclosed in this invention directly eliminates the most difficult inner diameter to be processed in the traditional process, which is time-consuming and labor-intensive, thereby reducing its production cost and improving production efficiency, so as to meet the broad and low-cost use needs of fiber to the home. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of an LC-SM direct-molded ceramic insert disclosed in this invention. Figure 2 This is a schematic diagram of the main structure of an LC-SM direct-formed ceramic ferrule disclosed in this invention; Figure 3 This is a schematic diagram of the structure of an LC-SM inner hole directly formed ceramic insert connected to a metal flange, as disclosed in this invention. The letters in the diagram represent the following component names: A. Insert body; B. Front chamfer; C. Inner hole; D. V-groove; E. Tail end chamfer; F. Metal flange. Detailed Implementation

[0022] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. Example 1

[0023] like Figure 1 , Figure 2 and Figure 3 An LC-SM direct-formed ceramic insert includes an insert body, a front chamfer at the front end of the insert body, an inner hole penetrating the insert body, V-grooves symmetrically arranged on the sides of the insert body, and a tail chamfer at the tail end of the insert body; the tail chamfer is an arc structure; the inner hole diameter is 0.1255μm, and the inner hole ellipticity is ≤0.0003μm; the insert length is 6.5mm, the insert outer diameter is 1.249mm, and the insert concentricity is ≤0.6μm; the inner hole surface roughness Ra is ≤0.02μm; the surface roughness Ra of the front chamfer and the tail chamfer is ≤0.03μm, and the clearance with the metal flange is ≤0.002mm.

[0024] A manufacturing process for the LC-SM direct-formed ceramic ferrule includes the following steps: Step S1, Mold and PIN preparation: The mold is made of S136H steel by vacuum quenching + deep cryogenic treatment + aging tempering. The surface of the mold cavity is polished with diamond to Ra≤0.005μm. Three sets of temperature sensors are installed in the cavity to monitor the molding temperature in real time. The PIN is a WC-Co alloy variable diameter structure with a TiN-AlN composite coating deposited on the surface. Step S2, Raw material modification: After uniformly mixing high-purity zirconia powder, stabilizing phase, sintering aid, binder and plasticizer, the mixture is ball-milled and spray-dried to obtain granulated powder; Step S3, Precision Injection Molding: Add the granulated powder to the injection molding machine for injection molding; after molding, a ceramic ferrule blank is obtained, and the inner diameter of the blank is consistent with the diameter of the middle section of the PIN pin; Step S4, staged degreasing treatment: Place the blank into a degreasing oven, heat it from room temperature to 250℃ at a heating rate of 1℃ / min, and hold it for 4 hours; then heat it to 450℃ at a heating rate of 0.5℃ / min and hold it for 6 hours; finally cool it down to room temperature at a cooling rate of 1℃ / min. Step S5, staged sintering treatment: First, the temperature is raised from room temperature to 700℃ at a rate of 2℃ / min and held in air for 3 hours; then, the temperature is raised from 700℃ to 950℃ at a rate of 1℃ / min and held in air for 4 hours; subsequently, the temperature is raised from 950℃ to 1345℃ at a rate of 0.6℃ / min and held in air for 4 hours; finally, the temperature is lowered to room temperature at a rate of 0.8℃ / min. Step S6, High-precision post-processing: Precision grinding with diamond grinding wheels to control the length at 6.5mm and the end face parallelism ≤0.001mm; machining with a centerless grinder to achieve an outer diameter of 1.249mm and roundness ≤0.0003mm; using a diamond micro-grinding tool, with the outer diameter as the reference, making minor corrections along the deviation direction of the inner hole axis to ensure concentricity ≤0.6μm; using a CNC diamond brush machine, first machining the inner arc, then machining the outer arc, and the chamfered surface is ultrasonically cleaned to remove burrs; Step S7, Finished Product Inspection and Assembly: Inspect the inner diameter, concentricity, length, outer diameter and other dimensional parameters according to relevant national standards. After passing the inspection, assemble with the metal flange to complete the finished product preparation.

