DE10260774B4 - soldering device - Google Patents

Abstract

contraption (1) for soldering of two stripped film cable ends (6, 7) with each other, wherein between the two to be connected foil cable ends (6, 7) a transverse to conductor tracks (16) extending Lotträgerband (5) is arranged, which for melting the solder material during the soldering is traversed by an electric current, characterized in that a measuring device (22) is provided, which is a thickness change (Δx) of a from the film cable ends (6,7) and the Lotträgerband (5) formed stack while the soldering process detected.

Description

The The invention relates to a device for soldering two stripped film cable ends, according to the generic term of claim 1.

in the Motor vehicle construction are becoming more and more popular Flat Laminated Cables (FLC), or generally Flat Flexible Cables (FFC) used. In the present invention, these become flat Laminated Cables, or Flat Flexible Cables referred to as a film cable, including a variety of parallel ribbon-like conductor tracks between two foil-like, insulating plastic sheaths understands. For the wiring of electrical components in motor vehicles due to the difficulty of connecting two foil cable ends often in length Pre-assembled foil cable used. Must be the length of the Foil cable but only slightly reduced become or become a longer one Foil cable needed, so must a secure and permanent connection of the two foil cable ends be created. Furthermore need for repair or expansion cases suitable joining techniques are developed.

crimps, as usual with round ladders are, can in film cables are used only conditionally, because of the small contact area on the one hand a very limited ampacity the result would be and second, the manual production of such crimp connections is problematic with foil cables. In addition, because of the vehicle-related Vibration the risk of interruption of contact due to additional fretting corrosion extraordinary big.

From the DE 100 50 798 C1 For example, a method of joining flat foil cables is known. Between the two foil cable ends, a metal strip tinned with a solder coating is placed across the conductor tracks. The foil cable ends are pressed against each other with the tinned metal strip lying between them, and then the electric current is applied to the metal strip, which heats the solder coating to the melting point and produces a connection with the conductor tracks of the foil cables. After the solder joint, the metal strip is severed in the spaces between two adjacent tracks and separated on the longitudinal sides protruding ends of the metal strip. This prevents that after the soldering the individual tracks of the film cable bridged in the transverse direction and thus be closed briefly. In the DE 100 50 798 C1 however, there are no indications as to how the status and quality of the soldering process can be monitored simply, safely and directly.

The present invention employs with the task a simple and technically reliable device for connecting two ends of the foil cable, with which the connection process monitors can be.

These The object is solved by the subject matter of the independent claim. Advantageous embodiments are the subject of the dependent Claims.

The invention is based on the general idea to develop a device for soldering two stripped film cable ends such that by a measuring device, the thickness change Δx one of the film cable ends 6 . 7 and the solder carrier tape 5 formed stack is detected during the soldering process. For this purpose, the stripped-foil ends are positioned in the soldering device together with the solder carrier strip and a flux, and pressed together. During the soldering process, the Lotüberzug the Lotträgerbandes melts and thereby reduces the thickness of the Lotträgerbandes or the entire arrangement, consisting of the two film cable ends and the intermediate Lotträgerband.

About the thickness change the stack or the Lotträgerbandes let yourself on the degree of fusion of the solder coating and thus on the progress or the end of the soldering process shut down. Based on experience too long a soldering process too much warming the foil cable ends and thus a smearing of the plastic sheath as well an uncontrolled flow of the solder, whereas in too short a soldering one for optimal solder required melting temperature of the solder coating is not reached. In both cases is an insufficient connection of the two film cable ends the Episode. That is why it is especially important to have the optimal duration of the soldering to determine.

in the Contrary to the previously known methods in which the end of the soldering process was not detectable by simple means, provides the solution according to the invention in This point represents a significant improvement in the process.

A particularly advantageous embodiment of the solution according to the invention is characterized in that the film cable ends to be connected are held during the soldering between two pressure plates, which approximate similar to the change in thickness during the soldering process, and that the at least one measuring device an An touched plate. During the soldering process, the electric current heating the solder carrier tape is increased at a constant rate, whereby the melting temperature of the solder coating is reached after some time. The onset of reaching the melting temperature decrease in the thickness of the Lotträgerbandes causes the operation of the proximity switch designed as measuring device, which then turns off the power and thus the heating energy. The solder coat solidifies and creates a firm connection of the two film cable ends due to the rapid solidification. Too strong or too weak heating of the Lotträgerbandes is thereby excluded, which has the consequence that the soldering process is carried out optimally.

