What tool is needed for making harnesses. The device and the manufacture of harnesses. Manufacture of cable harness products

A set of designed wires and cables connected to one another in some way and, if necessary, equipped with electrical installation elements (lugs, connectors, etc.) is called tourniquet. According to their purpose, the harnesses are divided into intra-block and inter-block.

Intrablock harnesses serve for the electrical connection of individual units, blocks and electrical parts inside the device, and interblock are used for electrical connection of various electronic equipment and devices into one system.

The design of the intra-unit harness installation is determined by the type of the device case, the requirements for their maintenance and repair. Depending on the placement of nodes in the body, such bundles can be: flat fixed with detachable connections; flat movable with one-piece connections; volumetric mobile; volumetric with movable outlets. Permanent connections for in-block installation are used mainly in electronic equipment designed for harsh operating conditions.

A typical technological process for the manufacture of a bundle consists of cutting wires and insulating tubes, laying wires on a template, tying them into a bundle, developing the ends of the bundle wires and marking them, controlling the manufactured bundle (continuity), protecting the bundle with insulating tape and its final control (visual inspection on compliance with the standard and continuity).

Harness layout template it is a rectangular plate made of plastic or plywood, on the surface of which a full-size harness diagram is applied and end and corner pins are fixed (Fig. 4.8).

Laying the wire begins by fixing it on the corner stud. Then the wire is laid according to the bundle scheme, bending it on the corner studs and fixing it on the end stud. The start and end pins have the same number. When all the wires are on the template, they are tied with linen thread.

In harnesses where it is impossible to replace damaged wires, spare wires are provided, the amount of which is 8-10% of total number wires in the bundle, but not less than two. The length and section of the spare wires must be equal to the largest length and section of the wires present in the bundle. The length of the harness taps must be sufficient to connect to the nodes and elements of the device circuit without tension; in addition, you should have some margin of length (10-12 mm) for re-stripping and soldering each end of the wire.

When making harnesses, the following requirements must be met:

two or more parallel insulated wires running in the same direction and with a length of more than 80 mm must be bundled;

longer wires should be laid at the top of the bundle so that the branch of the bundle comes out from under them. Wires of small sections (0.2 mm 2) should be laid in the central part of the bundle;

depending on the operating conditions, as well as on the insulation of the wires included in the bundle, it is necessary to knit with threads, braid or tapes made of synthetic materials or winding with electrical insulating tapes or films. It is also possible to use electrically insulating tubes instead of winding with a tape or to perform mechanical and automatic knitting of bundles with threads with a tension that does not violate the insulation of the wires;

the knitting step of the harness loops depends on the diameter of the harness and is selected from Table 4.3.

in places where the tourniquet is exposed (before and after it), bandages from 2-3 loops placed nearby should be made. At the beginning and end of knitting, there should also be bandages, which consist of two to five loops and have end knots. A loop must be made in front of each wire coming out of the bundle. An example of knitting and laying with a bandage is shown in Fig. 4.9;

depending on the number of wires and the diameter of the bundles, knitting must be done in one, two or more threads. Before knitting, it is recommended to grate or soak the threads with ceresin. Knots of linen threads after knitting must be covered with glue (for example, BF-4) or varnish; the ends of kapron threads after knitting must be melted.

After knitting the wires into a bundle, their ends are checked. In this case, all ends of the wires are marked in accordance with the wiring diagram.

Marking of wires, cable products and bundles during electrical installation, it must be possible to check electrical circuits, finding faults and repairing equipment. For marking, the following methods are used: laying in a bundle of wires that have different colors; coloring or numbering of polyvinyl chloride tubes used to clamp the ends of the insulation (the tubes are marked on the machine or the numbers are written by hand with marking ink);

putting plastic tags on the wires with symbols of the connection points;

making a mark on the insulation using colored printing foil (for wires with PVC and polyethylene insulation and cables of the PK type);

use of a metal tag (mainly for cables of the RK type);

use of adhesive marking tape (with a bandage of 1.5 ... 3 turns per wire or cable).

The marking is applied to both ends of the wire, cable or bundle at the points of their connection. The designation of wires, cables and bundles on marking tags, tapes and tubes or directly on the wires must correspond to the mark shown in the technical documentation. If the tag put on the wire or cable is not glued, it is tied on the wire (cable) with a knot or loop.

To mark wires with an insulation diameter of up to 1 mm, use colored marking tubes with an inner diameter corresponding to the wire diameter.

The marking of wires in the bundle is done using tags or tapes made of polymeric materials. The length of the tags or the width of the tapes must be no more than 12 mm.

Then the harness is controlled by dialing, for which they are connected by a device (indicator) in series to the ends of the wires of the harness with the same numbers.

The control of complex harnesses is carried out on special semi-automatic stands according to a given program. All information about such control is recorded in the computer.

Harnesses, wires and cables are fixed to the REA housing or its elements using: brackets, tapes, clamps, adhesives, mastics, compounds, threads, ribbons, plastic self-adhesive tapes.

Staples, tapes and clamps must correspond to the shape of the tourniquet and, when fastened, prevent its displacement.

In order not to damage the insulation of the wires when fastened with metal brackets and clamps, it is necessary to place elastic gaskets made of insulating material under them, protruding beyond the edge of the brackets (clamps) by at least 1 mm.

The distance between brackets or clamps when attaching them to linear sections must be selected depending on the diameter of the bundle (wire or cable) in the range from 100 to 300 mm. Identical wires with a cross section of less than 0.35 mm 2 must be fastened with a distance between the fastening points of not more than 80 mm.

When glue or mastic is used to fix wires, bundles and cables, the distance between the gluing points should be selected depending on the diameter of the wire (bundle or cable) according to Table 4.4

Bundles with a diameter of more than 15 mm, when glued, are fixed with threads through a hole in the chassis.

The passage of a bundle, wire or cable through a hole in a metal chassis must be done through an insulating sleeve that is installed in the hole.

