Device for focusing a viscous medium dispensed from an output opening of an output device of a jet device, jet system and production plant

Abstract

Device (5) for focusing a viscous medium dispensed from a dispensing opening (3) of a dispensing device (2) of a jet device (1), wherein means for generating a gas flow (11) and a nozzle device (7) with at least one gas outlet (9) and an opening (8) for the viscous medium are provided, characterized in that means (6) for attachment to the dispensing device (2) of the jet device (1) are provided, wherein the means (6) are configured to rotate the nozzle device (7) about the dispensing device (2) and wherein at least one gas outlet (9) has a conical shape

Description

State of the art

[0001] The invention relates to a device for focusing a viscous medium dispensed from an output opening of an output device of a jet device, a jet system and a production plant according to the preamble of the independent claim.

[0002] Jetting is a known method for the non-contact dispensing of drops of a viscous medium, such as an adhesive or solder, onto a substrate. A device and a method for jetting drops are known, for example, from WO 99 / 64 167 A1. In this device, the viscous medium is contained in a dispensing chamber and is jetted out of a dispensing valve by a rapid reduction in the volume of this chamber.

[0003] Dispensing devices with gas outlets and media dispensing openings are known from DE 195 00 053 C1 and WO 2010 / 007 033 A1. Furthermore, a spray nozzle device for spraying a spray jet containing a coating material is described in DE 10 2012 113 124 A1, wherein the spray nozzle device comprises a spray nozzle and at least one control nozzle. Disclosure of the invention Advantages of the invention

[0004] The device according to the invention for focusing a viscous medium dispensed from an output opening of an output device of a jet device offers the advantage that the shape and / or direction of the viscous medium can be influenced by means of the device.

[0005] This can, for example, influence the shape the viscous medium takes after coming into contact with a substrate.

[0006] A further advantage of the device according to the invention is that so-called satellites, which may be present as unwanted side droplets in addition to a main droplet of the viscous medium after the dispensing of the viscous medium, can be directed into the main droplet by means of the device by a gas stream directed towards the viscous medium, thus preventing the side droplets or satellites from hitting the substrate at unwanted locations.

[0007] The device according to the invention serves to focus the viscous medium by means of the gas flow. Focusing is understood to mean that the diameter of the viscous medium is reduced in at least one direction upon impact with the substrate compared to the diameter without focusing. Thus, the device according to the invention advantageously enables the creation of particularly small structures during jetting. Structure dimensions of up to 50 µm can be achieved.

[0008] A further advantage of the device according to the invention is that the nozzle assembly allows for a particularly compact design of the device. Several functions are integrated into the nozzle assembly by means of at least one gas outlet and an opening for the viscous medium located within the nozzle assembly.

[0009] The direction and shape of the gas flow can be precisely controlled by the at least one gas outlet of the nozzle device, through which the gas stream passes before impacting the viscous medium. No separate means are required to manipulate the gas flow. If the device according to the invention is to be used for changing applications with varying requirements for the gas stream directed onto the viscous medium, simply changing the nozzle device is sufficient. It is not necessary to change the entire device for focusing the discharged viscous medium.

[0010] The fact that the nozzle device has an opening for the viscous medium allows it to be positioned centrosymmetrically around the path the viscous medium takes, either within the dispensing device or between the dispensing device and the substrate. This enables the nozzle device to be mounted directly on or near the dispensing opening of the jet device without obstructing the viscous medium. This facilitates particularly precise positioning of the gas outlet and, consequently, precise adjustment of the gas flow relative to the viscous medium.

[0011] A further advantage of the device according to the invention is that it makes it possible to increase the distance between the dispensing orifice of the dispensing device and the substrate, for example to 5 mm or more, without losing targeting accuracy. This makes it possible to apply even small structures of the viscous medium to substrates with a surface unevenness greater than 3 mm by jetting. Such large surface unevenness is typically found in three-dimensional circuit carriers such as molded interconnected devices, pressure sensors, electrical circuits, and flexible electrical circuits.

[0012] Due to its particularly compact design, the device according to the invention is especially well suited for use in space-constrained applications, for example in a production plant. This also ensures particularly easy retrofitting into an existing setup for jetting a viscous medium.

