Reflow equipment

[tony359]

Hello all,

I am experimenting a bit with reflowing larger components - ideally I'd like to reflow a PS4 APU or a GPU for example.

I know it's impossible to reflow such large components with just hot air so I bought a pre-heating plate, T-8280 classic Chinese machine, which seems to be working fine besides it's a little slow, which shouldn't be a big deal.

Now, my hot air station is a Aoyue 852A++ and I feel it's a bit weak when used with larger nozzle. I tried reflowing a laptop chipset using one of those large, rectangular, nozzles and I failed miserably, burning the whole thing.

I'm aware my SMD station is awful at blowing an even stream of air out of those large nozzles so I made a little "propeller" modification to the wand (which I think it's now standard with the newer version) but still it did not work.

You can see from the pic below a test I did when brand new before installing my mod, you can clearly see the unevenness of the temperature on the internal grille

I tried with my largest round nozzle and it worked like a charm, but when I attempted to reflow the CPU, which is a bit larger than the chipset, I couldn't really reflow it properly.

I have two thermocouples which are monitored by a laptop and also an IR thermometer to monitor temperature. I wait till the board/chip is 180 degrees, then I apply hot air (set to 310 degrees) to reflow. I see many people online using much higher temps on their hot air machine but that's without a pre-heating plate and I'd like to keep the temps as low as possible to avoid damaging components.

Now, I appreciate the proper way to reflow a large chip is NOT by using a hot air station. However, I don't want to invest in a proper reflow machine simply because I won't be using it a lot.

The question for the community is: is it worth investing in a better hot air machine, one which delivers a more even flow of hot air and also maybe one which has a higher flow available for using with those larger nozzles?

Thanks for your input!

[diif]

Re: Reflow equipment

Now, I appreciate the proper way to reflow a large chip is NOT by using a hot air station. However, I don't want to invest in a proper reflow machine simply because I won't be using it a lot.

The question for the community is: is it worth investing in a better hot air machine, one which delivers a more even flow of hot air and also maybe one which has a higher flow available for using with those larger nozzles?

Thanks for your input!

Many hot air stations use hot air instead of IR for the top heater.
Get yourself a decent hot air station like the Atten ST-862D or Quick 861D, they are more than capable of reflowing with 1200W.
My Atten also makes removing HDMI sockets so much easier than my old hot air.

[tony359]

Re: Reflow equipment

ah, interesting as hot air used as top element.

Those seem to be within my budget - I see the Quick 861DE has 200L airflow which is probably more suitable for the larger nozzle, what do you think? (turns out my Aoyue is 23L/m so probably even the 120L model should do LOL)

I'm watching Louis Rossman review of those

[diif]

Re: Reflow equipment

Yeah, I don't have my speed past 30%.

[tony359]

Re: Reflow equipment

what about larger BGA's? Shall I use the larger nozzle - which is basically the same diameter of the wand - and increase the flow?

[diif]

Re: Reflow equipment

I'd use the 22mm universal nozzle that comes with some Atten kits, if i was using it for BGA rework. Have a practice with some scrap boards to work out the necessary temperature, distance and air speed to as closely follow a reflow profile as possible.

[tony359]

Re: Reflow equipment

Indeed I’m experimenting with scrap boards and trying to folllow a profile I’ve set on an app which is monitoring the thermocouples- even though I found that an IT thermometer is more reliable. As you say, I think I’ve found a good combination of temperatures and air speed to make it work reliably - it’s just that when the chip is large, I feel that my airflow is not enough.

I see the Quick machines have larger rectangular BGA nozzles available while the Atten don’t. I’d be tempted to get the 200L machine just to make sure it’s ok with larger nozzles - even though it’s a bit too expensive.

I know that for smaller parts 200L are really not necessary- and maybe 120L are ok anyways - what is your thought?

Thanks!

[diif]

Re: Reflow equipment

You're lacking heat not airflow with your current station, it's the reason i upgraded from a hot air station like you have to the Atten.
Some of the Atten stations come with a universal nozzle allowing for all of the super cheap nozzles to be attached.

[tony359]

Re: Reflow equipment

I can reach 480 degrees with my station (I think?) but I'm trying to keep the temps as low as possible to avoid damaging the components - considering I have a pre-heating plate.

Using larger rectangular nozzles, I can barely feel any air coming out of them so I feel that my station is not suitable for them.

I feel that a bit more air and a larger round nozzle may be enough to reflow with more success. I am also well aware that blowing 200L/m air on a board will probably blow half of the components away!

Basically my question is: would I ever need more than 120L/m - this is imagining that I may want to reflow, say, a PS4 APU using the square nozzle which is pretty big?

And has anybody ever checked the temperature evenness of the air coming out of the Atten/Quick? The Aoyue tends to blow a massively uneven flow of air which makes it impossible to use with the BGA nozzles.

Thanks again for your input.