Circuit board low-temperature hot tin stripping and disassembling device

Abstract

The utility model relates to a kind of low-temperature hot tin and disassembling device of circuit board.The low-temperature hot tin and disassembling device of circuit board includes tin solder melting part, mechanical separation part, intervening transmission part;Tin solder melting part is the heating tank body with liquid heat-conducting medium, for heating circuit board, make tin solder melt from solid state to flowable state;Mechanical separation part can be used to split component and substrate on circuit board, centrifugal dispersion shaft is equipped in mechanical separation part, and centrifugal dispersion shaft includes motor-driven centrifugal spindle and dispersion rod arranged on the surface of centrifugal spindle;Intervening transmission part is used to transmit and convey circuit board from tin solder melting part to mechanical separation part, including grid and rotating lever driven by motor, and grid is obliquely fixed above the tail end of tin solder melting part.The utility model keeps tin solder in molten state or only softened state by reducing the working temperature of liquid heat-conducting medium, cooperates subsequent enhanced mechanical separation mode, and promotes the separation between tin solder, component and substrate.

Description

Technical Field

[0001] This utility model belongs to the technical field of circuit board desoldering, and specifically relates to a low-temperature thermal desoldering and disassembly device for circuit boards. Background Technology

[0002] The desoldering process for printed circuit boards (PCBs) can be categorized into non-thermal and thermal treatment methods, depending on whether heating is involved. Non-thermal treatment methods primarily include chemical etching, electrolysis, and mechanical cutting. Chemical etching uses a chemical solution to dissolve the tin layer and then precipitate it out. Electrolysis uses the principle of oxidation-reduction to convert the metal on the PCB into metal ions, which then enter the solution and are reduced back to metal. Mechanical cutting uses mechanical tools to peel off the tin layer. Thermal treatment involves heating the PCB until the solder melts, then separating it from the substrate; this is the mainstream method.

[0003] The melting temperature of solder varies between 200℃ and 300℃ depending on its composition and content. When using heat treatment to remove solder, the working temperature is generally set at around 300℃. For example, Chinese patent document CN217775122U discloses a constant-level solder bath heating conveyor, which consists of a frame and a transport assembly. The frame has a solder bath, and the transport assembly includes a chain plate, pressure pins, a drive sprocket, a driven sprocket, three wire brush rollers, and three feed sprockets. The pressure pins are fixed to the outer wall of the chain plate. During operation, the heating element is turned on, and the temperature is set to 320℃. After the solder bath temperature rises to the specified temperature, the motors are turned on, and then feeding begins. The motherboards of waste electronic products are placed on the feeding platform, and the motherboards are fed into the solder bath via the feed sprockets and wire brush rollers. The motherboards are heated while being transported, and a circulating pump extracts molten solder so that the molten solder level just covers the partition.

[0004] Chinese patent document CN104625285A discloses a method for recycling and processing waste circuit boards, which uses molten salt as a heating medium to heat the solder until it melts. The specific steps are as follows: (1) Remove plastic, batteries and wires from the waste circuit board; (2) Immerse the solder side of the waste circuit board face down in the molten salt until the solder melts. The temperature of the molten salt is 250-310℃, and the immersion time of the solder side of the waste circuit board in the molten salt is 0.1-3 minutes; (3) Remove the components on the substrate of the waste circuit board and wash the substrate and components with water; (4) Recover the molten solder from the molten salt and then cool the molten solder until it solidifies.

[0005] Chinese patent document CN100496192C also discloses a similar processing approach, which discloses a method and apparatus for desoldering and separating components in a liquid thermally conductive medium on a printed circuit board. The apparatus includes a heating tank and a recovery tank arranged side-by-side, and a clamping arm for transferring the circuit board between the heating tank and the recovery tank. The thermally conductive medium is silicone oil, and desoldering oscillators and separation oscillators are respectively installed on the heating tank and the recovery tank. During operation, the circuit board to be processed is first held horizontally in the thermally conductive medium with the component side facing upwards. The thermally conductive medium is heated to 220°C, and ultrasonic vibration is applied to the medium to promote the detachment of the molten solder. Then, the circuit board is moved above the recovery tank, where mechanical vibration further promotes the detachment of the components and solder.