[0013] These advantages are achieved by the device according to the invention for focusing a viscous medium dispensed from an output opening of an output device of a jet device, wherein means for generating a gas flow and a nozzle device with at least one gas outlet and an opening for the viscous medium are provided.

[0014] The measures listed in the dependent claims enable advantageous further developments and improvements of the device specified in the main claim for focusing a viscous medium dispensed from an output opening of an output device of a jet device.

[0015] It is particularly advantageous if the opening for the viscous medium is designed to accommodate the dispensing device. This means that the dispensing device is inserted into the opening for the viscous medium. In this case, for example, the nozzle device can be mounted directly on the dispensing device, whereby the at least one gas outlet of the nozzle device is automatically aligned radially with respect to the opening for the viscous medium. In this case, it is particularly preferred if the opening for the viscous medium has a geometry designed for a positive-locking connection with the outer surface of the dispensing device.

[0016] If the opening for the viscous medium is designed to accommodate the dispensing device, it is further particularly advantageous if the nozzle device is designed such that the opening for the viscous medium of the nozzle device is flush with the dispensing opening of the dispensing device. In this case, the axial orientation of the nozzle device with respect to the opening for the viscous medium is also advantageously predetermined.

[0017] In the case of a positive-locking connection between the opening for the viscous medium and the outer surface of the dispensing device, the penetration of the viscous medium into the area between the nozzle device and the dispensing device can be avoided, since there is no gap between the nozzle device and the dispensing device.

[0018] The device according to the invention has means for attaching the device to the dispensing device of the jet device. This prevents any relative movement between the nozzle device and the dispensing device. Thus, the generated gas flow is always precisely aligned with the path that the viscous medium travels between the dispensing device and the substrate.

[0019] Furthermore, attaching the device to the dispensing device enables a particularly compact design, as no separate fastening means are needed in the vicinity of the device.

[0020] Furthermore, in a non-inventive embodiment, it is advantageous if the means for fastening to the dispensing device of the jet device are designed for a static fastening of the device to the dispensing device. This results in a particularly stable connection.

[0021] Means for attachment to the dispensing device of the jet device allow, according to the invention, the nozzle device to rotate around the dispensing device or around the opening for the viscous medium. By rotating the nozzle device around the dispensing device, the gas stream exiting the at least one gas outlet is also set into rotation around the viscous medium. With a sufficiently fast rotation of the gas stream, this makes it possible to direct, for example, satellites, which can form in all directions around the viscous medium, into the main droplet of the viscous medium with just one gas stream by rotating around it.

[0022] Because rotating the gas stream around the viscous medium allows the viscous medium between the dispensing device and the substrate to be influenced from all radial directions with only one gas stream, it is possible to achieve a particularly high velocity of the gas at the same flow rate of the supplied gas compared to arrangements with multiple gas streams. Accordingly, a further advantage of this arrangement is that it is not necessary to divide the gas stream into several partial gas streams, which would then have a correspondingly lower flow velocity.

[0023] Mounting the nozzle device on the dispensing device in such a way that rotation around the opening for the viscous medium is enabled represents a particularly simple structural possibility for rotating the gas flow around the viscous medium.

[0024] In an advantageous embodiment of the device according to the invention, the nozzle assembly has several gas outlets for dividing the gas flow into several partial gas flows. This enables particularly precise manipulation of the shape and direction of the viscous medium. Furthermore, this makes it particularly easy to adjust shapes of the viscous medium that deviate from a round shape after it hits the substrate, such as an oval or linear shape.

[0025] It is particularly advantageous if the device according to the invention comprises a gas outlet arranged in a ring around the opening for the viscous medium. This generates, in a structurally particularly simple manner, a gas flow that isotropically focuses the viscous medium on its path between the dispensing device and the substrate. Thus, it becomes possible to provide particularly uniformly circular droplets on the substrate using the device according to the invention.

[0026] In an advantageous embodiment of the device according to the invention, at least one of the gas outlets has a conical shape. This reduces the diameter of the gas flow and increases the flow velocity.

