Tin wire conveying mechanism on tin soldering machine

Abstract

The invention provides a tin wire conveying mechanism on a tin soldering machine, and belongs to the technical field of PCB machining equipment. The clamping jaw mechanism is used for controlling the tin wire to retract when the tin soldering machine stops, the retraction is not the retraction of the tin feeding nozzle, but the retraction of the tin wire at the tin feeding nozzle, namely the retraction close to the heated end of the tin wire, so that the control precision of the lead-out length of the tin wire and the tin soldering quality are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of PCB board processing equipment and relates to a tin wire conveying mechanism on a soldering machine. Background Art

[0002] The soldering machine is a device that uses liquid tin to wet the substrate to achieve a bonding effect. It is a general equipment for PCB board processing. It generally includes a welding wire reel, a tin breaking mechanism, a bite wheel group, a conduit, a tin delivery nozzle and an electric soldering iron. The tin delivery nozzle is located at the electric soldering iron. The bite wheel group pulls the tin wire from the welding wire reel and delivers it to the tin delivery nozzle. After the wall is broken (to remove oxides on the surface of the tin wire, etc.), the welding wire is sent into the conduit through the bite wheel group. After being led out of the conduit, it is pulled out by the tin delivery nozzle close to the electric soldering iron. The electric soldering iron heats the tin wire delivered by the tin delivery nozzle to complete the welding.

[0003] The above is a common tin wire conveying path in the prior art, that is, it passes through the welding wire drum, tin breaking mechanism, bite wheel group, catheter and tin feeding nozzle in sequence. In this method, the tin wire before the bite wheel group is in a tensioned state, while the tin wire in the catheter is in a "slightly bent" state. During the soldering operation, since the "soldering points" are often distributed alternately, the welding process is generally an intermittent operation, and the welding wire is also intermittently conveyed. In the gap between welding operations, in order to prevent the extended part of the welding wire from continuing to be heated and melted, there is a method of "retracting" the tin feeding nozzle in the prior art, that is, the tin feeding nozzle is controlled to be slightly away from the electric soldering iron during the operation gap, and the tin feeding nozzle is reset when the operation is performed again to continue to heat the tin wire. The defects of this method are: 1. Since the tin wire in the catheter is not in a straight and tensioned state, the tin wire "moves" in the catheter during the retraction and resetting of the tin feeding nozzle, causing the length of the tin wire extending out of the tin feeding nozzle to fluctuate randomly, with a certain range 1. The uncertainty within the range, that is, sometimes longer and sometimes shorter, and then the heating condition and the amount of molten tin at the end of the tin wire near one end of the electric soldering iron also have a certain range of randomness, which affects the welding straightness and yield rate; 2. During the soldering operation, when soldering multiple solder joints on the same PCB board or multiple PCB boards on the same fixture, the tin wire only has a short pause during the switching of multiple solder joints. At this time, the accuracy requirement of the extended part of the solder wire is not very high. However, when the solder wire is replacing the PCB board or the PCB board fixture, due to the long pause time, the extended part of the solder wire is continuously heated for a long time (even if the electric soldering iron is powered off, the residual heat still acts on the solder wire), and there are situations such as tin dripping and solder wire sag (the part extending out of the tin feeding nozzle), resulting in defective products; 3. When the welding material used is a small-diameter solder wire, the adverse effects caused by 1 and 2 mentioned above are more obvious. Summary of the invention

[0004] The purpose of the present invention is to provide a tin wire conveying mechanism on a soldering machine in view of the above-mentioned problems existing in the prior art. The technical problem to be solved by the present invention is how to improve the tin feeding accuracy.

[0005] The purpose of the present invention can be achieved through the following technical solutions: a tin wire conveying mechanism on a soldering machine, which uses a clamping mechanism to control the retraction of the tin wire when the soldering machine is paused. The retraction referred to here is not the retraction of the tin feeding nozzle, but the retraction of the tin wire at the tin feeding nozzle, that is, the retraction close to the heated end of the tin wire. In this way, the remaining amount of the retracted tin wire can be accumulated in the conduit. This is because the inner diameter of the conduit is larger than the tin wire. A tin wire of 0.5 to 2 cm can be accumulated in the conduit through a small bend in a conduit of 30 to 60 cm in length.