Appropriately be provided that the Lotträgerband is formed of copper. Copper has excellent heat and electric conductivity and guaranteed thus a same temperature at different locations of the Lotträgerbandes and thus the degree of melting of the solder coating. At the same time, local overheating in the solder carrier tape avoided.

The Lotträgerband can be coated with a constantly thick layer of solder or with thicker lotan clusters in the area of the desired connection points. In the latter case arise larger and easier to measure thickness changes while of the soldering process. Also advantageous is an excess of solder, which a large-scale and stable solder guaranteed. Because by the Lotträgerband caused electrical short-circuit connections, so-called cross-shorts between already cut through adjacent copper interconnects of the film conductor Need to become, interferes Lotüberschuss not here.

A further advantageous embodiment of the inventive solution characterized in that for holding the Lotträgerbandes clamping jaws made of high-temperature materials with an oxide passivation layer, in particular made of high-alloy Crom nickel steel, are provided. Oxidpassivierte Crom-nickel jaws prevent a hard soldering of the solder carrier tape in the cheeks and at the same time due to the very low thermal conductivity a high outflow of heat in the clamping jaws, whereby one band over the entire solder carrier consistent and therefore cheap soldering temperature is reached.

Further important features and advantages of the invention will become apparent from the Dependent claims, from the drawings and the accompanying figure descriptions based on the drawings.

It it is understood that the above and the following yet to be explained features not only in the specified combination, but also in other combinations or alone, without to leave the scope of the present invention.

preferred embodiments The invention are illustrated in the drawings and in the following descriptions are explained in more detail, wherein the same reference numerals on the same or similar or functionally identical components relate.

there demonstrate:

1 an exploded view of two partially stripped film cable ends with Lotträgerband,

2 a view of a device according to the invention for soldering foil cable ends,

3 a diagram showing the decrease in the thickness of the Lotträgerbandes as a function of time during the soldering process,

4 a diagram illustrating the increase in the current as a function of time during the soldering process.

1 shows a first foil cable end 6 and a second foil cable end 7 which are to be soldered together. In the foil cable ends 6 and 7 are each a variety of ribbon-like conductor tracks 16 , of which three in each example 1 are shown arranged. For soldering the foil cable ends 6 . 7 they must overlap with their ends over a certain length L and be stripped on one side, so that in this overlap area, the tracks 16 with a free metallic surface of a surrounding plastic sheath 18 protrude. Before inserting the foil cable ends 6 . 7 in a soldering device 1 (see. 2 ) will end between the two foil cables to be connected 6 . 7 in the area of the overlap a Lotträgerband 5 inserted. The solder carrier tape 5 will be across the film cable ends 6 . 7 put it, so it's the tracks 16 crosses approximately at right angles and on the longitudinal sides of the film cable ends 6 . 7 survives.

According to 1 has the solder carrier tape 5 which is favorably formed of copper and thus has a high electrical or thermal conductivity, a local Lotauflage 17 on, the a complete Lotüberzug the Lotträgerbandes 5 either replace or strengthen locally. The distance of the local lot pad 17 corresponds to the transverse distance of the conductor tracks 16 in the respective Foli enkabelende 6 . 7 , The embodiment with consistently thick Vorbelotung the Lotträgerbandes 5 is processed in the same way.

After positioning the solder carrier tape 5 between the two foil cable ends 6 . 7 can these in the soldering device 1 (see. 2 ) be placed. Here are the tracks 16 gem. 2 arranged perpendicular to the image plane. According to 2 will be the two foil cable ends 6 . 7 and the intermediate Lotträgerband 5 through a pressure plate 10 against one below as a base plate 4 designated further pressure plate pressed and thereby in the soldering device 1 fixed. The two protruding ends of the Lotträgerbandes 5 are each via a power supply line 23 connected to a power source, not shown.

A pressure spring 3 , which are on the one hand on a crosshead 2 and on the other hand on the pressure plate 10 supports, generates the for fixing the two film cable ends 6 . 7 in the soldering device 1 necessary contact force. The pressure spring 3 is at one end in a holder 8th at the crosshead 2 while at the other end they sink into a depression 21 on the pressure plate 10 intervenes. The crosshead 2 is laterally over a first bracket 12 with an adjusting screw 11 on a second bracket 19 arranged, with the first bracket 12 in the area of the adjusting screw 11 a hole and the second bracket 19 in the area of the adjusting screw 11 has a slot, so that a distance of the crosshead 2 from the pressure plate 10 can be adjusted.

