Glass tube and method of making and use thereof

Abstract

The application relates to a glass tube and a preparation method and application thereof. The preparation method of the glass tube comprises the following steps: 1) drilling a glass rod along the axial direction to obtain a first blank of the glass tube; 2) milling and grinding the outer surface of the first blank of the glass tube to obtain a second blank of the glass tube; 3) heating the second blank of the glass tube to a preset temperature, rotating the second blank of the glass tube around the axial direction at the preset temperature, and keeping warm to obtain a third blank of the glass tube; and 4) cooling the third blank of the glass tube to 200-300 DEG C under the condition of rotating around the axial direction, and then naturally cooling to room temperature to obtain the glass tube. The technical problem to be solved by the application is how to prepare a glass tube with a small inner diameter and a large wall thickness, so that the glass tube still has good performance when the inner diameter is less than or equal to 30 mm and the wall thickness is greater than or equal to 0.5 mm, the concentricity is less than or equal to 0.01 mm, the wall thickness deviation is less than or equal to 0.02 mm, the inner surface roughness is less than or equal to 50 nm, and the outer surface roughness is less than or equal to 50 nm.

Description

Technical Field

[0001] The present invention belongs to the technical field of glass tube processing, and in particular relates to a glass tube and a preparation method and application thereof. Background Art

[0002] Glass tubes are an important form of special glass products. They are widely used in special optical fibers, optical fiber imaging components, medicine bottle glass, chemical pipelines, experimental glass tubes, gas or liquid transportation and other fields, and play an important role.

[0003] At present, glass tubes of high borosilicate glass and neutral glass can be prepared by a process of pool furnace melting combined with mechanical forming. However, the glass tubes produced by this preparation process have the characteristics of large inner diameter and thin wall thickness, so it is not suitable for the preparation of glass tubes with small inner diameter and large wall thickness; moreover, the equipment investment required for the implementation of this process is large and the technical threshold is high; at the same time, the cost and difficulty of switching product specifications and changing formulas during the production process are high. Therefore, this process is only suitable for glass tube products with mature technology and large-scale production, and cannot meet the needs of small-batch, customized high-precision glass tube preparation.

[0004] For the preparation of small-batch, customized high-precision glass tubes, the existing technology can only rely on manual blowing for molding. However, due to the influence of the operator's technical level and uncontrollable factors in the production process, this process is prone to many problems such as uneven wall thickness, uneven inner and outer diameters, eccentricity, poor coaxiality, and high curvature of the glass tube. It is completely unable to meet the application requirements of high-precision glass tubes in technical fields such as optical fiber, information display, gas storage and transportation, and pharmaceutical packaging. Summary of the Invention

[0005] The main purpose of the present invention is to provide a glass tube and a preparation method and application thereof. The technical problem to be solved is how to prepare a glass tube with a small inner diameter and a large wall thickness, so that the glass tube can still have good performance when the inner diameter is ≤30 mm and the wall thickness is ≥0.5 mm, with a concentricity of ≤0.01 mm, a wall thickness deviation of ≤0.02 mm, an inner surface roughness of ≤50 nm, and an outer surface roughness of ≤50 nm, thereby being more suitable for practical use.

[0006] The purpose of the present invention and the technical problem solved are achieved by adopting the following technical solutions. According to the present invention, a method for preparing a glass tube comprises the following steps:

[0007] 1) drilling a hole in a glass rod along its axis to obtain a first glass tube blank;

[0008] 2) milling the outer surface of the first glass tube blank to obtain a second glass tube blank;

[0009] 3) heating the second glass tube blank to a preset temperature, rotating the second glass tube blank about its axis at the preset temperature, and maintaining the temperature to obtain a third glass tube blank;

[0010] 4) The third glass tube blank is cooled to 200-300° C. while rotating around its axis, and then naturally cooled to room temperature to obtain a glass tube.

[0011] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0012] Preferably, the aforementioned preparation method, before the drilling in step 1), further comprises the following steps:

[0013] 1a) melting glass into liquid to obtain molten glass;

[0014] 1b) casting the molten glass into a glass rod of a preset size;

[0015] 1c) Cutting both ends of the glass rod flat and then cleaning them with purified water; the flat cutting of both ends means that after cutting, the parallelism of the two end surfaces is ≤0.05 mm and the end surface roughness is ≤3 μm.

[0016] Preferably, in the aforementioned preparation method, the cutting step in step 1c) includes: placing the glass round rod on a precision flat-head water-cutting platform bracket, and driving the cutting saw blade of the precision flat-head water-cutting platform by a driving mechanism for cutting; or, fixing the glass round rod on a precision flat-head water-cutting platform bracket, and driving the precision flat-head water-cutting platform bracket by a driving mechanism to move to the cutting saw blade of the precision flat-head water-cutting platform for cutting; the cutting saw blade is made of 100-200 mesh silicon carbide or diamond material, and the saw blade speed is 20-30 m / s.

