CH709630B1 - Method and apparatus for focusing a viscous medium dispensed from a dispensing opening of a dispenser of a jet device. - Google Patents

Abstract

The invention relates to a method for focusing a viscous medium dispensed from an output opening (3) of an output device (2) of a jet device (1), at least one gas flow (11) between the dispensing of the viscous medium and the impact of the viscous medium a substrate (4) is directed to the viscous medium, wherein the viscous medium is focused by means of the gas stream (11). Furthermore, the invention comprises an apparatus for carrying out this method.

Description

description

PRIOR ART The invention is based on a method and a device for focusing a viscous medium dispensed from a dispensing opening of a jet device as generically defined in the independent claims.

For the contactless dosing of drops of a viscous medium, such as an adhesive or a solder, on a substrate jetting is known. An apparatus and a method for jetting drops are known, for example, from WO 1999/064 167 A1. Herein, the viscous medium is in an output chamber and is jetted from a dispensing valve by a rapid reduction in the volume of that dispensing chamber.

Disclosure of the invention

ADVANTAGES OF THE INVENTION The method according to the invention for focusing a viscous medium dispensed from a dispensing opening of a jet device offers the advantage that the shape and / or the direction of the viscous medium can be influenced. In this way, for example, it can be influenced which shape the viscous medium has after striking a substrate.

This advantage is achieved according to claim 1 by a method for focusing a viscous medium dispensed from a dispensing opening of a dispenser of a jet device, wherein at least one gas flow is between dispensing the viscous medium and impinging the viscous medium on a substrate the viscous medium is directed, whereby the viscous medium is focused by means of the gas flow.

Another advantage of the inventive method is that so-called satellites, which may be present as unwanted secondary drops in addition to a main drop of the viscous medium after the dispensing of the viscous medium, can be directed by the directed to the viscous medium gas stream into the main drops and thus preventing the side drops or satellites from striking undesired locations on the substrate.

According to the invention, the viscous medium is focused by means of the gas flow. Focusing is to be understood here as meaning that a diameter of the viscous medium in at least one direction when hitting the substrate is reduced compared to the diameter without focusing. Thus, it is advantageously made possible by the inventive method to achieve particularly small structures in jetting.

The measures listed in the dependent claims advantageous refinements and improvements of the independent claim 1 specified method for focusing a dispensed from a dispensing opening of a jet device viscous medium are possible.

It when the discharge opening is detected by the gas stream is particularly advantageous. In this way, the gas stream can be used at the same time for cleaning the dispensing opening, for example, from residues of the viscous medium which have remained at the dispensing opening.

Also, the fact that the discharge opening is detected by the gas flow, can be achieved that even during the output process, a satellite formation is suppressed because secondary drops that would form during the tearing off of the viscous medium from the discharge opening, remain directly in the main drop ,

Alternatively, it is also particularly advantageous if the discharge opening is not detected by the gas flow. In this case, a particularly accurate manipulation of the shape of the viscous medium by means of the gas flow is possible, since not by impingement of the gas flow on the discharge opening turbulence or similar disturbances arise.

In this case, moreover, the impact of the gas stream on the viscous medium can take place deliberately only shortly above or in the region of the impact of the viscous medium on the target location on a substrate. As a result, the shape and the diameter of the viscous medium, which has this after hitting the substrate, can be adjusted very precisely.

In an advantageous embodiment of the inventive method, the gas stream consists of several partial gas streams. As a result, a particularly accurate manipulation of the shape and the direction of the viscous medium is possible. Furthermore, as a result of this, molds that are different from a round shape of the viscous medium after impinging on the substrate can be adjusted in a particularly simple manner, such as, for example, an oval or line-like shape.

In an advantageous embodiment of the inventive method, the gas stream rotates around the viscous medium. In this way can be achieved with a correspondingly fast rotation of the gas stream to the viscous medium that with only a gas stream by rotating around the viscous medium, for example, satellites that can arise in all directions around the viscous medium in the main drops of the viscous medium ,

Characterized in that when rotating the gas stream to the viscous medium, only one gas stream can be used, it can be achieved that the gas at the same flow rate of the gas supplied compared with arrangements with multiple gas streams is brought to a particularly high speed. Accordingly, a further advantage of this arrangement is that in this case it is not necessary to divide the gas stream into a plurality of partial gas streams, which would then have a correspondingly lower flow velocity.

