Preparation method of LTCC (Low Temperature Co-Fired Ceramic) heating tube
By optimizing the preparation process of LTCC heating pipes, including multiple key steps, the problems of complex processes and unstable product quality are solved, efficient and low-cost production is achieved, and the LTCC heating pipes with excellent performance are prepared.
Patent Information
- Application Number
- CN202510477282.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-16
- Publication Date
- 2025-06-10
AI Technical Summary
The existing LTCC heating tube preparation process is complex and the product quality is unstable, resulting in low production efficiency and high cost.
The optimized process flow is adopted, including making LTCC belts, making through holes, filling holes, printing conductive heating lines, making conductive pads, spraying glue, laminated and wrapping pipes, isostatic molding, glue discharge and sintering, and these steps are used to form LTCC heating pipes with excellent performance.
It improves production efficiency, reduces production costs, and prepares LTCC heating pipes with excellent performance, with broad application prospects.
Smart Images
Figure CN120129101A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of heating tubes, and particularly relates to a preparation method of an LTCC heating tube. Background Art
[0002] With the continuous development of electronic technology, the performance and function requirements for electronic components are getting higher and higher. As an important electronic ceramic manufacturing technology, LTCC technology has unique advantages. LTCC heating tubes have broad application prospects in many fields, such as electronic cigarettes, industrial heating, medical equipment, etc. At present, the preparation process of LTCC heating tubes still has problems such as complex preparation process and unstable product quality. Summary of the Invention
[0003] To achieve the above object, the present invention provides a preparation method of an LTCC heating tube, including the following steps: S10 Making LTCC green tapes: Mix ceramic powder, glass powder, binder, dispersant, and plasticizer to form a slurry, cast and dry the slurry to obtain a thin sheet material, and cut out a first green tape, a second green tape, and a third green tape with increasing length dimensions on the thin sheet material; S20 Making through-holes: Process through-holes on the second green tape and the third green tape respectively; S30 Filling holes: Fill conductive paste into the through-holes in step S20; S40 Printing conductive heating circuits: Print conductive heating circuits on the surface of the first green tape or the second green tape or the third green tape, and the conductive heating circuits are in contact and conduct with the conductive paste in the through-holes; S50 Making conductive pads: Print conductive pads on the surface of the third green tape, and the conductive pads are in contact and conduct with the conductive paste in the through-holes; S60 Spraying glue: Spray glue on the first green tape and the second green tape; S70 Stacking and wrapping the tube: Stack the second green tape on the third green tape and ensure that the through-holes are aligned, stack the first green tape on the second green tape, and wait for the three green tapes to be bonded tightly to each other and wrapped around the outer periphery of the mandrel to form a round tube, and the ends of each layer are aligned and bonded; S80 Isostatic pressing: Put the round tube into a hot isostatic press for pressing; S90 Debinding; S100 Sintering: Put the round tube into a sintering furnace for sintering; S110 Welding leads: Weld external leads on the conductive pads to make an LTCC heating tube.
[0004] In some possible embodiments, in step S10, the slurry is applied to the base film with a flow delay, and the cast slurry is leveled by a doctor blade or a wire bar, so that the thickness of the cast slurry is controlled within 0.01 - 2.0 mm, and the drying temperature is controlled within 60 - 80 °C.
[0005] In some possible embodiments, in step S30, the slurry for filling the holes is silver paste, silver-palladium paste, silver-platinum paste, silver-ruthenium paste or copper paste. The conductive slurry is filled by screen printing or injection. After filling the slurry, the second green tape and the third green tape are dried at a temperature of 60 - 80 °C.
[0006] In some possible embodiments, in step S40, the slurry for printing the conductive heating circuit is silver paste, silver-palladium paste, silver-platinum paste, silver-ruthenium paste or copper paste. The conductive heating circuit is printed on the second green tape by screen printing, printing, spraying, deposition or sputtering. After printing the conductive heating circuit, the second green tape is dried at a temperature of 60 - 80 °C.
[0007] In some possible embodiments, in step S60, glue is sprayed on one side of the second green tape that adheres to the first green tape, and glue is sprayed on one side of the second green tape that adheres to the third green tape.
