Dispensing Solder Paste Automatically

Through-hole chips are slowly falling by the wayside, and if you want to build something with new parts you will be using surface mount components. This means spreading paste and throwing it in the toaster oven. Of course, if you don’t want to take the time to get a stencil for your solder paste, you can always lay it down by hand. For that, [owhite] has created a tiny, handheld, robotic solder paste dispenser. It’s a robotic pen that dispenses just the right amount of solder paste on your pads.

The design of this solder paste dispenser is basically a syringe filled with paste and a stepper motor to push the plunger down. Devices like this already exist, and the i-extruder can be had for somewhere around two hundred bucks. Why buy when you can build, so [owhite] set out to create his own.

The key to a successful solder paste pen, it seems, is driving the plunger with a small NEMA 8 stepper motor, using a very fine pitch on the threads of the gears pushing the plunger down, and surprisingly finding a small-diameter syringe. [owhite] found the last bit in the form of a gas-tight syringe with a nylon gasket. The electronics consist of just a Teensy 3.2, DRV8825 stepper driver, footswitch, and an OLED for a UI.

With just a few parts, [owhite] managed to create a solder paste pen that’s better than the commercial i-extruder, and with a bit of practice can be used to place paste on some SMD pads.

Bring Up a PCB with Fewer Headaches

What’s the first thing you do when a new set of boards from the fab house hits the doorstep? Apply solder paste, populate the components, and stick it in the reflow oven? That’s one way to do it. But a lot of non-obvious things can go wrong at the fab house, like shorts and undrilled vias. One tiny mistake can mean hours of frustration and sanity questioning as you troubleshoot some problem that’s now buried under solder paste and 0603s.

Over on IO, [Bhavesh] tries to nip these problems in the bud with a comprehensive and explanatory guide to properly bringing up a PCB. Though it’s based on fab house boards, this soup-to-nuts plan is good for any project from kit building to custom stripboard circuits. When new boards arrive, [Bhavesh] does several continuity checks and visually inspects them with a microscope. In the case of a stripboard layout, it’s a good idea to verify there’s no continuity across cut traces. He goes on to cover solder paste, touching on proper handling and storage, application, and problem correction.

Our favorite part of this guide is the component sheets. Making these is a great preventive measure, like lining up all your ingredients on the counter before you bake a cake. If you know what you need, why not have it all ready?  [Bhavesh] uses a sheet for each component type, lists all the relevant values in ascending order, and lays out component reels next to them.

The guide covers solder paste, too—his stencils were late to arrive, so the guide deals with applying paste by hand. He suggests a plan for populating the board by starting in one corner and working in circle, placing small components first. Then it’s on to reflow and those all-important post-reflow checks for bridges and bad joints before letting the magic smoke out.

A great time to catch mistakes is before you send the order to the fab house. Hackaday’s own [Joshua Vasquez] has you more than covered there.

Tools of the Trade – Solder Paste Dispensing

The general process of circuit board assembly goes like this: You order your PCBs. You also order your components. For surface mount components, you apply solder paste to the pads, put the components on top, and then heat the board up so the solder paste flows and makes a bond. Then for through hole components you put the leads through the holes, and solder them with an iron or a solder wave or dip. Then you do an inspection for defects, program any microcontrollers, and finally test the completed board to make sure everything runs.

The tricky part is in volumes. If you’re only doing a few boards, it’s usually easiest to assemble them by hand. In the thousands you usually outsource. But new tools, and cheap hacked tools, have made it easier to automate small batches, and scale up into the thousands before outsourcing assembly.

In this new series which we’re calling Tools of the Trade we’ll be covering a variety of tools used for building products, and we’re starting with circuit board assembly. Let’s investigate our tools of the trade: solder paste dispensing. Continue reading “Tools of the Trade – Solder Paste Dispensing”

Solder Stencils with a 3D Printer

If you are soldering with paste, a stencil makes life a lot easier. Sure, you can apply paste by hand with a syringe, but a modern PCB might have hundreds or even thousands of pads. Like a lot of us, [Robert Kirberich] doesn’t like paying to have stencils made and he wondered if he could use his 3D printer to make stencils. He found the answer was yes.

Continue reading “Solder Stencils with a 3D Printer”

Solder Paste Dispenser has No 3D Printed Parts!

If you’ve never used a solder paste dispenser, you’re missing out. Think about always using a crappy soldering iron, and then for the first time using a high-end one. Suddenly you’re actually not bad at soldering things! It’s kind of like that.

Most solder paste dispensers make use of compressed air, which requires an extra setup to use that you might not have. The goal of this project was to make a solder paste dispenser that doesn’t use compressed air, and doesn’t have any 3D printed parts (in case you don’t have a 3D printer) — and it looks like the inventor, [MikeM], succeeded!

Continue reading “Solder Paste Dispenser has No 3D Printed Parts!”

BGA Hand Soldering Video

By 2016, most people have got the hang of doing SMD soldering in the garage–at least for standard packaging. Ball Grid Array or BGA, however, remains one of the more difficult packages to work with [Colin O’Flynn] has an excellent video (almost 30-minutes, including some parts that are sped up) that shows exactly how he does a board with BGA.

Continue reading “BGA Hand Soldering Video”

THP Semifinalst: Laser Solder Paste


A relative latecomer to The Hackaday Prize, [AltMarcxs] has nevertheless come up with a very interesting tool for fabrication, the likes of which no one has ever seen before. It’s a rotating laser soldering paste applicator, meant to be an add-on to a CNC machine. What does it do? RIght now it looks extremely cool while being an immense time sink for [AltMarcxs], but the potential is there for being much more than that, ranging from a pick and place machine that also dispenses solder paste, to the closest thing you’ll ever get to a carbon fiber printer.

[AltMarcxs]’s build consists of two 3W laser diodes focused just beyond the tip of the syringe. The syringe dispenses solder paste, and rotating the diodes around, [Alt] is able to put a melted solder blob anywhere on a piece of perfboard. He put up a reasonably well focused video demonstrating this.

With a few homebrew pick and place machines making the semifinalist cut for The Hackaday Prize, it’s easy to see the utility of something like this: Putting a board in a machine, pressing a button, and waiting a bit for a completely populated and soldered board is a dream of the electronic hobbyist rivaled only by a cheap and easy way to make PCBs at home. [AltMarxcs]’s machine could be one step on the way to this, but there are a few other ideas he’d like to explore first.

The build also has wire feeders that allow a bit of copper wire to be soldered to the newly formed metal blob. There are plans to replace this with a composite fiber, replace the paste in the syringe with a UV resin, cut the fiber and cure the resin with the laser, and build something much better than other carbon fiber 3D printers we’ve seen before.

SpaceWrencherThe project featured in this post is a semifinalist in The Hackaday Prize.