A laser machining method for reed switch sealing

Abstract

The application discloses a laser processing method for sealing of a magnetic reed switch. The end face of the shell of the magnetic reed switch is non-contact and slightly melted by laser, so that the end face of the shell is melted, and a spherical sealing end face is formed, and the sealing effect can simultaneously meet the requirements of air tightness, no bubbles in the shell, no fracture of the metal reed, spherical appearance of the glass at the welded and attached position, and production yield. The damage of the magnetic reed switch in the packaging process can be effectively reduced, the processing yield and efficiency are effectively improved, and high integration with an automatic work station can be realized, and the method is suitable for large-scale automatic mass production.

Description

Technical Field

[0001] This invention relates to a sealing processing method for reed switches, specifically to a laser processing method for sealing reed switches. Background Technology

[0002] A reed switch mainly consists of two reeds sealed inside a glass tube. The two reeds overlap but have a small gap between them; a suitable external magnetic field will cause the two reeds to make contact. The contacts on these two reeds are plated with a very hard metal, usually rhodium and ruthenium. This hard metal layer greatly improves the lifespan of the switching cycle. The glass tube is usually filled with nitrogen or similar inert gases, and some reed switches are even made into a vacuum state to improve the switching voltage performance. The sealing process of a reed switch is a crucial step in the manufacturing process. The contacts and reeds of a reed switch are quite small and delicate, and because the reed switch is encapsulated in glass, the sealing process is very fragile and difficult to damage, making it challenging to manufacture.

[0003] Chinese patent (publication number: CN113035639A) discloses a method in which the short pin 1 and the long pin 7 of a reed switch are fused and sealed to both ends of a glass tube 2 by brazing. However, the existing technology uses thermoforming welding for encapsulation, which suffers from problems such as high power consumption, low yield, high cost, and low efficiency, making it unsuitable for automated production. In addition, the welding head is in contact with the glass for a long time, which can damage the welding head, requiring replacement after a period of time, increasing consumable costs and wasting resources.

[0004] To address the aforementioned technical problems, this invention provides a laser processing method for sealing reed switches. This method employs non-contact welding, which effectively reduces damage to the reed switch during the packaging process, significantly improves processing yield and efficiency, and allows for high integration with automated workstations, making it suitable for large-scale automated mass production. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by providing a laser processing method for sealing reed switches. By using a laser to non-contactly melt the end face of the reed switch housing, the end face is melted, forming a spherical sealing end face. This method simultaneously meets the requirements of airtightness, no air bubbles in the housing, no breakage of the metal reed, a spherical appearance of the glass at the weld joint, and high production yield. It effectively reduces damage to the reed switch during the packaging process, significantly improves processing yield and efficiency, and allows for high integration with automated workstations, making it suitable for large-scale automated mass production.

[0006] To achieve the above objectives, the specific processing method adopted in this invention is as follows: (a) First, clamp and fix the inner core and the outer shell to ensure that the upper and lower inner cores of the reed switch are located in the center of the outer shell; (b) Then, irradiate one side of one end face of the outer shell with a first laser beam and irradiate the other side of one end face of the outer shell with a second laser beam. The two sides of the end face of the outer shell are heated and softened, and adhere to the metal rod of the inner core to form a hemispherical welded end face; (c) Rotate the reed switch 180°, irradiate one side of the other end face of the outer shell with a first laser beam and irradiate the other side of the other end face of the outer shell with a second laser beam. The two sides of the other end face of the outer shell are heated and softened, and adhere to the metal rod of the inner core to form a spherical welded end face together with the hemispherical welded end face in step (b), forming a spherical sealing end face; (d) Cool the sealing end face and check whether the cooled spherical sealing end face meets the requirements.

[0007] The above technical solution can obtain a spherical sealing surface with a full appearance and meeting performance requirements. The sealing effect of the spherical sealing surface can achieve the technical effects of airtightness, no air bubbles in the outer shell, no breakage of the metal spring, and meeting the requirements of production yield.

[0008] Furthermore, to prevent insufficient welding area from leading to sealing failure or abnormal welding end face formation, the angle between the laser beam and the side of the outer shell is 30 degrees. ° -60°.

[0009] Furthermore, in order to improve the success rate of forming the spherical sealing end face, step (b) or / and step (c) also includes blowing air towards the metal rod direction on the heat-softened shell end face while irradiating with the laser beam.

[0010] Preferably, the outer casing is made of plexiglass.

[0011] Furthermore, in order to ensure the consistency of the sealing end faces at both ends of the reed switch, the first laser beam and the second laser beam are symmetrically arranged, and the laser beams are irradiated at the same height and are symmetrical left and right on the outer casing.

[0012] Preferably, the wavelength of the laser beam is selected to be 800-1000nm.