[0025] In step S1, the vacuum quenching temperature is 1050℃ and the holding time is 2h; the cryogenic treatment temperature is -196℃ and the holding time is 3.5h; the aging tempering temperature is approximately 515℃ and the holding time is 2.5h; the Co mass percentage in the WC-Co alloy in step S1 is 8%; the diameter of the middle section of the variable diameter structure in step S1 is 166.2μm, and the diameters at both ends are 166.0μm; the thickness of the bottom TiN layer of the TiN-AlN composite coating in step S1 is 1.5μm, and the thickness of the top AlN layer is 0.5μm; the high-purity zirconia powder, stable phase, and sintering aid in step S2... The mass ratio of the binder, adhesive, and plasticizer is 80:3.5:0.5:7:4; the particle size of the high-purity zirconia powder is 0.8 μm; the stable phase is a compound of Y₂O₃ and Sc₂O₃ in a mass ratio of 3.5:0.3; the sintering aid is a compound of MgO and La₂O₃ in a mass ratio of 3:2; the binder is a compound of polyvinyl butyral and hydroxypropyl methylcellulose in a mass ratio of 6:0.5; the weight average molecular weight of the polyvinyl butyral is 80,000; the plasticizer is a compound of dibutyl phthalate, polyethylene glycol PEG-400, and tributyl citrate in a mass ratio of 1.8:0.9:1.3.

[0026] The specific parameters for injection molding in step S3 are as follows: barrel temperature is 150℃, injection pressure is 80MPa, injection speed is 50mm / s, holding pressure is 60MPa, holding time is 10s, and mold temperature is 40℃.

[0027] After testing, the ceramic ferrule had a 100% product qualification rate and a 0.0% crack rate. Example 2

[0028] An LC-SM direct-formed ceramic insert includes an insert body, a front chamfer at the front end of the insert body, an inner hole penetrating the insert body, V-grooves symmetrically arranged on the sides of the insert body, and a tail chamfer at the tail end of the insert body; the tail chamfer is an arc structure; the inner hole diameter is 0.1251μm, and the inner hole ellipticity is ≤0.0003μm; the insert length is 6.5mm, the insert outer diameter is 1.249mm, and the insert concentricity is ≤0.6μm; the inner hole surface roughness Ra is ≤0.02μm; the surface roughness Ra of the front chamfer and the tail chamfer is ≤0.03μm, and the clearance with the metal flange is ≤0.002mm.

[0029] A manufacturing process for the LC-SM direct-formed ceramic ferrule includes the following steps: Step S1, Mold and PIN preparation: The mold is made of S136H steel by vacuum quenching + deep cryogenic treatment + aging tempering. The surface of the mold cavity is polished with diamond to Ra≤0.005μm. Three sets of temperature sensors are installed in the cavity to monitor the molding temperature in real time. The PIN is a WC-Co alloy variable diameter structure with a TiN-AlN composite coating deposited on the surface. Step S2, Raw material modification: After uniformly mixing high-purity zirconia powder, stabilizing phase, sintering aid, binder and plasticizer, the mixture is ball-milled and spray-dried to obtain granulated powder; Step S3, Precision Injection Molding: Add the granulated powder to the injection molding machine for injection molding; after molding, a ceramic ferrule blank is obtained, and the inner diameter of the blank is consistent with the diameter of the middle section of the PIN pin; Step S4, staged degreasing treatment: Place the blank into a degreasing oven, heat it from room temperature to 250℃ at a heating rate of 1℃ / min, and hold it for 4 hours; then heat it to 450℃ at a heating rate of 0.5℃ / min and hold it for 6 hours; finally cool it down to room temperature at a cooling rate of 1℃ / min. Step S5, staged sintering treatment: First, the temperature is raised from room temperature to 700℃ at a rate of 2℃ / min and held in air for 3 hours; then, the temperature is raised from 700℃ to 950℃ at a rate of 1℃ / min and held in air for 4 hours; subsequently, the temperature is raised from 950℃ to 1347℃ at a rate of 0.6℃ / min and held in air for 4 hours; finally, the temperature is lowered to room temperature at a rate of 0.8℃ / min. Step S6, High-precision post-processing: Precision grinding with diamond grinding wheels to control the length at 6.5mm and the end face parallelism ≤0.001mm; machining with a centerless grinder to achieve an outer diameter of 1.249mm and roundness ≤0.0003mm; using a diamond micro-grinding tool, with the outer diameter as the reference, making minor corrections along the deviation direction of the inner hole axis to ensure concentricity ≤0.6μm; using a CNC diamond brush machine, first machining the inner arc, then machining the outer arc, and the chamfered surface is ultrasonically cleaned to remove burrs; Step S7, Finished Product Inspection and Assembly: Inspect the inner diameter, concentricity, length, outer diameter and other dimensional parameters according to relevant national standards. After passing the inspection, assemble with the metal flange to complete the finished product preparation.