[0008] In some possible embodiments, in step S70, the second green tape and the third green tape are laminated along the same axis in the same misalignment direction to ensure that the through-hole axes coincide. The first green tape and the second green tape are laminated in the same misalignment direction as the second green tape and the third green tape; after being wrapped around the mandrel, the head and tail ends of each green tape are aligned axially and bonded and fixed, and the bonding seams of each green tape are angularly offset in the circumferential direction of the circular tube structure, and the radial projections of the bonding seams in the cross-section are not collinear.
[0009] In some possible embodiments, in step S80, the process parameters of the hot isostatic press are: temperature 40 - 80 °C, pressure 1 - 100 MPa, time 30 - 90 min.
[0010] In some possible embodiments, in step S90, the circular tube is placed in a muffle furnace and heated to 300 - 500 °C at a rate of 1 - 5 °C / min, and held for 0.5 - 5 h.
[0011] In some possible embodiments, in step S100, the circular tube is placed in a sintering furnace and heated to 700 - 1000 °C at a rate of 1 - 5 °C / min, and held for 0.5 - 3 h.
[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: The preparation method of the LTCC heating tube of the present invention can effectively improve production efficiency and reduce production costs by optimizing the process parameters and operation processes of each step, and can prepare an LTCC heating tube with excellent performance, having broad application prospects. Brief Description of the Drawings
[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0014] Figure 1 It is a process flow chart of the method for preparing an LTCC heating tube provided by an embodiment of the present invention; Figure 2 It is a cross-sectional schematic diagram of a round tube formed after wrapping the tube provided by an embodiment of the present invention.
[0015] Reference numerals: the first green tape 11, the second green tape 12, the third green tape 13. Detailed Description of the Embodiments
[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.
[0017] Hereinafter, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present disclosure, unless otherwise stated, the meaning of "a plurality" is two or more.
[0018] Refer to Figure 1 A method for preparing an LTCC heating tube shown below, which includes the following steps: S10 Prepare LTCC green tapes: Mix ceramic powder, glass powder, binder, dispersant, and plasticizer evenly to make a slurry with an appropriate viscosity. Cast and dry the slurry to obtain a thin sheet material, and cut out the first green tape 11, the second green tape 12, and the third green tape 13 with increasing length dimensions on the thin sheet material; Furthermore, the slurry can be coated on the base film by a casting device, and a doctor blade or a wire bar is used to scrape the casting slurry flat, so that the thickness of the casting slurry is controlled within 0.01 - 2.0 mm, and the drying temperature is controlled within 60 - 80 °C, thereby obtaining a sheet material. The length and width range of the first green tape 11 / second green tape 12 / third green tape 13 cut from the sheet material is 10 - 200 mm. The green tape prepared by the above method not only has high bending strength and sufficient tensile and compressive strength, avoiding cracking or cracking during subsequent processing, but also the first green tape 11 / second green tape 12 / third green tape 13 are cut from the same sheet material, with good consistency and high reliability.
[0019] S20 Making through-holes: Through-holes are respectively processed on the second green tape 12 and the third green tape 13 by means of laser drilling, mechanical punching, etc. The sizes of the through-holes are the same, and the shapes of the through-holes can be circular, semi-circular, square or other special-shaped holes.
[0020] S30 Filling the holes: The conductive paste is filled into the through-holes in step S20 by means of screen printing or injection. The conductive paste can specifically be silver paste, silver-palladium paste, silver-platinum paste, silver-ruthenium paste or copper paste. After filling the holes, the second green tape 12 and the third green tape 13 are placed at a temperature of 60 - 80 °C for drying to preliminarily cure the hole-filling paste.
[0021] S40 Printing the conductive heating circuit: The conductive heating circuit is printed on the surface of the first green tape 11 or the surface of the second green tape 12 or the surface of the third green tape 13 by means of screen printing, printing, spraying, deposition or sputtering. The paste for printing the conductive heating circuit is silver paste, silver-palladium paste, silver-platinum paste, silver-ruthenium paste or copper paste. The width of the heating area should be greater than or equal to 3.0 mm, and the resistance range of the conductive heating circuit is 0.1 - 10 Ω. The two ends of the conductive heating circuit are respectively in contact and conduct with the conductive paste in the hole filling in step S30. After printing, the second green tape 12 is placed at a temperature of 60 - 80 °C for drying to preliminarily cure the conductive heating circuit.
