EP0228119A1 - Centering device for the realization of the pin insertion of a multipin case - Google Patents

Abstract

Centering device for the pinout of a multispindle housing, housing intended to receive an integrated circuit board, and the pins of which have the shape of a rod provided with a flat head, the rod passing through a flat part called the support of the housing in previously metallized holes and protruding from one of the faces of the support of a length sufficient to ensure the fixing of the housing, and the flat head bearing on the other face of the support by means of a metal preform made of an alloy suitable for fixing the pins by fusion, this centering device being characterized in that it consists of three parts, the first part being formed of a first metal plate, the second part being formed of a second metal plate serving as a gauge for centering the pins pierced with holes arranged in a geometric pattern conforming to the pattern chosen for the arrangement of the pins on the housing and calibrated so as to secure both the retention and the centering of the rods in the holes of the housing, and the third part consisting of a clamping device for locking the support of the housing provided with its pins on the first metal plate, and in this that the materials chosen to make the first plate have a coefficient of expansion close to that of the housing support in the temperature range where the pins are fixed, this first metal plate on which the housing support is blocked during the fixing of the pins, being only brought to this fixing temperature.

Description

The invention relates to a centering device for carrying out the pinout of a multispindle housing, housing intended to receive an integrated circuit board, and the pins of which have the shape of a rod provided with a flat head, the rod passing through a flat part called the support of the housing in previously metallized holes and protruding from one of the faces of the support of a length sufficient to ensure the fixing of the housing, and the flat head bearing on the other face of the support via of a metallic form in an alloy suitable for ensuring by fusion the fixing of the pins.

The invention also relates to the method for producing such a housing by means of this device.

A multispindle housing of this type is described in European patent application EP 188 838 published on July 30, 1986. However, the pin centering devices used to date, and moreover not described in the cited document, present many disadvantages.

These centering devices known to those skilled in the art are graphite dies, pierced with holes calibrated to the diameter of the pin rods, and distributed according to the geometrical arrangement provided for these pins. These centering devices are each subject to a housing during the fixing operation of the pins and are therefore subjected, together with the housings, to the high temperatures necessary for this fixing. Consequently, the repetition of these operations renders this kind of centering device quickly out of use. These known centering devices can only be used a very small number of times.

It is obvious that this characteristic makes the preparatory work for the manufacture of a series of very long housings, since it is necessary to prepare beforehand a series of a large number of dies, which must be produced with precision, and which must be renewed frequently. This preparation is therefore expensive in terms of raw material and working hours.

The use of such pin centering devices partly explains the extremely high cost of multispindle housings to date.

However, multispindle type housings, by which we mean having at least 300 or 400 pins, are expected to take a big development in the near future.

This is why the present invention provides a device as defined in the preamble, which overcomes these drawbacks.

According to the present invention, this device is characterized in that it consists of three parts, the first part being formed of a first metal plate, the second part being formed of a second metal plate serving as a gauge for centering the drilled pins. of holes arranged in a geometric pattern conforming to the pattern chosen for the arrangement of the pins on the housing and calibrated so as to both maintain and center the rods in the holes in the housing, and the third part consisting of a clamping device for blocking the support of the housing provided with its pins on the first metal plate, and in that the materials chosen to produce the first plate have a coefficient of expansion close to that of the support of the housing in the temperature range where the pins are fixed, this first metal plate on which the housing support is blocked during the fixing of the pitchers hes, being alone brought to this fixing temperature.

Among other things, such a device provides the following advantages:
It is unique for a whole series of manufactured cases, that is to say reusable a large number of times, because the part which is produced with precision and which serves as a gauge for centering the pins, is not worn at high temperatures at the same time as the case during the spindle fixing operation. Only a simple metal plate without precision accompanies the case during this operation.

This device therefore makes the manufacture of the boxes much less expensive. On the other hand, the pins of the housings produced using this device have particularly good mechanical resistance to tearing.

The invention will be better understood using the following description illustrated by the appended figures, of which:
- Figure 1a which shows in simplified section a part of the multispindle housing before the introduction of the pins;
- Figure 1b which shows, in simplified section, a part of a multispindle housing provided with its pins;
- Figure 2a which shows, in a position remote from the housing, the centering device according to the invention;
- Figure 2b which shows, in the centering position of the pins, the centering device according to the invention;
- Figure 2c which shows in the fixing position of the pins, the centering device according to the invention.
- Figures 3 which show in detail, the clamping device of the housing on the first plate of the device according to the invention, Figure 3a being a side view, Figure 3b being a sectional view perpendicular to the view of Figure 3a, and FIG. 3c being a top view which shows the relative positions of a locking device and the two plates forming the centering device.