[0017] Preferably, in the aforementioned preparation method, the drilling step in step 1) is as follows:

[0018] 1d) placing a glass round rod cleaned with pure water on a CNC cylindrical grinder and securing the glass round rod with a fixture;

[0019] 1e) milling the outer surface of the glass rod using a diamond grinding wheel with a grit size of 80 to 200 mesh;

[0020] 1f) Mounting the milled glass rod on a CNC ultrasonic drilling machine, selecting a tool and ultrasonic frequency according to design requirements, and drilling the milled glass rod to obtain a first glass tube blank; the diameter of the tool is ≤30 mm, and the ultrasonic frequency is 100-300 kHz; the inner wall roughness of the first glass tube blank is ≤1 μm.

[0021] Preferably, in the aforementioned preparation method, step 2) of milling the outer surface of the first glass tube blank is to place the first glass tube blank on a CNC cylindrical grinder and mill its outer surface; the roughness of the outer surface of the second glass tube blank is ≤3μm.

[0022] Preferably, in the aforementioned preparation method, the glass used to prepare the glass tube has a glass transition temperature of T1 and a softening point temperature of T2, both in °C; in step 3), the preset temperature is >T1 and <T2; the heating rate is 2-10 °C / min; the rotation speed is 10-60 rpm, and the holding time is 10-60 min.

[0023] Preferably, in the aforementioned preparation method, the cooling rate of step 4) is 2 to 10°C / min; and the rotation speed is 10 to 60 rpm.

[0024] The objectives and technical problems of the present invention are achieved by the following technical solutions: A glass tube according to the present invention has an inner diameter of 30 mm or less, a wall thickness of 0.5 mm or more, a concentricity of 0.01 mm or less, a wall thickness deviation of 0.02 mm or less, an inner surface roughness of 50 nm or less, and an outer surface roughness of 50 nm or less.

[0025] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0026] Preferably, the aforementioned glass tube is prepared according to the aforementioned preparation method.

[0027] The purpose of the present invention and the technical problem solved are achieved by adopting the following technical solutions: According to the present invention, a glass tube according to the above is used in the fields of optical fiber, information display, gas storage and transportation or medical packaging technology.

[0028] By means of the above technical solution, the glass tube and its preparation method and application proposed in the present invention have at least the following advantages:

[0029] The glass tube, the preparation method and the application thereof are characterized in that: a first blank of the glass tube containing an inner hole is formed by drilling a glass rod along an axial direction; then, the outer surface of the first blank of the glass tube is milled and polished to make the concentricity of the inner hole and the outer circle of a second blank of the glass tube less than 0.01 mm and the wall thickness deviation less than 0.02 mm; finally, the inner and outer surfaces of the glass tube are planarized by using the surface tension of the glass at high temperature through the whole-rotation heating of the glass tube, so that the roughness of the inner and outer surfaces of the glass tube is reduced to less than 50 nm; meanwhile, the whole-rotation of the glass tube can avoid the deformation and eccentricity of the glass tube during the heating process; after the performance indexes of the glass tube are determined, the glass tube can maintain good performance through slow cooling and natural cooling; through the cooperation of the above four steps, the glass tube with good quality, small inner diameter and large wall thickness can be prepared; the glass tube prepared by the technical scheme has an inner diameter of less than or equal to 30 mm, a wall thickness of more than or equal to 0.5 mm, a concentricity of less than or equal to 0.01 mm, a wall thickness deviation of less than or equal to 0.02 mm, an inner surface roughness of less than or equal to 50 nm and an outer surface roughness of less than or equal to 50 nm.

[0030] Further, the numerical control ultrasonic drilling is used for the drilling method of the glass rod, which can realize the efficient processing of the inner hole of the glass tube, can make the inner wall roughness of the glass tube less than 1 μm, and can avoid the problems such as the glass tube fragmentation caused by the mechanical drilling processing.

[0031] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application and can be implemented according to the content of the description, the following is a detailed description of the preferred embodiments of the present application. DETAILED DESCRIPTION

[0032] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following describes the specific implementation, structure, features and effects of the glass tube, the preparation method and the application thereof according to the present application. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0033] The present invention provides a method for preparing a glass tube, comprising the following steps: drilling a glass rod along its axis to obtain a first glass tube blank; milling the outer surface of the first glass tube blank to obtain a second glass tube blank; heating the second glass tube blank to a preset temperature, rotating the second glass tube blank around its axis at the preset temperature, and keeping the temperature constant to obtain a third glass tube blank; cooling the third glass tube blank to 200-300° C. while rotating around its axis, and then naturally cooling it to room temperature to obtain a glass tube.

