[SOLVED] Hot air rework station

[alexan_e]

Hi

My new hot air rework station just arrived (ATTEN858D+), it has digital temperature setting 100-450 degree Celsius and an analog potentiometer for air speed.
It has 3 nozzles 10, 7 and 4mm diameter.
I'm currently using the thinnest for smd chips.

My question is which temperature should i use to desolder a chip?
for example a 64 or 100 pin square qfp.
I assume i should use the lowest possible that can still melt the joints to dessolder so that the ic doesn't overheat.

Also about the air speed, is the lowest setting the best (so that you don't overhead other components in the pcd ) ?
I'm thinking maybe a low air speed will not transfer as much heat as a higher speed.

I would appreciate any suggestion or link to guides about proper settings.

Thank you
Alex

 

[KJ6EAD]

**broken link removed**
It looks like this?

SMD How To - 8 - SparkFun Electronics
Just practice on scrap boards. It's easy to blow a board clean by accident and if you smell thermally decomposing tertiary amines, your board is ruined.:sad:

 

[alexan_e]

Thank you for your reply.
Yes it like that (with a + in the model), and includes the 3 thin tube nozzles.
It's not a matter of practice, i can dessolder ic's but i use a setting of 400 and i think it is too much that is why I'm asking for proper temperature settings.

Alex

 

[pranam77]

Just with one setting, you cant expect desoldering of all IC's. It all depends how much heat is applied plus how much heat is sunk by the device plus its leads. It all depends on practically trying it out on junk boards or skill fully handling the original board by gradually increasing and reaching the working temerature required for a device. Anyways, the lead melts at 250+
Practically saying, i dont have the Digital display in my re-work station but still i work by looking at the potentiometer positions of the Knobs.
Cheers

 

[rajudp]

my hot-air rework station not having digital temperature display, i manually check for the hot, do not keep in a place fixed for desoldering if heat is more it will damage the pcb, i will move the nozzle around the pins till i can remove it

 

[asmar]

hi for bga ic the temp is about 250c on board as i know and i use the hotair gun, before u see resistor become red in gun hotair it will not harmed the ic or board ,for air i put on level 5 but it is different between hotair to other the same for temp i use level 4 in general if u use it to remove a big ic u increase the air level also u must use the flux
br

 

[steinar96]

Too much air can blow SMD components away. I've found low air and no nozzle to be convenient when soldering SMD parts. Usually i set the temperature between 250 and 300 degrees. Too high will destroy the board

 

[alexan_e]

I use the air station only for desoldering smd chips QFP or SO ,
i can't use bga because i make my own pcb and it is impossible to use BGA if you don't have multiple layers.
I read some guides about soldering using air and the temperature was about 250 Celsius but I solder everything with my soldering iron using liquid flux so i haven't tried that way.
For desoldering i found that i need a temperature setting between 350-375 Celsius and an air speed about 4/8.
I use the thinest nozzle which gives more control to avoid throwing hot air to the component casing.

Alex