As shown in Figure 1a, in section simplified, the multispindle housing mainly consists of a support 120 plane, the two faces of which bear the references 121 and 122. This support is pierced with holes 3 intended to receive the pins. Each hole is metallized prior to the positioning of the pins, by metallization 13 supplemented by an annular metallization 11 on the face 121 and 12 on the face 122. By means of the annular metallizations 11, the metallizations of the holes, and therefore subsequently the pins are connected to a circuit 110 which may be multilayer. Zone 31 is intended to receive the integrated circuit board.

FIG. 1b shows, in simplified section, a part of the housing, provided with its pins, as obtained by means of the production method using the centering device according to the invention.

This finished housing includes an integrated circuit board 130 whose output pads are connected to the circuit 110 for example by flexible wires 6, and which is protected for example by the cover 141.

This housing further comprises pins 5 formed of a rod 2 and a flat head 1. These pins are made tear-off because the flat head 1 of the pins bears on the face 122 of the support 120, and because the pins are fixed by a metallic compound filling the gap 23 between the pins and the walls of the metallized holes, until forming the fillets 21 and 22.

It is therefore essential to hold the pins of the housing by a centering device, when fixing them in the holes, in order to obtain a good distribution of the metallic fixing compound in the interval 23.

For a housing whose support 120 is made of ceramic, the centering device known to date for those skilled in the art generally consists of a graphite plate pierced with calibrated holes. Graphite has the property of being easily machinable and of a moderate price. But this material has a coefficient of expansion which is not best suited to that of ceramic in the temperature range where the pins are fixed. However, it is brought to the high temperature of the metal compound used for fixing the pins, at the same time as the housing. Under these conditions, it is quickly rendered unusable by thermal and mechanical degradation: it crumbles after a very small number of uses.

The present invention, on the contrary, proposes a centering device which can be reused a large number of times, and which can therefore be used in the manufacture of a large number of housings.

As shown in Figure 2a, in a position remote from the housing, this centering device comprises three parts. The first part is formed by a first metal plate 100. The second part is formed by a second metal plate 101 serving as a gauge for centering the pins, pierced with holes 103 arranged in a geometric pattern conforming to the pattern chosen for the arrangement of the pins on the housing. These holes 103 are calibrated so as to ensure both the maintenance and the centering of the rods 2 in the holes 3 of the housing. The third part is intended to block the housing 120 on the first metal plate 100, once the pins have been centered by means of the caliber 101.

This locking device is shown in detail in Figures 3a and 3b. On the one hand, it comprises at least two strips 51 of thickness less than the distance between two pins. These strips are integral with a backsplash 52 which maintains their spacing. This spacing must correspond to an interval between a certain number of pins. The slats 51 are mounted on the backsplash 52, mutually parallel and perpendicular to the backsplash. They can slide in the grooves 61 of a fixed terminal 60 (Figure 3a).

The blocking device further comprises, integral with the first metal plate 100, a stirrup 53 fixed by the lugs 48, made of a material which is both refractory to the fixing temperatures of the pins and capable of possessing at these temperatures elastic properties suitable for the upper part 54 of this stirrup constitutes, at these same temperatures, a spring. This material may for example be bronze-beryllium. In the upper part 54 of this stirrup, turns a screw 55 which drives a plate 56 (FIG. 3b) parallel to the upper part 54 of the stirrup. The stirrup and the plate 56 form a system known as the "Mohr clamp". The material intended to produce the slats 51, the backsplash 52 and the plate 56 is chosen from any material whose sole property is to be refractory to the fixing temperatures of the pins. The position of the plate 56 and the dimensions of the bracket 53 are such that the strips 51 can be easily slid under the plate 56 perpendicular to the plane of the first plate 100 on which the bracket is fixed.

At least two of these blocking devices will be necessary to block the support 120 on the first plate 100, during the operation of fixing the pins. To this end, these two locking devices will be arranged on two opposite parallel sides of the support 120.

If the support 120 of the multi-spindle housing is made of ceramic, the metallic material from which the first plate 100 of the centering device is made, must have a coefficient of expansion compatible with ceramic in the temperature range where the support is carried to ensure the fusion of the metallic compound for fixing in the gap 23 between the pins and the walls of the metallized holes of the support 120. In fact, it is this single plate 100 which will be brought to the fixing temperatures of the pins at the same time as the housing 120.

