With this tool you can precisely dispense extreme small dots of solder paste, needed for 0402 and 0201. Although this solder paste dispenser is cheap and uncomplicated, it works better for micro SMD than the most automatic dispensers.

There are many solder paste dispensers on the market, often motor controlled or pneumatically. But can you use them for extremely small solder dots for 0402 or 0201 SMD components? It is important that you are able to dispense micro-dots of solder paste, else it will easy lead to solder bridges. The problem with SMD soldering is always the excess of tin. That’s why I invented this hand-tool solder paste dispenser.

The dispenser is going in production soon in end 2019, look for updates here... 
The price will be just € 29.95 plus shipping.
Let me know if you are interested, then I know how much I have to let fabricated.

I've used the syringe dispenser for assembling the prototype of the SAM 15x15: See the 0402 SMD parts R1 and R2:

In de video below, the solder paste has a low viscosity, which makes smaller dots possible:

Low viscosity solder paste for dispenser

The viscosity of solderpase is very critical to be able to apply micro-dots with a dispenser. If the solder paste is too dry, the needle may clog. Low viscosity paste works best, and it also sticks better to the PCB.
Note: common solder paste that work fine for stencils don't work with a dispenser, it is too syrupy:

You can try to make the solder paste thinner by mixing it with for instance no-clean Topnik gel flux and Topnik flux RF800:

Precisely dispense the smallest amount of solder paste

The main thing that goes wrong with soldering surface-mounted devices is the excess of solder. On this extremely small PCB from an iPod touch, which contains 0201 size SMD, you can see how little solder paste is used:

After the components have been placed, you can solder the board as you like, with a reflow oven or hot air. I use the Atten AT858D to solder SMD parts, it is important that you can control both the temperature and the airflow.

Assembling 0402 SMD parts

Loupe

I use a loupe with 10x magnification. But keep in mind: the loupe must have a double lens to see the small SMD components well. Unfortunately, almost all loupes use just one lens.

Tweezers

Use tweezers with a curved pointed tip:

Notes

Fill the syringe by sucking the solder paste out of its container, 10mm is sufficient.

You can use the solder paste in the syringe no longer than a few days. Due to the pressure, the components in the solder paste separate themselves from each other. Initially, there appears a very thin solder paste, with an abundance of flux. Thereafter the syringe will be clogged with thick paste without flux.

Purchase 10 syringes that you throw away every time the solder paste is no longer good.

FAQ 

• What type of solder paste do you use?
  I used Sn63/Pb37 25-45um.
• What is the diameter of the needle?
  I used an outer diameter of 0.5mm.
• How many SMD are you able to tin with one filling?
  You can fill thousands of SMD pads until the syringe is empty. However, the life span is more defined by the drying out of the solder.