CircuitSpecialists CDI825A Rework Station

CircuitSpecialists CDI825A Rework Station
Manufacturer	CircuitSpecialists
Model	CDI825A
AKA	{{{aka}}}
Obtained	Unknown
Location	Electronics Area
Team	Electronics
Induction Required	No
Booking	{{{booking}}}
Status	Defunct
Risk Assessment	Yes, see [[{{{riskassessment}}}|the assessment]]
Tools:   all pages • list • Power Tools • Broken tools     {{}}

An adjustable temperature and pressure SMD rework station. Works well, mostly gets used for heat shrink tubing.

Warning: The rework station will continue to put out hot air until the button is pressed. This behaviour is different to many other rework stations, which automatically detect when the tool is returned to its cradle. Be aware of what it is pointing at, and try not to melt the PVC cable trunking / sockets / switches.

There is an assortment of different sized nozzles available. These are stored in the tin with the handwritten label "Rework Station Spares"

Usage

If you've never used a hot air station before, you may want to do some practice first on something broken which you don't care about. The steps below are a rough guide, feel free to improve them.

1. Turn on the hot air station at the wall switch. Assuming it was left in a safe condition, it shouldn't do anything yet. To start the hot air, press the small red button below the digital air pressure readout.
2. Set the temperature to around 400c and set the air flow to a sensible level. If you are removing a chip with many small parts around it, you likely want to set the flow rate quite low to avoid blowing small components away. Between 20 and 25 is likely safe for the surrounding small components.
3. From a distance begin warming the board. This is to reduce thermal shock which can lead to cracks in solder pads and traces. Over the course of 30 to 60 seconds, gradually move closer towards the part you want to remove.
4. After the board is warm, move the nozzle quite close to the part and begin moving it around to ensure an even distribution of heat.
5. You can periodically, but very gently, try to remove the part with tweezers. If it doesn't want to come off, don't force it, it needs more heat! Being too eager at this stage can lead to pads being ripped off, which makes the repair much harder.

Once you've removed the broken part, you want to do some clean up. A bit of flux helps with this. Flow some new solder onto the pads, and then remove most of it (gently) using solder wick and an iron. Do not press down hard, very little downward force is required, or you might rip off pads. Finally, you want to add a very small amount of solder to the pads - a small amount can be spread around with the tip of an iron.

To fit a new part, you basically want to do the same as described for the removal, but you also want to start bringing the part in slowly so that it also gets warmer. With some good flux, the part should mostly want to sit into the place it should go. A small amount of nudging / encouragement with tweezers helps.