PCB welding device capable of preventing tin beads from being generated

Abstract

The utility model discloses a PCB welding device capable of preventing tin bead generation, which relates to the technical field of PCB welding, and comprises a tin cylinder, a jet pipe, a shielding gas delivery pipe and a flow guide sleeve, the shielding gas delivery pipe is communicated with the tin cylinder, the flow guide sleeve is fixed at the top end of the tin cylinder, the flow guide sleeve is sleeved on the periphery of the jet pipe, and the top end of the tin cylinder is provided with a flow guide port communicated with the flow guide sleeve. Protective gas is conveyed into the tin cylinder through the protective gas conveying pipe, so that the internal pressure of the tin cylinder is increased, and tin liquid is sprayed out from the top end of the jet flow pipe to weld the PCB; the flow guide sleeve not only can collect the backflow tin liquid to prevent the tin liquid from splashing to generate tin beads, but also can guide shielding gas to be discharged along the periphery of the jet flow pipe to block air on the periphery of the jet flow pipe, protect the backflow tin liquid on the periphery of the jet flow pipe and prevent the tin liquid from being oxidized to generate tin slag, and the flow guide sleeve can be gradually filled with the shielding gas. The shielding gas can extrude air out of the flow guide sleeve, the tin liquid collected in the flow guide sleeve is protected, and tin slag generated by oxidation of the tin liquid is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of PCB board welding, in particular to a PCB board welding device that prevents the generation of tin beads. Background Art

[0002] Wave soldering technology is often used in PCB board welding process. Wave soldering is to make the welding surface of the plug-in board directly contact with high-temperature liquid tin to achieve the purpose of welding. During the welding process, the tin cylinder of the selective wave soldering machine contains molten liquid tin, and the selective wave soldering machine sprays the molten liquid tin through the jet pipe to form a tin wave, thereby achieving welding of the welding points of the PCB board.

[0003] In actual production, most of the molten liquid tin ejected from the jet pipe will flow back into the tin tank under the action of gravity, and the tin tank also contains molten liquid tin. Therefore, the liquid tin flowing back will hit the liquid surface of the liquid tin in the tin tank, splashing out liquid tin to form tin beads. The splashing tin beads will adhere to the PCB board above the jet pipe, thereby contaminating the PCB board, making the PCB board unclean, and even causing bridge phenomenon. The liquid tin ejected from the jet pipe will be oxidized when it comes into contact with air during the reflux process, which is easy to cause the generation of tin slag. The tin slag falling into the tin tank is also easy to cause the splash of tin liquid in the tin tank. Utility Model Content

[0004] The utility model provides a PCB welding device for preventing tin beads from being generated, so as to solve the problems in the prior art.

[0005] The technical problem solved by the utility model is achieved by the following technical solutions:

[0006] A PCB board welding device for preventing the generation of tin beads comprises a tin cylinder for storing tin liquid and a jet pipe fixedly connected to the tin cylinder, wherein the lower end of the jet pipe is located in the tin cylinder, and the top end of the jet pipe is located above the tin cylinder. The device also comprises a protective gas delivery pipe, which is connected to the tin cylinder and is used to deliver protective gas that does not chemically react with the tin liquid into the tin cylinder, so as to increase the internal pressure of the tin cylinder, thereby causing the tin liquid to be ejected from the top end of the jet pipe; a guide sleeve is fixed to the top end of the tin cylinder, the guide sleeve is arranged on the periphery of the jet pipe, and a guide port connected to the guide sleeve is provided at the top end of the tin cylinder.

[0007] Preferably, the top surface of the tin cylinder is a convex surface protruding upward.

[0008] Preferably, an air inlet is provided on the top surface of the tin cylinder, and the air inlet is connected to the protective gas delivery pipe.

[0009] Preferably, a solenoid valve is installed on the protective gas delivery pipe.

[0010] Preferably, an air pressure sensor is provided on the protective gas delivery pipe.

[0011] Preferably, the guide sleeve is composed of an upper cone and a lower cone connected to the bottom end of the upper cone, the inner diameter of the top end of the upper cone is smaller than the inner diameter of the bottom end, and the inner diameter of the top end of the lower cone is larger than the inner diameter of the bottom end.

[0012] Preferably, the guide port is a circular hole opened at the center of the upper end surface of the tin cylinder, the upper end of the jet pipe passes through the guide port, and an annular gap is formed between the guide port and the jet pipe.

[0013] Preferably, the upper end of the jet pipe passes through the tin cylinder and is sealed to the tin cylinder, and the guide ports are evenly distributed on the periphery of the jet pipe.