[0013] Furthermore, in order to prevent air bubbles from forming in the shell, in steps (b) and (c), the irradiation time of the first laser beam and the second laser beam is set to 4-5 seconds.

[0014] Preferably, in step (b) and / or step (c), the blowing direction is coaxial or parallel to the irradiation direction of the laser beam.

[0015] Preferably, in order to improve the fullness and airtightness of the spherical end face, the blowing pressure is 5-10 L / min.

[0016] Compared with the prior art, the beneficial effects of the present invention are: (1) the sealing of the reed switch is achieved by non-contact melting with laser beam, which has a good sealing effect, can effectively reduce the damage to the reed switch during the packaging process, effectively improve the processing yield and efficiency, and can achieve high integration with automated workstations, making it suitable for large-scale automated mass production; (2) by setting the angle between the laser beam and the reed switch, the sealing performance of the sealing end face and the formation of the spherical shell can be improved; (3) by setting the blowing step and the blowing air pressure range, the fullness and airtightness of the spherical end face can be improved. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the reed switch structure in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the laser sealing structure of one end of the reed switch in an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the laser sealing structure at the other end of the reed switch in an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the laser-sealed structure of the reed switch in an embodiment of the present invention.

[0021] Figure 5 This is a flowchart of the laser sealing process for a reed switch in an embodiment of the present invention.

[0022] In the diagram: 1. Glass outer shell; 2. Metal magnetic reed inner core; 3. Metal connecting rod. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely 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.

[0024] Example 1:

[0025] This embodiment relates to a laser processing method for sealing reed switches. For example... Figure 1 As shown, the finished magnetic reed switch consists of a glass shell 1 and a metal magnetic reed core 2, which is connected to a metal connecting rod 3.

[0026] In this embodiment, a laser processing method for sealing a magnetic reed switch is introduced, taking the connection of a nickel sheet inner core with a diameter of 0.2 mm to a glass shell 1 with an outer diameter of 2.5 mm and a thickness of 0.15 mm as an example.

[0027] like Figure 2 As shown, before assembly and sealing, the glass shell 1 is a hollow cylinder. First, a clamp is used to hold the metal magnetic reed core 2 and the glass shell 1, and then the glass shell 1 is fitted over the metal magnetic reed core 2 and fixed. Next, the focus of the first laser beam is adjusted to point A on one end face of the glass shell, and the focus of the second laser beam is adjusted to point B on the same end face. The first and second laser beams are symmetrically arranged, with points A and B at the same height and symmetrically positioned. The laser beams are controlled to emit light. After reaching point A, the glass shell at point A softens due to heat and adheres to the metal connecting rod 3, forming a hemispherical welded end face. Similarly, another hemispherical welded end face is formed at point B.

[0028] Subsequently, as Figure 3 As shown, the drive reed switch rotates 180°, the first laser beam irradiates point C on the other end face of the outer shell, and the second laser beam irradiates point D on the other end face of the outer shell. Points C and D are at the same height and are symmetrically arranged. The two sides of the other end face of the outer shell soften due to heat and adhere to the metal rod of the inner core. Together with the hemispherical welding end face at the AB end, they form a spherical welding end face, forming a spherical sealing end face.

[0029] Finally, as Figure 4-5 As shown, the spherical sealing end face is cooled, and the cooled spherical sealing end face is inspected to check whether the shape and airtightness of the sealing end face meet the requirements; at the same time, the glass shell is checked for air bubbles, and the metal spring is checked for breakage to meet the production yield requirements.

[0030] Thus, spherical sealed enclosures can be formed at both ends of the glass shell 1. Since the metal magnetic reed core 2 and the glass shell 1 are very small, the welding can be completed in a single light emission.

[0031] Furthermore, the angle between the laser beam and the side of the glass casing 1 is 30°. ° Under a microscope, the cross-sectional distances of the formed spherical section were measured in two directions: the horizontal X-axis and the perpendicular Y-axis. The measured values ​​of different angles between the laser beam and the side of the outer shell, and their impact on the spherical sealing end face, are shown in Table 1 below.

[0032]

[0033] Table 1

[0034] Furthermore, to improve the welding effect and allow the glass shell to soften and fall towards the metal rod after heating, air is blown onto the softened glass shell 1 end face towards the metal rod while the laser beam is irradiating it. This assists in the spherical formation of the welding end face, resulting in a tighter adhesion of the glass shell. Preferably, the blowing direction is coaxial or parallel to the laser beam direction, and the blowing pressure is selected as 10L / min.

[0035] Preferably, a 100W continuous laser is used, with a laser beam center wavelength of 808nm. The laser beam output mode is continuous, the processing power is set to 35W, and the light output time is set to 4s. The laser can output a flat-top beam with uniform energy distribution. The finished reed switch meets the requirements for airtightness, bubble-free glass shell, no breakage in the nickel sheet core, spherical appearance of the glass at the welded joint, and production yield.

