DE19610586B4 - Printed circuit board and accurate placement and soldering of electronic components on the surface of the circuit board - Google Patents

Abstract

Surge arrester assembly, consisting from a printed circuit board (1) with electronic components (4, 5, 6) with cylindrical designs which are on the surface (10) the circuit board (1) in receptacles (2, 3) used and in particular using reflow soldering technology at connection surfaces (7) soldered are, characterized in that the positionally accurate assembly at least a cylindrical component (4) into the surface (12) the circuit board (1) of the outer contour the respective components (4) adapted recordings in the form of a to the long sides over the entire width of the printed circuit board (1) through groove (2) for a surge arrester (4) are incorporated, wherein the shape of the groove (2) the electronic Component (4) fixed in a precise position, wherein the inner surfaces (9) or margins (8) of the receptacles (2, 3) are partially edge metallized and several electrical connection surfaces (7) on both edges (8) for form the electronic components (4).

Description

The The invention relates to a printed circuit board for registering the same with electronic components on the surface of the circuit board, being the electronic components with a reflow soldering technique electrically conductive and stable to be connected. Especially should the invention trained PCB for the use in surge protection modules be used, being used as electronic components surge, PTC's, varistors and diodes are to be used.

It is known to pass the surge arrester a reflow soldering process on the circuit board and the other electronic Components, such as PTCs, Varistors and diodes as chip devices, using the conventional Contact clamping technology. There are problems with the positionally accurate Orientation of the overvoltage conductor on, when this at the assembly or during the soldering process not in the desired Position is held and so it may cause contact problems can come or in the further processing or assembly of the circuit board Difficulties may arise.

By the different procedures with which the different components are brought to the circuit board, are for contacting several operations required. There are also additional ones Contact sheets for the equipment the printed circuit board with the other components (PTC's and varistors) required, the material and manufacturing costs also increase.

At the Reflow soldering it is usual, on the circuit boards at locations that receive an electronic component are to apply according to solder material. After that is on the still pasty State located solder the respective component mounted and in Following this completely stocked PCB heated, until the solder melts and after cooling by the re-solidified Lotmaterial is held on the circuit board and electrically will be contacted.

As long as the solder material still no intimate connection of the electronic component with the circuit board, ie directly after the placement of the components, causes the respective electronic component can slip and so become the desired position. Since the reflow soldering process usually in Durchlauföfen, as for example from the DE 40 16 366 C2 are known to be carried out, in particular during transport of the pre-equipped printed circuit board precautions must be taken to prevent the slipping of the components from the desired position by the movement or vibration.

To prevent such slippage, for example, from the EP 0 540 497 A2 It is known to use a die which, however, can only dictate the surface shape of the solder applied to solder pads. However, a fixation of the component at least to a certain extent is not possible with this solution. The positioning is to be facilitated by the fact that the solder joints produced have a flat surface.

The use of an adhesive, with which components are to be mounted on a printed circuit board, goes out of the DE 41 26 913 A1 out. Here, the connection of the respective component is made with an adhesive on the circuit board. After that, the actual soldering process is performed and the complete connection is finally made. In addition to the additional required adhesive whose supply requires a corresponding increased effort in the PCB assembly, high demands are placed on the adhesive to be used. Since this is exposed to an increased temperature influence during the soldering process, it can lead to hazards caused by any solvent used in the adhesive.

From the DE 1 942 135 is a printed circuit previously known to be mounted on the electronic components, in this case, the electronic components are inserted into breakthroughs on a support plate. The components are in this case introduced and held with a slide fit in the breakthroughs. The adhesion and clamping between the printed circuit board and the component is therefore particularly dependent on the design of the device. Another disadvantage is the fact that the components protrude on the top and bottom of the circuit board and thus complicate the installation of the circuit board in a housing, since the circuit board rests flat on a housing side or arranged parallel to it in particular for small enclosures should.