[0022] It should be noted that in S40, if the conductive heating circuit is printed on the inner side of the first green tape 11, the conductive heating circuit will be formed on the inner wall of the heating tube after being wrapped. If the conductive heating circuit is printed on the outer side of the third green tape 13, the conductive heating circuit will be formed on the outer wall of the heating tube after being wrapped. If the conductive heating circuit is printed on the outer side of the first green tape 11 or printed on the second green tape 12 or printed on the inner side of the third green tape 13, the conductive heating circuit will be formed inside the heating tube after being wrapped.
[0023] S50 Fabricate the conductive pads: The conductive pads are printed on the third green tape 13 by means of screen printing, printing, spraying, deposition or sputtering. The paste for printing the conductive pads is the same as the paste for printing the conductive heating circuit, which is silver paste, silver-palladium paste, silver-platinum paste, silver-ruthenium paste or copper paste. The conductive pads should be in contact and conduction with the conductive paste in the via filling in step S30. After printing, the third green tape 13 is placed at a temperature of 60 - 80 °C for drying to preliminarily cure the conductive pads.
[0024] S60 Spray glue: Glue is sprayed on the side of the first green tape 11 that is in contact with the second green tape 12, and glue is also sprayed on the side of the second green tape 12 that is in contact with the third green tape 13. The glue has good bonding performance and high temperature resistance to ensure that the first green tape 11 and the second green tape 12, as well as the second green tape 12 and the third green tape 13, are firmly bonded.
[0025] S70 Stack and wrap the tube: The third green tape 13, the second green tape 12 and the first green tape 11 are sequentially placed into the stacking fixture. Among them, the third green tape 13 is located at the bottom layer. When placing the second green tape 12, it should be aligned with the positioning slots on the stacking fixture so that the via filling paste on the second green tape 12 is aligned and in contact with the via filling paste on the third green tape 13. Then the first green tape 11 is stacked on the second green tape 12. The three green tapes are tightly bonded to each other and wrapped around the outer periphery of the mandrel to form a circular tube.
[0026] Furthermore, to ensure the subsequent stable wrapping of the tube, the second green tape 12 and the third green tape 13 are first stacked along the same axis in the same misalignment direction, and it is ensured that the axial directions of their through holes coincide. This stacking method not only ensures the continuity and coaxiality of the through holes, but also introduces slight structural differences through misaligned stacking, which helps to disperse and evenly distribute the stress during the subsequent wrapping process.
[0027] Then, the first green tape 11 and the second green tape 12 are stacked in the same misalignment direction as the second green tape 12 and the third green tape 13. This consistent misalignment stacking sequence and direction control can effectively avoid stress concentration and structural defects during the stacking process, and at the same time provide a basis for the good combination between multiple green tapes.
[0028] The stacked multi-layer raw tape is wrapped around the mandrel, and the tension and speed of the wrapping are precisely controlled during the wrapping process to ensure that each raw tape fits tightly without wrinkles or looseness. After the wrapping is completed, the head and tail ends of each raw tape are aligned axially and bonded and fixed. This axial alignment and bonding fixation method ensures the structural integrity and dimensional stability of the heating pipe in the axial direction, and prevents axial displacement or deformation during subsequent processing and use. In the circumferential direction of the circular tube structure, the bonding seams of each raw tape are distributed with an angular offset, and the radial projections of each bonding seam in the cross section are not collinear. By making the bonding seams angularly offset in the circumferential direction, the concentrated stress of the bonding seams on the same straight line is avoided, thereby significantly reducing the risk of cracking caused by stress concentration in the bonding seams, and improving the overall structural strength and reliability of the heating pipe. At the same time, the non-collinear radial projection further enhances the stability of the structure, so that the heating pipe can evenly disperse the stress when subjected to various mechanical and thermal stresses, thereby extending the service life.
[0029] S80 isostatic pressing: The round tube obtained by rolling is placed in a hot isostatic press to form the round tube, so that the first green belt 11, the second green belt 12 and the third green belt 13 are tightly combined with each other and the mechanical strength of the round tube is enhanced. The process parameters of the hot isostatic press are: temperature 40-80°C, pressure 1-100MPa, time 30-90min. During the pressing process, the pressure is evenly distributed to avoid defects in the round tube.
[0030] S90 debinding: Place the round tube in a muffle furnace for debinding. The temperature of the muffle furnace is raised to 300-500℃ at a rate of 1-5℃ / min and kept at this temperature for 0.5-5H to remove organic solvents and other substances in the round tube to avoid cracks or delamination during the sintering process.
