MXPA98002053A - Method and apparatus to distribute fluid on a substrate no pl - Google Patents

Abstract

The present invention relates to a method for applying solder to a plurality of locations on a three-dimensional non-planar electronic substrate, comprising: providing a solder transfer device, including a movable base with an array of pins connected to the base, each shank having a distal end which is capable of moving vertically with respect to the base, independently of rest of the spike arrangement, immersing the distal ends of the spikes in a solder paste tray, moving the base towards the electronic substrate not flat, so that the distal ends of the spike arrangement come into contact with the plurality of locations, to apply the solder paste to the locations, and to agitate the ultrasonic shape of the spike arrangement to stimulate weld transfer from the spikes to the sutra

Description

METHOD AND APPARATUS FOR DISTRIBUTING FLUIDS ON A NON-PIANO SUBTRACT TECHNICAL FIELD The present invention relates to an apparatus and apparatus for distributing fluid, and more particularly to a method and apparatus for distributing solder paste, adhesive or other liquid or paste-like material in a plurality of locations on a non-flat substrate.

BACKGROUND OF THE INVENTION Recent developments in the automotive industry have focused on the elimination of wire harnesses and wire boxes down the vehicle's instrument panels. A development described in US Patent Application Serial No. 08 / 642,723, which has been assigned to the assignee of the present application, describes a method of superimposing circuit patterns directly on the structural components of the instrument panel. This method is promising because it reduces the weight of the vehicle, reduces the problems of assembly and packaging and simplifies the overall design. A problem that has arisen with the application of circuit patterns directly on the structural components of the vehicle is that these structural components are usually three-dimensional or non-planar, therefore, the circuit pattern must be applied on the non-planar surface. Therefore, the distribution of the solder paste in small places on the circuit pattern to form the electrically conductive solder joints once the circuit pattern has been applied to the non-planar surface is problematic because there is no efficient technology to apply welding in a plurality of small places on a non-flat surface. Screen printing methods require substantially flat surfaces and require special tools and construction features of limited utility for printing in cavities. The distribution by means of a syringe is possible with multiple three-dimensional surfaces, however, the speed of the travel of the distributor head in the X direction and the Y direction together with the axial positioning on the Z axis and the theta angle require a prohibitively long time in a high speed manufacturing scenario. The same problem exists during the application of electronic devices installed on the surface for non-flat surfaces. These electronic devices installed on the surface usually require an adhesive to keep the device in place when applied to an angled surface. However, efficient technology does not exist to quickly apply this adhesive in small places on non-flat surfaces. Accordingly, it is desirable to provide a method and apparatus for applying solder paste and other fluids, such as glue, on non-planar three-dimensional substrates.

DESCRIPTION OF THE INVENTION The present invention solves the aforementioned drawbacks of the fluid dispensing devices of the prior art by providing a device for transferring fluid that includes a movable base in an array of spikes extending from the base, wherein each spike includes As a distal end that is movable with respect to the base, independent of the rest of the spike arrangement, as such, the distal ends of the spikes can transfer fluid in small places on non-planar surfaces. More specifically, the present invention provides an apparatus for applying fluid to a plurality of locations on a non-planar substrate, including a movable base and an array of pins connected to the base. Each spike has a distal end that moves in the vertical direction relative to the base, independently of the rest of the spike arrangement, wherein each distal end is adapted to transfer fluid to a location on the non-planar substrate. The distal ends of the spikes have a greater affinity for the fluid that the fluid has for itself, and a lower affinity for the fluid from which the fluid has for the substrate. Accordingly, the distal ends can be submerged in the fluid and it is possible to bring them into contact with the substrate so that the individual distal ends can collapse towards the base as the distal ends come into contact with the substrate to facilitate further movement of the base. to the substrate for the application of fluid in each of one of a plurality of locations. The fluid can be a paste for welding, gluing, etc. The present invention further provides a method for applying solder paste in a plurality of locations on a non-flat electronic substrate, the method comprising: 1) providing a device for transferring the paste, which includes a mobile base with an array of pins connected to the base, each spike has a distal end that moves in the vertical direction with respect to the base independent of the rest of the spike arrangement; 2) immersing the distal ends of the pins in a tray of solder paste; and 3) moving the base towards the non-planar electronic substrate so that the distal ends of the spike arrangement contact the plurality of locations to apply the solder paste to the locations.