[0027] Furthermore, it is advantageous if at least one gas outlet has an inclination relative to the normal to the nozzle device plane. This allows a gas flow inclined towards the jet axis, i.e., the line connecting the outlet opening of the jet device and the point of impact of the viscous medium on the substrate. However, it is also possible to provide at least one gas outlet with an inclination that does not run exclusively in the direction of the jet axis. This inclination makes it possible to create a

[0028] To generate a gas flow which, when the nozzle assembly is mounted in a manner that allows rotation around the opening for the viscous medium, sets the nozzle assembly in motion. In this case, the gas flow serves as the driving force for the rotation of the nozzle assembly.

[0029] A jet system, which is understood to be a combination of a jet device and a device according to the invention, and a production plant with a device according to the invention also exhibit the advantages of the device according to the invention listed above. Example drawings

[0030] Exemplary embodiments of the invention are shown in the drawings and explained in more detail below. They show: Fig. 1 a view of a cross-section of an output device for a viscous medium of a jet device with a device for carrying out the method according to the invention, Fig. Two cross-sections of nozzle devices with different geometries. Description of the exemplary embodiment

[0031] In Fig. Figure 1 shows a section 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 can be a plunger valve, a resonant pressure valve, or an aerosol jet valve.

[0032] The viscous medium is dispensed from an outlet opening 3 of the dispensing device 2. Typical diameters of the outlet opening 3 of the dispensing device 2 are in the range between 50 and 4000 µm.

[0033] The viscous medium can be, for example, a fixing adhesive or a conductive adhesive. Silver conductive adhesives, such as the commercially available Heraeus PC3001 or Henkel Ablebond 84-1 LMI SR4, are used as conductive adhesives.

[0034] The viscous medium is dispensed in the form of drops from the dispensing opening 3 of the jet valve and, after a flight phase, strikes a substrate 4.

[0035] Depending on the shape of the dispensing opening 3 and whether the substrate 4 remains stationary or is moved, different geometries of the viscous medium at the point of impact on the substrate 4 can be set. For example, it is conceivable to use dispensing devices 2 with one or more dispensing openings 3.

[0036] Furthermore, in Fig. 1 A device 5 according to the invention for focusing the viscous medium discharged from the discharge opening 3 of the jet device 1 is attached to the jet valve. Fig. Figure 1 shows a non-inventive fastening of the device 5 to the jet valve via a screw clamp connection 6.

[0037] According to the invention, the device 5 for focusing the viscous medium is not fixedly attached to the jet valve. For example, it is conceivable to provide a fastening, preferably by means of ball bearings, of the device 5 according to the invention to the dispensing device 2, which allows rotation of the nozzle device 7 of the device 5 according to the invention about the opening for the viscous medium. This can be achieved, for example, by attaching ball bearings to the device 5 according to the invention, which are received by a flange that in turn can be attached to the dispensing device 2.

[0038] Furthermore, it is from Fig. Figure 1 shows that the device 5 for focusing the viscous medium comprises a nozzle device 7. This has an opening 8 for the viscous medium. Preferably, as shown in Fig. Figure 1 shows the opening 8 for the viscous medium designed to receive the output device 2, that is, the output device 2 is inserted into the opening 8 for the viscous medium.

[0039] Furthermore, it is preferred how Fig. As can be seen from Figure 1, the opening 8 for the viscous medium of the nozzle device 7 is adapted to the contour of the dispensing device 2, resulting in a positive-locking connection. Furthermore, the opening 8 for the viscous medium of the nozzle device 7 is dimensioned such that the nozzle device 7 is flush with the dispensing opening 3 of the dispensing device 2.

[0040] In this embodiment, the nozzle device 7 has two continuous gas outlets 9. The gas outlets 9 serve to supply gas in the direction of the dispensed viscous medium.

[0041] The gas can be guided directly through the gas outlets 9 or by means of focusing nozzles 10 inserted into the gas outlets 9. The latter is shown in the Fig. This is the case in the embodiment shown in Figure 1. The focusing nozzles 10 are connected to the gas supply on the side facing away from the substrate 4. Alternatively, the gas supply can also be attached directly to the gas outlet 9. The gas flow 11 can be further accelerated by a conical taper of the gas outlets 9 or the focusing nozzles 10.

[0042] The gas can be supplied, for example, via a house network or a gas cylinder, and guided, for example, via a hose system to the gas outlet 9 or the focusing nozzle 10. This is in Fig. 1 not shown. Suitable gases include inert gases such as nitrogen or, alternatively, air.