[0006] The applicant has experimented with heating waste circuit boards using both molten salt and thermal oil in engineering practice. The actual experimental results showed that at operating temperatures of 200-300℃, significant fumes were generated, and most of the molten solder remained adhered to the substrate without separating. Furthermore, components on the circuit boards frequently experienced flash explosions at these temperatures. Clearly, these flash explosions not only hinder the subsequent recycling of components but may also pose further hazards. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a low-temperature thermal desoldering and disassembly device for circuit boards, which reduces the probability of flash explosion of components in waste circuit boards in a heated environment and enables higher separation efficiency between solder, components and substrate.

[0008] The solution of this utility model to the aforementioned technical problem is as follows:

[0009] Circuit board low-temperature thermal desoldering and disassembly device, including

[0010] The solder molten section is a heating tank filled with liquid heat-conducting medium, used to heat the circuit board, so that the solder melts from a solid state to a flowable state;

[0011] The mechanical separation section can be used to separate components from the substrate on a circuit board;

[0012] Intermediate transfer section, used to transfer and transport circuit boards from the solder melting section to the mechanical separation section;

[0013] A chain conveyor belt is installed inside the solder molten section. The liquid heat-conducting medium submerges the chain conveyor belt, so that when the solder surface of the circuit board faces downward, the solder surface can fully contact the liquid heat-conducting medium.

[0014] The mechanical separation section has a material inlet and a material outlet. The mechanical separation section is equipped with a centrifugal dispersing shaft, which includes a motor-driven centrifugal main shaft and dispersing rods arranged on the surface of the centrifugal main shaft.

[0015] The intermediate transfer section includes a grid and a rotating lever driven by a motor. The grid is tilted and fixed above the tail end of the solder molten section and connected to the tail end of the chain conveyor belt. The rotation of the rotating lever can move the circuit board from the solder molten section to the mechanical separation section.

[0016] The inventive concept of this application lies in adopting a different approach from existing technologies. The purpose of heating with a liquid heat-conducting medium is solely for melting the solder, not for melting and detaching it. This allows the heating temperature to be controlled at approximately 180-200℃. The solder melts from a solid state into a flowable state but does not detach from the substrate, thus reducing the amount of smoke and dust generated and preventing components on the circuit board from exploding. The solder primarily separates from the substrate at the mechanical separation section. A centrifugal dispersing shaft exerts a strong force on the circuit board, causing the solder and components to separate from the substrate under centrifugal force. Several dispersing rods arranged on the surface of the centrifugal shaft enhance the impact on the components, promoting their detachment. Secondly, as mentioned earlier, solder separation is conventionally performed within the molten solder section, where the component pins hinder the solder's detachment. However, in the separation mode of this application, when the component separates from the substrate, its pins pull out the molten solder, either entirely or partially, thus promoting the separation of the component from the substrate. Third, the intermediate transfer section includes an inclined grid, which allows some of the liquid heat transfer medium adhering to the circuit board to return to the solder molten part, thus helping to maintain a constant content of heat transfer medium.