[0034] The present invention forms a first glass tube blank including an inner hole by first drilling a glass rod along its axis. Then, the outer surface of the first glass tube blank is milled using the inner hole for positioning, so that the concentricity of the inner hole and the outer circle of the obtained second glass tube blank is better than 0.01 mm and the wall thickness deviation is less than 0.02 mm. Finally, the glass tube is rotated and heated as a whole, and the inner and outer surfaces of the glass tube are flattened by the action of the surface tension of the glass at high temperature, thereby reducing the roughness of the inner and outer surfaces of the glass tube to less than 50 nm. At the same time, the overall rotation of the glass tube can prevent deformation and eccentricity of the glass tube during the heating process. After the performance indicators of the glass tube are determined, the glass tube is cooled slowly and cooled in combination with natural cooling to maintain optimal performance. Through the combined effect of the above four steps, the technical solution of the present invention can produce a high-quality glass tube with a small inner diameter and large wall thickness.

[0035] Preferably, before drilling a hole in the glass rod along its axis, the following steps are further included in sequence:

[0036] The glass is melted into liquid, and then the molten glass liquid is cast into glass rods of preset sizes. This process design is particularly suitable for small-batch, customized glass varieties. If the glass tube to be processed is a common glass variety, the melting and casting steps of the glass rod can be omitted, and instead, the subsequent steps can be carried out by directly purchasing commercially available glass rods.

[0037] Cut the ends of the glass rod flat and rinse thoroughly with purified water. The glass rod can be cut using any glass cutting method known in the art, as long as it meets standard cutting requirements. To ensure the quality and efficiency of subsequent glass rod drilling, the present invention preferably requires that the parallelism of the end faces of the cut ends of the glass rod be ≤0.05 mm and the end face roughness be ≤3 μm.

[0038] In a specific embodiment of the present invention, the glass rod is cut using a precision flat-top water-cutting platform. Specifically, the glass rod can be placed on a precision flat-top water-cutting platform support, with the drive mechanism driving the cutting saw blade of the precision flat-top water-cutting platform for cutting; or the glass rod can be fixed to the precision flat-top water-cutting platform support, with the drive mechanism driving the precision flat-top water-cutting platform support to move to the cutting saw blade of the precision flat-top water-cutting platform for cutting. To ensure the cutting effect of the glass rod, the present invention preferably uses a cutting saw blade made of 100-200 mesh silicon carbide or diamond material, and a rotational speed of 20-30 m / s.

[0039] After the glass round rod is cut and cleaned, the glass rod can be drilled along its axial direction. Specifically, the drilling steps are as follows: the glass round rod cleaned with pure water is placed on a CNC external cylindrical grinder and fixed with a fixture; then, the outer surface of the glass round rod is milled with a diamond grinding wheel with a grit size of 80 to 200 mesh; finally, the milled glass round rod is mounted on a CNC ultrasonic drilling machine, and the tool and ultrasonic frequency are selected according to the design requirements, and the milled glass round rod is drilled to obtain the first glass tube blank. The outer surface of the glass round rod is milled before drilling, the purpose of which is to improve the precise control of the process parameters during drilling. The present invention preferably has a diameter of the tool ≤30 mm and an ultrasonic frequency of 100 to 300 kHz. Through the drilling operation in this step, not only a hollow inner cavity can be obtained in the glass rod, but also the drilling operation adopts CNC ultrasonic drilling, which can realize efficient processing of the inner hole of the glass tube, and can make the inner wall roughness of the glass tube reach below 1μm, while also avoiding problems such as glass tube breakage caused by mechanical drilling.

[0040] After drilling a hole in the glass rod, a first glass tube blank is obtained, and then the outer surface of the first glass tube blank is milled to obtain a second glass tube blank. The specific operation of milling the outer surface of the first glass tube blank is to place the first glass tube blank on a CNC external cylindrical grinder and mill its outer surface. The roughness of the outer surface of the second glass tube blank is controlled to be ≤3μm to ensure the accuracy of process parameter control during subsequent drilling operations.

[0041] Next, the second glass tube blank is placed in a heating furnace for heating and heat preservation to achieve flattening of the inner and outer surfaces of the glass tube. During the heat preservation process, the glass tube is rotated as a whole about its axis. The overall rotation of the glass tube prevents deformation and eccentricity of the glass tube during the heating process, thereby producing a glass tube with a small inner diameter and large wall thickness with excellent performance.

[0042] The heating and holding temperatures are determined by the properties of the glass tube; different glass tube materials require different heating and holding temperatures for flattening. The glass tube preparation method of the present invention is suitable for the production of various glass tubes in small batches and on a customized basis. The glass material is not specifically limited in this invention.