Each with a locking screw 20 are the two second hangers 19 at the base plate 4 screwed, wherein between the respective second brackets 19 and the base plate 4 an upper jaw 14 and a lower jaw 15 is arranged, which in each case a longitudinal end of the Lotträgebandes 5 fix. The two clamping jaws 14 . 15 Conveniently formed of high temperature materials with an oxide passivation layer, in particular of high-alloy chromium-nickel steel, thereby preventing a brazing the Lotträgerbandes 5 at the clamping jaws 14 . 15 , Between the second bracket 19 and the upper jaw 14 is also a plate spring 13 arranged the clamping action between the two clamping jaws 14 . 15 generated. The plate spring 13 Here is a quick release similar task, which allows the Lotträgerband 5 Quick to fix and quickly back out of the soldering device 1 to solve. Melt the solder pad 17 the Lotträgerbandes 5 in the region of the clamping jaws 14 . 15 , then make the disc springs 13 for tracking the upper clamping jaws 14 , This ensures a favorable electrical contact.

Essential to the invention is the arrangement of a measuring device 22 with at least one measuring device 9 , in particular a proximity switch 9 ' , between the crosshead 2 or the first bracket 12 and the pressure plate 10 , According to 2 There are two proximity switches 9 ' in the region of the lateral edges of the film cable ends to be joined together 6 . 7 or the pressure plate 10 arranged and over other power supply lines 24 connected to a power source, not shown. The at least one proximity switch 9 ' detects a thickness change Δx of the Lotträgerbandes 5 , The two proximity switches 9 ' work as an on / off switch upon reaching a defined change in position or threshold Δx = Δx _S. If they are connected in series, then it is ensured that the same path change has occurred on both sides or over the entire width of the foil cable stack. This takes into account the fact that the soldering process is not always homogeneous in time over the entire width.

According to 3 the time change of the thickness of the stack is shown. Referring to it shows 4 the temporal evolution of the current I, with which the Lotträgerband 5 is charged. In a first period A, the thickness x _{V of} the stack remains constant, whereas the current I increases from zero in proportion to the time. The transition between the first period A and a second period B marks the beginning of the decrease in the thickness x of the stack or the solder carrier tape 5 , At this time, the Lotträgerband has 5 Electric current flowing through it heats up so much that it acts as a local solder pad 17 , applied solder material begins to melt. With increasing current I in the second period B according to 4 an ever faster decrease of the thickness x occurs (cf. 3 ). At the time t _solder , a threshold value of the thickness change Δx = Δx _{S is} exceeded and thus the proximity _switch 9 ' operated, whereby the power cut is activated. The current I then drops to zero (see. 4 ).

The decrease in the thickness x of the stack according to 3 also progresses after the time t _solder until reaching the transition to a third period of time C. The transition between the period B and the period C marks the falling below the melting point and thus solidification of the solder material. The third period C is according to 3 characterized by a constant but compared to the period A significantly lower thickness x _{N of} the stack.

in the Below, the operation of the invention will be briefly described.

First, the two foil cable ends 6 . 7 according to 1 on an overlap length L unilaterally or both sides stripped, so that in this overlap area the tracks 16 with its free metallic surface from the plastic wrap 18 protrude. Before connecting the foil cable ends 6 . 7 between these in the area of the overlap L is a transverse to the interconnects 16 running Lotträgerband 5 inserted. In the sectional view according to 2 This results in a three-layer structure. The longitudinal ends of the Lotträgerbandes 5 are each between the upper and the lower clamping jaws 14 . 15 in the soldering device 1 clamped and each with a power supply line 23 coupled. The foil cable ends 6 and 7 and the intermediate Lotträgerband 5 be from the pressure plate 10 , to the base plate 4 pressed.

For soldering the tracks 16 becomes the solder carrier tape 5 with electric current, in particular alternating or direct current, applied, so that this heats up. The current can be at a constant rate, typically about 5 to 10 A / s (see. 4 ), increase. When the melting temperature is exceeded, the solder pad melts 17 and forms a solder connection between the tracks 16 of the first foil cable end 6 and the second foil cable end 7 , The flow of the solder pad 17 goes with a decrease in the thickness x of the Lotträgerbandes 5 associated.