[0036] Example 2:

[0037] This embodiment takes a nickel sheet core with a diameter of 0.1 mm connected to a glass shell with an outer diameter of 2 mm and a thickness of 0.2 mm as an example.

[0038] In addition to the same processing steps as in Embodiment 1, the angle between the laser beam and the side of the glass housing 1 is further 45 degrees. ° Under a microscope, the cross-sectional distances of the formed spherical section were measured in two directions: the horizontal X-axis and the perpendicular Y-axis. The measured values ​​of different angles between the laser beam and the side of the outer shell, and their impact on the spherical sealing end face, are shown in Table 2 below.

[0039]

[0040] Table 2

[0041] Furthermore, to improve the welding effect and allow the glass shell to soften and fall towards the metal rod after heating, air is blown onto the softened glass shell 1 end face towards the metal rod while the laser beam is irradiating it. This assists in the spherical formation of the welding end face, resulting in a tighter adhesion of the glass shell. Preferably, the blowing direction is coaxial or parallel to the laser beam direction, and the blowing pressure is selected as 10L / min.

[0042] Preferably, a 100W continuous laser is used, with a laser beam wavelength of 915nm. The laser beam output mode is continuous, the processing power is set to 30W, and the output time is set to 5s. The laser can output a flat-top beam with uniform energy distribution. The finished reed switch meets the requirements of airtightness, no air bubbles in the glass shell, no breakage in the nickel sheet core, spherical appearance of the glass at the welded joint, and production yield meeting the product requirements.

[0043] Example 3:

[0044] This embodiment takes a nickel sheet core with a diameter of 0.1 mm connected to a glass shell with an outer diameter of 2 mm and a thickness of 0.2 mm as an example.

[0045] In addition to the same processing steps as in Embodiment 2, the angle between the laser beam and the side of the glass housing 1 is further 60°. °Under a microscope, the cross-section of the formed spherical shape was measured in two directions: the horizontal X-axis and the perpendicular Y-axis. The measured values ​​of different angles between the laser beam and the side of the outer shell, and their effects on the spherical sealing end face, are shown in Table 3 below.

[0046]

[0047] Table 3

[0048] Furthermore, to improve the welding effect and allow the glass shell to soften and fall towards the metal rod after heating, air is blown onto the softened glass shell 1 end face towards the metal rod while the laser beam is irradiating it. This assists in the spherical formation of the welding end face, resulting in a tighter adhesion of the glass shell. Preferably, the blowing direction is coaxial or parallel to the laser beam direction, and the blowing pressure is selected as 5L / min.

[0049] In this embodiment, a 100W continuous laser with a beam wavelength of 980nm is used. The laser beam output mode is continuous, the processing power is set to 30W, and the output time is set to 4.5s. The laser can output a flat-top beam with uniform energy distribution. The finished reed switch meets the requirements for airtightness, bubble-free glass shell, no breakage in the nickel core, spherical glass at the weld joint, and production yield.

[0050] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A laser processing method for sealing reed switches, characterized in that, The processing method includes the following steps: (a) First, clamp and fix the inner core and outer shell to ensure that the upper and lower inner cores and outer shell of the reed switch are in the correct corresponding positions; (b) The first laser beam is then irradiated on one side of one end face of the outer shell, and the second laser beam is irradiated on the other side of one end face of the outer shell. The two sides of the end face of the outer shell are heated and softened, and adhere to the metal rod of the inner core to form a hemispherical fusion end face. The angle between the first laser beam and the second laser beam and the side face of the outer shell is 30°-60°. The wavelengths of the first laser beam and the second laser beam are 800-1000nm. The irradiation time of the first laser beam and the second laser beam is 4-5 seconds. (c) Rotate the reed switch 180°, the first laser beam irradiates one side of the other end face of the housing, and the second laser beam irradiates the other side of the other end face of the housing. The two sides of the other end face of the housing are heated and softened, and adhere to the metal rod of the inner core. Together with the hemispherical welding end face in step (b), they form a spherical welding end face, forming a spherical sealing end face. While the first and second laser beams are irradiating, air is blown towards the metal rod from the heated and softened end face of the outer shell. The blowing direction is either coaxial or parallel to the irradiation direction of the first and second laser beams, respectively. (d) Cool the sealing end face and check whether the cooled spherical sealing end face meets the requirements.

2. The laser processing method for sealing a reed switch according to claim 1, characterized in that, The outer shell is made of plexiglass.

3. The laser processing method for sealing a reed switch according to claim 1, characterized in that, The first laser beam and the second laser beam are symmetrically arranged on the outer casing, and the positions of the first laser beam and the second laser beam are at the same height and are symmetrical from left to right.

4. The laser processing method for sealing a reed switch according to claim 1, characterized in that, The blowing air pressure is 5-10 L / min.

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