[0030] In step S1, the vacuum quenching temperature is 1060℃ and the holding time is 2.3h; the cryogenic treatment temperature is -198℃ and the holding time is 3.8h; the aging tempering temperature is approximately 518℃ and the holding time is 2.7h; the Co mass percentage in the WC-Co alloy in step S1 is 8%; the diameter of the middle section of the variable diameter structure in step S1 is 166.2μm, and the diameters at both ends are 166.0μm; the thickness of the bottom TiN layer and the thickness of the top AlN layer in the TiN-AlN composite coating in step S1 is 1.5μm; the mass ratio of the high-purity zirconia powder, stabilizing phase, sintering aid, binder, and plasticizer in step S2 is 81:3.7:0.6:7.5:4.5; the high-purity zirconia powder... The zirconium oxide powder has a particle size of 0.8 μm; the stable phase is a compound of Y₂O₃ and Sc₂O₃ in a mass ratio of 3.6:0.32; the sintering aid is a compound of MgO and La₂O₃ in a mass ratio of 3.5:2.2; the binder is a compound of polyvinyl butyral and hydroxypropyl methylcellulose in a mass ratio of 6.3:0.6; the weight average molecular weight of polyvinyl butyral is 85,000; and the plasticizer is a compound of dibutyl phthalate, polyethylene glycol PEG-400, and tributyl citrate in a mass ratio of 2:1:1.5.

[0031] The specific parameters for injection molding in step S3 are as follows: barrel temperature is 160℃, injection pressure is 85MPa, injection speed is 60mm / s, holding pressure is 63MPa, holding time is 12s, and mold temperature is 40℃.

[0032] After testing, the ceramic ferrule had a 100% product qualification rate and a 0.0% crack rate. Example 3

[0033] An LC-SM direct-formed ceramic insert includes an insert body, a front chamfer at the front end of the insert body, an inner hole penetrating the insert body, V-grooves symmetrically arranged on the sides of the insert body, and a tail chamfer at the tail end of the insert body; the tail chamfer is an arc structure; the inner hole diameter is 0.1255μm, and the inner hole ellipticity is ≤0.0003μm; the insert length is 6.5mm, the insert outer diameter is 1.249mm, and the insert concentricity is ≤0.6μm; the inner hole surface roughness Ra is ≤0.02μm; the surface roughness Ra of the front chamfer and the tail chamfer is ≤0.03μm, and the clearance with the metal flange is ≤0.002mm.

