3DP Applications

Extruding Solder Paste for Electronics Printing – the Peter Jansen Way

Electronics printing is an idea that is still being explored, perhaps most fully realized by Voxel8’s developer’s kit.  Though there are a number of projects seeking to make home electronics prototyping a reality, when it came to individually mounting surface components for electronics, Peter Jansen, of the Tricorder Project, decided, like he often has, that surely, a better way could be designed.

Manually dispensing solder paste using syringes or even using stencils to reliably quicken the process just wasn’t efficient enough. In his own experience, he noticed, “I find that after stenciling I’ll spend a good deal of time moving the paste around with fine tweezers to help prevent bridging (although often there are still bridges), and so I usually end up manually soldering fine pitch TQFP parts, which is very time consuming. For a project in my queue, I’ve designed a board that has about 300 parts (summing to a little under 2000 pads), most of which are 0402 capacitors or 0.4mm pitch leadless QFNs over a board that’s about 10cm on an edge — which is likely beyond my capacity to easily, reliably, or comfortably assemble by hand.”

solder paste extruderHaving designed and built 3D printers before, Jansen explored using paste extruders, similar to those used in desktop 3D printing for materials like ceramics, frosting, silicone, or latex. He considered several 3D printed open source extruder designs on Thingiverse, the Universal Paste Extruder by Richrap in particular. But finding it too large and heavy for his purposes, Jansen set about building his own version of a paste extruder – one with a simpler, more flexible system, using a lead screw. He decided on this since he felt “that the lead screw approach can likely be done very compactly, with a minimum of weight, and support quickly changing paste syringes.

His “more of a sketch in hardware” design, while not perfect, appears straightforward and elegant. Its advantages are quite apparent too: “the syringe is very easily accessible, and very quick to change. It’s (the design) also fairly compact, but could be even more compact — the size is largely driven by the orientation and width of the servo motor.” The ability to reverse the lead screw also allows the user to quickly swap out paste syringes but more essentially, provides precise control over depositing the paste.  The open source project may also allow others to improve the extruder, possibly leading to their own electronics printer, an idea evoked by Rabbit Proto’s own printhead or Voxel8’s multimaterial printer.

To check out this design and more of Peter Jansen’s work, visit www.thetricorderproject.org/blog