[0017] It should be further pointed out that, compared with the technical solution disclosed in Chinese Patent Document CN100496192C, it has two obvious advantages: (1) In Chinese Patent Document CN100496192C, the heat-conducting medium at 220°C, combined with ultrasonic vibration, makes it easy for small-particle components to fall into the heating tank under the action of buoyancy, and a certain amount of small-particle components will be mixed in the collected solder. In practical applications, a corresponding separation mechanism needs to be set up, and small-particle components will carry out some heat-conducting medium, requiring relatively frequent adjustment of its liquid level. In this application, the temperature of the liquid heat-conducting medium is relatively low, and the solder melting is not as sufficient and thorough, making it difficult for components to separate from the substrate in the heating tank, and the probability of components falling into the heating tank is low. (2) Compared with the clamping arm in Chinese Patent Document CN100496192C, this application realizes the transfer of circuit boards simply, reliably and effectively through the cooperation of the grid and the rotating lever. The clamping arm disclosed in Chinese patent document CN100496192C is difficult to clamp different types of circuit boards in actual working environments.

[0018] As an improvement, the mechanical separation section is equipped with impact bars, allowing the circuit board to collide with them after being thrown up by the centrifugal dispersing shaft. If the circuit board thrown up by the centrifugal dispersing shaft only collides with the inner wall of the mechanical separation section, the inner wall only serves as an impact, causing only a loosening between the components and the substrate. The impact bars not only enhance the impact effect but also allow the components on the substrate to separate from it due to the sudden stop, thus promoting the separation of components from the substrate.

[0019] As a further improvement, the dispersing rods are arranged in a spiral shape on the surface of the centrifugal spindle, so that the circuit board can be pushed from the material inlet of the mechanical separation section to the material outlet by the dispersing rods during the dispersing process, thus playing a dual role.

[0020] As an improvement, the grille is provided with a brush sleeve with bristles on its surface. The brush sleeve can rotate under the drive of the brush sleeve drive unit to rub the solder surface of the circuit board. The brush sleeve has two functions: first, to brush away the liquid heat-conducting medium adhering to the solder surface of the circuit board; second, to brush away some of the molten solder that protrudes from the substrate surface. The remaining solder can be detached from the substrate when the component pins are removed.

[0021] As a further improvement, the brush sleeve drive unit includes gears fixed to the end of the brush sleeve, and the meshing of adjacent gears allows all gears to rotate under the drive of the same motor. The gear transmission structure is relatively stable and has a long service life.

[0022] As a further improvement, the rotary lever is a nested lever with a spring between the two segments. When the rotary lever is not pressing against the circuit board, it can extend between adjacent brush sleeves to agitate the bristles. This design allows the rotary lever to apply pressure to the circuit board, enhancing the effectiveness of the brush sleeves. When the rotary lever is not pressing against the circuit board, it can extend between adjacent brush sleeves to shake off the liquid heat-conducting medium and solder from the bristles.

[0023] As an improvement, the solder molten section has a sloping bottom and is equipped with a receiving hopper located at the lowest point of the bottom of the solder molten section to receive solder and components that sink to the bottom of the solder molten section. The receiving hopper is used to collect solder and components that fall into the solder molten section.

[0024] As an improvement, an end-of-line screening mechanism is also included to separate solder, components, and the substrate; a lifting mechanism is provided between the material outlet of the mechanical separation section and the end-of-line screening mechanism. The mechanical separation section generally only handles the detachment of solder and components from the substrate. The lifting mechanism also facilitates the cooling of the solder, which is beneficial for subsequent separation.

[0025] As a further improvement, the end screening mechanism is a double-layer vibrating screen structure, where solder and components fall from the upper vibrating screen to the lower vibrating screen. The material on the upper vibrating screen is a substrate, and the material on the lower vibrating screen is a component.

[0026] As a further improvement, it also includes a waste gas collection and treatment system to render the generated waste gas harmless.

[0027] As an alternative, the mechanical separation section can also be a drum desoldering mechanism, having a material inlet and a material outlet. The drum is driven to rotate by a motor, and impact bars are arranged inside the drum, positioned laterally within the drum so that the circuit board collides with the impact bars as the drum rotates. Compared to a centrifugal dispersing shaft, the drum desoldering mechanism preferably requires the inclusion of impact bars to increase the agitation effect and promote the detachment of components from the substrate.

