Stainless steel ceramic heater and process thereof

Abstract

The application discloses a stainless steel ceramic heater and a process thereof, wherein the stainless steel ceramic heater comprises a base material layer, an outer wall of the base material layer is coated with a first ceramic insulation layer, a surface of the first ceramic insulation layer is covered with a metal resistance layer, the metal resistance layer is etched with a resistance circuit through rotary laser, and the resistance circuit is coated with a second ceramic insulation layer on the outer side. The application has the advantages of fast heating speed, small thermal inertia, high power density, good temperature uniformity, long service life, high laser etching process precision, wide application range, etc.

Description

Technical Field

[0001] This invention relates to the technical field of heating devices for hot runner systems, specifically to a stainless steel ceramic heater and its manufacturing process. Background Technology

[0002] Currently, copper-sheathed heaters are widely used in hot runner systems. These heaters consist of a heating wire embedded within a copper sheath. However, this structure has the following problems: 1. High thermal inertia and slow heating rate, which cannot meet the high efficiency requirements of modern injection molding; 2. The heating wire is prone to aging and breakage, resulting in a limited lifespan; 3. Poor temperature uniformity affects the quality of plastic parts; 4. Copper bushings are expensive and complex to manufacture; Thick film heaters have emerged in recent years, but their process relies on expensive thick film printing equipment and has extremely high requirements for materials and sintering processes, making them unsuitable for small and medium-sized manufacturing enterprises.

[0003] Therefore, there is an urgent need in this field for a new type of hot runner heater that can heat up quickly, has a long lifespan, good temperature uniformity, moderate cost, and is suitable for mass production. Summary of the Invention

[0004] The purpose of this invention is to provide a stainless steel ceramic heater and its process to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a stainless steel ceramic heater, comprising a substrate layer, a first ceramic insulating layer coated on the outer wall of the substrate layer, a metal resistance layer covering the surface of the first ceramic insulating layer, a resistance line etched on the metal resistance layer by a rotating laser, and a second ceramic insulating layer coated on the outer side of the resistance line.

[0006] Preferably, the substrate layer is made of 404 stainless steel tubing.

[0007] Preferably, the substrate layer, the first ceramic insulating layer, the metal resistive layer, and the second ceramic insulating layer are sintered at high temperature to form a dense and robust whole.

[0008] A manufacturing process for a stainless steel ceramic heater includes the following steps: Step S1: Substrate layer pretreatment; The substrate layer of the 404 stainless steel pipe is subjected to sandblasting, cleaning, and degreasing treatment. Step S2: Apply the first ceramic insulating layer; Ceramic insulating material is coated on the outer wall of the substrate layer of 404 stainless steel pipe by spraying, dip coating or plasma spraying, followed by preliminary sintering; Step S3: Cover with a metal resistor layer; A layer of metallic resistive material is coated on the surface of the first ceramic insulating layer to ensure a tight fit. Step S4: Rotate the laser to etch the resistor circuit; The substrate layer of a 404 stainless steel tube with a metal resistance layer is fixed on a rotating fixture. A laser is used to cut along the rotating surface to form a predetermined resistance circuit. The remaining metal part after cutting is the heating resistor. Step S5: Apply the second ceramic insulating layer; A ceramic insulating layer is then coated on the outside of the etched resistor lines. Step S6: High-temperature co-firing; The entire structure is sintered at high temperature to densify the ceramic layers and form a strong bond between the layers. Step S7: Lead soldering and testing; High-temperature resistant leads were soldered to both ends of the resistor circuit, and resistance, insulation, temperature rise and life tests were performed.

[0009] Preferably, step S1, the substrate layer pretreatment, includes: S11. Degreasing: First, clean the oil stains off the surface of the substrate layer; S12, Sandblasting: Sandblast the cleaned substrate layer to remove oxide scale and welding slag; S13. Post-cleaning: Acid pickling is performed on the sandblasted substrate layer to remove residues, neutralize, and rinse thoroughly. S14. Drying: Dry the substrate layer after pickling.

[0010] Preferably, the metal resistor material includes any one of iron-chromium-aluminum, nickel-chromium, or metal foil.

[0011] Preferably, after lead soldering and testing in step S7, final assembly and inspection are carried out: overall assembly is performed, including the installation of external junction boxes, and finally electrical performance testing and visual inspection are conducted to ensure product qualification.

[0012] Preferably, in step S4, the resistive circuit is formed by rotating the laser to etch the resistive circuit into a spiral shape.