[0043] Preferably, the temperature range for heating and holding is above the glass transition temperature and below the softening point of the glass; that is, the glass used to prepare the glass tube has a glass transition temperature of T1 and a softening point of T2, both in °C. The preset temperature in step 3) is T, where T1 < T < T2. To achieve better flattening technical effects, the preset temperature of the glass tube preparation process parameter is as close to T2 as possible. In the present invention, preferably, T1 + 0.4 × (T2 - T1) < T < T2; further preferably, T1 + 0.5 × (T2 - T1) < T < T2; further preferably, T1 + 0.6 × (T2 - T1) < T < T2; further preferably, T1 + 0.7 × (T2 - T1) < T < T2; further preferably, T1 + 0.8 × (T2 - T1) < T < T2; and further preferably, T1 + 0.9 × (T2 - T1) < T < T2.

[0044] In order to achieve better flattening technical effects, the present invention preferably controls the heating process in step 3) to be slowly heated so that the glass can be fully heated and the temperature of each area is more uniform. At the same time, considering various factors such as the efficiency of glass tube processing and energy consumption, the present invention specifically controls the heating rate of the heating to be 2 to 10°C / min; more preferably, the heating rate is 4 to 6°C / min.

[0045] Finally, the third glass tube blank is cooled using a slow cooling system, preferably a two-stage cooling method, to ensure that after annealing, both the inner and outer surfaces of the glass tube maintain good performance indicators. In the first stage, the temperature is slowly cooled to 200-300°C, allowing for slow annealing. In the second stage, the temperature is naturally cooled to room temperature to increase the cooling rate, taking into account both production efficiency and manufacturing costs. In the present invention, the cooling rate of the first stage is preferably 2-10°C / min; more preferably, the cooling rate is 4-6°C / min.

[0046] Extensive experimental data indicates that for the same glass material, higher heating and holding temperatures result in higher flattening efficiency, as evidenced by shorter holding times and lower roughness on the inner and outer surfaces of the glass tube. The preferred rotational speed during holding is 10 to 60 rpm, with a holding time of 10 to 60 minutes.

[0047] The present invention also provides a glass tube with small inner diameter and large wall thickness, wherein the inner diameter is ≤30 mm, the wall thickness is ≥0.5 mm, the concentricity of the glass tube is ≤0.01 mm, the wall thickness deviation is ≤0.02 mm, the inner surface roughness is ≤50 nm, and the outer surface roughness is ≤50 nm.

[0048] The glass tube is preferably prepared according to the aforementioned preparation method.

[0049] The present invention also proposes an application of the aforementioned glass tube in the technical fields of optical fiber, information display, gas storage and transportation, or medical packaging.

[0050] The present invention will be further described below with reference to specific embodiments, but this should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above-mentioned contents of the present invention still fall within the scope of protection of the present invention.

[0051] Unless otherwise specified, the materials and reagents mentioned below are commercially available products familiar to those skilled in the art. Unless otherwise specified, the methods described are all well-known methods in the art. Unless otherwise defined, technical or scientific terms used shall have the same meanings as those commonly understood by those skilled in the art.

[0052] Example 1:

[0053] In this embodiment, a high-precision glass tube was prepared. The glass used was K9 glass, which has a glass transition temperature of 560°C and a softening point of 714°C. The specific steps are as follows:

[0054] 1) Melting glass into liquid to obtain molten glass; casting the molten glass into a glass round rod with a diameter of 40 mm, i.e., a first glass round rod blank.

[0055] 2) Cut both ends of the first glass rod blank flat and clean them with pure water to obtain a second glass rod; after cutting, the parallelism of the two end faces is ≤0.05mm, and the end face roughness is ≤3μm. The specific operation of cutting the end of the first glass rod blank is: place the first glass rod blank on the precision flat-head water-cutting platform bracket, and drive the cutting saw blade of the precision flat-head water-cutting platform to cut the glass rod by the driving mechanism; or, fix the first glass rod blank on the precision flat-head water-cutting platform bracket, and drive the precision flat-head water-cutting platform bracket to move to the cutting saw blade of the precision flat-head water-cutting platform to cut the glass rod by the driving mechanism; the cutting saw blade used is made of 100 mesh silicon carbide or diamond material, and the saw blade speed is 30m / s.

[0056] 3) The second glass rod is placed on a CNC cylindrical grinder, secured with a fixture, and the outer surface of the second glass rod is ground using a diamond grinding wheel to produce a third glass rod. After the above processing steps, the diameter of the third glass rod in this embodiment is 38 mm, and the diamond grinding wheel has an 80-mesh grit size.