It when the gas stream passes before striking the gas stream to the viscous medium at least one gas outlet of a nozzle device is particularly advantageous. Through the nozzle device or the gas outlets of the nozzle device, the direction and the shape of the gas stream can be adjusted in a particularly targeted manner.

The nozzle device may further comprise an opening for the viscous medium. This has the advantage that the nozzle device can be attached directly to or in the vicinity of the dispensing opening of the jet device, without the nozzle device being in the way of the viscous medium.

It is particularly advantageous if the gas stream is divided by a plurality of gas outlets located in the nozzle device into a plurality of partial gas streams. This ensures that not several devices are required for generating a gas stream, but only a device for generating a gas stream, which is then divided by the nozzle into a plurality of partial gas streams.

A way to be realized with particularly simple means to put the gas stream or the partial gas streams in a rotation around the viscous medium, in the event that the nozzle device has an opening for the viscous medium, achieved in that the nozzle device rotated around the opening for the viscous medium.

The device according to the invention for focusing a viscous medium dispensed from a dispensing opening of a jet device with means for producing a gas flow directed onto the viscous medium also has the advantages listed above.

embodiment

Drawings Exemplary embodiments of the invention are illustrated in the drawings and are explained in more detail below. It shows:

Fig. 1 is a view of a cross section of a dispensing device for a viscous medium of a jet device with a device for carrying out the inventive method.

Fig. 2 cross sections of nozzle devices with different geometries.

DESCRIPTION OF THE EXEMPLARY EMBODIMENT FIG. 1 shows a detail of a jet device 1. The jet device 1 has an output device 2 for dispensing the viscous medium, for example in the form of a jet valve, a jet needle or a jet nozzle. In particular, this may be a plunger valve, a resonance pressure valve or an aerosol jet valve.

The invention will be described below without limitation of generality with reference to a jet valve as the output device 2.

The viscous medium is discharged from a discharge port 3 of the dispenser 2. Typical diameters of the dispensing opening 3 of the dispenser 2 are in the range between 50 and 4000 microns.

The viscous medium may be, for example, a fixing adhesive or a conductive adhesive. For example, silver conductive adhesives, such as, for example, the commercially available PC3001 from Heraeus or Ablebond 84-1 LMI SR4 from Henkel, are used as conductive adhesives.

The viscous medium is dispensed in the form of drops from the discharge port 3 of the jet valve and, after a flight phase, impinges on a substrate 4.

Depending on the shape of the discharge opening 3 and depending on whether the substrate 4 remains static or is moved, different geometries of the viscous medium at the point of impact on the substrate 4 are adjustable. For example, it is conceivable to use dispensing devices 2 with one or more dispensing openings 3.

Furthermore, it can be seen from FIG. 1 that a device 5 for focusing the viscous medium dispensed from the discharge opening 3 of the jet device 1 is attached to the jet valve. The attachment to the jet valve is preferably carried out via a Schraubklemmverbindung 6 on the jet valve.

However, there are also conceivable structures in which the device 5 is not firmly attached to the focusing of the viscous medium to the jet valve. For example, the device 5 for focusing the viscous medium may be rotatably mounted around the jet valve by ball bearings mounted on the jet valve. This can be realized, for example, in that 5 ball bearings are mounted on the device according to the invention, which are received by a flange, which in turn can be attached to the output device 2. It is also possible that the device 5 for focusing the viscous medium is not mounted on the jet valve, but separate from it.

Furthermore, it can be seen from FIG. 1 that the device 5 for focusing the viscous medium preferably comprises a nozzle device 7. In this embodiment, the nozzle device 7 on two continuous gas outlets 9. The gas outlets 9 serve to supply gas in the direction of the medium discharged from the jet valve.