[0043] The viscous medium is dispensed from the dispensing opening 3 of the dispensing device 2 of the jet device 1. This occurs in the form of a main droplet, from which secondary droplets may detach. The main droplet and the secondary droplets travel from the dispensing opening 3 of the jet device 1 towards a target location on the substrate 4.

[0044] By means of the device 5 for focusing the dispensed medium, a gas stream 11 is created, or in the Fig. In the embodiment shown in Figure 1, two partial gas streams 12, 13 are generated, which are directed in the direction of the jet axis 14, i.e. the connecting line between the output opening 3 of the jet device 1 and the point of impact of the viscous medium on the substrate 4.

[0045] This is achieved by inclining the gas outlets (9) in the nozzle assembly 7 or the focusing nozzles 10, which extend through the nozzle assembly 7, at an angle to the jet axis 14. This angle is preferably less than 45° and preferably greater than 3°. A laminar gas flow 11 is preferably generated through the gas outlets (9) or the opening of the focusing nozzles 10.

[0046] It is also in one of the Fig. In an alternative embodiment shown in Figure 1, it is conceivable to provide the gas outlets 9 with an inclination that does not run exclusively in the direction of the jet axis 14. This inclination makes it possible to generate a gas flow 11 which, when the nozzle assembly 7 is mounted in a manner that allows rotation around the opening 8 for the viscous medium, sets the nozzle assembly 7 into rotation. In this case, the gas flow 11 serves as the driving force for the rotation of the nozzle assembly 7.

[0047] During the flight of the viscous medium or the main droplet, the gas stream 11, or in this case the two partial gas streams 12, 13, collide with the viscous medium. This causes the secondary droplets to be directed into the main droplet.

[0048] Furthermore, the main droplet is compressed, i.e. focused, by the gas stream 11, so that it hits its target location on the substrate 4 with a smaller diameter than would have been the case if no gas stream 11 had been directed towards it.

[0049] It is not only conceivable that the focusing of the main droplet occurs uniformly from all directions to achieve a round shape of the droplet after impact with the substrate 4. The focusing can also occur to varying degrees from different directions, for example, through the arrangement of the gas outlets 9, so that a geometry of the droplet on the substrate 4 deviates from a round shape.

[0050] By means of the in Fig. In the arrangement shown in Figure 1, the droplet is shaped, for example, into an elongated form perpendicular to the plane of the paper. No focusing towards the plane of the paper occurs here. If, as in this embodiment, the focusing of the droplet does not occur equally from all directions, the droplet can thus have a larger diameter upon impact with the substrate 4 in the directions where no focusing occurs than would have been the case if no gas stream 11 had been directed towards it.

[0051] Typical flow rates for gas flow 11 are between 20 and 200 cm³ / h. 3 / min of the gas or air used for gas flow 11.

[0052] The in Fig. The nozzle device 7 shown in Figure 1 can be configured in different geometries. For example, it can have two, three, or four gas outlets 9. Examples of nozzle device geometries 7 are shown in Figure 1. Fig. 2 shown.

[0053] Fig. Figure 2a shows a cross-section of the nozzle device 7, as shown in the figure in Fig. The setup shown in Figure 1 is used. The opening 8 for the viscous medium is located in the center. The two other openings are the two gas outlets 9.

[0054] Fig. Figure 2b shows a cross-section of a nozzle device 7 with a centrally arranged opening 8 for the viscous medium and three gas outlets 9.

[0055] Fig. Figure 2c shows a cross-section of a nozzle device 7 with a centrally arranged opening 8 for the viscous medium and four gas outlets 9.

[0056] Fig. Figure 2d shows a cross-section of a nozzle device 7 with a centrally arranged opening 8 for the viscous medium and a gas outlet 9 arranged in a ring around the opening 8 for the viscous medium. The gas outlet 9 shaped in this way focuses the viscous medium particularly uniformly from all directions; after the droplet hits the substrate 4, it has a round geometry.

[0057] To participate in the Fig. In order to ensure cohesion between the areas of the nozzle device 7 shown in 2d outside and inside the annular opening of the gas outlet 9, these are connected to each other by two webs.