When passing wires, harnesses and cables from the fixed part of the device to the moving part (for example, from the case to the board or panel, etc.), it is recommended to place them in such a way that the wires are twisted and not bent when the moving part is removed. At the same time, the moving parts of the tourniquet do not need to be tied and leave the necessary margin in length.

Soldering and tinning: purpose, application and physical and chemical bases. Solder, fluxes, their brands and applications. Soldering technology with soft and hard solders, temperature conditions, heat sink. Group methods of soldering. Equipment and tools: purpose, design and methods of work. Methods for soldering wires of various grades and sections. Ultrasonic soldering. Laser soldering. Requirements for soldering connections, quality control. Appointment and application of tinning, quality control. Automation of soldering and tinning processes

Soldering- physico-chemical process of obtaining a joint as a result of the interaction of solid and liquid metal (solder). The layers resulting from this interaction at the boundaries of the seam and the surfaces of the parts to be joined are called junctions. To obtain junctions, it is necessary to remove oxide films from the joined surfaces and create conditions for the interaction of solid and liquid metals. During the crystallization of the more fusible solder that has interacted with the material of the brazed parts, a brazed joint is obtained.

One of the advantages of soldering is the ability to connect many elements that make up the product into a single whole in one go. Soldering, like no other connection method, meets the conditions of mass production. It allows you to connect dissimilar metals, as well as metals with. glass, ceramics, graphite and other non-metallic materials.

Tinning is the process of soldering electrical elements (ERE terminals, contact pads printed circuit boards, metallized holes, cores of mounting wires and cables, etc.) It is necessary to improve the solderability of the joined surfaces of the elements during their installation.

To make a good solder joint you need:

7. prepare the surfaces of the soldered parts;

8. activate soldered metals and solder;

9. provide interaction at the boundary "base metal - liquid solder;

10. create conditions for the crystallization of the liquid metal layer of the solder.

Surface preparation involves removing contaminants and oxide films from it that interfere with wetting - its molten solder. Films are removed mechanically or by chemical means. For mechanical cleaning

a thin surface layer of metal is removed with sandpaper, a wire brush, etc. To increase productivity in processing large surfaces (for example, printed circuit boards), hydroabrasive treatment or cleaning with rotating brushes made of synthetic material into which abrasive particles are introduced is used. Surface roughness after mechanical cleaning contributes to the spreading of flux and solder, since small scratches on the surface are the smallest capillaries.

Chemical treatment (degreasing) of the surface of the product is carried out in solutions of alkalis or organic solvents (acetone, gasoline, alcohol, carbon tetrachloride, freon, alcohol-gasoline and alcohol-freon mixtures) by wiping, lowering into a bath, etc.

Cleaned parts must be immediately sent for tinning and soldering, since the shelf life for copper is 3-5 days, for silver - 10-15 days.

Activation of the joined metals and solder occurs with the help of various fluxes, the creation of a special gaseous medium or physical and mechanical effects (mechanical vibrations, ultrasonic vibrations, etc.). Activation is necessary, since when metals are heated and solder melts, their surface layers interact with atmospheric oxygen, which leads to the formation of a new oxide film.

Soldering with flux is the most common. The molten flux spreads over the soldered surface and the solder, wets them and interacts with them, as a result of which the oxide film is removed. But the use of fluxes can lead to the fact that their residues after soldering, as well as the products of their interaction with oxide films, create slag inclusions in the brazed joint. This reduces the strength of the joint and leads to its corrosion. To avoid this, flux residues after soldering are washed off (wiped) usually with organic solvents.

To ensure interaction at the "base metal - liquid solder" interface, it is necessary to achieve good wetting of the base metal surface (ERE leads, petals, wires, etc.) with molten solder. The strength, corrosion resistance and other properties of solder joints. The process of wetting and spreading of solder is influenced by certain technological factors (the method of removing the oxide film, the brand of flux used, the soldering mode, etc.).

Crystallization of the liquid metal layer is carried out after the removal of the source of thermal energy. The crystallization process has a significant impact on the quality of solder joints.

Solder and fluxes for soldering designed to perform technological processes of hot tinning and soldering of non-ferrous and ferrous metals and metallic and non-metallic materials metallized by them. They are divided into:

solders for low-temperature soldering with a melting point of less than 450 °C;

solder for high temperature folder with melting point above 450°C.

The symbol for solder grades consists of the letters "P" or "Pr" and the following abbreviated names of the main components: tin - O, lead - C, antimony - Su, bismuth - Vi * cadmium or cobalt - K, silver - Cp, copper - M , indium - Yin, zinc - C, nickel - N, gallium - Gl, germanium - G, titanium - T, gold - Zl, manganese - Mts, boron - B, phosphate - F, brass or lithium - L, iron - F , aluminum - A. Further, the content of the main component is indicated as a percentage of the mass. The letter "P", which stands at the end of the brand with a hyphen, means that the solder has an increased purity.

The main brands of solders and their melting temperature (T pl) are shown in Table 4.5.

Fluxes are intended for use in technological processes of soldering and hot tinning in order to remove the oxide film from soldered surfaces and solder, protect the surface of metals and solder from oxidation during soldering, as well as reduce the surface tension of molten solder at the metal-solder-flux interface

The symbol for flux grades consists of the letter "F" (flux) and the abbreviated name of its constituent components: K - rosin, Sp - alcohol, T - triethanolamine, Et - ethyl acetate, C - salicylic acid, B - benzoic acid, Bf - cadmium boron fluoride (or zinc), P - polyester resin, D - diethyl amine, SC - semicarbozide, Gl - glycerin, Fs - orthophosphoric acid, C - zinc chloride, A - ammonium chloride, B - water, L - laprol, Kp - catapine, M - maleic acid.

Fluxes can be low-temperature (use temperature less than 450 °C) and high-temperature (with use temperature over 450 °C). Depending on the corrosive effect on the metal to be brazed, they are divided into the following groups: non-corrosive inactive, non-corrosive weakly active, slightly corrosive active, corrosive active, corrosive highly active.

