Rework Profile?

[J.BO]

Hi All,
I have a new Hakko 810-B rework station and am wondering if anyone has a good rework profile setup? I'm trying to find the sweet spot for temps so as not to ruin the component or surrounding components. My current profile:
Stage 1 - 50 seconds @ 400 F, Airflow @ 4
Stage 2 - 40 seconds @ 600 F, Airflow @ 5
Stage 3 - 30 seconds @ 840 F, Airflow @ 5
Stage 4 - Unlimited time (Cool Down) @ 250 F, Airflow @ 5
The component pretty much removes itself right as you hit stage 3 so I just move the rework gun out of the way and do a manual cool down. I'm also using the Panasonic Thermal Pad to dissipate the heat from the board. Lastly, due to the nature of the board design and placement, I cannot use an under-board pre-heater of any kind, it's all from the top.

 

[Diver300]

The reflowing that I have done has been far cooler than that.

I use an oven for most things, but when I use a hot air gun, I don't go over 320 °C (608 °F). The time taken depends on the size of the component. An 0603 passive on FR4 will come off in 5 seconds, but complete GPS receiver with ceramic antenna will take 3 minutes.

 

[J.BO]

Diver,
Yes, I agree, my initial profile is definitely too hot. It was just an experimental first run. I actually just found a rework profile for the specific BGA from the manufacturer, so I'm gonna plug that in and check it out. Looks like 260 C is gonna be peak body temp of the package. Thanks!

 

[gophert]

I find rework to be Just like cooking, "the closer (and higher) the heat, the rarer the meat". Don't do a preheat, you're just slowly heating the inside of the chip to that temp. Try to heat the surface quickly, melt the solder, pull the part(s) and cool. 600 to 625F will likely be a sweet spot.

 

[J.BO]

gophert,
Thanks, I'll give the quick blast a try!

 

[kubeek]

Really depends on the pcb and the component. I typically deal with 6-layer pcbs and components with largish power pads like 5x5mm, and that calls for a preheat to about 120°C an then blast the component with hot air.
Air flow would be as high as possible without blowing small components of the board, as they will get reflowed sooner.
Also a good idea to use some thermal shielding around the component, and these extracors are invaluable. The suction cup in the middle is fed vacuum and is stuck to the chip and springloaded, so as soon as the solder melts the chip gently pops away from the pcb. Great for large chips.

EXTRACTORS - Extractors for desoldering jobs using Hot Air Stations

www.jbctools.com

 

[J.BO]

Thanks for all of the replies. With my rework station, I was able to remove a 4x4 mm BGA in 16 seconds @ 500 F with an airflow of 7 out 10. I don't think anything was compromised at that temp for that short of time.