[0006] Specifically, when the bite wheel group is started, the electromagnet is energized, and under the action of the magnetic repulsion force, the hollow sleeve is close to the guide nozzle side, and the springs on the wire clamping cone are not squeezed by the guide ribs and are scattered. At this time, the tin wire can be continuously fed according to the predetermined speed, sent from the guide nozzle to the electric soldering iron, and melted by heat to perform the soldering operation. When the soldering is paused, the electromagnet is energized. At this time, the bite wheel group is also paused, and the magnetic repulsion disappears. The reset spring drives the hollow sleeve to reset to the side close to the guide tube. The springs on the wire clamping cone are squeezed by the guide ribs and shrink. When shrinking, they can clamp the tin wire and push the tin wire toward the guide tube for a certain distance during the upward movement of the hollow sleeve, thereby achieving the retraction of the tin wire, and the length of the tin wire extending out of the guide nozzle is reduced.

[0007] The advantages of this approach are: 1. The gap between the inner arm of the guide tube and the tin wire no longer creates uncertainty about the length of the tin wire extending out of the tin feeding nozzle, that is, the length of the extended part of the tin wire is precisely controllable; 2. When the soldering machine is operating intermittently, the end of the tin wire can quickly approach and move away from the soldering iron, and the amount of tin in the soldering is more precise and stable; 3. The end of the tin wire close to the soldering iron is prone to bend and droop when heated. During intermittent operation, it is easy to cause the end of the tin wire to not be able to accurately approach the heating position of the soldering iron. In this solution, the process of the tin wire retracting into the guide nozzle realizes the distance between the end of the tin wire and the soldering iron, and can also straighten the free end of the tin wire so that it can reach the predetermined position near the soldering iron when it is extended again, that is, the forward position of the welding wire is more precise. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a structural diagram of an electric soldering machine.

[0009] Figure 2 It is a structural diagram of the tin feeding nozzle.

[0010] Figure 3 This is a cross-sectional view of the solder feeding nozzle when it is holding the solder wire.

[0011] Figure 4 This is a cross-sectional view of the tin feeding nozzle when the tin wire is feeding.

[0012] Figure 5 yes Figure 3 Enlarged view of part A in the figure.

[0013] Figure 6 yes Figure 4 Enlarged view of part B in the middle.

[0014] In the figure, 1. bite wheel assembly; 2. guide tube; 3. tin feeding nozzle; 31. pipe sleeve; 32. guide nozzle; 33. hollow sliding sleeve; 34. wire clamping cone; 35. guide rib; 36. electromagnet; 37. reset spring; 4. welding wire reel; 5. tin breaking mechanism; 6. electric soldering iron. DETAILED DESCRIPTION

[0015] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0016] like Figure 1 As shown, the soldering machine includes a bite wheel group 1, a guide tube 2, a tin feeding nozzle 3, a solder wire reel 4, a tin breaking mechanism 5, and an electric soldering iron 6. The tin wire is fed by the bite wheel group 1, passes through the guide tube 2, and then is led out from the tin feeding nozzle 3. Figure 2 , Figure 3 and Figure 4 As shown, the tin delivery nozzle 3 includes a sleeve 31 connected to the conduit 2, a guide nozzle 32 connected to the sleeve 31 and a clamping mechanism located between the sleeve and the guide nozzle 32. The clamping mechanism includes a hollow sleeve 33 slidably connected to the sleeve 31 along the feeding direction of the tin wire. The end of the hollow sleeve 33 close to the sleeve is provided with a wire clamping cone 34, and the small diameter end of the wire clamping cone 34 faces one side of the sleeve. The wire clamping cone 34 includes a plurality of circumferentially uniformly distributed spring pieces, and there is a gap between adjacent spring pieces. The inner wall of the sleeve has a guide rib 35. An electromagnet 36 is arranged between the sleeve and the sleeve 31, and a reset spring 37 is arranged between the hollow sleeve 33 and the guide nozzle 32.