[0034] A manufacturing process for the LC-SM direct-formed ceramic ferrule includes the following steps: Step S1, Mold and PIN preparation: The mold is made of S136H steel by vacuum quenching + deep cryogenic treatment + aging tempering. The surface of the mold cavity is polished with diamond to Ra≤0.005μm. Three sets of temperature sensors are installed in the cavity to monitor the molding temperature in real time. The PIN is a WC-Co alloy variable diameter structure with a TiN-AlN composite coating deposited on the surface. Step S2, Raw material modification: After uniformly mixing high-purity zirconia powder, stabilizing phase, sintering aid, binder and plasticizer, the mixture is ball-milled and spray-dried to obtain granulated powder; Step S3, Precision Injection Molding: Add the granulated powder to the injection molding machine for injection molding; after molding, a ceramic ferrule blank is obtained, and the inner diameter of the blank is consistent with the diameter of the middle section of the PIN pin; Step S4, staged degreasing treatment: Place the blank into a degreasing oven, heat it from room temperature to 250℃ at a heating rate of 1℃ / min, and hold it for 4 hours; then heat it to 450℃ at a heating rate of 0.5℃ / min and hold it for 6 hours; finally cool it down to room temperature at a cooling rate of 1℃ / min. Step S5, staged sintering treatment: First, the temperature is raised from room temperature to 700℃ at a rate of 2℃ / min and held in air for 3 hours; then, the temperature is raised from 700℃ to 950℃ at a rate of 1℃ / min and held in air for 4 hours; subsequently, the temperature is raised from 950℃ to 1348℃ at a rate of 0.6℃ / min and held in air for 4 hours; finally, the temperature is lowered to room temperature at a rate of 0.8℃ / min. Step S6, High-precision post-processing: Precision grinding with diamond grinding wheels to control the length at 6.5mm and the end face parallelism ≤0.001mm; machining with a centerless grinder to achieve an outer diameter of 1.249mm and roundness ≤0.0003mm; using a diamond micro-grinding tool, with the outer diameter as the reference, making minor corrections along the deviation direction of the inner hole axis to ensure concentricity ≤0.6μm; using a CNC diamond brush machine, first machining the inner arc, then machining the outer arc, and the chamfered surface is ultrasonically cleaned to remove burrs; Step S7, Finished Product Inspection and Assembly: Inspect the inner diameter, concentricity, length, outer diameter and other dimensional parameters according to relevant national standards. After passing the inspection, assemble with the metal flange to complete the finished product preparation.

[0035] In step S1, the vacuum quenching temperature is 1065℃ and the holding time is 2.5h; the cryogenic treatment temperature is -198℃ and the holding time is 4h; the aging tempering temperature is approximately 520℃ and the holding time is 3h; the Co mass percentage in the WC-Co alloy in step S1 is 8%; the diameter of the middle section of the variable diameter structure in step S1 is 166.2μm, and the diameters at both ends are 166.0μm; the thickness of the bottom TiN layer and the top AlN layer of the TiN-AlN composite coating in step S1 is 1.5μm, and the thickness is 0.5μm; the mass ratio of the high-purity zirconia powder, stabilizing phase, sintering aid, binder, and plasticizer in step S2 is 83:3.8:0.65:8:5; the high-purity zirconia powder... The particle size of the solid is 0.8 μm; the stable phase is a compound of Y2O3 and Sc2O3 in a mass ratio of 3.6:0.33; the sintering aid is a compound of MgO and La2O3 in a mass ratio of 4:2.5; the binder is a compound of polyvinyl butyral and hydroxypropyl methylcellulose in a mass ratio of 6.5:0.65; the weight average molecular weight of polyvinyl butyral is 90,000; the plasticizer is a compound of dibutyl phthalate, polyethylene glycol PEG-400, and tributyl citrate in a mass ratio of 2.1:1.1:2.

[0036] The specific parameters for injection molding in step S3 are as follows: barrel temperature is 165℃, injection pressure is 90MPa, injection speed is 65mm / s, holding pressure is 65MPa, holding time is 13s, and mold temperature is 40℃.