To avoid field joint corrosion, residues of corrosive and even mildly corrosive fluxes must be removed immediately after soldering. Remove fluxes with liquids in which they dissolve. For some brands of fluxes, these may be organic solvents, for others, water.

The most common brands of fluxes are given in Table 4.6.

In addition to fluxes, protective liquids are used to protect the mirror of molten low-temperature solder from oxidation in tinning and soldering baths (for example, ZhZ-1, ZhZ-2, TP-22). They are a mixture of petroleum oils with organic components.

The quality of solders and soldering fluxes is determined by technological characteristics: spreading coefficient (K p) and wetting time (t CM). Coefficient K p \u003d Sp /Sq, where S p is the area occupied by solder; Sq - area of unmelted solder in the initial state; tCM - the time during which the mounting element is tinned (should be no more than 3 s).

Soldering technology with soft and hard solders, temperature conditions, heat sink. The technological process of soldering consists of the following operations:

preparation of surfaces of connected elements for soldering; fixing the connected elements tightly to one another; applying a dosed amount of flux and solder; heating parts to a predetermined temperature and holding for a certain time; *

cooling of the soldered joint without shifting the parts included in it;

clearing the connection; soldering quality control.

Soft (low-temperature) solders (see Table 4.5) are used for electrical installation of equipment. Therefore, the temperature regimes for their use depend on the permissible temperature for those elements that take part in the installation. Soldering can be done with a soldering iron or in molten solder baths. When tinning and soldering with molten solder, the required bath temperature increases for each grade of solder according to the formula

tp = tnk + (45...80) °С,

where t n - solder temperature, tHK - crystallization start temperature (first digit T pl in table 4.5). Exceeding value (45...80) °С above tHK depends on the mass of the product to be soldered, the immersion time, the flux used, the restrictions on thermal effects in accordance with the technical specifications for the ERE.

To avoid overheating of soldered EREs, a heat sink is used, which is fixed to the ERE terminals during soldering.

There are other methods of heat removal during individual and group soldering of circuit boards. Mounting plate 2 (fig.4.10, a) is installed in fixture 5, made by injection molding in the form of a thermal block. The case is built-in racks 3 pressed by springs 6, bearing support copper sockets 4 from above, having slots for leads. Mounting plate 2 is installed on these heat sinks so that the leads of the radioelements fit into the slots of the sockets. The board is fixed in the device by turning the clamping bar 1. Thus, during the period of individual soldering, heat removal is carried out by the entire body of the device.

When group soldering hinged elements on the circuit board, the method of heat removal is used, carried out with the help of shot from aluminum wire with a diameter of 3 mm (Fig. 4.10, b). The shot 3 is loaded into the holder 1, where the circuit board 2 is inserted before group soldering by immersion or hydrostatic method. At the end of soldering, the shot spills out.

Hard (high-temperature) solders are used for structural soldering of mechanical joints in the manufacture of large-sized parts (for example, chassis, cases, etc.). High-temperature soldering of mechanical joints is performed in high frequency current fields (HF), in furnaces or baths with molten salt.

Induction soldering (TVCh). A technological device for induction soldering or soldering with high frequency currents (HFC) is an inductor, which is a coil made of a highly conductive tubular material through which a coolant is pumped. An HDTV generator serves as equipment for soldering. Typically, induction brazing is used to join elements operating at microwave frequencies, such as microwave waveguides. The quality of the connection is improved when the soldering process is carried out in a vacuum or in a protective gas environment (hydrogen, nitrogen, or mixtures thereof). A big disadvantage of HDTV soldering is the need for special devices for each assembly unit.

Soldering in ovens with a controlled atmosphere ensures uniformity of heating. The soldered materials are heated in an active gaseous medium. In this case, fluxing can be omitted.

Soldering in bathtubs with molten salt is used to assemble large-sized products. The composition of the melt is selected in such a way that it provides the desired temperature and has a fluxing effect on the surfaces to be joined. The units assembled for soldering (the gap between the soldered parts should be within 0.05 ... 0.1 mm) are preheated in an oven to temperatures 80 ... 100 ° C below the melting point of the solder. This is necessary to avoid warping of parts, as well as to maintain the temperature in the bath. After soaking in the melt for 0.5 ... 3 minutes, the part, together with the fixture, is removed from the bath and cooled, and then thoroughly washed with water to remove flux residues.

Group methods of soldering. Group soldering methods in the production of REA are classified according to the sources of thermal energy, which is the main factor in the formation of solder joints (Fig. 4.11). Soldering elements with pin leads, which are placed on printed circuit boards, in mass production is carried out by two methods: immersion and solder wave.

Different options for implementing the group methods of the folder are shown in Figure 4.12. When soldering, the printed circuit board is immersed in molten solder for 2 ... 4 s to a depth (0.4 ... 0.6) h, where h - board thickness. As a result of the capillary effect, the mounting holes are filled with solder (Fig. 4.12, a). The simultaneous effect of temperature on the entire surface of the board leads to its overheating and can cause increased warpage. To reduce the area of action of the solder, a special mask (made of paper or fiberglass) is glued to the board from the mounting side, in which holes for the contact pads are provided. Remaining flux solvent that got into the solder evaporates intensively, which leads to local non-solders. To reduce the number of non-solders, dip soldering is used with the board tilted (angle 5 ... 7 °) (Fig. 4.12, b) or apply mechanical vibrations to the board with a frequency of 50 ... 200 Hz and an amplitude of 0.5 ... 1 mm (Fig. 4.12, d, e). Good results can be obtained by drawing the board along the solder mirror (Fig. 4.12, in). In this case, the board is mounted on the fixture at an angle of 5°, immersed in solder and pulled along its surface. With this method, suitable conditions arise for the removal of oxidation products.