The gas can be passed directly through the gas outlets 9 or by means of introduced into the gas outlets 9 focusing nozzles 10. The latter is the case in the embodiment shown in Fig. 1. On the side facing away from the substrate 4, the focusing nozzles 10 are connected to the gas supply. Alternatively, the gas supply can also be attached directly to the gas outlet 9. For example, by a conical inlet of the gas outlets 9 or the Fokussierdüsen 10, the gas stream 11 can be additionally accelerated.

The gas can be made available via a home network or, for example, via a gas cylinder and, for example, via a hose system to the gas outlet 9 or the focusing nozzle 10. This is not shown in Fig. 1. Suitable gases are, for example inert gases such. As nitrogen or alternatively, for example, air.

From the discharge port 3 of the dispenser 2 of the jet apparatus 1, the viscous medium is discharged. This is done in the form of a main drop, from which undesirable secondary drops can split off. The main drop and the sub-drops fly from the discharge opening 3 of the jet apparatus 1 toward the destination on the substrate 4.

By means of the device 5 for focusing the output medium, a gas stream 11 or in the embodiment shown in FIG. 1, two partial gas streams 12, 13 are generated, which in the direction of the jet axis 14, ie the connecting line between the output port. 3 the jet device 1 and the impact location of the viscous medium on the substrate 4, are directed.

This is achieved by the gas passages in the nozzle device 7 and the focusing nozzles 10, which lead through the nozzle device 7, are inclined at an angle to the jet axis 14. This angle is preferably less than 45 ° and preferably greater than 3 °. Through the gas passages 9 and the opening of the focusing nozzles 10, a laminar gas flow 11 is preferably generated.

During the flight of the viscous medium or of the main droplet, the gas stream 11 meets or, in this case, the two partial gas streams 12, 13 strike the viscous medium. As a result, the secondary drops are directed into the main drops.

Furthermore, the main drop is compressed by the gas flow 11, so focused so that it impinges with a smaller diameter at its destination on the substrate 4, as would have been the case if no gas flow 11 had been directed to him.

It is not only conceivable that the focusing of the main drop is uniform from all directions to achieve a round shape of the drop after hitting the substrate 4. The focusing can take place to different degrees, for example by the arrangement of the gas outlets 9 also from different directions, so that a deviating from a round shape geometry of the drop on the substrate 4 sets.

By means of the arrangement shown in Fig. 1, the drop is brought, for example, in a form which is formed perpendicular to the plane of the paper oblong. A focusing directed at the paper level does not take place here. If, as in this embodiment, the focus of the drop is not made equally from all directions, the drop can thus even have a larger diameter when hitting the substrate 4 in the directions in which no focusing takes place, as is the case would have been if no gas flow 11 had been directed at him.

Typical flow rates for the gas stream 11 are between 20 and 200 cm 3 / min of the gas or air used for the gas stream 11.

The nozzle device 7 shown in Fig. 1 may be configured in different geometries. For example, it may have two, three or four gas outlets 9. Examples of geometries of the nozzle device 7 are shown in FIG.

Fig. 2a shows a cross section of the nozzle device 7, as in the structure shown in Fig. 1 verwen is used. In the middle is the opening 8 for the viscous medium. The two further openings are the two gas outlets 9.

Fig. 2b shows a cross section of a nozzle device 7 with a centrally disposed opening 8 for the viscous medium and three gas outlets. 9

Fig. 2c shows a cross section of a nozzle device 7 with a centrally disposed opening 8 for the viscous medium and four gas outlets. 9

Fig. 2d shows a cross section of a nozzle device 7 with a centrally disposed opening 8 for the viscous medium and a gas outlet 9, which is arranged in an annular manner around the opening 8 for the viscous medium. Through such a shaped gas outlet 9, the viscous medium is particularly uniformly focused from all directions; it results after the impact of the drop on the substrate 4, a round geometry of the drop.

In order to ensure a cohesion of the regions of the nozzle device 7 outside and within the annular opening of the gas outlet 9 in the nozzle device 7 shown in Fig. 2d, these are interconnected by two webs.

The webs have the smallest possible width in order not to hinder the gas flow 11 in the passage through the gas outlet 9. The webs are in a different plane than the cross-sectional plane shown in Fig. 2d, so that the webs are not shown in Fig. 2d.