Accordingly, an object of the present invention is to provide a method and apparatus for distributing fluid in a plurality of small locations on a non-planar surface of a substrate. The above object and other objects, features and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1-1 illustrate schematically a sequence of immersing a pin in a solder paste and applying the pin to a substrate for distributing the solder paste on the substrate according to the present invention. . Figure 2a shows a schematic side view of an apparatus for applying fluid to a plurality of locations on a non-planar substrate in accordance with the present invention; Figure 2b shows the apparatus and substrate of Figure 2a with the apparatus in contact with the substrate; Figure 3 shows a cross-sectional view, arranged in schematic form, of a transfer pin according to an alternative embodiment of the present invention; Figures 4a-4c illustrate, as a schematic, cross-sectional views of a sequence of application of a fluid to a non-planar surface according to the embodiment illustrated in Figure 3; and Figures 5a-5d illustrate schematically a method for applying a fluid to a non-planar substrate surface according to a second alternative embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 1 illustrate schematically a sequence of the transfer of solder paste to a solder plate on a substrate. As shown, a spike 10 with a distal end portion 12 moves toward and dips into a tray of solder paste 14 in Figures la and Ib, and is removed from the solder paste with a remaining weld drop 16. on the distal end 12 of the spike 10, as shown in Figure lc. The pin 10 is then placed on a substrate 18 with a solder plate 20 thereon, as shown in FIG. Id. The distal end 12 of the pin 10 then comes into contact with the plate 20 and is removed from the plate. 20 to leave the drop of solder paste 16 on the plate 20, as shown in the figures le and lf. Now referring to Figures 2a and 2b, a method and apparatus for applying solder to a non-planar surface of a substrate is shown schematically. The apparatus 24 for applying welding to a plurality of locations on a non-planar substrate 26 includes a movable base 28 with an array of pins 30 slidably installed in vertical movement with respect to the base 28. Each of the spike arrangement 30 includes a distal end 32 adapted to transfer solder paste to a solder location. As shown, the substrate 26 includes a non-planar surface 34. Because the pegs 30 are allowed to float relative to the base 28, the distal ends 32 of the pegs 30 will conform to the curved shape of the non-planar surface 34 of the substrate 26 for the application of welding in small places along the surface 34. The pins 30 can be moved simply by gravity or they can be under counting control and the data can be transferred from the CAD equipment to establish the height of the spike according to the surface of the substrate 34. The pins 30 can then be operated in a pneumatic or electromechanical manner at a desired height to properly position the distal ends 30 of the pins to transfer the solder paste. Figure 3 shows an alternative spike design 40 in which the spike unit has a distal end portion 44 which moves in the vertical direction with respect to the spigot 42 by means of a compression spring 46 which engages an axis 48 to allow the respective vertical movement. The implementation of the modality shown in Figure 3 is illustrated in Figures 4a-4c. As shown, an impeller 52 is used to move the mobile base 54 that includes the pins 42 connected thereto. As illustrated in Figure 3, each spigot consists of a shaft 48 which is spring-loaded with respect to the spigot 42 and a distal end portion 44 connected to the shaft 48. As illustrated, the distal ends 44 may comprise different geometries for transfer different amounts of pasta. As shown in Figure 4a, the distal ends 44 are dipped into the paste 56 in the tray 58. The impeller 52 then moves the base 52 and the pegs move away from the tray 54 and places the pegs on the three-dimensional substrate 60 at which will apply the paste. The impeller 52 then moves the base 54 so that the distal ends 44 contact the substrate 60 to apply the paste to the substrate. As shown in Figure 4c, the impeller 52 then retracts the base 54 and the pegs move away from the substrate 60 leaving the solder paste on the substrate 60. A second alternative embodiment of the invention is illustrated in Figures 5a-5d. As shown in this embodiment, the tray 70 is covered with a plate 72 having holes 74, 76, 78 formed therethrough to allow only selected spikes of the spike arrangement 80 to pass through the plate 72 to be submerged in the solder paste 82 (or adhesive, etc.). Accordingly, as shown in FIG. 5d, only certain pins of the spike arrangement 80 have solder paste 82 therein as a result of the holes 74, 76, 78 formed in the stencil plate 72 of the array 70. As shown in FIG. Figure 5c, the array of pins 80 then moves in contact with a substrate 84 by depositing the drops of solder paste 82 at selected locations along the non-planar surface of the substrate 84. Co or illustrated in Figure 5d, the spike arrangement 80 then moves away from the substrate 84 leaving the drops of solder paste 82 on the substrate 84. Using this concept, stencil tray plates can be specifically designed with suitable holes formed therethrough which correspond to preferred locations for the application of the solder paste on a substrate. The relative affinity of the solder paste for the distal end of the shank is greater than the cohesion strength of the solder paste, which allows the distal ends of the shank to collect drops from the solder paste. This is achieved by rheological and surface-active modification of the pulp together with specialized coatings on the spike. The affinity of the paste is also greater for the welding plate than for the spigot, which allows the efficient transfer of the paste during the process. The spikes can be coated with some material such as sintered Teflon, titanium nitride or the surface can be tempered. The transfer pins may have a variety of designs of the distal end head. The distal ends of the pins may be straight, flared, pointed, grooved, serrated, etc. The distal ends may also be rounded or may include a ball joint configuration to allow the shaping of slopes on angled surfaces. As already described, it is possible to use multiple pins to transfer the desired amount of solder paste, and the pins can be spring-loaded or activated individually or in a group with a number of electronic or mechanical devices. Ultrasonic agitation can be used to provide efficient transfer of the solder paste. The pins may also be hollow to provide an array of syringes to supply a large volume of paste in a small area. The arrangement of syringes can be operated pneumatically, and the spike arrangement, alternatively, can be heated or cooled to help transfer the paste to be welded or to assist in the subsequent reflow process.