Selective soldering(fig.4.12, e) provides selective supply of solder to soldered parts through special dies made of stainless steel. Between the board and the filters there is a layer of heat-resistant rubber. With selective soldering, the temperature of the board and the heating of the ERE are reduced, the consumption of solder is reduced, but the cost of manufacturing special dies can be significant.

Wave soldering is the most common method of group soldering. In this case, the board moves in a straight line across the crest of the solder wave. Its advantages are high productivity and short time of solder interaction with the board, which reduces ERE overheating and dielectric warpage. A variation of wave soldering is cascade soldering (Fig. 4.12, g), in which several waves are used.

The high quality of soldering is ensured by the method of immersing the board in a bath, in which there is a grid with cells of 0.2x0.2 mm, for example, made of nickel (Fig. 4.12, h). When the board touches the grid, the solder is pressed through the cells and, under the action of the capillary effect, enters the gap between the leads and the metallized holes. When moving back, excess solder is drawn into the capillaries of the mesh, which prevents the occurrence of “icicles”

Equipment and tools: purpose, design and methods of work. Depending on the type of production, soldering is carried out individually with a heated soldering iron or by various group methods.

Soldering with a soldering iron used for electrical installation in a single or small-scale production.

Design electric soldering iron shown in Figure 4.13. The required temperature regime for individual soldering is provided by the thermophysical characteristics of the soldering iron used: the temperature of the working end of the tip (tip 1 on, Fig. 4.13), the stability of this temperature, which is maintained using a thermocouple 4, the power of the heating element 14.

The temperature of the working end of the tip is set to 30 ... 100 ° C higher than the melting point of the solder, since during the soldering process the temperature of the soldering tip decreases due to heat costs when the soldered parts are heated. The recommended power of soldering irons for soldering microcircuits is 4 ... 18 W, for printed wiring 25...60 W, for soldering wires (bundles) 50... 100 W.

Soldering iron tips use copper, which is plated with a layer of nickel to increase its wear resistance. The sequence of the soldering process with a soldering iron: flux elements of the field connection with a brush dipped in liquid flux; heat the elements of the field connection by touching them with a soldering iron tip; introduce a twig of solder into the soldering zone; withstand heating until the solder reaches normal spreading and fills all the gaps between the surfaces to be joined.

After soldering is completed, the parts must not be touched until the solder is completely hardened. The total time of soldering one mounting joint with a soldering iron is 1...3 s and cannot be more than 5 s.

If soldering and tinning is performed manually, it is necessary to ensure the removal of heat from ERE, semiconductor devices, ICs, etc., which are sensitive to its effects (according to specifications for these elements). Heat sinks in the form of clips are fixed on the leads of soldered elements between the soldering points and the body of the element. After soldering, the heat sinks are removed no earlier than after 5 s. For reuse heat sinks change or cool.

Scheme of installation for selective soldering shown in Figure 4.14. Board 3 with leads, pre-coated with flux, is installed on the die 5. Each soldering place has its own die, the hole of which must coincide with this place. In this position, the board is fixed with a clamp 4. The molten solder 1 is in a volume closed on all sides, and its temperature is maintained by the molten salt bath 8, heated by electric heating elements 9. Through the bronze diaphragm 7, the vibrator 6 informs the molten solder with oscillations with a frequency of 100 Hz, which improves soldering quality. The solder is fed through the dies to the places of soldering by lowering the piston 2.

Scheme of installation for wave soldering shown in Figure 4.15. In the bath with molten solder, the temperature of which is maintained by a salt bath 2 with heating elements 1, there is a branch pipe with a vane pump 4 driven by an electric motor using a shaft 3. The wave height depends on the speed of the electric motor and is regulated by its change.

Cascade soldering differs from the wave one by the presence of several waves (Fig. 4.16) created by thresholds 3 on the inclined surface of the base 5. The molten solder 8 is supplied by the pump 7 through the slot 4 at a constant speed to these thresholds and flows down. Side walls 1 protect the solder from running off in other directions. As in the previous schemes, the temperature of the solder is maintained by a salt bath 9 with electric heaters 6.

These types of soldering are most appropriate for large-scale and mass production of boards with one-sided arrangement of attachments. They provide continuous movement of boards during soldering and its local heating.

Methods for soldering wires of different grades and sections. After processing, as described above, installation copper wires and cable cores that do not have a coating must be tinned. Separate cores of wires must be twisted after stripping the insulation before tinning. When tinning conductors of wires and cables, flux is recommended to be applied at a distance of 0.3 to 2 mm from the insulation. Non-tinned sections of the core between the insulation and the tinned part of the wire are allowed up to 1 mm. The cross sections of the conductors must correspond to the load current. The total cross-sectional area of the cores of the wires and the conclusions of the ERE, attached to the contact, should not exceed the smallest cross-sectional area of the contact.

When soldering wires and cable cores, the following requirements must be met: the wires must be connected to each other using electrical contacts. Options for fixing wire cores and ERE leads on contacts different designs shown in Figure 4.17:

no more than three wires can be soldered into each soldered contact hole. In this case, each wire must be fixed in the hole independently, without twisting it with other wires and ERE leads. If the mounting hole is small for soldering, it is necessary to use the reference wiring contacts; the wire must be attached to the screw terminals only with the help of cable lugs (for one screw terminal no more than two wires). Clamping contacts must be sealed with paint or varnish;

wires of small sections (less than 0.2 mm 2) must be mounted carefully; laying of wires must be carried out only once, so as not to break them off;

the supply of the drive in the form of a loop is placed on the board, but there should not be a wire hanging over its edge; the wire to the place of soldering must be brought from below; connection of mounting wires to the contacts must be carried out in such a way that the length of the bare part of the core of the mounting wire from its insulation to the soldering point is no more than 2 and no less than 0.5 mm (after soldering). When the contact spacing is less than 5mm, the wire exposure should not exceed 1.5mm.

Attaching the mounting wires to the screw terminal blocks is carried out different ways. With one of them, rings are made from stripped and tinned wire cores with a diameter greater than the diameter of the screw (Fig. 4.18, a). In another way, cable lugs with screw holes are attached to the wire cores by soldering, welding or crimping (Fig. 4.18, b).