[0031] S100 sintering: Place the round tube in a sintering furnace for sintering. Depending on the metal slurry used, select a sintering furnace with an oxidizing atmosphere or a reducing atmosphere. The sintering furnace is heated to 700-1000°C at a rate of 1-5°C / min and kept warm for 0.5-3H. During the sintering process, the particle structure of the green tape material will be rearranged to enhance the mechanical strength, thermal stability and electrical properties of the round tube. In addition, the conductive heating circuit, hole filling slurry and pad are solidified to ensure the reliability of electrical performance.
[0032] S110 welding lead: Use automatic welding equipment to weld the lead on the pad on the outer surface of the sintered round tube to ensure that the connection between the lead and the pad is firm and reliable to make a LTCC heating tube.
[0033] In order to further clearly and completely describe the technical solution of the present invention, some preferred embodiments with determined process parameters are listed below: Embodiment 1: In this embodiment, the preparation of LTCC green tape is carried out first. Ceramic powder, glass powder, binder, dispersant, and plasticizer are mixed in a certain proportion to make a slurry with appropriate viscosity. Then, the slurry is added to the base film through a casting device, and the casting slurry is leveled with a doctor blade, controlling the slurry thickness to be 0.01 mm and the drying temperature to be 60 °C to obtain a thin sheet material. The first green tape 11, the second green tape 12, and the third green tape 13 with increasing length dimensions are cut out on the thin sheet material.
[0034] Next, vias are processed on the second green tape 12 and the third green tape 13 respectively. The size and position of the holes are determined according to the design requirements. Then, conductive paste is filled into the holes with silver paste, and after filling the paste, the second green tape 12 and the third green tape 13 are placed in an oven at 60 °C for drying.
[0035] A conductive heating circuit is printed on the surface of the first green tape 11 or the second green tape 12 or the third green tape 13. Silver paste is used as the paste for the conductive heating circuit, and it is printed by screen printing. After printing, the second green tape 12 is placed in an oven at 60 °C for drying. A conductive pad is printed on the surface of the third green tape 13, and the conductive pad is in contact and conducts with the conductive paste in the via.
[0036] Glue is sprayed on the side of the first green tape 11 that adheres to the second green tape 12, and glue is sprayed on the side of the second green tape 12 that adheres to the third green tape 13. Then, the second green tape 12 is laminated on the third green tape 13, and the first green tape 11 is laminated on the second green tape 12, ensuring that the vias on the second green tape 12 coincide with the vias on the third green tape 13. After the three green tapes are tightly bonded to each other in pairs, the three green tapes are rolled together around the outer circumference of the mandrel to form a circular tube, and the two ends of the three green tapes are aligned and bonded tightly respectively.
[0037] The circular tube is placed in a hot isostatic press for pressing. The process parameters of the hot isostatic press are: temperature 50 °C, pressure 20 MPa, time 30 min, to make the three green tapes and the ends of the green tapes closely combined. Then, the circular tube is placed in a muffle furnace and heated to 300 °C at a rate of 1 °C / min and held for 0.5 h for debinding. After debinding is completed, the circular tube is placed in a sintering furnace and heated to 700 °C at a rate of 1 °C / min and held for 0.5 h for sintering. Finally, leads are welded to the conductive pads on the outer surface of the circular tube to make an LTCC heating tube.
[0038] Embodiment 2: This embodiment is similar to Embodiment 1, but is different in some specific parameters. For example, the thickness of the casting slurry is controlled at 1.0 mm, and the drying temperature is 70 °C. Silver-palladium paste is used for hole filling, and the drying temperature is 70 °C. Silver-platinum paste is used for printing the conductive heating circuit, and printing is carried out by means of printing, and the drying temperature is 70 °C. The process parameters of the hot isostatic press are: temperature 60 °C, pressure 10 MPa, and time 60 min. When debinding, the temperature is raised to 400 °C at a rate of 3 °C / min and held for 3 h. When sintering, the temperature is raised to 850 °C at a rate of 3 °C / min and held for 2 h.
[0039] Embodiment 3: In this embodiment, the thickness of the casting slurry is 2.0 mm, and the drying temperature is 80 °C. Silver-ruthenium paste is used for hole filling, and the drying temperature is 80 °C. The conductive heating circuit is printed with copper paste, and spraying is used, and the drying temperature is 80 °C. The temperature of the hot isostatic press is 80 °C, the pressure is 20 MPa, and the time is 90 min. When debinding, the heating rate is 5 °C / min, the temperature is raised to 500 °C, and held for 5 h. When sintering, the heating rate is 5 °C / min, the temperature is raised to 1000 °C, and held for 3 h.