[0028] As an improvement, a feed chute is provided between the solder molten section and the mechanical separation section to facilitate the transfer of the circuit board.

[0029] As an improvement, the roller has inclined lifting plates on its inner wall, allowing the circuit board to move from one end of the roller to the other as it rotates. The lifting plates on the inner wall of the roller allow the circuit board to move laterally and rotate longitudinally within the roller, facilitating the separation of components from the substrate. Furthermore, under centrifugal force, the separated components remain between the lifting plates, reducing the likelihood of them re-attaching to the substrate. In existing technology, the roller rotates at low speed, and components are mainly detached through mutual friction between the circuit boards; however, the detached components often re-attach to the substrate.

[0030] As an improvement, the roller is provided with through holes for solder to flow out, and a solder receiving interface is provided at the bottom of the roller for solder to be discharged. Due to the characteristics of the roller, the solder can be separated in advance, and only the separation of components from the substrate needs to be performed subsequently.

[0031] As a further improvement, one end of the roller is connected to the material outlet, and a discharge sealing cover is provided at one end of the roller.

[0032] In summary, the beneficial effects of this utility model are:

[0033] By lowering the operating temperature of the liquid heat-conducting medium, the solder is kept in a molten state or only in a softened state. At this point, the bond between the component pins and the solder is stronger than in existing technologies. Combined with subsequent enhanced mechanical separation methods, the component pins can facilitate the separation of the solder. The solution described in this application essentially eliminates flash explosions of components, reduces the amount of fumes, and improves the separation efficiency of solder, components, and the substrate. Attached Figure Description

[0034] Figure 1This is a schematic diagram of the structure of Embodiment 1 of the present utility model;

[0035] Figure 2 for Figure 1 Enlarged view of section A in the middle;

[0036] Figure 3 This is a schematic diagram of the structure of the grille and rotating lever in Embodiment 1 of this utility model;

[0037] Figure 4 This is a schematic diagram of the centrifugal dispersing shaft in Embodiment 1 of this utility model;

[0038] Figure 5 This is a schematic diagram of the circuit board colliding with the impact bar in this utility model;

[0039] Figure 6 This is a schematic diagram of the structure of the grille in Embodiment 2 of this utility model;

[0040] Figure 7 for Figure 6 Enlarged view of section B;

[0041] Figure 8 This is a cross-sectional view of the rotary lever in Embodiment 2 of this utility model;

[0042] Figure 9 This is a schematic diagram of the structure of Embodiment 3 of this utility model;

[0043] Figure 10 This is a side sectional view of the mechanical separation part in Embodiment 3 of this utility model.

[0044] In the diagram: 10. Solder melting section; 11. Chain conveyor belt; 12. Receiving hopper; 13. Electric heating tube; 20. Mechanical separation section; 21. Material inlet; 211. Baffle plate; 22. Material outlet; 231. Centrifugal main shaft; 232. Dispersing rod; 24. Impact bar; 25. Drum; 251. Drum fixing frame; 26. Lifting plate; 27. Solder receiving interface; 28. Discharge sealing cover; 281. Control handle; 30. Intermediate transfer section; 31. Grille; 32. Rotating lever; 33. Brush sleeve; 34. Brush sleeve drive unit; 40. End screening mechanism; 41. Upper vibrating screen; 42. Lower vibrating screen; 50. Lifting mechanism; 60. Waste gas collection and treatment mechanism; 70. Feed chute; 81. Substrate; 82. Components; 83. Solder; 84. Pin. Detailed Implementation Example 1

[0045] like Figure 1 As shown, the circuit board low-temperature hot desoldering and disassembly device described in this application includes three core functional units: a solder melting section 10, a mechanical separation section 20, and an intermediary transfer section 30.