The laying of wires in the cable lug is carried out in the following sequence: an electrical insulating tube with an inner diameter equal to the outer diameter of the wire is put on the wire; the core of the wire after cutting and tinning is inserted into the tip; the paws of the tip are crimped and soldered to the core of the wire from the inside to the paws; crimp the following paws on the insulation of the wire; an electrical insulating tube is put on top of the tip

(fig.4.18, b).

Ultrasonic soldering. Ultrasonic vibrations introduced into the solder destroy oxide films on the metal surface, improve its wetting with liquid solder, flow of solder into capillary recesses, promote degassing of the melt, which improves the quality of the soldered joint.

The cavitation that occurs under the action of ultrasound in the solder contributes to the destruction of oxide films, and acoustic currents carry away particles of oxides and contaminants, and remove metal at the sharp edges of the contact. Exposed areas of the metal are easily wetted with solder.

Laser soldering. Laser radiation differs from other sources of electromagnetic energy in a very narrow directionality. Concentrated heating by focused beam energy has a number of advantages, the main of which are: non-contact energy supply to products due to the removal of the source from the object of heating; the possibility of energy transfer through optically transparent shells both in a controlled environment and in a vacuum; heat different materials regardless of their electrical, magnetic and other properties in a wide range of regulation and control of soldering parameters. Depending on the design features and mass of soldered products, as well as the properties of the materials to be joined, various equipment of different capacities is used.

Requirements for solder joints, quality control. To

Solder joints are subject to the following requirements:

when fluxing, it is impossible to allow the flux to get inside the ERE and on the contact parts of the electrical connections;

the shape of soldered joints should be frame with concave fillets of solder (Fig. 4.19) and without excess solder. It should allow visually viewing through thin layers of solder the contours of the individual electrical elements included in the connection;

the surface of the solder fillets around the entire perimeter of the solder joint should be concave, continuous, smooth, glossy or light matte, without dark spots and side inclusions.

The quality of the soldering is checked by external inspection, and, if necessary, using a magnifying glass. Well-made soldering should be considered one on which the contours of the parts to be joined are clearly visible, but all the holes are filled with solder. The solder must have glossy surface, without sags, cracks, sharp slopes. Possible types of defects in solder joints are shown in Fig. 4.20.

The mechanical strength of the soldering is checked with tweezers with polyvinyl chloride tubes put on its ends (when there are instructions for this in the TD). The tension force along the wire axis should be no more than 10 N. It is forbidden to bend the wire near the soldering point. After control and acceptance, the place of soldering is painted with a transparent colored varnish.

Appointment and use of tinning, automation of soldering and tinning processes. The high requirements for fixed connections of parts and elements during electrical installation carried out by soldering make it necessary to perform a hot tinning operation.

Usually, hot tinning of electrical installation elements is carried out only if their solderability is unsatisfactory (the need for solderability control is laid down in the TD). When tinning, the following requirements must be met:

tinning of electrical elements (ERE terminals, contact pads of printed circuit boards, metallized holes, cores of mounting wires, etc.) should be carried out mainly with the same solders as subsequent soldering. Temperature-sensitive EREs are tinned with low melting point solders. As well as during soldering, when tinning such EREs, it is necessary to use heat sinks;

the application of flux to tinned surfaces during manual tinning should be carried out for the minimum time necessary to ensure wetting of the surface with solder. In mechanized tinning, the entire surface that touches the solder is fluxed;

when tinning, the distance along the length of the ERE lead from the solder mirror to the ERE body must be at least 1 mm (or in accordance with the specifications for the ERE);

when tinning the ERE leads manually by immersion in solder or electric soldering irons, the duration of the process should not exceed the time specified in the technical specifications for the ERE. When there is no such restriction, the duration of tinning is taken to be no more than 5 s.

The technical equipment of the Contract Manufacturing of our company allows us to carry out such a type of work as the manufacture of small and medium-sized batches of non-standard wire harnesses with increased requirements for reliability and quality (industrial electronics, automotive equipment, mechanical engineering, etc.)

Our specialists have mastered the modern advanced technology of braiding wire harnesses,
for this we use the installation of braiding and shielding harnesses in production Cobra 450/1000.

An additional polyester thread braid over the shielding braid makes it possible to use the wire harness at temperatures up to 120°C.

If necessary, additional sealing of the connectors with special compounds is carried out.

For maximum automation and acceleration of the technological process of manufacturing harnesses, we have at our disposal various desktop machines for measuring cutting and stripping wires (Komax Kappa 330 and Cosmic 927R), a semi-automatic press for crimping terminals and contacts Metal TT.

Technological possibilities and limitations in the production of harnesses

Wire types	stranded stranded and solid copper, single wires
Types of insulation	polyvinyl chloride, bonded polyethylene, Teflon (TFE), Tefzel (ETFE), Kynar (PVDF), silicone rubber, fiberglass, Nylon, Mylar, Vulkene, neoprene, Hypalon, other wound or embossed insulation
Min. section
Max. section
Min. wire length	at least 10 mm of insulation must remain
Max. wire length	999.5 meters
Min. stripping length	3 mm (standard value);
Max. stripping length	full stripping: 9 mm on stranded wire, 40 mm on solid wire
Half-sweep	41 mm or any combination for a total of 82 mm, on stranded or solid wire
Lot size	not limited
Max. performance*	1000 wires per hour

*Performance depends on wire type, insulation, wire length, stripping length, wire size.

Apart from various types harnesses, you can order the production of all kinds of information cables for your equipment from us. We are ready to supply any necessary equipment for the production of your cable products.

Radio-electronic equipment (REA) is present in almost all branches of modern industry and occupies a significant part in the development and production complex products. Flexibility to use new technological solutions in this moment becomes key factor allowing companies to take a leading position in the market. At the same time, as they say, “becoming the best is not difficult, it is more difficult to remain the best.” There are many examples of how world-famous companies that have reached great heights in their field, due to errors in the choice of technologies, have literally found themselves on the verge of survival. In this article we will talk about interesting, but complex world cable assemblies and bundles, without which it is difficult to imagine the development of the global industry.