[0037] After testing, the ceramic ferrule had a 100% product qualification rate and a 0.0% crack rate. Example 4

[0038] An LC-SM direct-formed ceramic insert includes an insert body, a front chamfer at the front end of the insert body, an inner hole penetrating the insert body, V-grooves symmetrically arranged on the sides of the insert body, and a tail chamfer at the tail end of the insert body; the tail chamfer is an arc structure; the inner hole diameter is 0.1255μm, and the inner hole ellipticity is ≤0.0003μm; the insert length is 6.5mm, the insert outer diameter is 1.249mm, and the insert concentricity is ≤0.6μm; the inner hole surface roughness Ra is ≤0.02μm; the surface roughness Ra of the front chamfer and the tail chamfer is ≤0.03μm, and the clearance with the metal flange is ≤0.002mm.

[0039] A manufacturing process for the LC-SM direct-formed ceramic ferrule includes the following steps: Step S1, Mold and PIN preparation: The mold is made of S136H steel by vacuum quenching + deep cryogenic treatment + aging tempering. The surface of the mold cavity is polished with diamond to Ra≤0.005μm. Three sets of temperature sensors are installed in the cavity to monitor the molding temperature in real time. The PIN is a WC-Co alloy variable diameter structure with a TiN-AlN composite coating deposited on the surface. Step S2, Raw material modification: After uniformly mixing high-purity zirconia powder, stabilizing phase, sintering aid, binder and plasticizer, the mixture is ball-milled and spray-dried to obtain granulated powder; Step S3, Precision Injection Molding: Add the granulated powder to the injection molding machine for injection molding; after molding, a ceramic ferrule blank is obtained, and the inner diameter of the blank is consistent with the diameter of the middle section of the PIN pin; Step S4, staged degreasing treatment: Place the blank into a degreasing oven, heat it from room temperature to 250℃ at a heating rate of 1℃ / min, and hold it for 4 hours; then heat it to 450℃ at a heating rate of 0.5℃ / min and hold it for 6 hours; finally cool it down to room temperature at a cooling rate of 1℃ / min. Step S5, staged sintering treatment: First, the temperature is raised from room temperature to 700℃ at a rate of 2℃ / min and held in air for 3 hours; then, the temperature is raised from 700℃ to 950℃ at a rate of 1℃ / min and held in air for 4 hours; subsequently, the temperature is raised from 950℃ to 1349℃ at a rate of 0.6℃ / min and held in air for 4 hours; finally, the temperature is lowered to room temperature at a rate of 0.8℃ / min. Step S6, High-precision post-processing: Precision grinding with diamond grinding wheels to control the length at 6.5mm and the end face parallelism ≤0.001mm; machining with a centerless grinder to achieve an outer diameter of 1.249mm and roundness ≤0.0003mm; using a diamond micro-grinding tool, with the outer diameter as the reference, making minor corrections along the deviation direction of the inner hole axis to ensure concentricity ≤0.6μm; using a CNC diamond brush machine, first machining the inner arc, then machining the outer arc, and the chamfered surface is ultrasonically cleaned to remove burrs; Step S7, Finished Product Inspection and Assembly: Inspect the inner diameter, concentricity, length, outer diameter and other dimensional parameters according to relevant national standards. After passing the inspection, assemble with the metal flange to complete the finished product preparation.

[0040] In step S1, the vacuum quenching temperature is 1075℃ and the holding time is 2.8h; the cryogenic treatment temperature is -199℃ and the holding time is 4.3h; and the aging tempering temperature is approximately 523℃ and the holding time is 3.3h.

[0041] In step S1, the WC-Co alloy contains 8% Co by mass; the variable-diameter structure in step S1 has a middle section diameter of 166.2 μm and two end diameters of 166.0 μm; the TiN-AlN composite coating in step S1 has a bottom TiN thickness of 1.5 μm and a top AlN thickness of 0.5 μm; the high-purity zirconia powder, stabilizing phase, sintering aid, binder, and plasticizer in step S2 have a mass ratio of 84:3.9:0.75:8.5:5.5; the high-purity zirconia powder has a particle size distribution of 84%. The thickness is 0.8 μm; the stable phase is a compound of Y2O3 and Sc2O3 in a mass ratio of 3.7:0.34; the sintering aid is a compound of MgO and La2O3 in a mass ratio of 4.5:2.8; the binder is a compound of polyvinyl butyral and hydroxypropyl methylcellulose in a mass ratio of 6.8:0.75; the weight average molecular weight of polyvinyl butyral is 95,000; the plasticizer is a compound of dibutyl phthalate, polyethylene glycol PEG-400, and tributyl citrate in a mass ratio of 2.3:1.2:2.3.