In the case of a ceramic support 120, it can be advantageously chosen to carry out metallization holes using a screen-conductive copper conductive compound under a non-oxidizing atmosphere, for example the compound known from French patent application FR-2 305 478 or FR-2 437 427.

These compounds admit a cooking temperature under nitrogen of between 850 ° C. and 950 ° C. and a very good electrical conductivity of the order of 1.5 milliohms per square for layers of thickness 20 / μm (20 microns).

The screen-printing ink intended for the metallization of the holes 3 is diffused in the holes for example by suction so as to coat the walls of the hole, then it undergoes baking. Crowns 11 and 12 are produced during the same operation, around the holes 3, on each of the faces 121 and 122 of the substrate 120, respectively. This technique is described for example in French patent application FR-85 05 262.

On the other hand, for this application, an advantageous metal for forming the pins is for example iron-nickel-cobalt.

Finally the study of the expansion coefficients of ceramics in the range of temperatures between 750 ° C and 850 ° C shows that materials such as molybdenum, or iron-nickel-cobalt alloys have perfectly adapted expansion coefficients to that of ceramics in this temperature range. These materials will therefore be perfectly suitable for constituting the first plate 100 of the centering device according to the invention.

It can then be chosen to fix the pins and fill the gap 23, for example a silver alloy (≃ 71%), copper (≃28%), nickel (≃ 1% by weight) which has a temperature range between solidus and liquidus between 780 ° C and 795 ° C allowing an uncritical melting cycle.

For this purpose an annular preform 14 of this ternary compound (or any other compound chosen for fixing the pins) can be made, and arranged on the face 122 of the support 120 between the flat head 1 of the pin to be fixed and the annular metallization 12.

The pins 5 and the annular preforms 14 being put in place, the plate 101 is threaded onto the rods 2 while the plate 100 keeps the flat heads 1 applied against the preforms 14 and the surface 122 of the support 120.

The centering device is then locked in this position by the clamping devices as shown in Figures 3a, 3b and 3c.

For each of the at least two locking devices, the lamella 51 are abrod slid, perpendicular to the plane of the first plate 100, in the guide slots 61, of the terminal 60 fixed to the plate 100 (Figure 3a).

Then, the strips 51 are then slid, perpendicular to the plane of the first plate 100, under the plate 56 of the Mohr forceps, the screw 55 having been released to allow their passage (Figure 3b).

The strips 51 are finally slid between two pins in slots 102 provided in the second plate 101. These slots have on the one hand an opening sufficient to allow the strips 51 to penetrate and on the other hand are spaced apart by the same distance as the distance for fixing the slats on the backsplashes 52 (Figure 3c).

The screw 55 is then tightened. The plate 100 therefore blocks the pins, by pressing on their flat head 1, exactly in the position where they have been centered by the second so-called calibration plate 101 (FIG. 2b).

Said plate 101 can then be removed. And only the assembly formed by the plate 100, the support 120 provided with pins and preforms 14, blocked together by the refractory clamping device, is brought to the melting temperature of the fixing alloy which composes the preforms 14 ( Figure 2c).

To obtain a good distribution of the fixing component of the pins, in the intervals 23, the assembly formed of the centering device-housing support must be such that the plate 100, the preforms 14 and the flat heads 1 are in a lower position. relative to the intervals 23, to the support 120 and to the rods 2.

 In fact, when the fixing compound of the pins is brought to its melting temperature, the preforms 14 melt and the fixing compound "rises" in the intervals 23, by capillarity.

• a) enfilage des broches 5 dans les trous mé­tallisés 3 du support 120, la tête plate 1 des broches s'ap­puyant sur la surface 122 de ce support munie des métallisa­tions annulaires 12 et des préformes annulaires 14 du composé de fixation ;
• b) maintien des têtes plates 1 à l'aide de la plaque 100 du dispositif ;
• c) enfilage des tiges 2 dans les trous 103 de la plaque 101 du dispositif afin d'assurer leur centrage ;
• d) fixation du boîtier 120 centré sur la pla­que 100 au moyen du dispositif de serrage ;
• e) enlèvement de la plaque 101 qui est mise de côté ;
• f) passage de l'ensemble boîtier-plaque 100 bloqué, à la température propre à assurer la fusion des pré­formes 14 ;
• g) refroidissement, démontage et récupération de la plaque 100 pour une utilisation ultérieure.

