I have been practicing for a few hours every day on dead boards, removing and replacing QFNs
I had settled on a general procedure and I was looking for guidance
I am using a QUICK hot air station
1)I start at a high temp 600-615C at 3-4 inches from the board at high flow rate (100 on the quick)
do this for 1-2 minutes with flux applied
2) move in to 2 inches,temp cut to 550, cut air flow to 50.any higher and risk for blowing other components away. I try to be at 90 degrees to the chip to
with gentle swirling motion of the air
3) tap with tweezers to check movement, at this point there is a narrow band of flux at the edges of the chip near the attachments
4) move in very tight 1/2 inch for brief period on all sides of the chip
- here I have run into trouble..I learned ..NEVER pull on the chip, if you do... its not ready to come off ( i ripped a pad clean off doing this)
5) move off and away to 2 inches, then back down to 1/2 to 1/4 inch..in bursts of 5 seconds or so...
6) gradually let the chip tell you when it it ready to come off
If my technique is wrong, please tell me
Like I said, practice is the only teacher I have right now.
Its been frustrating.
I had settled on a general procedure and I was looking for guidance
I am using a QUICK hot air station
1)I start at a high temp 600-615C at 3-4 inches from the board at high flow rate (100 on the quick)
do this for 1-2 minutes with flux applied
2) move in to 2 inches,temp cut to 550, cut air flow to 50.any higher and risk for blowing other components away. I try to be at 90 degrees to the chip to
with gentle swirling motion of the air
3) tap with tweezers to check movement, at this point there is a narrow band of flux at the edges of the chip near the attachments
4) move in very tight 1/2 inch for brief period on all sides of the chip
- here I have run into trouble..I learned ..NEVER pull on the chip, if you do... its not ready to come off ( i ripped a pad clean off doing this)
5) move off and away to 2 inches, then back down to 1/2 to 1/4 inch..in bursts of 5 seconds or so...
6) gradually let the chip tell you when it it ready to come off
If my technique is wrong, please tell me
Like I said, practice is the only teacher I have right now.
Its been frustrating.