[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. It heats up quickly and has low thermal inertia, reaching the set temperature within 5–10 minutes; 2. High power density, reaching 25–35 W / cm², meeting the high power requirements of hot runners; 3. Good temperature uniformity, improving the molding quality of plastic parts; 4. The multi-layered ceramic structure is resistant to high temperatures and corrosion, and has a long service life; 5. Laser etching process has high precision and allows for flexible design of resistor circuits; 6. No expensive thick film printing equipment is required, and the cost is lower than that of thick film heaters; 7. It can directly replace traditional copper-sheathed heaters and has a wide range of applications. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a stainless steel ceramic heater proposed in this invention; Figure 2 This is a schematic diagram of the laser etching process of the present invention; Figure 3 This is a schematic diagram of the manufacturing process of a stainless steel ceramic heater proposed in this invention. Figure 4 This is a schematic diagram of the substrate layer pretreatment process for the manufacturing process of a stainless steel ceramic heater proposed in this invention.

[0015] In the figure: 1. Substrate layer; 2. First ceramic insulating layer; 3. Metal resistive layer; 4. Resistive circuit; 5. Second ceramic insulating layer. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0017] Please see Figure 1-2 This invention provides a technical solution: a stainless steel ceramic heater, comprising a substrate layer 1, the substrate layer 1 being made of 404 stainless steel tube with an outer diameter of 12mm and a wall thickness of 1.5mm; a first ceramic insulating layer 2 coated on the outer wall of the substrate layer 1, the first ceramic insulating layer 2 having a thickness of 0.1–0.2mm and being made of alumina-based ceramic material; a metal resistance layer 3 covering the surface of the first ceramic insulating layer 2, the metal resistance layer 3 being made of 0.05–0.1mm iron-chromium-aluminum foil; a resistance line 4 formed on the metal resistance layer 3 by rotational laser etching, the spiral line being formed by rotational laser etching with a line width of 0.3mm and a line spacing of 0.3mm; a second ceramic insulating layer 5 coated on the outside of the resistance line 4, the second ceramic insulating layer 5 having a thickness of 0.1–0.2mm.

[0018] In this invention, the substrate layer 1, the first ceramic insulating layer 2, the metal resistive layer 3, and the second ceramic insulating layer 5 are sintered at high temperature to form a dense and solid whole. The overall sintering temperature is 900–1100℃, and the final power can reach 300–500W, with a power density of about 30 W / cm². Example

[0019] Please see Figure 1-2 This invention provides a technical solution: a stainless steel ceramic heater, comprising a substrate layer 1, which is made of 404 stainless steel tube with an outer diameter of 12mm and a wall thickness of 1.5mm. A first ceramic insulating layer 2 is coated on the outer wall of the substrate layer 1, the first ceramic insulating layer 2 having a thickness of 0.1–0.2mm and being made of alumina-based ceramic material. A metal resistance layer 3 is covered on the surface of the first ceramic insulating layer 2, the metal resistance layer 3 being made of nickel-chromium material. A resistance line 4 is formed on the metal resistance layer 3 by rotational laser etching, forming a spiral line with a line width of 0.3mm and a line spacing of 0.3mm. The laser etching forms segmented heating areas, which can achieve zoned temperature control. A second ceramic insulating layer 5 with a thickness of 0.1–0.2mm is coated on the outside of the resistance line 4.

[0020] In this invention, the substrate layer 1, the first ceramic insulating layer 2, the metal resistive layer 3, and the second ceramic insulating layer 5 are sintered at high temperature to form a dense and solid whole. The overall sintering temperature is 900–1100℃, and the final power can reach 300–500W, with a power density of about 30 W / cm².

[0021] See Figure 3-4 A manufacturing process for a stainless steel ceramic heater includes the following steps: Step S1: Pretreatment of substrate layer 1; The substrate layer 1 of the 404 stainless steel pipe is subjected to sandblasting, cleaning, and degreasing treatment. Step S2: Apply the first ceramic insulating layer 2; Ceramic insulating material is coated on the outer wall of the substrate layer 1 of 404 stainless steel pipe by spraying, dip coating or plasma spraying, followed by preliminary sintering; Step S3: Cover with metal resistor layer 3; A layer of metallic resistive material is coated on the surface of the first ceramic insulating layer 2 to ensure a tight fit. Step S4: Rotate and laser-etch resistor line 4; The substrate layer 1 of the 404 stainless steel tube with metal resistance layer 3 is fixed on a rotating fixture, and the laser is used to cut along the rotating surface to form a predetermined resistance circuit. The remaining metal part after cutting is the heating resistor. Step S5: Apply the second ceramic insulating layer 5; A ceramic insulating layer is coated again on the outside of the etched resistor line 4; Step S6: High-temperature co-firing; The entire structure is sintered at high temperature to densify the ceramic layers and form a strong bond between the layers. Step S7: Lead soldering and testing; High-temperature resistant leads were soldered to both ends of resistor line 4, and resistance, insulation, temperature rise and life tests were performed.

[0022] In this invention, step S1, the pretreatment of substrate layer 1, includes: S11. Degreasing: First, clean the oil stains off the surface of substrate layer 1; S12, Sandblasting: Sandblast the cleaned substrate layer 1 to remove oxide scale and welding slag; S13. Post-cleaning: Acid pickling is performed on the sandblasted substrate layer 1 to remove residues, neutralize and rinse it clean. S14. Drying: Dry the pickled substrate layer 1.