[0046] The solder melting section 10 is used to heat the circuit board, causing the solder to melt from a solid state into a flowable state. The solder melting section 10 is a heating tank containing a liquid heat-conducting medium, which can be molten salt or heat-conducting oil. An embedded electric heating tube 13 heats the liquid heat-conducting medium. The specific heating temperature is determined experimentally based on the specific composition of the solder. Generally, heating the liquid heat-conducting medium to around 180-200℃ meets the requirements for conventional soldering. At this point, the solder is in a softened, molten state but will not fall off the substrate. It should be noted that a flowable state does not only refer to a liquid state. The temperature of the liquid heat-conducting medium can also be lowered to 150℃ or even lower, as long as the solder is in a softened state; a softened state is also a type of flowable state. At this point, under centrifugal force, the softened solder can still separate from the substrate.

[0047] A conveyor belt 11 is installed within the solder molten section 10. The liquid heat-conducting medium covers the conveyor belt 11, ensuring sufficient contact between the solder surface and the liquid heat-conducting medium when the solder surface of the circuit board is facing downwards. Preferably, the liquid heat-conducting medium does not submerge the components of the circuit board, reducing the probability of components exploding due to heat. Secondly, a liquid level control component can be provided to ensure that the liquid heat-conducting medium just covers the surface of the conveyor belt 11. The liquid level control component is prior art and will not be described in detail.

[0048] The solder melting section 10 has an inclined bottom and is also equipped with a receiving hopper 12. The receiving hopper 12 is located at the lowest point of the bottom of the solder melting section 10 and can receive solder and components that sink to the bottom of the solder melting section 10. It should be noted that the solder and components that sink to the bottom of the solder melting section 10 are mainly solder and components that have already detached from the substrate, rather than solder and components that have detached from the substrate after being heated and melted. As described in the background section, at an operating temperature of 200-300°C, the applicant found that the molten solder still adheres to the substrate and does not separate from it.

[0049] The intermediate transfer section 30 is used to transfer and transport the circuit board from the solder melting section 10 to the mechanical separation section 20. Located above the tail end of the solder melting section 10, it mainly includes a grid 31 and a motor-driven rotating lever 32. The grid 31 is fixed at an angle and connects to the tail end of the chain conveyor belt 11, which pushes the circuit board onto the grid 31. The specific structure and cooperation relationship of the grid 31 and the rotating lever 32 are as follows... Figure 2 , Figure 3 As shown. Driven by the motor, the rotating lever 32 can enter the gap between adjacent metal rods of the grille 31. One rotating lever 32 corresponds to one gap, which pushes the circuit board on the grille 31 upward. During this process, some of the liquid heat-conducting medium carried out on the circuit board can drip back into the solder molten part 10.

[0050] like Figure 1 As shown, a mechanical separation section 20 is connected to the rear end of the solder fusion section 10. The mechanical separation section 20 has a material inlet 21 and a material outlet 22. The material inlet 21 is arranged facing upward to receive circuit boards falling from the grid 31. A baffle plate 211 extending upward is also provided on one side of the material inlet 21 to ensure that all circuit boards on the grid 31 can fall into the material inlet 21.

[0051] The mechanical separation section 20 is equipped with a centrifugal dispersing shaft, such as Figure 1 , Figure 4 The centrifugal dispersing shaft includes a motor-driven centrifugal main shaft 231 and dispersing rods 232 arranged on the surface of the centrifugal main shaft 231. The dispersing rods 232 are spirally arranged on the surface of the centrifugal main shaft 231, allowing the circuit board to be pushed from the material inlet 21 to the material outlet 22 of the mechanical separation section 20 during the dispersing process. An impact bar 24 is also provided above the interior of the mechanical separation section 20, allowing the circuit board to collide with the impact bar 24 after being thrown up by the centrifugal dispersing shaft, thus promoting the separation of components from the substrate. A schematic diagram of the circuit board colliding with the impact bar 24 is shown below. Figure 5 As shown, the circuit board substrate 81, carrying the component 82, collides with the impact bar 24 at a relatively high speed. The speed of the substrate 81 suddenly decreases, causing the component 82 to continue flying forward, thus separating the component 82 from the substrate 81. When the component 82 detaches from the substrate 81, the previously bent pins 84 can detach from the substrate along with some of the solder 83.