Cable assemblies and bundles in modern technology

A bundle (in the context of electrical engineering) is an assembly of two or more (up to several hundred) insulated wires connected into a bundle in some way. This assembly is used for electrical connection elements of various machines and devices.

A cable assembly (CS) refers to the connection of a connector and a cable, which, in fact, is already a finished product. The convenience of using the COP can be briefly described as follows: “paved - connected - it works”.

Rice. 2. Cable assembly

CS and harnesses are used in almost all key industries: aerospace, aviation, railway equipment, automotive, shipbuilding, military industry, general industrial applications. At the same time, the classification of harnesses and CS meets the requirements in force in each area (weight, safety, resistance to various influences, etc.). So, according to the method of application, the bundles are divided into intra-unit (for connecting elements inside the device) and inter-unit (for connecting different devices into one system).

Perhaps the most common example of an interconnect is a conventional stationary personal computer. Connection system block with monitor, keyboard, mouse, etc. occurs through the connection of cables to it. All these elements make up a single system. The contents of the computer system unit, where the wires connect the individual components, is a clear example of intra-unit installation. More complex system are interconnect cables used in aeronautical engineering to connect all equipment on board.

Manual production of KS and harnesses. Problems and disadvantages

Rice. 6. Removing the insulation from the wire with a thermal stripping device

Despite the development of production automation, the assembly of harnesses is often carried out using hand tools, which is due to the specifics of certain products and the impossibility of automating some assembly steps.

Specialists with experience in industries related to aviation and other military equipment, where specialized, difficult-to-process wires of the RK, MS, MGTF, MGSHV NV, BPVL brands are often used, can confirm that installers are often forced to use tools that are not quite characteristic, such as a medical scalpel. This tool is great for stripping silicone or rubber sheathed wires. Apparently, therefore, despite the high probability of spoiling the workpiece, this "non-core" tool is often used in production.

The next example of an unconventional method of stripping wires is the use of a soldering iron and thermal stripping devices (so-called "burners"). But such an operation can lead to overheating of the current-carrying core and sticking of molten insulation to the core.

At mechanical action high quality stripping is also not guaranteed, since it is difficult to avoid cutting the wire or scratching it, which can lead to the failure of the bundle during operation.

It is also obvious that when manual processing there is no need to talk about high productivity and speed of the process. These shortcomings, as well as the high labor intensity technological process without a guarantee of repeatability of quality (and, accordingly, a high percentage of defects) motivate manufacturers to introduce automated production lines and use modern technologies at all stages of the production cycle.

Rice. 7. Stripping the wire with a knife

Modern technologies for designing CS and bundles

Manufacturers who seek to improve the quality of their products and reduce the impact of the human factor are implementing automated lines and use modern technologies at all stages of the production cycle.

On the initial stage The design of the entire process is carried out to create harnesses, which avoids adjustments and delays in subsequent stages of production. Modern computer-aided design (CAD) systems significantly reduce the time for developing design and technological documentation, allow prototyping the position of the harness in the product in 3D format, quickly perform changes in the product design and track the entire life cycle product, starting from the first sketch of the bundle and ending with the final control stand.

Currently, the automation of the design of harnesses goes in two main directions:

Small companies, in which the production of cable products is not the main activity, use non-specialized CAD systems, manually transferring the development results obtained on them to the production site.
Large and narrow-profile manufacturers of harnesses with an automated production base use CAD systems that specialize in working with harnesses. This allows you to automatically transfer information about the developed product to automated sections and lines for cutting, stripping, etc.

One of these specialized design systems is See Electrical Expert, a development of the French company IGE + XAO Group, which offers automated software solutions for design in the field of electrical engineering and automation. This CAD includes a line of software modules and configurations, the main task of which is to create the logic of an electrical project. The proposed solution, used at different stages of the development of high-tech products, provides an end-to-end cycle "design-production", allows you to effectively solve the problems associated with the design of electrical cable harnesses by ensuring compatibility between electrical circuits, automatically carry out optimal cabling using the automatic wiring function , and also provides data on the length of the wires in the bundles, the mass and diameter of the branches of the bundles.

The advantage of SEE Electrical Expert is also compatibility with programs actively used in mechanical engineering and aviation industry: NX (Unigraphics), Catia, TeamCenter, AutoCAD, SolidWorks, SolidWorks Enterprise PDM.

CAD systems operate with large databases of radio-electronic components, templates and tools for fast and high-quality creation of design and engineering documentation for electronic products and harnesses. They also make it possible to speed up the technological preparation of production by transferring information directly from the design department to the production line, taking into account the technological features of each assembly.

Automated lines for the production of CS and harnesses, types of equipment, advantages, distribution

Before starting to manufacture harnesses, as a rule, an employee (production foreman) needs to receive all the necessary equipment. In the context of a huge range of products in industrial warehouses, an address storage system with automated inventory accounting is used, in which all products are marked and accounted for when received and issued from the warehouse. All information is consolidated into a single database, where you can track the need and balance of each component in the warehouse.

Next, the wires go to the dimensional cutting section. Automatic machines (such as EcoCut 3200, 3300, PowerCut 3700) can be used here for measuring wires and cables of various sections. Cutting is carried out with special knives that allow for a high-quality cut of the wire without deformation and flattening. The advantages of these machines is the possibility of building on their basis a technological line for measuring cutting with the use of an unwinding feeder, a printer for marking and a wire collector as part of the line.

At the next stage, the ends of the wires are stripped on stripping machines, the choice of which directly depends on the type of cable used and the stripping method. For today best solution This task is the use of machines manufactured by Schleuniger, the range of which includes a series of machines for various fields of application, such as:

RotaryStrip - for stripping hard-to-cut types of wire insulation that require additional twisting of the inner cores;
UniStrip - for stripping sheathed cables and wires;
JacketStrip - for removing the sheath of the cable, including non-circular section;
SheildCut - for cutting the shielding braid of the cable;
CoaxStrip - for stepped stripping of coaxial cables.