[0017] The electromagnet 36 includes a permanent magnet block fixed on the sliding sleeve and an electromagnetic coil arranged on the pipe sleeve 31 .

[0018] The clamping mechanism is used to control the retraction of the tin wire when the soldering machine is paused. The retraction here does not refer to the retraction of the tin feeding nozzle 3, but the retraction of the tin wire at the tin feeding nozzle 3, that is, the retraction close to the heated end of the tin wire. In this way, the remaining amount of the retracted tin wire can be accumulated in the conduit 2. This is because the inner diameter of the conduit 2 is larger than the tin wire. A tin wire of 0.5 to 2 cm can be accumulated in the conduit 2 through a small bend in a conduit 2 of 30 to 60 cm in length.

[0019] Specifically, when the biting wheel assembly 1 is started, the electromagnet 36 is in a powered state, and under the effect of magnetic repulsion, the hollow sliding sleeve 33 is close to the side of the guide nozzle 32, and the springs on the clamping cone 34 are not squeezed by the guide ribs 35 and are spread out. Figure 6As shown, at this time, the tin wire can be continuously fed according to a predetermined speed, sent from the guide nozzle 32 to the electric soldering iron 6, and melted by heat to perform soldering operation. When the soldering is paused, the electromagnet 36 is energized. At this time, the bite wheel group 1 is also paused, the magnetic repulsion disappears, and the reset spring 37 drives the hollow sliding sleeve 33 to reset to the side close to the conduit 2. The springs on the clamping cone 34 are squeezed by the guide ribs 35 and contracted. Figure 5 As shown, the tin wire can be clamped when contracted, and the tin wire is pushed toward the guide tube 2 for a certain distance during the upward movement of the hollow sliding sleeve 33, thereby achieving the retraction of the tin wire, and the length of the part of the tin wire extending out of the guide nozzle 32 is reduced.

[0020] After the bite wheel group acts on the tin wire, a deeper indentation is formed on its surface. The clamping jaw mechanism can effectively and reliably clamp and push the tin wire back. The indentation is beneficial to increase the heating area of ​​the tin wire and facilitate rapid melting.

[0021] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A tin wire conveying mechanism on a soldering machine, characterized in that: The invention comprises a bite wheel assembly (1), a guide tube (2) and a tin delivery nozzle (3); the tin wire is fed by the bite wheel assembly (1), passes through the guide tube (2) and is led out from the tin delivery nozzle (3); the tin delivery nozzle (3) comprises a pipe sleeve (31) connected to the guide tube (2), a guide nozzle (32) connected to the pipe sleeve (31) and a clamping mechanism located between the sleeve and the guide nozzle (32); the clamping mechanism comprises a hollow sliding sleeve (33) slidably connected to the pipe sleeve (31) along the feeding direction of the tin wire; the hollow sliding sleeve (33) is connected to the guide nozzle (32) and is provided with a plurality of guide nozzles (32). The hollow sliding sleeve (33) has a clamping cone (34) at one end close to the sleeve, the small diameter end of the clamping cone (34) faces one side of the sleeve, the clamping cone (34) includes a plurality of spring pieces evenly distributed in the circumferential direction, and there is a gap between adjacent spring pieces. The inner wall of the sleeve has a guide convex rib (35), an electromagnet (36) is arranged between the sliding sleeve and the pipe sleeve (31), and a return spring (37) is arranged between the hollow sliding sleeve (33) and the guide nozzle (32).

2. According to the tin wire conveying mechanism on the soldering machine according to claim 1, it is characterized in that: The electromagnet (36) comprises a permanent magnet block fixed on the sliding sleeve and an electromagnetic coil arranged on the pipe sleeve (31).

3. The tin wire conveying mechanism on a soldering machine according to claim 1, characterized in that: The electromagnetic coil is turned on and off synchronously with the start and stop of the biting wheel group (1) of the soldering machine.

Images