New revision (rev1) of my 3D printer controller board arrived a few weeks ago from the board manufacturer (http://jlcpcb.com). I did assemble a prototype with one driver for “smoke test”. Well it did “smoke” only a bit, because I accidentally put one chip in reverse. Lucky for me it was not the Trinamic driver – that one survived.
Anyhow today I made another board – this time with all components populated. Here is how it went up.
Mounted the PCB in an improvised jig to keep it secure on my table. The “jig” is made from 4 small PCBs from a different project. I secured them with blue tape, so they hold the main PCB in place.
Next was aligning the kapton stencil on top of the PCB. The stencil is made by http://oshstencil.com It is not aligned yet.
Here it is aligned on top of the board and secured with another piece of blue tape:
Getting ready to apply solder paste. I use “credit card” squeegee from OshStencil.
Paste away. I usually put too much, but it is easier to have some left over, than scraping the last bit of paste over and over again.
Here it is – paste applied. You can see that my footprint for TR3 needs to be fixed – the paste opening is way too big. Oh well – rev2 I guess.
By the way because my stencil application jig is not particularly sturdy you can see the solder paste is smudged over the fine point IC pads. It is not the end of the world. It makes a few solder bridges, but easily fixable. It is better, when I use solder paste printer, but I don’t have a framed stencil for this board they are $$$.
And it goes in the CHMT48VB pick-and-placer.
And the machine goes – here is a short video clip of the beginning of the job. Note that the board is split in two jobs. The second job is with different set of nozzles. I don’t have the nozzle change in the video – sorry.
The board after all components are placed by the machine. I use the machine only for tedious parts. I place other components by hand.
After manually placing the rest of the SMD parts, the board is ready for solder re-flow. I use hot air gun. I have a T962 oven, but it always seems like too much effort to use it. Here is the result of my hot air application. You can see quite a few bridges on the drivers. Click on the picture for full resolution image.
All cleaned up
Now to solder all true-hole connectors. This is the most tedious and time consuming part. Here it is all done. Front:
I did a quick check and there are no shorts on any power supply lanes. On to testing the firmware.