The robotics society has access to PCB manufacturing facilities in the EEE department. Mike Harbour in the EEE first floor labs is the technician in charge of this. (Note that currently this service is unavailable as the equipment downstairs is being refurbished.) If you need better resolution than provided in lvl 1, then check out the external facilities.
Using the facilities in lvl 1
Information about preparing designs to send to EEE can be found in the EAGLE configuration for EEE PCBs webpage.
The PCBs made in EEE:
- Are 2-layer
- Have solder-mask
- Don't have silk-screen
- Don't have Plated Through Holes (PTH) - so you will have to solder connections between layers yourself
- Take up to 2 weeks to be made
- iMall: These are the cheapest pcb manufacturers we have seen so far. They are fairly slow but cheap.
- PCBTrain: These are more expensive, but arrive much quicker.
Soldering difficult components
As we don't have access to solder stencils and pick-and-place machines, it can be quite difficult to solder lead-less packages (chips without pins). Below are listed some precautions and procedures we have found to be good.
QFN packages are chips with only pads underneath: that is they have no pins. Soldering this can be done, but requires some precautions.
- Make sure that you have the correct footprint. This means correct to 100 microns!
- If possible, leave plenty of space around each difficult component.
- Make sure you have a heatgun/reflow station
- Make sure you have access to soldering flux!
- Vic (our lab technician) has all the pro tools necessary for this type of solder work available in his office on lvl 1.
This is how its done
Improving the state of affairs
See the proposed Operation Solderable project.