[0042] The specific parameters for injection molding in step S3 are as follows: barrel temperature is 175℃, injection pressure is 95MPa, injection speed is 75mm / s, holding pressure is 68MPa, holding time is 14s, and mold temperature is 40℃.

[0043] After testing, the ceramic ferrule had a 100% product qualification rate and a 0.0% crack rate. Example 5

[0044] An LC-SM direct-formed ceramic insert includes an insert body, a front chamfer at the front end of the insert body, an inner hole penetrating the insert body, V-grooves symmetrically arranged on the sides of the insert body, and a tail chamfer at the tail end of the insert body; the tail chamfer is an arc structure; the inner hole diameter is 0.125μm, and the inner hole ellipticity is ≤0.0003μm; the insert length is 6.5mm, the insert outer diameter is 1.249mm, and the insert concentricity is ≤0.6μm; the inner hole surface roughness Ra is ≤0.02μm; the surface roughness Ra of the front chamfer and the tail chamfer is ≤0.03μm, and the clearance with the metal flange is ≤0.002mm.

[0045] A manufacturing process for the LC-SM direct-formed ceramic ferrule includes the following steps: Step S1, Mold and PIN preparation: The mold is made of S136H steel by vacuum quenching + deep cryogenic treatment + aging tempering. The surface of the mold cavity is polished with diamond to Ra≤0.005μm. Three sets of temperature sensors are installed in the cavity to monitor the molding temperature in real time. The PIN is a WC-Co alloy variable diameter structure with a TiN-AlN composite coating deposited on the surface. Step S2, Raw material modification: After uniformly mixing high-purity zirconia powder, stabilizing phase, sintering aid, binder and plasticizer, the mixture is ball-milled and spray-dried to obtain granulated powder; Step S3, Precision Injection Molding: Add the granulated powder to the injection molding machine for injection molding; after molding, a ceramic ferrule blank is obtained, and the inner diameter of the blank is consistent with the diameter of the middle section of the PIN pin; Step S4, staged degreasing treatment: Place the blank into a degreasing oven, heat it from room temperature to 250℃ at a heating rate of 1℃ / min, and hold it for 4 hours; then heat it to 450℃ at a heating rate of 0.5℃ / min and hold it for 6 hours; finally cool it down to room temperature at a cooling rate of 1℃ / min. Step S5, staged sintering treatment: First, the temperature is raised from room temperature to 700℃ at a rate of 2℃ / min and held in air for 3 hours; then, the temperature is raised from 700℃ to 950℃ at a rate of 1℃ / min and held in air for 4 hours; subsequently, the temperature is raised from 950℃ to 1350℃ at a rate of 0.6℃ / min and held in air for 4 hours; finally, the temperature is lowered to room temperature at a rate of 0.8℃ / min. Step S6, High-precision post-processing: Precision grinding with diamond grinding wheels to control the length at 6.5mm and the end face parallelism ≤0.001mm; machining with a centerless grinder to achieve an outer diameter of 1.249mm and roundness ≤0.0003mm; using a diamond micro-grinding tool, with the outer diameter as the reference, making minor corrections along the deviation direction of the inner hole axis to ensure concentricity ≤0.6μm; using a CNC diamond brush machine, first machining the inner arc, then machining the outer arc, and the chamfered surface is ultrasonically cleaned to remove burrs; Step S7, Finished Product Inspection and Assembly: Inspect the inner diameter, concentricity, length, outer diameter and other dimensional parameters according to relevant national standards. After passing the inspection, assemble with the metal flange to complete the finished product preparation.

