Electric circuits are frequently constructed by adhering components of the circuit to interconnects with conductive epoxy. Non-conductive epoxies are also utilized in circuit fabrication. Many epoxy systems comprise two components comprising a resin and a hardener. These components are kept separate and mixed immediately prior to application. Depending on the epoxy components, the mixed epoxy may cure in a matter of minutes or hours at room or elevated temperatures. Further, additional components might be added to the epoxy mixture, such as solid fillers.
Regardless, where the epoxy system comprises at least two components to be mixed, complete and thorough mixing to achieve homogeneity in the mix is highly desired to produce a suitable finished epoxy. Such can be achieved, for example, by manually or mechanically stirring a mix of such liquids or components with a stirring device. Static mixing systems have also been utilized in the prior art for mixing epoxy components. One example employs a double-barrelled syringe-like device having a static mixer received at the end thereof. The static mixing system comprises a tube having a static mixer received therein in the form of a plurality of end-to-end oriented split helixes over which the epoxy fluid passes. The nozzles from each syringe barrel feed opposite sides of the first helix. At the juncture with the next helix, the flows are split 50--50 and mix with each other. The split and mixing occurs again at the juncture with the next helix. Thus, longitudinal flow of the epoxy through the static mixing tube, assuming it is long enough, should result in complete homogenous mixing of the two-component system.
The volume of liquid within the mixing tube at the conclusion of processing is typically discarded along with the static mixing tube. Where the mixing tube needs to be of considerable length to achieve adequate mixing, the volume of discarded epoxy components can be significant. This can be costly, for example, where the epoxy being mixed is conductive epoxy. Such typically comprises silver or other metal flakes which significantly add to the cost of the epoxy system. Further, the ultimate volume of mixed epoxy might be quite small due to cost of the epoxy in utilization in the final bonding, such as 60 ml or less. The smaller the desired volume of mixed epoxy, the greater is the percentage of discarded epoxy components of the total mixed volume.
Further, the above static mixing system typically must be increased in length to achieve adequate mixing where the components being mixed differ greatly in volumetric ratio in the finished mix. For example, some epoxy systems use a volumetric ratio of 20:1 of resin to hardener. Typically, the greater the volumetric ratio of mixed components, the more difficult the mixing whether conducting static or dynamic mixing. Longer required static mixing tubes for large volumetric ratios of different components only adds to the discardable product problem.
Accordingly, it would be desirable to develop systems and methods which perhaps enable better epoxy mixing and minimization of discarded material. Although the invention spawned primarily from concerns associated with mixing relatively small volumes of expensive two-part epoxy systems, the artisan will appreciate applicability of the invention in other fluid mixing methods and systems.