These machines have the ability to select different wire stripping sequences.

The Mercury-4 laser stripping machine for wires and cables deserves special attention, in which the use of a hydrocarbon laser allows non-contact stripping of any polymeric materials for cable insulation of various types.

Universal machines of the MultiStrip, EcoStrip, PowerStrip and MegaStrip series combine the functions of dimensional cutting and stripping of wires and allow, in accordance with a given program, to process a wire with a cross section of up to 300 mm 2 and a diameter of up to 35 mm, while ensuring the processing of the inner cores of a multicore cable.

To install lugs (or contacts) on the wire, special crimping machines (UniCrimp) are used, as well as equipment that can combine the functions of stripping and crimping (the StripCrimp family of machines).

An equally important stage in the production of harnesses is wire marking, for which it is advisable to use special marking printers (for example, HotStamp 4140 hot stamping printer, TTP 4000 thermal transfer printer or AlphaJet ink jet printer), which apply symbols to wires in accordance with electric circuit. The choice of equipment depends on the type of cable insulation.

Depending on the specifics of production, additional machines for twisting wires (WireTwister - manufacturing a twisted pair with control of the twist pitch), braiding machines that form a shielding or protective layer on the surface of the bundle (manufacturer OMA), etc. can be connected to the process.

It is important to note that the above preparatory operations occupy the bulk of the work in the manufacture of harnesses, so the use of automated equipment significantly reduces the complexity of manufacturing, increases the repeatability and reliability of technological processes, which, in the absence of the influence of the human factor, significantly increases the level of quality and reliability of harness products.

The assembly of complex harnesses is carried out on a specialized mechanical desktop (Fig. 8), or on the interactive panel Orbita P150 (Fig. 9), which displays the automatically created electronic model cable assembly or bundle.

Rice. 9. Interactive panel Orbita P150

The advantages of the interactive panel over a conventional desktop are obvious: it allows you to visualize not only the assembly and desoldering process, but also all the additional information on each assembly stage. The assembler, using a system for electronic reading of markings from wires (Fig. 10), traces the wires of the bundle in accordance with the design documentation, while the trace of the read wire is highlighted on the panel itself.

Rice. 10. Electronic marking of wires using barcodes

An integral part of the technological process for the production of CS and harnesses is the operation of sealing cable connectors (filling), designed to protect the cable connection inside the connector from moisture, high vibration and impact loads during operation of the product. Since the operation involves the use of mainly manual labor, a high percentage of marriage is possible, since the most important point in this operation is the preparation of the compound - mixing components of different viscosity. From quality ready mix depends on the performance of the product and its service life. When manually mixing, a large amount of air is injected into the mixture, which negatively affects the quality of the product. It is important to remember that the quality of the fill is difficult to control in a closed slot.

To ensure high-quality pouring of connectors, it is necessary to move from manual labor to automated systems for mixing compounds. To modern solutions that allow for high-quality preparation of material components (including with vacuum, heating), as well as repeatable mixing of components in correct proportion, include high-speed laboratory and planetary mixers (for example, SpeedMixer manufactured by Hauschild & Co).

One of the production management systems that allows you to set up an automated production process in terms of managing orders for the manufacture of products, technical preparation of production, logistics and production planning, is the automated system "Orbita: Production Management". This system allows you to link together all the elements of production, creating a single information field for the work of each division of the enterprise, providing fast transfer of information from site to site, end-to-end control of all production indicators, production load planning and job scheduling. In addition, it allows you to manage the workload of personnel and work centers.

Despite the high purchase price technological equipment, the cost of its purchase and implementation pays off in a few years.

Quality control of conduits and harnesses using modern automated control systems

Rice. eleven. Homemade stand for checking harnesses

The final stage of production is to check the quality of the assembled bundles, which determines the service life, productivity and, as a result, the competitiveness of the product.

Checking the harness for compliance with the circuit, as a rule, is performed on special dialing stands or on wired testers that allow you to measure insulation and breakdown resistance, carry out a complete check of the harnesses for compliance with the circuit, the absence of a short circuit.

Not all enterprises have up-to-date systems for quality control of conduits and harnesses. Moreover, not every production generally has an idea of the existence modern systems control.

So, for example, at one of the enterprises specializing in the production of electrical products, where harnesses and RCs are created “from scratch”, to this day, in conditions of mass production, the continuity of the harnesses is carried out using a multimeter or a self-made automatic test stand (Fig. 11 ). The device of such a table is simple. Depending on the connector used on the harness, a replaceable module with installed mating connectors is connected to it. Each plug-in module is designed for a certain type of connector (Fig. 12). The harness is connected to the required module, after which a specific type of harness (cable) is selected in a special program, and the verification process begins. Test results are reflected in the program. Due to limited range replaceable modules The range of controlled harnesses is not complete. Therefore, the use of a multimeter is indispensable.

CS and harnesses for military and space purposes are undergoing military acceptance (VP) of the RF Ministry of Defense, and manufacturers are extremely interested in using the latest technical solutions.

Mentioning modern equipment, I would like to single out the most popular in Russia automated installation control system TECT-9110-VXI (Informtest holding), designed to measure and verify such parameters as: insulation resistance (“Megger”); capacity; electrical strength; circuit isolation; circuit integrity; short circuit between circuits; insulation resistance; electrical strength of all circuits.

According to experts, the main advantage of this system lies in its composition, which combines various modules, the number of which is determined by the number of channels required by the consumer. The main executive modules included in the TEST-9110-VXI "Flight" are:

Rice. 13. Using a multimeter when the harness is ringing

Meter IS4. It performs the functions of a high-precision multimeter, megohmmeter and precision AC and DC voltage source.
Switches VVK5, VVK6, VVK6M and VVK7. They provide switching of the meter to the tested channel and automation of tests.
Ethernet-VXI controller module, which performs the function of information and technical interaction with a personal computer.
VXI crate providing accommodation for all modules included in TEST-9110-VXI.