[0057] 4) The third glass rod is mounted on a CNC ultrasonic drilling machine. A tool and ultrasonic frequency are selected according to the design requirements, and a hole is drilled through the third glass rod to obtain a first glass tube. In this embodiment, the tool diameter is 30 mm and the ultrasonic frequency is 100 kHz. The resulting first glass tube has an inner diameter of 30 mm, an outer diameter of 38 mm, and an inner wall roughness of 1 μm. This first glass tube is referred to as the first glass tube blank.

[0058] 5) The first glass tube is placed on a CNC cylindrical grinder and subjected to a second milling process on its outer surface to obtain a second glass tube. In this embodiment, the second glass tube has an outer diameter of 36 mm and an outer surface roughness of 3 μm. This second glass tube is referred to as the second glass tube blank.

[0059] 6) The second glass tube is placed in a rotary heating furnace and slowly heated at a rate of 5°C / min to a set temperature. The second glass tube is then rotated at the set temperature to produce a third glass tube with smooth inner and outer surfaces. In this embodiment, the heating temperature is set to 620°C, the rotation speed of the second glass tube is 10 rpm, and the heating time is 60 minutes. The third glass tube is referred to as the third glass tube blank.

[0060] 7) While the third glass tube is rotated at 10 rpm, the temperature is slowly lowered to 200° C. at 5° C. / min, and finally naturally cooled to room temperature, thereby obtaining a finished high-precision glass tube.

[0061] After testing, the high-precision glass tube obtained in this embodiment has an outer diameter of 36 mm, an inner diameter of 30 mm, a wall thickness of 3 mm, a concentricity of 0.01 mm, a wall thickness deviation of 0.02 mm, an inner surface roughness of 50 nm, and an outer surface roughness of 50 nm.

[0062] Example 2:

[0063] In this embodiment, a high-precision glass tube was prepared. The glass used was K9 glass, which has a glass transition temperature of 560°C and a softening point of 714°C. The specific steps are as follows:

[0064] 1) Melting glass into liquid to obtain molten glass; casting the molten glass into a glass round rod with a diameter of 30 mm, i.e., a first glass round rod blank.

[0065] 2) Cut both ends of the first glass rod blank flat and clean them with pure water to obtain a second glass rod; after cutting, the parallelism of the two end faces is ≤0.05mm, and the end face roughness is ≤2μm. The specific operation of cutting the end of the first glass rod blank is: place the first glass rod blank on the precision flat-head water-cutting platform support, and use the driving mechanism to drive the cutting saw blade of the precision flat-head water-cutting platform to cut the glass rod; or, fix the first glass rod blank on the precision flat-head water-cutting platform support, and use the driving mechanism to drive the precision flat-head water-cutting platform support to move to the cutting saw blade of the precision flat-head water-cutting platform to cut the glass rod; the cutting saw blade used is made of 150 mesh silicon carbide or diamond material, and the saw blade speed is 20m / s.

[0066] 3) The second glass rod is placed on a CNC cylindrical grinder, secured with a fixture, and the outer surface of the second glass rod is ground using a diamond grinding wheel to produce a third glass rod. After the above steps, the diameter of the third glass rod in this embodiment is 29 mm, and the diamond grinding wheel has a grit size of 200 mesh.

[0067] 4) The third glass rod is mounted on a CNC ultrasonic drilling machine. A tool and ultrasonic frequency are selected according to the design requirements, and a hole is drilled through the third glass rod to obtain a first glass tube. In this embodiment, the tool diameter is 25 mm and the ultrasonic frequency is 200 kHz. The resulting first glass tube has an inner diameter of 25 mm, an outer diameter of 29 mm, and an inner wall roughness of 1 μm. This first glass tube is referred to as the first glass tube blank.

[0068] 5) The first glass tube is placed on a CNC cylindrical grinder and subjected to a second milling process on its outer surface to obtain a second glass tube. In this embodiment, the second glass tube has an outer diameter of 28 mm and an outer surface roughness of 2 μm. The second glass tube is referred to as the second glass tube blank.

[0069] 6) The second glass tube is placed in a rotary heating furnace and slowly heated at a rate of 10°C / min to a set temperature. The second glass tube is then rotated at the set temperature to produce a third glass tube with smooth inner and outer surfaces. In this embodiment, the heating temperature is set to 680°C, the rotation speed of the second glass tube is 30 rpm, and the heating time is 20 minutes. The third glass tube is referred to as the third glass tube blank.

[0070] 7) While the third glass tube is rotating at 30 rpm, the temperature is slowly lowered to 300° C. at 10° C. / min, and finally cooled naturally to room temperature, thereby obtaining a finished high-precision glass tube.

[0071] After testing, the high-precision glass tube obtained in this embodiment has an outer diameter of 28 mm, an inner diameter of 25 mm, a wall thickness of 1.5 mm, a concentricity of 0.01 mm, a wall thickness deviation of 0.01 mm, an inner surface roughness of 30 nm, and an outer surface roughness of 30 nm.