[0052] The outer shell of the mechanical separation section 20 is equipped with thermal insulation material, and an electric heating tube is embedded inside the thermal insulation material. The heating program of the mechanical separation section 20 can be activated as needed. The applicant found in the experiment that when the heating temperature of the liquid heat-conducting medium is relatively low, the pins of the components are often covered with solder. At this time, it is necessary to raise the temperature to separate the solder on the pins.

[0053] like Figure 1 As shown, this device also includes three auxiliary functional units: an end screening mechanism 40, an lifting mechanism 50, and a waste gas collection and treatment mechanism 60.

[0054] A lifting mechanism 50 is provided between the material outlet 22 of the mechanical separation section 20 and the end screening mechanism 40. This mechanism is used to transport the separated solder, components, and substrate to the end screening mechanism 40, where the three are separated. The lifting mechanism 50 is existing technology and will not be described in detail. For example, an NE series plate chain bucket elevator can be used.

[0055] The end-screening mechanism 40 adopts a double-layer vibrating screen structure, including an upper vibrating screen 41 and a lower vibrating screen 42. Solder and components fall from the upper vibrating screen 41 to the lower vibrating screen 42. The material on the upper vibrating screen 41 is a substrate, which exits from the corresponding outlet of the upper vibrating screen 41. The material on the lower vibrating screen 42 is a component, which exits from the corresponding outlet of the lower vibrating screen 42. Below the lower vibrating screen 42 is a solder receiving interface 27. Obviously, the temperature of the liquid heat transfer medium discharged from the solder receiving interface 27 is significantly lower than the temperature of the liquid heat transfer medium dripping from the grid 31. The end-screening mechanism 40 is enclosed in a box, and an exhaust gas outlet is provided at the top.

[0056] The exhaust gas collection and treatment mechanism 60 includes a fume hood disposed above the solder molten section 10. The fume hood is connected to the exhaust gas outlet of the end screening mechanism 40 and is transported by a fan to the combustion mechanism for combustion treatment. Example 2

[0057] The difference between Example 2 and Example 1 is as follows: Figure 6 , Figure 7 As shown, a brush sleeve 33 with bristles on its surface is arranged on the grille 31. The bristles can be made of metal. The brush sleeve 33 can rotate under the drive of the brush sleeve drive unit 34 to rub the solder surface of the circuit board. On the one hand, it can promptly brush the liquid heat-conducting medium carried out by the circuit board back to the molten solder part 10. On the other hand, it can remove the solder portion on the solder surface of the circuit board, which is beneficial for the subsequent centrifugal separation of components from the substrate. This technical feature is particularly significant for solder that is only in a softened state.

[0058] The applicant found that the amount of small and large component particles recovered in the solder molten section 10 was relatively small. One possible reason is that when the brush sleeve 33 rubs against the solder surface of the circuit board, the components are no longer subject to the buoyancy of the liquid heat-conducting medium and are less likely to fall off the substrate. Therefore, the receiving hopper 12 mainly receives solder particles brushed off by the brush.

[0059] The brush sleeve drive unit 34 includes a gear fixed to the end of the brush sleeve 33, and the meshing of adjacent gears allows all gears to rotate under the drive of the same motor.