[0040] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.
Claims
1. A method for preparing a LTCC heating tube, characterized in that: The following steps are involved: S10: making LTCC green tape: mixing ceramic powder, glass powder, binder, dispersant and plasticizer to make slurry, casting the slurry and drying it to obtain a sheet material, and cutting the sheet material into a first green tape (11), a second green tape (12) and a third green tape (13) with increasing lengths; S20: making through holes: making through holes on the second green tape (12) and the third green tape (13); S30 hole filling: filling the through hole of step S20 with a conductive paste; S40 printing a conductive heating circuit: printing a conductive heating circuit on the surface of the first green tape (11) or the surface of the second green tape (12) or the surface of the third green tape (13), wherein the conductive heating circuit is in contact with the conductive paste in the through hole and is in conduction; S50: manufacturing a conductive pad, printing the conductive pad on the surface of the third raw tape (13), the conductive pad being in contact with the conductive paste in the through hole; S60 Glue spraying: spraying glue on the first green belt (11) and the second green belt (12); S70 stacking and wrapping tube: stack the second green tape (12) on the third green tape (13) and ensure that the through holes are aligned, stack the first green tape (11) on the second green tape (12), and wait for the three layers of green tape to be bonded in pairs and tightly wrapped around the outer circumference of the mandrel to form a circular tube, and align the ends of each layer and bond them; S80 isostatic pressing: the round tube is placed in a hot isostatic press; S90 glue removal; S100 sintering: put the round tube into the sintering furnace for sintering; S110 welding leads, welding external leads on the conductive pads to make LTCC heating tubes.
2. The method for preparing a LTCC heating tube according to claim 1, characterized in that: In step S10, the slurry is coated on the base film during casting, and the casting slurry is scraped flat by a scraper or a wire rod, so that the thickness of the casting slurry is controlled at 0.01-2.0 mm, and the drying temperature is controlled at 60-80°C.
3. The method for preparing a LTCC heating tube according to claim 1, characterized in that: In step S30, the hole filling paste is silver paste or silver palladium paste or silver platinum paste or silver ruthenium paste or copper paste, and the conductive paste is filled by screen printing or injection. After filling, the second green tape (12) and the third green tape (13) are placed at a temperature of 60-80°C for drying.
4. The method for preparing a LTCC heating tube according to claim 1, characterized in that: In step S40, the paste for printing the conductive heating circuit is silver paste, silver palladium paste, silver platinum paste, silver ruthenium paste or copper paste, and the conductive heating circuit is printed on the second green tape (12) by screen printing, printing, spraying, deposition or sputtering. After printing the conductive heating circuit, the second green tape (12) is placed at a temperature of 60-80° C. for drying.
5. The method for preparing a LTCC heating tube according to claim 1, characterized in that: In step S60, glue is sprayed on the side of the first green tape (11) that is bonded to the second green tape (12), and glue is sprayed on the side of the second green tape (12) that is bonded to the third green tape (13).
6. The method for preparing the LTCC heating tube according to claim 1, characterized in that: In step S70, the second green tape (12) and the third green tape (13) are stacked along the same axial direction in the same offset direction to ensure that the through holes overlap axially, and the first green tape (11) and the second green tape (12) are stacked in the same offset direction as the second green tape (12) and the third green tape (13); after being wrapped around the mandrel, the head end and the tail end of each green tape are aligned axially and bonded, and the bonding seams of each green tape are distributed with an angular offset in the circumferential direction of the circular tube structure, and the radial projections of each bonding seam in the cross section are not collinear.
7. The method for preparing a LTCC heating tube according to claim 1, characterized in that: In step S80, the process parameters of the hot isostatic press are: temperature 40-80°C, pressure 1-100 MPa, and time 30-90 min.
8. The method for preparing a LTCC heating tube according to claim 1, characterized in that: In step S90, the round tube is placed in a muffle furnace, and the temperature is increased to 300-500°C at a rate of 1-5°C / min, and kept at this temperature for 0.5-5 hours.
9. The method for preparing a LTCC heating tube according to claim 1, characterized in that: In step S100, the round tube is placed in a sintering furnace, and the temperature is raised to 700-1000°C at a rate of 1-5°C / min, and kept at this temperature for 0.5-3H.