[0072] Example 3:

[0073] In this embodiment, a high-precision glass tube is prepared. The glass used is LaK3 glass, which has a glass transition temperature of 663°C and a softening point of 742°C. The specific operation steps are as follows:

[0074] 1) Melting glass into liquid to obtain molten glass; casting the molten glass into a glass round rod with a diameter of 25 mm, i.e., a first glass round rod blank.

[0075] 2) The ends of the first glass rod blank are cut flat and cleaned with pure water to obtain a second glass rod; after cutting, the parallelism of the two end faces is ≤0.05mm, and the end face roughness is ≤1μm. The specific operation of cutting the ends of the first glass rod blank is: the first glass rod blank is placed on the precision flat-head water-cutting platform support, and the driving mechanism drives the cutting saw blade of the precision flat-head water-cutting platform to cut the glass rod; or, the first glass rod blank is fixed on the precision flat-head water-cutting platform support, and the driving mechanism drives the precision flat-head water-cutting platform support to move to the cutting saw blade of the precision flat-head water-cutting platform to cut the glass rod; the cutting saw blade used is made of 200 mesh silicon carbide or diamond material, and the saw blade speed is 30m / s.

[0076] 3) The second glass rod is placed on a CNC cylindrical grinder, secured with a fixture, and the outer surface of the second glass rod is ground using a diamond grinding wheel to produce a third glass rod. After the above steps, the diameter of the third glass rod in this embodiment is 24 mm, and the diamond grinding wheel has a grit size of 200 mesh.

[0077] 4) The third glass rod is mounted on a CNC ultrasonic drilling machine. A tool and ultrasonic frequency are selected according to the design requirements, and a hole is drilled through the third glass rod to obtain a first glass tube. In this embodiment, the tool diameter is 21.5 mm, and the ultrasonic frequency is 300 kHz. The resulting first glass tube has an inner diameter of 21.5 mm, an outer diameter of 24 mm, and an inner wall roughness of 1 μm. This first glass tube is referred to as the first glass tube blank.

[0078] 5) The first glass tube is placed on a CNC cylindrical grinder and subjected to a second milling process on its outer surface to obtain a second glass tube. In this embodiment, the second glass tube has an outer diameter of 23.5 mm and an outer surface roughness of 1 μm. This second glass tube is referred to as the second glass tube blank.

[0079] 6) The second glass tube is placed in a rotary heating furnace and slowly heated at 6°C / min to a set temperature. The second glass tube is then rotated at the set temperature to produce a third glass tube with smooth inner and outer surfaces. In this embodiment, the set heating temperature is 720°C, the rotation speed of the second glass tube is 60 rpm, and the heating time is 10 minutes. The third glass tube is referred to as the third glass tube blank.

[0080] 7) While the third glass tube is rotated at 10 rpm, the temperature is slowly lowered to 250° C. at 5° C. / min, and finally naturally cooled to room temperature, thereby obtaining a finished high-precision glass tube.

[0081] After testing, the high-precision glass tube obtained in this embodiment has an outer diameter of 23.5 mm, an inner diameter of 21.5 mm, a wall thickness of 1.0 mm, a concentricity of 0.01 mm, a wall thickness deviation of 0.01 mm, an inner surface roughness of 20 nm, and an outer surface roughness of 20 nm.

[0082] Example 4:

[0083] In this embodiment, a high-precision glass tube is prepared. The glass used is ZF4 glass, which has a glass transition temperature of 407°C and a softening point of 684°C. The specific operation steps are as follows:

[0084] 1) Melting glass into liquid to obtain molten glass; casting the molten glass into a glass round rod with a diameter of 25 mm, i.e., a first glass round rod blank.

[0085] 2) The ends of the first glass rod blank are cut flat and cleaned with pure water to obtain a second glass rod; after cutting, the parallelism of the two end faces is ≤0.05mm, and the end face roughness is ≤1μm. The specific operation of cutting the ends of the first glass rod blank is: the first glass rod blank is placed on the precision flat-head water-cutting platform support, and the driving mechanism drives the cutting saw blade of the precision flat-head water-cutting platform to cut the glass rod; or, the first glass rod blank is fixed on the precision flat-head water-cutting platform support, and the driving mechanism drives the precision flat-head water-cutting platform support to move to the cutting saw blade of the precision flat-head water-cutting platform to cut the glass rod; the cutting saw blade used is made of 200 mesh silicon carbide or diamond material, and the saw blade speed is 30m / s.