[0046] In step S1, the vacuum quenching temperature is 1075℃ and the holding time is 2.8h; the cryogenic treatment temperature is -196℃ and the holding time is 4.5h; the aging tempering temperature is approximately 525℃ and the holding time is 3.5h; the Co mass percentage in the WC-Co alloy in step S1 is 8%; the diameter of the middle section of the variable diameter structure in step S1 is 166.2μm, and the diameters at both ends are 166.0μm; the thickness of the bottom TiN layer of the TiN-AlN composite coating in step S1 is 1.5μm, and the thickness of the top AlN layer is 0.5μm; the mass ratio of the high-purity zirconia powder, stabilizing phase, sintering aid, binder, and plasticizer in step S2 is 85:4:0.8:9:6; the high-purity zirconia powder... The particle size of the solid is 0.8 μm; the stable phase is Y2O3 and Sc2O3 compounded in a mass ratio of 3.7:0.35; the sintering aid is MgO and La2O3 compounded in a mass ratio of 5:3; the binder is polyvinyl butyral and hydroxypropyl methylcellulose compounded in a mass ratio of 7:0.8; the weight average molecular weight of polyvinyl butyral is 100,000; the plasticizer is dibutyl phthalate, polyethylene glycol PEG-400 and tributyl citrate compounded in a mass ratio of 2.4:1.3:2.6.

[0047] The specific parameters for injection molding in step S3 are as follows: barrel temperature is 180℃, injection pressure is 100MPa, injection speed is 80mm / s, holding pressure is 70MPa, holding time is 15s, and mold temperature is 40℃.

[0048] After testing, the ceramic ferrule had a 100% product qualification rate and a 0.0% crack rate.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A ceramic ferrule with directly formed inner bore in an LC-SM configuration, characterized in that, The device includes a ferrule body, a front chamfer located at the front end of the ferrule body, an inner hole penetrating the ferrule body, V-grooves symmetrically arranged on the sides of the ferrule body, and a tail chamfer located at the tail end of the ferrule body; the tail chamfer is an arc structure; the inner hole diameter is 0.1256±0.0004μm, and the inner hole ellipticity is ≤0.0003μm; the ferrule length is 6.5±0.02mm, the ferrule outer diameter is 1.249±0.0005mm, and the ferrule concentricity is ≤0.6μm; the inner hole surface roughness Ra is ≤0.02μm; the surface roughness Ra of the front chamfer and the tail chamfer is ≤0.03μm, and the clearance with the metal flange is ≤0.002mm.