The pins can also be heated to allow the transfer of the solder paste drops, fused to the plate and / or the components. This eliminates the reflow process of the solder paste at elevated temperature for temperature sensitive substrates. The arrangement of transfer pins can be configured in a personal way for the specific part on which the solder paste is to be distributed, or it can be a generic arrangement in which specific pins can be used for specific distribution situations. This attribute allows flexible and fast manufacturing. This same device can be used to quickly distribute other materials for electronic packaging in three dimensions as fluxes, conformal coatings and adhesives for use in devices for surface installation. The adhesive bond of the apparatus for surface installation is useful, not only for processing lower side components through a welding wave, but also for anchoring the devices to flat and angled surfaces during pre-reflow handling. Although the best modes of carrying out the invention have been described in detail, those familiar with the technique to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.

Claims (1)

1. CLAIMS A method for applying solder paste to a plurality of locations on a non-planar electronic substrate, the method comprising: providing a solder transfer device, including a movable base with an array of pins connected to the base, each pin having a distal end moving in the vertical direction with respect to the base independent of the rest of the spike arrangement; immersing the distal ends of the spikes in a tray of solder paste; moving the base towards the non-planar electronic substrate so that the distal ends of the spike arrangement come into contact with the plurality of locations to apply the solder paste to the locations. The method of claim 1, wherein the step of providing a welding transfer device comprises providing a movable base with an array of spikes slidably installed for vertical movement with respect to the base, wherein the spike includes an end distal adapted to transfer solder paste at a location for soldering. The method of claim 1, wherein the step of providing a welding transfer device comprises providing a movable base with an array of spikes rigidly secured to the base and wherein each spike includes a distal end portion secured to the spike and with spring tightening with respect to the spike to facilitate vertical movement of the distal end portion with respect to the spike. An apparatus for applying solder paste to a plurality of locations on a non-planar electronic substrate, the apparatus comprises: a movable base; and an array of spikes connected to the base, each spike with a distal end moving in the vertical direction relative to the base independent of the rest of the spike arrangement, where each of the distal ends is adapted to transfer paste to welding to a solder location, whereby the distal ends can be immersed in the solder paste and the base moved to the non-planar electronic substrate, so that the distal ends can retract towards the base according to the distal ends they are coupled to the substrate to facilitate further movement of the base towards the substrate in order to apply the solder paste in each of the plurality of locations. The apparatus of claim 4, wherein each of the spike arrangement is slidably installed for vertical movement with respect to the base and each spike includes a distal end portion adapted to transfer solder paste at a solder location. The apparatus of claim 4, wherein each of the spike arrangement is rigidly secured to the base, and wherein each of the spikes includes a distal end portion secured to the spike and with spring tightening relative to the spike. spike for facilitating vertical movement of the distal end portion with respect to the spike. The apparatus of claim 4 further comprises a tray for welding with a plate placed thereon, the plate coh a plurality of holes therethrough to allow only selected ears of the spike arrangement to pass through the plate to transfer the paste for welding to the non-planar electronic substrate. An apparatus for applying a fluid to a plurality of locations on a non-planar substrate, the apparatus comprises: a movable base; and an array of spikes connected to the base, each spike with a distal end moving in the vertical direction relative to the base, independent of the rest of the spike arrangement, where each distal end is adapted to transfer fluid to a location on the substrate having a greater affinity for the fluid from which the fluid has itself and a lower affinity for the fluid from which the fluid has for the substrate, where the distal ends can be submerged in the fluid and move in contact with the substrate so that the distal ends may retract towards the base as the distal ends engage the substrate to facilitate further movement of the base toward the substrate for the application of fluid at each of the plurality of locations. The apparatus of claim 8, where the fluid consists of solder paste. The apparatus of claim 8, wherein the fluid consists of gluing.