SU1147527A1 - Method of wiring on printed-circuit boards and soldering conductors - Google Patents

Abstract

THE METHOD OF INSTALLATION AND PIKA OF A BOILER'S PRINTING SYSTEM, including thermal insulation of the insulation on the conductor and its maintenance, by placing the conductor in the molten solder, laying the conductor on the contact pad and the subsequent soldering, in this case In order to improve the quality of the connection by eliminating repeated heating of the contact pad, a conductor with uncured solder is placed on the pad with a pad heated to the lower limit of the soldering temperature. W

Description

This invention relates to soldering, in particular to the soldering of insulated conductors with contact pads of printed circuit boards.

The known method of mounting and soldering the conductors on the board consists in forming a loop of the conductor in the hole of the board, thermal insulation of the insulation on it is made by placing it in the device, which is a tube with a heating element, laying and soldering the loop to the contact pad, on which the solder was previously applied in an amount sufficient to provide a mechanically strong and electrically stable compound ij.

. However, according to this method, the insulation is removed in two stages: during heating and during installation. In the connection between the conductor and the contact pad, inclusions (insulation residues) remain, which reduce its mechanical strength. The decrease in reliability is affected by the negative impact of thermal shock on the contact pad and the corresponding charge of the board, since the tube is heated to the temperature of destruction of the insulation (375 ° C), and the soldering temperature should not exceed 260 C.

The disadvantages include the use of boards with pre-deposited on the contact pads. solder, since applying solder only to those areas of a typical preparatory board that are involved in a particular electrical circuit causes an increase in the labor intensity of making the board, and galvanic deposition of solder to all contact pads unnecessarily increases the consumption of scarce material.

The closest to the proposed technical essence and the achieved result is the method of mounting and soldering the conductors of the printed circuit board, including thermal insulation destruction on the conductor and its maintenance: by placing the conductor into molten solder, laying the conductor on the contact pad and subsequent soldering 2 .

However, a period of time elapses between operations of thermal destruction of the insulation while simultaneously servicing and soldering, during which the maintenance conductor cools down

This causes the necessary additional heating of the conductor and the con-. tact pad during soldering.

The purpose of the invention is to improve the quality of the connection by eliminating multiple heating of the contact pad.

This goal is achieved in that according to the method of mounting and soldering the conductors of the printed circuit board, including thermal destruction of the insulation on the conductor and its wrapping by placing the conductor in the molten solder, laying the conductor on the contact pad and subsequent soldering, the conductor with non-hardened mm is soldered onto the contact pad pa flax, heated to the lower limit of the soldering temperature.

FIG. 1 shows the formation of a conductor in the hole of the board; in fig. 2 — thermal destruction of the insulation on the conductor and its maintenance in FIG. 3; 3 — bending of the conductor to the contact pad; in fig. 4 laying the conductor on the contact pad pa lick; in fig. 5 - soldering the conductor to the contact area; in fig. 6 - return to the original position.

The method is carried out as follows.

The cycle begins with the formation of conductor 1 in the hole of the board 2 (Fig. 1). Then the device for thermal destruction of the insulation 3 on conductor 1 rises (Fig. 2) and the conductor 1 is lowered into the bath with solder 4 heated to a temperature of tinning (375 s ). Thermal destruction of the insulation occurs (melting and partial combustion), the remnants of which remain in the form of slag on the surface of the bath, and the wounding of the conductor 1. In the extreme upper position of the device for breaking the insulation 3 between it and the board 2 there is a gap of approximately the distance from the edge of the hole in the plate 2 to the edge of the contact pad. This is necessary in order not to overheat the contact pad during the maintenance of the conductor 1, and in addition, at the border between the untreated and the trimmed portions of the conductor, a portion of the insulation melted during tinning adheres. After exposure (2-3 s), the device for thermal destruction of the insulation 3 is lowered simultaneously with this, the blade 5 rises, and the slide 6 moves in the direction of the contact pad on which the conductor 1 is soldered. As a result of lowering the device for thermal destruction of the insulation 3 and its horizontal offset relative to the board 2, the conductor 1, when exiting the bath with solder 4, bends with the inner edge of the bath towards the contact pad on which it is soldered. By the time the driver’s code is turned out from the bath, pa 5 comes into contact with it (Fig. 4). At this moment the conductor 1 is in a heated state and the solder on it has not yet hardened. Palnik 5 lays down and presses the conductor 1 to the contact pad (Fig. 5) and loses in this position. Due to the fact that the conductor 1 is in a heated state (above the soldering temperature) and has not hardened on it, the soldering time is shorter than when soldering the conductor 1 with a temperature corresponding to the temperature of the production room, and depending on the size of the contact pad -20 ° C. Thus, not only does the heat load on the pad decrease, but the soldering time is also reduced. At the end of the soldering, the board 2 is moved by the coordinate table to the next soldering point. After aligning the axes of the hole of the board 2 and the needle 7, the cycle is repeated until all the connections provided by the circuitry are made.

Claims (1)

I METHOD OF INSTALLATION AND SALTING PRO- ’ I of the printed circuit board, including thermal destruction of the insulation on the conductor and its tinning; by placing the conductor in molten solder, laying the conductor on the contact pad and subsequent soldering, so that, with the aim of to improve the quality of the connection by eliminating repeated heating of the contact pad, a conductor with a non-hardened solder after tinning is laid on the contact pad with a soldering iron heated to the lower limit of the soldering temperature.