[0060] To improve the friction effect of the brush bristles on the circuit board, the rotary lever 32 is a nested lever. For example... Figure 8 As shown, the rotating lever 32 is a two-section lever with a spring in the middle, allowing the rotating lever 32 to press against the top of the circuit board. When the rotating lever 32 is not pressing against the circuit board, it can extend between adjacent brush sleeves 33 to agitate the bristles on the brush sleeves 33, causing the solder and liquid heat-conducting medium on the bristles to fall into the solder molten part 10. Example 3

[0061] The difference between Example 3 and Example 1 is as follows: Figure 9 , Figure 10 As shown, the mechanical separation section 20 is replaced by a drum desoldering mechanism, and a feed chute 70 is provided between the solder melting section 10 and the mechanical separation section 20. The drum 25 is driven to rotate by a motor, and a Y-shaped drum fixing frame 251 is provided inside the drum 25 to fix the drum 25 to the motor output shaft. Impact bars 24 are arranged inside the drum 25, and the impact bars 24 are laterally located inside the drum 25 and arranged along the extension direction of the drum 25, so that the circuit board can collide with the impact bars 24 when the drum 25 rotates. The drum 25 is provided with through holes for solder to flow out, and a solder receiving interface 27 for solder to be discharged is provided at the bottom of the drum 25. Obviously, the number of impact bars 24 can be set, for example, three impact bars 24 are evenly arranged around the central axis of the drum, which is beneficial to improving the separation efficiency.

[0062] The roller 25 has inclined lifting plates 26 on its inner wall, which allows the circuit board to move from one end of the roller 25 to the other as the roller 25 rotates. One end of the roller 25 is connected to the material outlet 22, and a discharge sealing cover 28 is provided at one end of the roller 25. The discharge sealing cover 28 has a control handle 281, which can be driven manually or electrically to move left and right, thereby controlling the opening and closing of one end of the roller 25.

[0063] The mechanical separation section 20 is also surrounded by insulation material. Preferably, an electric heating element 13 is also embedded in the insulation material to facilitate temperature control.

Claims

1. Circuit board low-temperature thermal desoldering and disassembly device, including The solder melting section (10) is a heating tank containing a liquid heat-conducting medium, used to heat the circuit board so that the solder melts from a solid state to a flowable state; The mechanical separation section (20) can be used to separate components and substrates on a circuit board; Intermediate transfer section (30) is used to transfer and transport the circuit board from the solder melting section (10) to the mechanical separation section (20). Its features are: A chain conveyor belt (11) is provided inside the solder molten section (10). The liquid heat-conducting medium submerges the chain conveyor belt (11), so that when the solder surface of the circuit board faces downward, the solder surface can fully contact the liquid heat-conducting medium. The mechanical separation section (20) has a material inlet (21) and a material outlet (22). The mechanical separation section (20) is provided with a centrifugal dispersing shaft, which includes a motor-driven centrifugal main shaft (231) and dispersing rods (232) arranged on the surface of the centrifugal main shaft (231). The intermediary transfer section (30) includes a grid (31) and a rotating lever (32) driven by a motor. The grid (31) is tilted and fixed above the tail end of the solder melting section (10) and connected to the tail end of the chain conveyor belt (11). The rotation of the rotating lever (32) can move the circuit board from the solder melting section (10) to the mechanical separation section (20).

2. The circuit board low-temperature thermal desoldering and disassembly device as described in claim 1, characterized in that: The mechanical separation section (20) is provided with an impact bar (24) so ​​that the circuit board can collide with the impact bar (24) after being thrown up by the centrifugal disintegration shaft.

3. The circuit board low-temperature thermal desoldering and disassembly device as described in claim 1 or 2, characterized in that: The dispersing rods (232) are arranged in a spiral shape on the surface of the centrifugal spindle (231), so that the circuit board can be pushed from the material inlet (21) of the mechanical separation section (20) to the material outlet (22) by the dispersing rods (232) during the dispersing process.

4. The circuit board low-temperature thermal desoldering and disassembly device as described in claim 1, characterized in that: The grille (31) is provided with a bristle sleeve (33) with bristles on its surface. The bristle sleeve (33) can rotate under the drive of the bristle sleeve drive unit (34) to rub the solder surface of the circuit board.