If the decrease in the thickness x of the stack exceeds a predetermined threshold value Δx = Δx _S , then the proximity switch is used 9 ' , which in principle can also be designed as an inductive pickup, and which detects the thickness change Δx of the stack during the soldering process, the Lotträgerband 5 flowing current switched off. This time is according to 3 or 4 is referred to as t _solder . The proximity switch 9 ' thus monitors the soldering process and determined by the thickness-dependent switching off of the current switching off the power supply and thus the end of the soldering process. Too long or too short heating of the solder carrier tape 5 and an associated bad solder joint is thereby avoided. The change in thickness in area B according to 3 takes place in a relatively narrow time window, so that the distance measurement with the proximity switches 9 ' sufficient.

In summary, the essential features of the invention can be characterized as follows:
For soldering the two foil cable ends 6 and 7 they must overlap on one or both sides stripped. Between the foil cable ends to be connected 6 . 7 becomes a Lotträgerband in the overlay area 5 transverse to the tracks 16 inserted.

The two foil cable ends 6 . 7 and the intermediate Lotträgerband 5 be through a pressure plate 10 against a base plate 4 pressed and thereby in the soldering device 1 fixed. The two protruding ends of the Lotträgerbandes 5 each to a power supply line 23 connected.

Between the crosshead 2 or the first bracket 12 and the pressure plate 10 is at least a measuring device 22 , in particular a proximity switch 9 ' arranged, which measures the thickness change Δx of the stack and shuts off the heating current when a threshold value is exceeded. This monitors the soldering process and achieves an optimal solder joint.

Claims (14)

Contraption ( 1 ) for soldering two stripped foil cable ends ( 6 . 7 ), wherein between the two to be connected foil cable ends ( 6 . 7 ) a transverse to tracks ( 16 ) running Lotträgerband ( 5 ), which is traversed by an electric current for melting the solder material during the soldering process, characterized in that a measuring device ( 22 ), which is a change in thickness (.DELTA.x) of one of the film cable ends ( 6 . 7 ) and the solder carrier tape ( 5 ) detected during the soldering process. Apparatus according to claim 1, characterized in that the measuring device ( 22 ) detects the change in thickness (Δx) at different areas of the stack. Apparatus according to claim 2, characterized in that the measuring device ( 22 ) the change in thickness (Δx) in the region of both side edges of the film cable ends to be joined together ( 6 . 7 ) detected. Device according to one of claims 1 to 3, characterized in that the measuring device ( 22 ) at least one measuring device ( 9 ) for detecting the change in thickness (Δx). Apparatus according to claim 4, characterized in that the at least one measuring element ( 9 ) generates a switching signal for switching off the electric current when detecting a threshold value (Δx _S ) of the thickness change (Δx). Device according to one of claims 4 or 5, characterized in that the at least one measuring element ( 9 ) as a proximity switch ( 9 ' ) is trained. Apparatus according to claim 6, characterized ge indicates that the proximity switch ( 9 '' ) is designed as an inductive pickup. Device according to one of claims 6 or 7, characterized in that a plurality of proximity switches ( 9 ' ) are electrically connected in series. Device according to one of claims 6 to 8, characterized in that the generation of the switching signal from one to at least one proximity switch ( 9 ' ) Dependent electrical voltage is dependent. Device according to one of claims 4 to 9, characterized in that - the film cable ends to be connected ( 6 . 7 ) during the soldering process between two pressure plates ( 4 . 10 ), which approach each other analogously to the change in thickness (Δx) during the soldering operation, and - that the at least one measuring element ( 9 ) a pressure plate ( 10 ). Device according to one of the preceding claims, characterized in that the solder carrier tape ( 5 ) is formed of copper. Device according to one of the preceding claims, characterized in that the solder material substantially only at such areas of the Lotträgerbandes ( 5 ) is arranged, which during the soldering process between to be soldered interconnects ( 16 ) lie. Device according to one of the preceding claims, characterized in that for holding the Lotträgerbandes ( 5 ) Clamping jaws ( 14 . 15 ) are provided from high-temperature materials with an oxide passivating layer, in particular of high-alloy Crom-nickel steel. Device according to one of the preceding claims, characterized in that the electrical current strength (I) during the soldering process starting from zero, in particular uniformly, is increased until a time t _solder and then falls back to zero.