2. A manufacturing process for a ceramic ferrule with direct inner hole forming according to claim 1, characterized in that, Includes the following steps: Step S1, Mold and PIN preparation: The mold is made of S136H steel by vacuum quenching + deep cryogenic treatment + aging tempering. The surface of the mold cavity is polished with diamond to Ra≤0.005μm. Three sets of temperature sensors are installed in the cavity to monitor the molding temperature in real time. The PIN is a WC-Co alloy variable diameter structure with a TiN-AlN composite coating deposited on the surface. Step S2, Raw material modification: After uniformly mixing high-purity zirconia powder, stabilizing phase, sintering aid, binder and plasticizer, the mixture is ball-milled and spray-dried to obtain granulated powder; Step S3, Precision Injection Molding: Add the granulated powder to the injection molding machine for injection molding; after molding, a ceramic ferrule blank is obtained, and the inner diameter of the blank is consistent with the diameter of the middle section of the PIN pin; Step S4, staged degreasing treatment: Place the blank into a degreasing oven, heat it from room temperature to 250℃ at a heating rate of 1℃ / min, and hold it for 4 hours; then heat it to 450℃ at a heating rate of 0.5℃ / min and hold it for 6 hours; finally cool it down to room temperature at a cooling rate of 1℃ / min. Step S5, staged sintering treatment: First, the temperature is raised from room temperature to 700℃ at a rate of 2℃ / min and held in air for 3 hours; then, the temperature is raised from 700℃ to 950℃ at a rate of 1℃ / min and held in air for 4 hours; subsequently, the temperature is raised from 950℃ to 1345-1350℃ at a rate of 0.6℃ / min and held in air for 4 hours; finally, the temperature is lowered to room temperature at a rate of 0.8℃ / min. Step S6, High-precision post-processing: Precision grinding with diamond grinding wheels to control the length at 6.5±0.02mm and the end face parallelism at ≤0.001mm; machining with a centerless grinder to achieve an outer diameter of 1.249±0.0005mm and a roundness at ≤0.0003mm; using a diamond micro-grinding tool, with the outer diameter as the reference, making minor corrections along the deviation direction of the inner hole axis to ensure concentricity at ≤0.6μm; using a CNC diamond brush machine, first machining the inner arc, then machining the outer arc, and removing burrs from the chamfered surface by ultrasonic cleaning; Step S7, Finished Product Inspection and Assembly: Inspect the inner diameter, concentricity, length, outer diameter and other dimensional parameters according to relevant national standards. After passing the inspection, assemble with the metal flange to complete the finished product preparation.

3. The manufacturing process of the LC-SM inner hole direct forming ceramic ferrule according to claim 2, characterized in that, In step S1, the vacuum quenching temperature is 1050-1080℃, and the holding time is 2-3 hours; the cryogenic treatment temperature is -196±4℃, and the holding time is 3.5-4.5 hours; the aging tempering temperature is approximately 515-525℃, and the holding time is 2.5-3.5 hours.

4. The manufacturing process of the LC-SM inner hole direct forming ceramic ferrule according to claim 2, characterized in that, The WC-Co alloy described in step S1 has a Co content of 8% by mass.

5. The manufacturing process of the LC-SM inner hole direct forming ceramic ferrule according to claim 2, characterized in that, The diameter of the middle section of the variable diameter structure described in step S1 is 166.2±0.1μm, and the diameters at both ends are 166.0±0.1μm.

6. The manufacturing process of the LC-SM inner hole direct forming ceramic ferrule according to claim 2, characterized in that, In step S1, the thickness of the bottom TiN layer of the TiN-AlN composite coating is 1.5 μm, and the thickness of the top AlN layer is 0.5 μm.

7. The manufacturing process of the LC-SM inner hole direct forming ceramic ferrule according to claim 2, characterized in that, The mass ratio of the high-purity zirconia powder, stabilizing phase, sintering aid, binder and plasticizer in step S2 is (80-85):(3.5-4):(0.5-0.8):(7-9):(4-6).

8. The manufacturing process of the LC-SM inner hole direct forming ceramic ferrule according to claim 7, characterized in that, The high-purity zirconia powder has a particle size of 0.8 μm; the stable phase is composed of Y2O3 and Sc2O3 in a mass ratio of (3.5-3.7):(0.3-0.35); the sintering aid is composed of MgO and La2O3 in a mass ratio of (3-5):(2-3); the binder is composed of polyvinyl butyral and hydroxypropyl methylcellulose in a mass ratio of (6-7):(0.5-0.8); the weight-average molecular weight of the polyvinyl butyral is 80,000-100,000; the plasticizer is composed of dibutyl phthalate, polyethylene glycol PEG-400, and tributyl citrate in a mass ratio of (1.8-2.4):(0.9-1.3):(1.3-2.6).

9. The manufacturing process of the LC-SM inner hole direct forming ceramic ferrule according to claim 2, characterized in that, The specific parameters for injection molding in step S3 are as follows: barrel temperature is 150-180℃, injection pressure is 80-100MPa, injection speed is 50-80mm / s, holding pressure is 60-70MPa, holding time is 10-15s, and mold temperature is 40℃.

Images