5. The circuit board low-temperature thermal desoldering and disassembly device as described in claim 4, characterized in that: The brush sleeve drive unit (34) includes a gear fixed to the end of the brush sleeve (33), and the adjacent gears mesh so that all gears can rotate under the drive of the same motor.

6. The circuit board low-temperature thermal desoldering and disassembly device as described in claim 5, characterized in that: The rotating lever (32) is a nested lever with a spring between the two levers. When the rotating lever (32) is not pressing the circuit board, the rotating lever (32) can extend between the adjacent bristle sleeves (33) to agitate the bristles on the bristle sleeves (33).

7. The circuit board low-temperature thermal desoldering and disassembly device as described in claim 1 or 4, characterized in that: The solder fusion section (10) has an inclined bottom and is equipped with a receiving hopper (12). The receiving hopper (12) is located at the lowest point of the bottom of the solder fusion section (10) to receive solder and components that sink to the bottom of the solder fusion section (10).

8. The circuit board low-temperature thermal desoldering and disassembly device as described in claim 1, characterized in that: It also includes an end screening mechanism (40) for separating solder, components and substrate; a lifting mechanism (50) is provided between the material outlet (22) of the mechanical separation section (20) and the end screening mechanism (40).

9. The circuit board low-temperature thermal desoldering and disassembly device as described in claim 8, characterized in that: The end screening mechanism (40) is a double-layer vibrating screen structure. Solder and components fall from the upper vibrating screen to the lower vibrating screen. The material on the upper vibrating screen is a substrate, and the material on the lower vibrating screen is a component.

10. The circuit board low-temperature thermal desoldering and disassembly device as described in claim 1, characterized in that: It also includes waste gas collection and treatment facilities (60).

11. Low-temperature thermal desoldering and disassembly device for circuit boards, including The solder melting section (10) is a heating tank containing a liquid heat-conducting medium, used to heat the circuit board so that the solder melts from a solid state to a flowable state; The mechanical separation section (20) can be used to separate components and substrates on a circuit board; Intermediate transfer section (30) is used to transfer and transport the circuit board from the solder melting section (10) to the mechanical separation section (20). Its features are: A chain conveyor belt (11) is provided inside the solder molten section (10). The liquid heat-conducting medium submerges the chain conveyor belt (11), so that when the solder surface of the circuit board faces downward, the solder surface can fully contact the liquid heat-conducting medium. The mechanical separation section (20) is a drum desoldering mechanism with a material inlet (21) and a material outlet (22). The drum (25) is driven to rotate by a motor. An impact bar (24) is arranged inside the drum (25). The impact bar (24) is located laterally inside the drum (25) so that the circuit board can collide with the impact bar (24) when the drum (25) rotates. The intermediary transfer section (30) includes a grid (31) and a rotating lever (32) driven by a motor. The grid (31) is fixed at one end of the solder melting section (10) and connected to the chain conveyor belt (11). The rotation of the rotating lever (32) moves the circuit board from the solder melting section (10) to the mechanical separation section (20).

12. The circuit board low-temperature thermal desoldering and disassembly device as described in claim 11, characterized in that: A feed chute (70) is provided between the solder melting section (10) and the mechanical separation section (20).

13. The circuit board low-temperature thermal desoldering and disassembly device as described in claim 11, characterized in that: The roller (25) has an inclined lifting plate (26) on its inner wall, so that the circuit board can move from one end of the roller (25) to the other end when the roller (25) rotates.

14. The circuit board low-temperature thermal desoldering and disassembly device as described in claim 11, characterized in that: The roller (25) is provided with a through hole for solder to flow out, and a solder receiving interface (27) for solder to be discharged is provided below the roller (25).

15. The circuit board low-temperature thermal desoldering and disassembly device as described in claim 11, characterized in that: One end of the roller (25) is connected to the material outlet (22), and a discharge sealing cover (28) is provided at one end of the roller (25).

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