[0058] The webs are designed to be as narrow as possible so as not to impede the gas flow 11 as it passes through the gas outlet 9. The webs are located on a different plane than the one in Fig. 2d cross-sectional plane shown, so that the webs in Fig. 2D not shown.

[0059] Suitable materials for manufacturing the nozzle device 7 include, for example, metals or plastics. Typical thicknesses of the nozzle device 7 are 1000 to 3000 µm, but greater or lesser thicknesses are also possible. The bores or gas outlets 9 in the nozzles have diameters between 10 and 1000 µm, preferably between 50 and 500 µm.

[0060] The distance between the dispensing opening 3 of the dispensing device 2 and the substrate 4 is typically in the range of a few millimeters, for example between 0.5 and 3 mm. Using the device 5 according to the invention, it is possible to increase the distance between the dispensing opening 3 of the dispensing device 2 and the substrate 4 even further, for example to 5 mm or more, without losing any accuracy.

[0061] Thanks to the device 5 according to the invention, it is possible to apply even small structures of the viscous medium to substrates 4 by jetting, even those with a surface unevenness greater than 3 mm. Three-dimensional circuit carriers such as molded interconnected devices, pressure sensors, electrical circuits, and flexible electrical circuits typically exhibit such large surface unevenness.

[0062] Using the method according to the invention, it is possible to focus the viscous medium at the target location on the substrate 4 to a diameter of only 50 µm. When using the device 5 according to the invention together with a jet device 1, for example, conductor tracks, for example as a replacement for wire bonds, and contacts of passive and active components with small connection geometries can be jetted.

[0063] In the Fig.In the embodiment shown in Figure 1, the dispensing opening 3 of the jet valve is not located in the gas flow 11. However, embodiments are also conceivable in which the dispensing opening 3 of the dispensing device 2 of the jet device 1 is encompassed by the gas flow 11. This ensures that no residues of the viscous medium remain at the dispensing opening 3. In this case, the gas flow 11 thus serves to clean the dispensing opening 3.

[0064] Furthermore, in this embodiment, the gas flow 11 can serve to optimize the separation behavior of the viscous medium at the output opening 3, so that, for example, satellite formation does not occur.

[0065] Depending on the type of application, the viscous medium used and the desired diameter of the viscous medium after impact at the target location, for example the angle at which gas flow 11 is directed towards the viscous medium can be changed, or the number of partial gas flows 12, 13 or, for example, the flow velocity can be adjusted.

[0066] For example, the volume flow rate of the gas stream can be 100 cm³. 3 The flow rate is / min, the nozzle device has two diametrically opposed gas outlets with an opening diameter of 100 µm, and the gas flow is inclined at an angle of 30° to the jet axis. This achieves a dispensing distance of between 5 and 8 mm for the conductive adhesives typically used above, ensuring reliable application of the adhesive to the substrate.

Claims

[1] Device (5) for focusing a viscous medium discharged from a discharge opening (3) of a discharge device (2) of a jet device (1), wherein means for generating a gas stream (11) and a nozzle device (7) with at least one gas outlet (9) and an opening (8) for the viscous medium are provided, characterized by that means (6) are provided for fastening to the output device (2) of the jet device (1), wherein the means (6) are designed to rotate the nozzle device (7) around the output device (2) and wherein at least one gas outlet (9) has a conical shape [2] Device according to claim 1, characterized by that the opening (8) for the viscous medium of the nozzle device (7) is designed to receive the dispensing device (2), and that the nozzle device (7) is designed such that the opening (8) ends in a plane with the dispensing opening (3) of the dispensing device (2). [3] Device according to claim 1 or 2, characterized by a plurality of gas outlets (9) located in the nozzle device (7) for dividing the gas flow (11) into a plurality of partial gas flows (12, 13). [4] Device according to one of claims 1 to 3, characterized by a gas outlet (9) having two webs and surrounding the opening (8) for the viscous medium in a ring shape. [5] Device according to one of claims 1 to 4, characterized by that at least one gas outlet (9) has an inclination to the normal to the nozzle device plane. [6] Jet system with a device (5) according to one of claims 1 to 5. [7] Production plant with a device (5) according to one of claims 1 to 5 or with a jet system according to claim 6.

Images