[0014] The utility model has the beneficial effects of: conveying protective gas into the tin cylinder through the protective gas conveying pipe, so that the internal pressure of the tin cylinder is increased, and the tin liquid is sprayed out from the top of the jet pipe to weld the PCB board; the guide sleeve can collect the refluxed tin liquid to prevent the tin liquid from splashing and producing tin beads, and can also guide the protective gas to be discharged along the periphery of the jet pipe, block the air outside the jet pipe, protect the tin liquid that is reflowing outside the jet pipe, and prevent the tin liquid from oxidizing and producing tin slag, and the guide sleeve will gradually be filled with protective gas, which can squeeze the air out of the guide sleeve, protect the tin liquid that has been collected in the guide sleeve, and reduce the tin liquid from oxidizing and producing tin slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the implementation scheme of the utility model or the technical scheme in the prior art, the drawings required for use in the implementation scheme or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation schemes of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 This is a schematic structural diagram of a PCB board welding device according to Embodiment 1;

[0017] Figure 2 This is a working state diagram of the PCB board welding device of Example 1;

[0018] Figure 3 A top view of the PCB welding device of Example 1;

[0019] Figure 4 It is a structural schematic diagram of Example 2;

[0020] Figure 5 Figure 4 Sectional view along line AA;

[0021] In the figure, 1, tin cylinder; 2, jet pipe; 3, protective gas delivery pipe; 4, guide sleeve; 41, upper cone; 42, lower cone; 5, guide port; 6, air inlet; 7, solenoid valve; 8, air pressure sensor. DETAILED DESCRIPTION

[0022] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below with reference to specific illustrations. Example 1

[0023] The present embodiment provides a PCB board welding device for preventing the generation of tin beads, comprising a tin cylinder 1 for storing tin liquid and a jet pipe 2 fixedly connected to the tin cylinder 1, wherein the tin cylinder 1 is fixedly connected to the lower end of the jet pipe 2 through a connecting rod, the lower end of the jet pipe 2 is located in the tin cylinder 1, and the top of the jet pipe 2 is located above the tin cylinder 1, and also comprises a protective gas delivery pipe 3, which is connected to the tin cylinder 1 and is used to deliver a protective gas that does not chemically react with the tin liquid into the tin cylinder 1, so that the internal pressure of the tin cylinder 1 is increased, so that the tin liquid is ejected from the top of the jet pipe 2; the protective gas is nitrogen, or an inert gas; a guide sleeve 4 is fixed to the top of the tin cylinder 1, and the guide sleeve 4 is sleeved on the periphery of the jet pipe 2, and a guide port 5 connected to the guide sleeve 4 is provided at the top of the tin cylinder 1, and the inner diameter of the guide port 5 is the same as the inner diameter of the lower end of the guide sleeve 4. The guide port 5 is a circular hole opened at the center of the upper end surface of the tin cylinder 1, and the upper end of the jet pipe 2 passes through the guide port 5, and an annular gap is formed between the guide port 5 and the jet pipe 2.

[0024] During welding, the shielding gas delivery pipe 3 delivers shielding gas into the tin cylinder 1, increasing the internal pressure of the tin cylinder 1, and the tin liquid is sprayed out from the top of the jet pipe 2, and the guide sleeve 4 collects the refluxed tin liquid; at the same time, the shielding gas in the tin cylinder 1 is discharged upward from the guide port 5, and the guide sleeve 4 guides the shielding gas to be discharged along the periphery of the jet pipe 2, blocking the air outside the jet pipe 2, protecting the tin liquid that is refluxed outside the jet pipe 2, and avoiding oxidation of the tin liquid, and the guide sleeve 4 will gradually be filled with shielding gas, which squeezes the air out of the guide sleeve 4, and protects the tin liquid that has been collected in the guide sleeve 4.

[0025] After welding is completed, the shielding gas delivery pipe 3 stops delivering shielding gas into the tin cylinder 1. When the shielding gas no longer blocks the tin liquid in the guide sleeve 4 from flowing downward into the guide port 5, the reflux tin liquid collected in the guide sleeve 4 flows back into the tin cylinder 1 through the guide port 5.

[0026] In order to facilitate the shielding gas delivered by the shielding gas delivery pipe 3 to be discharged smoothly from the annular gap between the guide port 5 and the jet pipe 2, the top surface of the tin cylinder 1 is set to be a convex surface that protrudes upward. The convex surface is an inner cone surface, and can also be a curved surface; in this way, the shielding gas can move to the center of the top surface of the tin cylinder 1 under the pressure of the tin liquid, and then be discharged from the annular gap, and will not accumulate at the top of the tin cylinder 1 and cannot be discharged.

[0027] In order to facilitate the shielding gas delivery pipe 3 to deliver shielding gas to the tin cylinder 1, an air inlet 6 is provided on the top surface of the tin cylinder 1, and the air inlet 6 is connected to the shielding gas delivery pipe 3. The shielding gas delivery pipe 3 discharges the shielding gas into the tin cylinder 1 through the air inlet 6. The lower end of the jet pipe 2 is located at the lower part of the tin cylinder 1, and the shielding gas delivered by the shielding gas delivery pipe 3 will accumulate at the upper part of the tin cylinder 1 and will not easily enter the jet pipe 2.