[0086] 3) The second glass rod is placed on a CNC cylindrical grinder, secured with a fixture, and the outer surface of the second glass rod is ground using a diamond grinding wheel to produce a third glass rod. After the above steps, the diameter of the third glass rod in this embodiment is 24 mm, and the diamond grinding wheel has a grit size of 200 mesh.

[0087] 4) The third glass rod is mounted on a CNC ultrasonic drilling machine. A tool and ultrasonic frequency are selected according to the design requirements, and a hole is drilled through the third glass rod to obtain a first glass tube. In this embodiment, the tool diameter is 22 mm and the ultrasonic frequency is 300 kHz. The resulting first glass tube has an inner diameter of 22 mm, an outer diameter of 24 mm, and an inner wall roughness of 1 μm. This first glass tube is referred to as the first glass tube blank.

[0088] 5) The first glass tube is placed on a CNC cylindrical grinder and subjected to a second milling process on its outer surface to obtain a second glass tube. In this embodiment, the second glass tube has an outer diameter of 23.5 mm and an outer surface roughness of 1 μm. This second glass tube is referred to as the second glass tube blank.

[0089] 6) The second glass tube is placed in a rotary heating furnace and slowly heated at 2°C / min to a set temperature. The second glass tube is then rotated at the set temperature to produce a third glass tube with smooth inner and outer surfaces. In this embodiment, the heating temperature is set to 500°C, the rotation speed of the second glass tube is 40 rpm, and the heating time is 30 minutes. The third glass tube is referred to as the third glass tube blank.

[0090] 7) While the third glass tube is rotated at 10 rpm, the temperature is slowly lowered to 200° C. at 2° C. / min, and finally naturally cooled to room temperature, thereby obtaining a finished high-precision glass tube.

[0091] After testing, the high-precision glass tube obtained in this embodiment has an outer diameter of 23.5 mm, an inner diameter of 22 mm, a wall thickness of 0.75 mm, a concentricity of 0.01 mm, a wall thickness deviation of 0.01 mm, an inner surface roughness of 10 nm, and an outer surface roughness of 10 nm.

[0092] Example 5:

[0093] In this embodiment, a high-precision glass tube was prepared. The glass used was BF33 glass, which has a glass transition temperature of 525°C and a softening point of 820°C. The specific steps are as follows:

[0094] 1) Melting glass into liquid to obtain molten glass; casting the molten glass into a glass round rod with a diameter of 18 mm, i.e., a first glass round rod blank.

[0095] 2) cutting and flattening the two ends of the first glass rod blank, and cleaning with purified water to obtain a second glass rod; after cutting, the parallelism of the two end faces is ≤0.05mm, and the end face roughness is ≤1μm. The specific operation of cutting the end of the first glass rod blank is: placing the first glass rod blank on the precise flat water cutting platform support, and cutting the glass rod by the cutting saw blade of the precise flat water cutting platform driven by the driving mechanism; or fixing the first glass rod blank on the precise flat water cutting platform support, and cutting the glass rod by the cutting saw blade of the precise flat water cutting platform driven by the driving mechanism; the cutting saw blade is made of 200 mesh silicon carbide or diamond material, and the saw blade rotation speed is 25m / s.

[0096] 3) placing the second glass rod on the numerical control cylindrical grinding machine, fixing it by the clamp, and grinding the outer surface of the second glass rod by the diamond grinding wheel to obtain a third glass rod. After the above steps, the diameter of the third glass rod in this embodiment is 17mm, and the granularity of the diamond grinding wheel is 200 mesh.

[0097] 4) installing the third glass rod on the numerical control ultrasonic drilling machine, selecting the tool and ultrasonic frequency according to the design requirements, drilling the third glass rod to obtain a first glass tube; in this embodiment, the selected tool diameter is 15.5mm, and the ultrasonic frequency is 300kHz; the obtained first glass tube has an inner diameter of 15.5mm, an outer diameter of 17mm, and an inner wall roughness of 1μm. Here, the first glass tube is the first blank of the glass tube.

[0098] 5) placing the first glass tube on the numerical control cylindrical grinding machine to perform second milling and grinding processing on the outer surface thereof to obtain a second glass tube; in this embodiment, the outer diameter of the second glass tube is 16.5mm, and the outer surface roughness is 1μm. Here, the second glass tube is the second blank of the glass tube.

[0099] 6) installing the second glass tube into the rotary heating furnace, slowly heating to the set temperature at 10℃ / min, and rotating the second glass tube at the set temperature to obtain a third glass tube with smooth inner and outer surfaces; in this embodiment, the set heating temperature is 700℃, the rotation speed of the second glass tube is 30r / min, and the heating time is 30 minutes. Here, the third glass tube is the third blank of the glass tube.

[0100] 7) rotating the third glass tube at 10r / min while slowly cooling to 200℃ at 5℃ / min, and finally naturally cooling to room temperature, which is the high-precision glass tube finished product.

