SU961883A1 - Apparatus for unsoldering soldered connections - Google Patents

Description

(54) DEVICE FOR UNSOLUTION OF UNSOLIDED CONNECTIONS

one

The invention relates to the field of soldering and can be used in the radio, electronic and instrument-making industry.

A known electric flax for removing molten solder, comprising a soldered tip body 5, a central suction channel connected to a source of discharges, and a heater placed around the channel.

In this pallet, the solder is heated by a pallet tip before melting and sucked through the connecting tube into the solder pan with the help of a vacuum unit 1.

The disadvantage of a steam iron is that, in the process of suction of the solder, air is also sucked out of the holes of the printed circuit board and quickly cools the solder to its solidification temperature. Therefore, in order to maintain the solder in the molten state, the steam tip must be continuously heated, which leads to overheating of the printed circuit board being processed. As a result, the board may be damaged or (when

solidification is not prevented by incomplete removal of the solder.

Also known is a device for soldering paired connections, comprising a tip with a central channel for solder, a collection of solder mounted on the end of the connecting tube and a power source. In this device, the removal of solder from the holes of the printed circuit board is carried out after the solder has melted with a pulse of the inductor magnetic flux, which induces eddy currents in the solder. As a result of the interaction of the magnetic flux of the inductor with eddy currents, mechanical forces arise in the solder, pushing the solder out of the holes in the collector 2.

Claims (2)

However, this device provides high-quality processing of vias of boards of only large diameter (more than 0.5 mm). When machining openings of a smaller diameter (0.2-0.5 mm), the cohesive forces of the molten solder particles between themselves and with the board material are often greater than the force developed as a result of the interaction of the inductor magnetic flux and eddy current in the solder. This is due to the fact that as the diameter of the vias of the printed circuit board decreases, the mass of the molten solder decreases and, therefore, the eddy currents in it sharply decrease, the effect of which with a magnetic field should lead to the appearance of mechanical extrusion forces. However, even in the case when the mentioned interaction of the forces leads to the solder soldering, it is not completely removed, namely in the central part of the hole, since the forces of adhesion of the solder particles are much less than the forces of the solder and the board. As a result, the solder spreads on the board, since the ejecting magnetic forces act not only in the axial, but also in the radial direction. All this leads to poor-quality processing holes. The purpose of the invention is to increase the reliability of removing molten solder from small-diameter holes. This goal is achieved by the fact that a device for soldering paired joints, a tip with a central channel for solder, a collection of solder mounted on the end of the connecting tube and a power source are equipped with a solenoid, the core of which is made in the form of a spring-loaded bushing freely mounted on the connecting tube fixed on its working end elastic cuff. The drawing shows a device for soldering paired connections on a printed circuit board, a general view. The device consists of a tip 1, a connecting tube 2 made of ceramic. At the end of the tube 2 there is a collection of solder 3, and inside it there is a tube 4 of non-wettable material (stainless steel, titanium). On the connecting tube 2, the sleeve 5 is freely mounted, spring-loaded relative to the flange 6 of the tube 2 by the spring 7. The sleeve 5 at the end has an elastic cuff 8, which is the core of the solenoid with the winding 9. The device is also equipped with a power source 10 connected to the tip heater (not shown) 1 and winding 9 solenoid. The device works as follows. The end face of the printed circuit board tip 1 is heated, the solder is heated in the hole of the printed circuit board and at the time of its melting by a switch (not shown) of the power supply 10, a pulse is applied to the coil 9 of the solenoid. The core 5 is pulled in and then hit sharply on the board by the action of the spring 7. As a result of the impact pulse of the core 5, the molten solder, when the board is fixed, inertia flies out of the processed hole of the printed circuit board and rushes along the central channel of the tip 1 and tube 4 into the collection solder 3, from where it is periodically removed. The reliability of the removal of molten solder from small diameter holes by the device is enhanced by the fact that the inertial forces arising from a shock pulse completely remove solder from both holes of any diameter and from the surface of the board being processed. Apparatus of the invention for soldering solder joints, preferably on a printed circuit board, comprising a tip with a central solder duct mounted on the end of the connecting tube, a solder receptacle and a power source, characterized in that, in order to improve the reliability of removing molten solder from small-diameter holes , the device is equipped with a solenoid, the core of which is made in the form of a spring-loaded sleeve freely mounted on the connecting tube with an elastic collar fixed on its working end oh. Sources of information taken into account during the examination 1. USSR author's certificate No. 305026, cl. In 23 K 3/02, 1969. 2. USSR author's certificate number 483207, cl. In 23 K 3/02, 1973 (prototype).