[0023] In this invention, the metal resistor material includes any one of iron-chromium-aluminum, nickel-chromium, or metal foil.

[0024] In this invention, after lead soldering and testing in step S7, final assembly and inspection are carried out: overall assembly is performed, including the installation of external junction boxes, and finally electrical performance testing and appearance inspection are performed to ensure product qualification.

[0025] In this invention, step S4 involves rotating the laser to etch the resistor line 4 to form a spiral resistor line.

[0026] This invention involves sandblasting, cleaning, and degreasing the substrate layer 1 of a 404 stainless steel pipe. A ceramic insulating material is coated onto the outer wall of the substrate layer 1 of a 404 stainless steel tube using spraying, dip coating, or plasma spraying methods. Preliminary sintering is then performed. A layer of metal resistive material is then applied to the surface of the first ceramic insulating layer 2, ensuring a tight fit. The substrate layer 1 of the 404 stainless steel tube with the metal resistive layer 3 is fixed on a rotating fixture. A laser is used to cut along the rotating surface to form a predetermined resistance circuit. The remaining metal portion after cutting serves as the heating resistor. A ceramic insulating layer is then coated again on the outside of the etched resistance circuit 4. The entire structure is then sintered at high temperature to densify the ceramic layer and create a strong bond between the layers. High-temperature resistant leads are welded to both ends of the resistance circuit 4, and resistance, insulation, temperature rise, and lifespan tests are performed.

[0027] The contents not described in detail in this specification are prior art known to those skilled in the art. Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A stainless steel ceramic heater characterized by: It includes a substrate layer (1), on the outer wall of the substrate layer (1) is coated with a first ceramic insulating layer (2), the surface of the first ceramic insulating layer (2) is covered with a metal resistive layer (3), a resistive line (4) is etched on the metal resistive layer (3) by a rotating laser, and a second ceramic insulating layer (5) is coated on the outside of the resistive line (4).

2. A stainless steel ceramic heater as claimed in claim 1, wherein: The substrate layer (1) is made of 404 stainless steel pipe.

3. A stainless steel ceramic heater as defined in claim 1, wherein: The substrate layer (1), the first ceramic insulating layer (2), the metal resistive layer (3), and the second ceramic insulating layer (5) are sintered at high temperature to form a dense and solid whole.

4. The process for manufacturing a stainless steel ceramic heater according to any one of claims 1 to 3, characterized in that: Includes the following steps: Step S1: Pretreatment of substrate layer (1); The substrate layer (1) of the 404 stainless steel pipe is subjected to sandblasting, cleaning and degreasing treatment; Step S2: Apply the first ceramic insulating layer (2); Ceramic insulating material is coated on the outer wall of the substrate layer (1) of 404 stainless steel pipe by spraying, dipping or plasma spraying, followed by preliminary sintering; Step S3: Cover with a metal resistor layer (3); A layer of metal resistive material is covered on the surface of the first ceramic insulating layer (2) to ensure a tight fit; Step S4: Rotate the laser to etch the resistor circuit (4); The substrate layer (1) of the 404 stainless steel tube with metal resistance layer (3) is fixed on the rotating fixture, and the laser is used to cut along the rotating surface to form a predetermined resistance line. The remaining metal part after cutting is the heating resistor. Step S5: Apply the second ceramic insulating layer (5); A ceramic insulating layer is coated again on the outside of the etched resistor line (4); Step S6: High-temperature co-firing; The entire structure is sintered at high temperature to densify the ceramic layers and form a strong bond between the layers. Step S7: Lead soldering and testing; High-temperature resistant leads were welded to both ends of the resistor line (4), and resistance, insulation, temperature rise and life tests were performed.

5. A process for the manufacture of a stainless steel ceramic heater as claimed in claim 4, wherein: The pretreatment of the substrate layer (1) in step S1 includes: S11, Degreasing: First clean off the oil stains on the surface of the substrate layer (1); S12, Sandblasting: Sandblast the cleaned substrate layer (1) to remove oxide scale and welding slag; S13, Post-cleaning; Acid pickling is performed on the sandblasted substrate layer (1) to remove residues, neutralize and rinse clean; S14. Drying: Dry the pickled substrate layer (1).

6. The process for manufacturing a stainless steel ceramic heater as claimed in claim 4, wherein: The metal resistor material includes any one of iron-chromium-aluminum, nickel-chromium, or metal foil.

7. The process for manufacturing a stainless steel ceramic heater as claimed in claim 4, wherein: After lead soldering and testing in step S7, final assembly and inspection are carried out: overall assembly is performed, including the installation of the external junction box, and finally electrical performance testing and visual inspection are conducted to ensure product qualification.

8. The process for manufacturing a stainless steel ceramic heater as claimed in claim 4, wherein: Step S4: Rotate the laser to etch the resistor circuit (4) to form a spiral resistor circuit.

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