[0101] After testing, the high-precision glass tube obtained in this embodiment has an outer diameter of 16.5 mm, an inner diameter of 15.5 mm, a wall thickness of 0.5 mm, a concentricity of 0.01 mm, a wall thickness deviation of 0.01 mm, an inner surface roughness of 10 nm, and an outer surface roughness of 10 nm.

[0102] According to the process parameters of the above embodiment and the performance data of the glass tube, it can be seen that during the surface flattening treatment of the glass tube, for glass tubes of the same glass material, the insulation temperature is between the glass transition temperature and the softening point temperature. The higher the insulation temperature, the shorter the insulation time, the lower the roughness of the inner and outer surfaces of the glass tube, and the higher the surface quality.

[0103] The technical features in the claims and / or the specification of the present invention may be combined, and the manner of combination is not limited to the combination obtained by reference in the claims. The technical solutions obtained by combining the technical features in the claims and / or the specification are also within the scope of protection of the present invention.

[0104] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiment based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a glass tube, characterized in that: It includes the following steps: 1) Drilling a hole in the glass rod along its axis to obtain a first glass tube blank; 2) milling the outer surface of the first glass tube blank to obtain a second glass tube blank; the outer surface roughness of the second glass tube blank is ≤3 μm; 3) heating the second glass tube blank to a preset temperature, rotating the second glass tube blank about its axis at the preset temperature, and maintaining the temperature to obtain a third glass tube blank; the glass used to prepare the glass tube has a glass transition temperature of T1 and a softening point temperature of T2, both in ° C.; the preset temperature is greater than T1 and less than T2; the rotation speed is 10 to 60 rpm, and the holding time is 10 to 60 minutes; 4) cooling the third glass tube blank to 200-300° C. while rotating about its axis, and then naturally cooling to room temperature to obtain a glass tube; the cooling rate is 2-10° C. / min; the rotation speed is 10-60 rpm; the glass tube has an inner diameter of ≤30 mm, a wall thickness of ≥0.5 mm, a concentricity of ≤0.01 mm, a wall thickness deviation of ≤0.02 mm, an inner surface roughness of ≤50 nm, and an outer surface roughness of ≤50 nm.

2. The preparation method according to claim 1, characterized in that Before the drilling in step 1), the following steps are also included: 1a) Melting glass into liquid to obtain molten glass; 1b) casting the molten glass into a glass rod of a preset size; 1c) Cutting both ends of the glass rod flat and clean them with purified water; the flat cutting of both ends means that after cutting, the parallelism of the two end surfaces is ≤0.05 mm and the end surface roughness is ≤3 μm.

3. The preparation method according to claim 2, characterized in that The cutting step in step 1c) includes: placing the glass round rod on a precision flat-top water-jet cutting platform bracket, and driving the cutting saw blade of the precision flat-top water-jet cutting platform by a driving mechanism to cut; or, fixing the glass round rod on a precision flat-top water-jet cutting platform bracket, and driving the precision flat-top water-jet cutting platform bracket by a driving mechanism to move to the cutting saw blade of the precision flat-top water-jet cutting platform for cutting; the cutting saw blade is made of 100-200 mesh silicon carbide or diamond material, and the saw blade speed is 20-30 m / s.

4. The preparation method according to claim 2, characterized in that Step 1) The drilling steps are as follows: 1d) placing the glass round rod cleaned with pure water on a CNC cylindrical grinder and securing the glass round rod with a fixture; 1e) milling the outer surface of the glass rod using a diamond grinding wheel with a grit size of 80-200 mesh; 1f) Mounting the milled glass rod on a CNC ultrasonic drilling machine, and drilling the milled glass rod using a tool and ultrasonic frequency selected according to design requirements to obtain a first glass tube blank; the diameter of the tool is ≤30 mm, and the ultrasonic frequency is 100-300 kHz; the inner wall roughness of the first glass tube blank is ≤1 μm.

5. The preparation method according to claim 1, characterized in that Step 2) milling the outer surface of the first glass tube blank comprises placing the first glass tube blank on a CNC cylindrical grinder and milling the outer surface thereof.

6. The preparation method according to claim 1, characterized in that Step 3) The heating rate is 2-10°C / min.

7. A glass tube prepared according to the preparation method according to any one of claims 1 to 6, characterized in that: Its inner diameter is ≤30mm, its wall thickness is ≥0.5mm, and its concentricity is ≤0.01mm, its wall thickness deviation is ≤0.02mm, its inner surface roughness is ≤50nm, and its outer surface roughness is ≤50nm.

8. Use of the glass tube according to claim 7 in the fields of optical fiber, information display, gas storage and transportation, or pharmaceutical packaging technology.