OpenPnP Solder Paste Dispensing Video

OpenPnP (see “Building a DIY SMT Pick&Place Machine with OpenPnP and Smoothieboard (NXP LPC1769)“) is a cool open source framework to run Pick&Place machines. I have mentored and supported Tobias Mailänder who extended the PnP machine with the ability to dispense solder past on PCBs. Below a video (courtesy of Tobias Mailänder) which shows the machine in action:

It is still a prototype, but things are working very well.

The dispensing head has an extra camera and is controlled by an NXP K20DX128 through OpenPnP. Firmware is implemented with GNU gcc for ARM and using Eclipse, running FreeRTOS. The camera allows to use the machine in mode with the support of OpenPnP: move to a pad automatically with the machine, and then paste manually.

Happy Pasting 🙂


8 thoughts on “OpenPnP Solder Paste Dispensing Video

  1. Hi Erich
    Impressive what you and Tobias are doing! I am not a hundred percent sure if you will be that happy with applying solder via a syringe? You never thought about using solder paste stencils? Of course does it comes with a price for the stencil but it would give you the opportunity to have a more reliable soldering process facing the small SMD components (small pitch). Those stencils are – as the pcb – not that expensive anymore.
    Regards Roman


    • Hi Roman,
      using stencils is the usual way to go, no doubt. But there are use cases where applying things like solder without stencil makes sense: if there is no stencil available, or for smaller/simpler boards where doing it that way is faster. The other advantage is that with OpenPnP the machine ‘knows’ the parts and pads, so this can be used for applying/fixing solder or other ways of using it.


  2. Stencil from PCBWay without frame cost $10 for any prototype. Alignment such stencil is bit of art, however making PCB nests helps lot in mass production.


    • Agreed, stencils are the way to go for beyond one part or even for a single board with many parts. Such a dispensing machine does not replace stencils, but still can play a role in its niche.


  3. I wonder if it could be taken a step further? would applying the part while vibrating it at ultrasonic frequencies heat the solder paste sufficiently through friction? or perhaps vibrate the board, rather than the part?

    Alternatively, if the pick&place held the part slightly above the board, would capillary action pull molten solder paste between pin and pad if applied at the boundary?


    • Hi Paul,
      I don’t think ultrasonic waves will be able to do this and to pass enough energy. What I have seen instead of the usual heat oven way is to use infrared light beams or laser.
      About your second point: with the usual solder paste there is not enough capillary pull for this. But the solder past has a kind of stickyness and will keep the part on the board.
      For smaller parts I can populate the bottom side, then pass it throught the oven, then take it out, populate the top side and put it into the oven again: the parts on the bottom will still stick to the board and not fall off.
      Of course this only works for smaller parts like resistors, capacitors or small IC’s.


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