Printed circuit boards

In printed-wired circuit boards, electrical connections are divided into permanent, made using printed wiring, and variables, made using volumetric conductors. Contact pads for connecting IET and bulk conductors, fragments of typical connections, are assigned to constants, and signal lines are related to variables.

Nowadays, methods of automated manufacturing of circuit boards with printed-wire connections, which have not only excellent switching characteristics, but also in some cases are better than those of a pure printed circuit board, have developed economic indicators. The most well-known methods are: wiring with wire insulation on the surface of a printed circuit board covered with an uncured adhesive plastic; wiring through the holes in the board and the formation of mounting loops on the other side of it (stitch mounting).

With the help of stitch mounting, it is possible to connect IET, mounted on surface mounting technology. On the IET boards and contact pads are placed on one side of the base, and on the other, volumetric wires are laid along the shortest paths. Through the puncture points (holes), the loops formed on the conductors are brought to the side with IEP and attached to the printed contacts by soldering with an overlap. Boards with double-sided stitch mounting represent a package pressed from two single-sided boards with an adhesive layer between them. Each of the bases can be single or multi-layered — from two to three foil-coated layers pressed from the side of a dielectric with fiberglass.

For stacking wired connections, PEVTL or PEVTLK wires with a diameter of 0.10 ... 0.14 mm, which do not require mechanical stripping of insulation, are used. When the wire is soldered to the contact area, the insulation is fused, drains to the place of soldering and is used as a flux. In places not subjected to pulsed heating, the insulation has good electrophysical properties, it is sufficiently resistant to bending and ensures not only the absence of contact when the conductors touch, but also small leakages and dielectric losses. After distributing the board is coated with varnish. High-performance digitally controlled robotic manipulators have been developed for stitch mounting.