As materials for the production of the nozzle device 7, for example, metals or plastics come into question. Typical thicknesses of the nozzle device 7 are 1000 to 3000 microns, but it is also possible larger or smaller thicknesses. The bores or the gas outlets 9 in the nozzle devices have a diameter of between 10 and 1000 .mu.m, preferably between 50 and 500 .mu.m.

The distance between the discharge opening 3 of the dispenser 2 and the substrate 4 is usually in the range of a few millimeters, for example between 0.5 and 3 mm. By means of the device 5 according to the invention, it is possible to further increase the distance between the dispensing opening 3 of the dispensing device 2 and the substrate 4, for example to 5 mm or larger, without losing sighting accuracy.

This makes it possible thanks to the inventive device 5, by Jetten also small structures of the viscous medium on substrates 4, which have a surface unevenness of greater than 3 mm. Such large surface irregularities usually include three-dimensional circuit carriers such as molded interconnected devices, pressure sensors, electrical circuits and flexible electrical circuits.

By means of the inventive method, it is possible to focus the viscous medium at the destination on the substrate 4 to a diameter of only 50 microns.

As a result, for example, conductor tracks, for example as replacement of wire bonds, and contacts of passive and active components can be jetted with small connection geometries.

In the embodiment shown in Fig. 1, the discharge port 3 of the jet valve is not in the gas stream 11. However, embodiments are also conceivable in which the output port 3 of the output device 2 of the jet device 1 is detected by the gas stream 11 , In this way it can be achieved that no residues of the viscous medium remain at the dispensing opening 3. The gas flow 11 thus serves in this case to clean the dispensing opening 3.

Furthermore, in this embodiment, the gas stream 11 serve to optimize the tear-off behavior of the viscous medium at the discharge opening 3, so that it does not come to a satellite formation, for example.

Depending on the type of application, the viscous medium used and the desired diameter of the viscous medium after striking the target location, for example, the angle at which the gas stream 11 is directed to the viscous medium, or the number of Partial gas streams 12, 13 or, for example, the flow rate can be adjusted.

In this case, for example, the volume flow of the gas stream can be 100 cm3 / min, the nozzle device has two diametrically arranged gas outlets with an opening diameter of 100 microns and the gas flow at an angle of 30 ° to the jet axis inclined. As a result, a metering distance of between 5 and 8 mm is achieved for a process-reliable application of the conductive adhesive to the substrate for the above-mentioned, typically used conductive adhesives.

Claims (9)

claims A method of focusing a viscous medium dispensed from a dispensing opening (3) of an output device (2) of a jet device (1), characterized in that at least one gas flow (11) is between the dispensing of the viscous medium and the viscous medium impinging on a substrate (4) is directed to the viscous medium, wherein the viscous medium is focused by means of the gas stream (11). 2. The method according to the preceding claim, characterized in that the discharge opening (3) is detected by the gas stream (11), in particular to clean the discharge opening of residues of the viscous medium. 3. The method according to claim 1, characterized in that the discharge opening (3) is not detected by the gas flow (11), in particular to avoid turbulence by impingement of the gas flow to the discharge opening. 4. The method according to any one of the preceding claims, characterized in that the gas stream (11) from a plurality of partial gas streams (12, 13) is formed. 5. The method according to any one of the preceding claims, characterized in that the gas stream (11) is guided such that it rotates around the viscous medium. 6. The method according to any one of the preceding claims, characterized in that the gas stream (11) before an impact of the gas stream (11) on the viscous medium at least one gas outlet (9) of a nozzle device (7) passes. 7. The method according to claim 6, characterized in that the gas stream (11) by several in the nozzle device (7) located gas outlets (9) into a plurality of partial gas streams (12, 13) is divided. 8. The method according to any one of claims 6 or 7, characterized in that the nozzle device (7) has an opening (8) for the viscous medium and the nozzle device (7) rotates about the opening (8) for the viscous medium. Device (5) for carrying out the method according to one of claims 1 to 8 for focusing a viscous medium dispensed from a dispensing opening (3) of a jet device (1), characterized by means for generating at least one between the dispensing of the viscous medium and impinging the viscous medium on a substrate on the viscous medium directed gas stream (11).