[0028] In order to facilitate the control of the shielding gas delivery to the tin cylinder 1 and to facilitate the detection of the shielding gas pressure in the tin cylinder 1, a solenoid valve 7 and an air pressure sensor 8 are installed on the shielding gas delivery pipe 3. The input end of the shielding gas delivery pipe 3 is connected to the high-pressure nitrogen bottle. After the solenoid valve 7 is opened, the nitrogen in the high-pressure nitrogen bottle can enter the tin cylinder 1 through the shielding gas delivery pipe 3. The air pressure sensor 8 detects the pressure in the shielding gas delivery pipe 3, and then detects the pressure of the shielding gas in the tin cylinder 1. The rate at which the shielding gas delivery pipe 3 delivers shielding gas to the tin cylinder 1 is greater than the rate at which the gas in the tin cylinder 1 is discharged from the guide port 5, so that a certain pressure can be maintained inside the tin cylinder 1, which is convenient for the top of the jet pipe 2 to spray out the molten tin.

[0029] The guide sleeve 4 is composed of an upper cone 41 and a lower cone 42 connected to the bottom of the upper cone 41. The inner diameter of the top of the upper cone 41 is smaller than the inner diameter of the bottom, and the inner diameter of the top of the lower cone 42 is larger than the inner diameter of the bottom. The structure of the upper cone 41 being narrow at the top and wide at the bottom can prevent the back-splash of the refluxed tin liquid in the guide sleeve 4, and at the same time facilitates the guidance of the protective gas to move toward the jet pipe 2, and provides efficient anti-oxidation protection for the refluxed tin liquid outside the jet pipe 2. The structure of the lower cone 42 being wide at the top and narrow at the bottom facilitates the guidance of the refluxed tin liquid in the guide sleeve 4 to move toward the guide port 5, so that the refluxed tin liquid in the guide sleeve 4 can all flow back from the annular gap into the tin cylinder 1, avoiding residual tin liquid in the guide sleeve 4. Example 2

[0030] This embodiment is substantially the same as the embodiment 1, except that the guide port 5 is not a circular hole with a larger inner diameter opened at the center of the upper end surface of the tin cylinder 1, but a hole with a smaller inner diameter evenly distributed on the periphery of the jet pipe 2, and the upper end of the jet pipe 2 passes through the tin cylinder 1 and is sealedly connected to the tin cylinder 1. The protective gas in the tin cylinder 1 is discharged upward through the multiple guide ports 5; the refluxed tin liquid in the guide sleeve 4 flows downward back into the tin cylinder 1 through the multiple guide ports 5. In this way, the protective gas in the tin cylinder 1 can be more evenly distributed around the jet pipe 2, thereby improving the isolation effect of the protective gas on the tin liquid.

[0031] The above shows and describes the basic principle and main features of the utility model and the advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection claimed by the utility model is defined by the attached claims and their equivalents.

Claims

1. A PCB soldering device for preventing the generation of tin beads, comprising a tin cylinder (1) for storing tin liquid and a jet pipe (2) fixedly connected to the tin cylinder (1), wherein the lower end of the jet pipe (2) is located in the tin cylinder (1), and the top end of the jet pipe (2) is located above the tin cylinder (1), characterized in that: It also includes a protective gas delivery pipe (3), which is connected to the tin cylinder (1) and is used to deliver protective gas that does not chemically react with the tin liquid into the tin cylinder (1), so as to increase the internal pressure of the tin cylinder (1), thereby causing the tin liquid to be ejected from the top of the jet pipe (2); a guide sleeve (4) is fixed to the top of the tin cylinder (1), and the guide sleeve (4) is sleeved on the outer periphery of the jet pipe (2); and a guide port (5) connected to the guide sleeve (4) is provided at the top of the tin cylinder (1).

2. The PCB soldering device for preventing solder beads from being generated according to claim 1, characterized in that: The top end surface of the tin cylinder (1) is a convex surface protruding upward.

3. The PCB soldering device for preventing solder beads from being generated according to claim 1, characterized in that: An air inlet (6) is provided on the top surface of the tin cylinder (1), and the air inlet (6) is connected to the protective gas delivery pipe (3).

4. The PCB soldering device for preventing solder beads from being generated according to claim 1, characterized in that: The protective gas delivery pipe (3) is provided with a solenoid valve (7).

5. The PCB soldering device for preventing solder beads from being generated according to claim 1, characterized in that: An air pressure sensor (8) is installed on the protective gas delivery pipe (3).

6. The PCB soldering device for preventing solder beads from being generated according to claim 1, characterized in that: The guide sleeve (4) is composed of an upper cone (41) and a lower cone (42) connected to the bottom end of the upper cone (41), the inner diameter of the top end of the upper cone (41) is smaller than the inner diameter of the bottom end thereof, and the inner diameter of the top end of the lower cone (42) is larger than the inner diameter of the bottom end thereof.

7. The PCB soldering device for preventing solder beads from being generated according to any one of claims 1 to 6, characterized in that: The guide port (5) is a circular hole opened at the center of the upper end surface of the tin cylinder (1). The upper end of the jet pipe (2) passes through the guide port (5), and an annular gap is formed between the guide port (5) and the jet pipe (2).

8. The PCB soldering device for preventing solder beads from being generated according to any one of claims 1 to 6, characterized in that: The upper end of the jet pipe (2) passes through the tin cylinder (1) and is sealed to the tin cylinder (1), and the guide ports (5) are evenly distributed on the periphery of the jet pipe (2).

Images