Another circuit board is from the JP 02224293 known. The circuit board has a recessed portion which serves to receive the electronic component. A disadvantage of this arrangement is that the length and width of the recording must correspond exactly to the outer dimensions of the electronic component.

It is therefore an object of the invention to provide a printed circuit board, which makes it possible electroni in the simplest way to set up the components on the circuit board and position accurately. The recordings should be designed so that they are easy to manufacture in the production process in series production and also record different lengths of the components.

According to the invention this object is achieved by the features of claim 1.

In the surface a trained according to the invention Printed circuit board are areas that are designed so that they pretend indentations that in their contour at least partially the plane Outer contour of the respective electronic components, with which to equip the circuit board is, are adjusted. Here are preferably grooves in the surface of the PCB incorporated, in which the electronic components to be equipped can be fitted. The contours of the grooves are formed so that the respective electronic components with which the circuit board are populated should, by their appropriately adapted form in the desired Be held in position.

at the invention trained circuit board, it is possible to use all components in Set up a production step together in one operation and then finally assembled PCB by reflow soldering finish and fix the electronic components and establish the required electrical connection.

By in the surface the printed circuit board incorporated areas into which the electronic components are used, it is possible by the recessed arrangement, the total required height to reduce or when using thicker circuit boards one Enlargement the required height to avoid. The use of PCBs larger in their overall height also affects the higher heat resistance while of the soldering process positive. For example, be formed according to the invention PCBs equipped with surge arresters, determine these essentially the total required height, which, as already stated, not increased or even can be reduced. There are terminal strips or disconnectors known with two rows of insulation displacement contacts. At the insulation displacement contacts cable wires are connected. Will the populated printed circuit board as a protective plug used and plugged into a sash, so are the least two insulation displacement contacts of the first row through the protective plug covered. Due to the low height of the protective plug is ensured that the second row of insulation displacement contacts with plugged protective plug freely accessible and is connectable.

On the surface the circuit board are connections present, which can be connected to the electrodes of the surge arrester and communicate with the entire layout of the PCB.

When electronic components (PTC's, Varistors) can inexpensive Components are used in chip form, which has at least one solderable surface feature, wherein the contacting of the respective components within the circuit board via a preferred for this recording is used to run these elements. The location orientation the components should be conveniently perpendicular to the PCB during assembly done, with the actual solder joint on the front sides of the respective components towards the pads (PAD'S), in addition to the Groove are arranged takes place.

The trained for receiving the respective components in the circuit board incorporated areas are dimensioned so that the depth of the circuit board largely exploitable and thus the largest possible soldering surface achievable is.

to increase wetting ability of the components can the formed as a groove areas at least partially edge metallized be. Here is the metallized part of the recording of the components trained areas preferably formed metallized on the longitudinal surfaces. The metallization can, as for example, through-plated Holes is known, done by galvanic Aufmetallisieren.

In front the actual assembly the printed circuit board with the electronic components becomes the using solder paste for all Components preferably in one operation either by means of stencil printing or applied in the form of a dispensing procedure. This can be achieved Be sure that only those areas that are essential for making the connection are required with solder paste be provided and thereby despite a secure production of required connection between PCB and components no additional Post processing is required.

The inventively trained circuit board and the method according to the invention have over the The known solutions described at the outset further have the advantage that that the number of required items is reduced and in particular no additional contact surfaces more are needed.

One on the bottom of the PCB bringing film covers the circuit board in this direction and when using a suitable sheet material is a voltage-resistant design (contact protection) of the entire assembly of this page possible. On the underside of the circuit board can also be applied by means of a Dispensverfahrens an insulator, which also allows a voltage-resistant design. When using a printed circuit board designed according to the invention, the production can be positively influenced with respect to the costs, since the expense can be reduced in particular by the possibility of automation. Another advantage is that the reject rate is lowered, since the positioning accuracy can also be improved by simple measures and consequently corresponding errors can be avoided.

following the invention with reference to an embodiment described in detail become. Showing:

1 an inventively designed circuit board before assembly, and

2 a circuit board equipped with components 1 ,

In the 1 is a circuit board formed according to the invention 1 represented over different areas 2 . 3 features in the material of the circuit board 1 are incorporated. This is once a transverse groove 2 in the surface 12 the circuit board 1 incorporated, which is provided for receiving a surge arrester, not shown in this figure. The printed circuit board used 1 has in contrast to previously used printed circuit boards with a thickness of 0.8 mm a total thickness of 1.2 mm, so that in the circuit board 1 a groove 2 can be incorporated with a sufficient depth. The width of the groove 2 should be chosen taking into account their depth and the outer dimensions of the surge arrester, so that the surge arrester used solely by the shape of the groove 2 held in the desired position and even when moving through a continuous furnace, a displacement or dislocation is avoided.

In addition to the groove 2 are not part of the invention slot contours 3 in the surface of the circuit board 1 incorporated, in which other electronic Bauelemen te, which are also not visible in this presentation, can be recorded.

The incorporated areas (groove 2 , Slot contours 3 ) can, for example, by milling or punching in the manufacture of the circuit board 1 be formed.

The slot contours 3 are preferred only on the inner surfaces ( 9 ) metallized with pads ( 7 ) are provided electrically, for example, copper can be electrodeposited.

After this solder paste at the appropriate places in the area of the incorporated structures suitable process has been applied, the assembly with the various electronic components in automated Form and a single operation are performed.

The in the 2 illustrated circuit board 1 is with a surge arrester 4 that in the groove 2 is inserted, and two varistors 5 as well as two PTC's 6 in slit contours 3 are used, stocked. It can be seen that the components used 4 . 5 and 6 in their dimensions with the as a groove 2 or slot contours 3 trained areas in their sizing are coordinated so that only the shape of the areas 2 and 3 prevents movement and the electronic components 4 . 5 and 6 be kept accurate in the desired position. Be at least single of the areas that make up the incorporated areas 2 and 3 border, beveled, this affects the process of assembly of the circuit board 1 posi tive, because the threading of the components 4 . 5 and 6 is relieved.

The according to 2 equipped printed circuit board 1 can now be fed to a reflow soldering process to a stable connection of the components 4 . 5 and 6 with the circuit board 1 and it can also during the required movement of the assembled printed circuit board 1 a shifting of the components 4 . 5 and 6 be prevented.

The in the circuit board 1 incorporated grooves 2 and slot contours 3 additionally increase the strength of the compound produced by the soldering process, since by adapting the respective contours, taking into account the outer contours of the component used in each case, the shape used has an influence on the ultimate achievable strength of the compound.

1

circuit board

2

transverse groove

3

slot contour

4

Surge arresters

5

varistors

6

PTC's

7

pads

8th

margins

9

inner surfaces

10

bottom

11

surface

12

surface

Claims (1)

Surge arrester assembly consisting of a printed circuit board ( 1 ) with electronic components ( 4 . 5 . 6 ) with cylindrical shapes that are on the surface ( 10 ) of the printed circuit board ( 1 ) in recordings ( 2 . 3 ) and in particular by means of reflow soldering technology at connection surfaces ( 7 ) are soldered, characterized in that for the positionally accurate equipping of at least one cylindrical component ( 4 ), into the surface ( 12 ) of the printed circuit board ( 1 ) the outer contour of the respective components ( 4 ) adapted recordings in the form of one of the longitudinal sides over the entire width of the printed circuit board ( 1 ) continuous groove ( 2 ) for a surge arrester ( 4 ), wherein the shape of the groove ( 2 ) the electronic component ( 4 ) fixed in an exact position, wherein the inner surfaces ( 9 ) or margins ( 8th ) of the recordings ( 2 . 3 ) are partially metallized border and several electrical pads ( 7 ) on both edges ( 8th ) for the electronic components ( 4 ) form.