The method using the centering device according to the invention therefore comprises the steps of:

• a) threading of the pins 5 into the metallized holes 3 of the support 120, the flat head 1 of the pins resting on the surface 122 of this support provided with annular metallizations 12 and annular preforms 14 of the fixing compound;
• b) holding the flat heads 1 using the plate 100 of the device;
• c) threading the rods 2 into the holes 103 of the plate 101 of the device in order to ensure their centering;
• d) fixing of the housing 120 centered on the plate 100 by means of the clamping device;
• e) removing the plate 101 which is set aside;
• f) passage of the blocked housing-plate 100 assembly, at the temperature suitable for ensuring the fusion of the preforms 14;
• g) cooling, dismantling and recovery of the plate 100 for later use.

In the centering device according to the invention, it is clear that only the plate 101 is fragile because it is produced with the precision necessary for centering the pins. This plate will be used for a long time because it is used exclusively for positioning and centering pins, and is never brought to the melting temperatures of the fixing alloy. It therefore has no opportunity to be damaged. On the other hand, the plate 101 which undergoes temperature rises is not very fragile. It will therefore not be easily deteriorated and will also make long use.

The boxes produced in accordance with the invention are therefore of reduced cost since the centering device is recoverable and the broaching process is simplified. On the other hand these boxes are very solid since the pins are tear-away.

Claims (7)

1. Centering device for carrying out the pinout of a multispindle box, box intended to receive an integrated circuit board, and the pins of which have the shape of a rod provided with a flat head, the rod passing through a flat part said support for the housing in previously metallized holes and protruding from one of the faces of the support of a length sufficient to ensure the fixing of the housing, and the flat head bearing on the other face of the support by means of a metal preform of an alloy suitable for ensuring the fixing of the pins by fusion, this centering device being characterized in that it consists of three parts, the first part being formed of a first metal plate, the second part being formed of '' a second metal plate serving as a gauge for centering the pins pierced with holes arranged in a geometric pattern conforming to the pattern chosen for the arrangement of the pins on the housing and calibrated so as to ensure both the maintenance and the centering of the rods in the holes of the housing, and the third part consisting of a clamping device for locking the support of the housing provided with its pins on the first metal plate, and in that the materials chosen to make the first plate have a coefficient of expansion close to that of the housing support in the temperature range where the pins are fixed, this first metal plate on which the housing support is blocked during the fixing pins, being only brought to this fixing temperature. 2. Centering device according to claim 1, characterized in that the clamping device for blocking the support of the housing on the first metal plate consists of: a) at least two parallel strips of thickness less than the distance between two pins, integral with a backsplash maintaining their spacing at an interval corresponding to the distance between several pins and being able to slide, perpendicular to the first metal plate, in grooves made in a fixed terminal subject to this first metal plate; b) a stirrup secured to this first metal plate, placed between the fixed terminal and the pad of the first plate occupied by the housing support, and made of a refractory material having elastic properties at the temperature of fixing of the pins; c) a screw, rotating in the upper part of the stirrup, which drives a plate parallel to the upper part of the stirrup;
the position of the plate and the dimensions of the bracket being such that the end of the strips can slide under the plate so that it can be brought into position above the housing support between pins, thanks to slots the distance of which is the same as that of the slats and which are formed in the second plate, and characterized in that the blocking is obtained by tightening the screw. 3. Centering device according to claim 2, characterized in that the clamp of the clamping device is made of beryllium bronze. 4. Centering device according to claims 1 to 3, characterized in that it comprises at least two clamping devices placed on either side of the housing support on parallel sides. 5. Centering device according to claims 1 to 4 characterized in that it is provided for making the broaching of a housing having a ceramic support, in that the materials intended to produce the first plate are chosen from molybdenum and iron-nickel-cobalt alloys, the fixing of the pins being made using a metallic compound whose melting temperature is of the order of 800 ° C. 6. Method of production using a centering device according to one of claims 1 to 5, characterized in that it comprises the steps of: a) threading of the pins into the metallized holes of the support, the flat head of the pins resting on the so-called lower surface of this support provided with annular metallizations and annular preforms of the metallic fixing compound; b) holding the flat heads using the first plate of the device; c) threading the rods into the holes of the second plate of the device in order to ensure their centering; d) fixing of the housing centered on the first plate by means of the clamping devices; e) removal of the second plate which is set aside; f) passage of the unit-blocked first plate assembly, at the temperature suitable for ensuring the melting of the metallic fixing preform; g) cooling, dismantling and recovery of the first plate for later use. 7. Production method according to claim 6 insofar as the latter depends on claim 5, characterized in that the pins are formed from an iron-nickel-cobalt alloy, and in that the annular preforms forming the metallic compound of fixing are made of a ternary silver-copper-nickel alloy in the weight proportions of approximately 71%, 28% and 1% respectively, the melting temperature of which is of the order of 800 ° C.

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