Another advantage of this control system is its flexibility, which allows using the same modules both in stationary and mobile versions (Fig. 14, 15). Thanks to this solution, the system can be used where the use of large universal machines is impractical. In addition, the use of one system in different versions allows you to stop using third-party testers with your software.

Rice. 14. TECT-9110-VXI mobile version

The advantages of the TECT-9110-VXI system include the possibility of delivery with the conclusion of the IP, as well as high measurement accuracy and speed of work, which reduce the time of verification and eliminate the influence of the "human factor".

Rice. 15. Fixed TECT-9110-VXI variant

The warranty for TECT-9110-VXI installation control systems is from three to ten years: not every manufacturer is ready to boast of such terms.

The quality control of the bundles is evaluated not only by electrical parameters, but also by such a mechanical characteristic as the quality of the crimping of the ferrule. This parameter is mainly controlled by the force of tearing the crimped lug from the wire using tensile testing machines (PullTester). The crimping force itself is checked using a special control unit (АСО 07). A more detailed study of a crimped joint can be carried out by analyzing a cross section of selected cable samples using micrographic analysis (such as MicroGraph System, ElektrolyteStaining Unit, SawInspect System 6).

In modern multifunctional automated machines, the quality control of the bundles is carried out directly during manufacture, and parameters such as crimp height and breaking force are controlled immediately before the start of each batch. When crimping the ferrules, the crimping force is controlled, which makes it possible to obtain up to 100% quality products at the outlet of the automatic line.

In the conditions of fierce competition in the market, it is difficult to count on good prospects without improvement production processes, without introducing the achievements of scientific and technological progress (STP) into them. In the field harness production The following promising developments can be attributed to the results of scientific and technical progress:

Rice. 16. Industrial robotic arm

Rice. 17. Augmented reality glasses

Interactive harness table for error-free harness assembly.
An industrial robotic arm (Fig. 16), whose functions are reduced to a number of typical actions in space: take-put, raise-lower, turn, move, etc. On the basis of such robots, it is possible to carry out the transportation of wires and cables to the assembly site and their orientation, and the built-in visual sensor devices, expanding the capabilities of the manipulator, allow for 100% control and sorting of products by appearance and dimensions, as well as to choose the desired part. Application industrial robots allows you to increase productivity by eliminating the influence of the "human factor" when performing an assembly operation.
Augmented reality glasses (Fig. 17), with the help of which digital information is entered into the observed reality using computer tools in real time, supplementing knowledge about the surrounding space or objects. The use of this technology opens up great opportunities for specialists in production. For example, a worker using such glasses can quickly receive information while being directly in front of the equipment and without occupying his hands.

The use of new technologies in production allows us to improve the organization of production, increases the efficiency of employees and the company's competitiveness in the market.

CAD systems significantly reduce the time for developing design and technological documentation, make it possible to mock up the position of the bundle in the product in 3D format, quickly perform changes in the design of the product and track the entire life cycle of the product, from the first sketch of the bundle to the final control stand.

Universal machines of the MultiStrip, EcoStrip, PowerStrip and MegaStrip series combine the functions of measuring cutting and stripping of wires and allow processing wires of various sections, while ensuring the processing of the inner cores of a multi-core cable.

Simple, cheap and beautiful to clean up the wires inside your electronic structure.
All you need is an empty soda bottle, scissors and a kettle. How to do this, read on.

When disassembling factory designs, everyone probably saw that the wires were tied into bundles.
In homemade designs, this is rare. It often happens that behind a heap of assorted wires, the boards and other elements of the circuit are barely visible. Often, such a pile of wires can also be seen inside the computer system unit, where wires from the PSU and signal buses fill the entire internal space and worsen the cooling of components, often a dangling wire stops one of the cooling fans, which leads to overheating and failure of expensive components.

Using the example of making a braid for wires of a computer PSU, I want to show how at home to quickly and cheaply tie the wires of your electronic structures into bundles, those who wish can thus put things in order in the wires inside their system unit.
So what do we need.

empty plastic bottle from soda. I used a poisonous green Mountain Dew bottle. This plastic glows brightly in ultraviolet light. To decorate the insides of the system unit with a window on the side surface and UV backlight lamps inside - it’s better not to think of it. For tying into a harness inside an amplifier or some other design, any bottle of the color you like is suitable.
We cut off the neck from the bottle and with scissors we cut a narrow tape about 3-5 mm wide in a spiral.

Then we tightly wrap the wiring harness with the resulting tape. To prevent the tape at the ends from untwisting, we fasten it with temporary wire ties. You can use nylon ties or pieces of heat shrink tubing. It is necessary to wind a coil to a coil, pulling as tightly as possible.

And now the most important thing. Surely everyone is aware that the plastic from which the bottles are made has pronounced heat-shrink properties. If you don’t know, then just try pouring boiling water over the bottle to see for yourself. After wrapping the wiring harness with a tape cut from a bottle, this tape must be warmed up. I used a hair dryer set to blow air at about 130c*. If the wiring harness has not yet been unsoldered, or you decide to ennoble the wires from the computer PSU in this way, then you can use the hot jet of steam coming from the spout of a boiling kettle. Only then do not forget to dry thoroughly from condensed moisture.

The rest of the photos were taken with UV light in a darkened room to make the braid stand out better.

After being treated with heat, the braid will shrink, tightly wrap around the wires and fix its shape, it will no longer try to unwind. The wire ties securing the ends of the tape can be removed. Wires in such a braid become rigid. They are easy to shape and hold well.

I hope that this simple cheap way will allow you to clean up the wires inside your electronic devices and may come in handy for someone to decorate the interior of your system unit or some other device that has transparent windows in its walls. Good luck!

Categories

Popular