Soldering robot V2

My first iteration of the soldering machine was based on Prusa MK3 chassis. It worked well enough but the wiring was very messy and I was not happy with it. It was more of an experimental platform than something useful.

For V2 I decided to use an old MendelMax 3 chassis that I had. As 3d printer that was quite outdated, but the motion platform was sturdy and reliable.

I re-used most of the carriage design from the first version. I added a GoPro fixture, so I can mound an LED light on the carriage itself instead of the side of the machine. In theory this should provide more consistent illumination for the camera.

I was also not happy with the fume exhaust design on the V1. It was using a small 40mm fan that was very noisy, the carbon activated filter piece was very small and it looked very ugly.

For the V2 I decided to put the fan and filter on top of the machine, next to the solder wire motor/extruder. It took quite a bit of experimentation to find the right hose to connect the two. I tried thin silicone hose, that was too thin and the walls would collapse during movement. I tried thicker vinyl hose but that was too rigid and would obstruct the movement of the head. Finally I settled on a corrugated PVC hose – it is flexible enough and would not collapse on it own.

The other experiment was to find what size fan I should use. I tried 60mm, 70mm and 80mm axial fans but they would not provide sufficient airflow, when the filter mount was attached. I finally settled on a 7035 centrifugal fan. I started with 120mm centrifugal fan, but that was too big and loud.

Here is a video of the fume exhaust system in action:


Soldering machine improvements

I was very confident in my soldering machine from the tests I conducted the previous week. I decided to program a whole board and try it out.

Alas the confidence was premature and multiple failures ensued. Here is an example

I tried many things, but the soldering wire was hitting the pin and was not melting. I tried re-aligning the needle to point to the solder iron tip instead of the pin. This did not produce improvements at all. I had to aim fairly high to avoid hitting the pin and now the solder was not flowing down and bulging.

I was getting frustrated and decided to look at a few videos of commercial soldering machines for inspiration.

After a few hours I devised a new mount for the soldering needle. The previous mount was allowing adjustments only in the angle of the soldering iron as well as the needle. This configuration seems quite limited. Applying maximum effort here is the new plan:

Now the syringe is mounted on this dual clamp. The clamp allows for both items to rotate. The other end of the clamp is connected to a 3mm steel rod, which adds another degree of rotation. Finally the rod is connected to the mount plate with a plank which allows both: XY movement as well as rotation.

Here is the final assembly after a few dozen failed 3D printing jobs

The new mounting system adds quite a bit of flexibility to the position of the needle that guides the solder wire. Hopefully I’ll be able to find a location which works in most cases.